業績情報

• Change in Thermodynamic Entropy and Free Volume of Epoxy Resin During Tensile Deformation　　　　　　　　　　　　　　　
  Takuma Inoue; Yutaka Oya; Jun Koyanagi; Takenobu Sakai
  Polymers, 巻：17, 号：4, 2025年02月
  The relationship between thermodynamic entropy generation and free volume changes during the tensile deformation of epoxy resin was investigated. Thermodynamic entropy generation was evaluated using differential scanning calorimetry (DSC) for samples at various strain levels, while free volume changes were measured with positron annihilation lifetime spectroscopy (PALS). Volumetric strain was assessed through the digital image correlation (DIC) method. The results showed that both thermodynamic entropy and free volume increase during tensile deformation, and the average free volume radius becomes more uniform. It was observed that thermodynamic entropy generation and free volume each exhibit a linear relationship with volumetric strain. Additionally, thermodynamic entropy generation increased linearly with free volume. These findings suggest that the increase in thermodynamic entropy during tensile deformation is attributed to irreversible changes, such as the expansion of free volume within the material.
  研究論文（学術雑誌）
  DOI：https://doi.org/10.3390/polym17040477
  Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85219006444&origin=inward
  Scopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=85219006444&origin=inward
  DOI ID：10.3390/polym17040477, eISSN：2073-4360, SCOPUS ID：85219006444
• Mechanical Behavior Dependence on Geotextiles Interweave Configuration Used in Coastal Restoration　　　　　　　　　　　　　　　
  Carlos Rolando RIOS-SOBERANIS; Takenobu SAKAI; Shuichi WAKAYAMA; Emilio PEREZ-PACHECO; Jorge Carlos; CANTO-PINTO
  Advanced Experimental Mechanics, 巻：9, 開始ページ：3, 終了ページ：10, 2025年01月, ［査読有り］, ［招待有り］
  英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.11395/aem.24-0017
  DOI ID：10.11395/aem.24-0017
• Comparation of Polyethylene and Polypropylene on the Time-Temperature Superposition Principle by Molecular Dynamics Simulations　　　　　　　　　　　　　　　
  Yuan Shihong; Takenobu Sakai
  Advanced Experimental Mechanics, 巻：10, 開始ページ：1, 終了ページ：6, 2025年01月, ［査読有り］, ［最終著者］
  英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.11395/aem.25-0001
  DOI ID：10.11395/aem.25-0001, 共同研究・競争的資金等ID：30455017
• CFRP 接着接合部へのコンタミネーション混入による機械的特性変化に関する分子動力学的研究
  坂井 建宣; 寺澤 黎門; 蔭山 健介
  日本複合材料学会誌, 巻：50, 号：5, 開始ページ：177, 終了ページ：184, 2024年09月, ［査読有り］, ［筆頭著者, 責任著者］
  The Japan Society for Composite Materials, 日本語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.6089/jscm.50.177
  DOI ID：10.6089/jscm.50.177, ISSN：0385-2563, eISSN：1884-8559, 共同研究・競争的資金等ID：30455017
• Investigating the influence of free volume and temperature on time-temperature superposition principle by MD simulation
  Yuan Shihong; Takenobu Sakai
  Mechanical Engineering Journal, 巻：11, 号：6, 開始ページ：24, 終了ページ：00242, 2024年09月, ［査読有り］, ［最終著者］
  Japan Society of Mechanical Engineers, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1299/mej.24-00242
  DOI ID：10.1299/mej.24-00242, eISSN：2187-9745, 共同研究・競争的資金等ID：30455017
• Analyzing the Sound of Materials: Application of Acoustic Emission Technique for Monitoring Material Behavior
  Carlos Rolando Ríos-Soberanis; Takenobu Sakai; Shuichi Wakayama
  Materials Science Forum, 巻：1118, 開始ページ：111, 終了ページ：117, 2024年03月, ［査読有り］
  During the last years, some concerns have arisen in relation to the outcome of mechanisms of failure in composite materials according to its mechanical behavior. Such interest resulted in the development of new complex structures in order to enhance its mechanical resistance and the controlling of damage processes. Nevertheless, it is imperative to understand the degree of mechanical performance that these materials can achieve when under external stresses. In this regard, applying Acoustic Emission (AE) technique is widely known as a very effective technology for identifying and monitoring damage progression on different kind of materials and structures providing valuable information. AE is a non-destructive technique (NDT) capable of detecting micro damage initiation and propagation along several types of failure modes such as reinforcement/matrix interfacial debonding, matrix cracking, delamination, fracture, etc. This paper examines applications of AE regarding to composite materials where fracture processes are generally more complex and data interpretation is correspondingly more difficult. Finally, in order to continuously improve the reliability of this technique, several researches have advanced its trustworthiness through innovations in AE technology. Some perspectives are discussed.
  Trans Tech Publications, Ltd., 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.4028/p-hk3qly
  DOI ID：10.4028/p-hk3qly, eISSN：1662-9752
• Evaluation of the curing reaction of epoxy resins by electrochemical measurement and molecular orbital method
  Koki Matsumura; Tetsuya Morimoto; Takenobu Sakai
  Advanced Composite Materials, 開始ページ：1, 終了ページ：15, 2024年03月, ［査読有り］, ［最終著者, 責任著者］
  Informa UK Limited, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1080/09243046.2024.2325639
  DOI ID：10.1080/09243046.2024.2325639, ISSN：0924-3046, eISSN：1568-5519
• Evaluation of Volumetric Strain on Polyamide 6 by Thermodynamic Entropy Generation
  Takenobu Sakai; Yutaka Oya; Jun Koyanagi
  Experimental Mechanics, 巻：64, 号：1, 開始ページ：105, 終了ページ：111, 2023年11月, ［査読有り］, ［筆頭著者, 責任著者］
  Springer Science and Business Media LLC, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1007/s11340-023-01009-x
  DOI ID：10.1007/s11340-023-01009-x, ISSN：0014-4851, eISSN：1741-2765
• Effects of different loading methods in molecular dynamics on deformation behavior of polymer crystals　　　　　　　　　　　　　　　
  Koki Yoshida; Kensuke Kageyama; Takenobu Sakai
  Mechanics of Time-Dependent Materials, 2023年09月, ［査読有り］, ［最終著者, 責任著者］
  英語, 研究論文（学術雑誌）
  共同研究・競争的資金等ID：30455019;30455017
• CFRP のモードⅠおよびモードⅡ試験への AE 法によるき裂先端位置標定と損傷モード評価の適用　　　　　　　　　　　　　　　
  坂井 建宣; 三浦 翔; 蔭山 健介
  実験力学, 巻：23, 号：2, 開始ページ：132, 終了ページ：137, 2023年07月, ［査読有り］, ［筆頭著者, 責任著者］
  日本語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.11395/jjsem.23.132
  DOI ID：10.11395/jjsem.23.132
• Identification of invisible fatigue damage of thermosetting epoxy resin by non-destructive thermal measurement using entropy generation
  Natsuko Kudo; Ryohei Fujita; Yutaka Oya; Takenobu Sakai; Hosei Nagano; Jun Koyanagi
  Advanced Composite Materials, 巻：33, 号：2, 開始ページ：233, 終了ページ：249, 2023年06月, ［査読有り］
  Informa UK Limited, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1080/09243046.2023.2230687
  DOI ID：10.1080/09243046.2023.2230687, ISSN：0924-3046, eISSN：1568-5519
• CFRP の損傷モード評価におけるAE センサの周波数特性の影響　　　　　　　　　　　　　　　
  白石 知久; 坂井 建宣; 蔭山 健介
  実験力学, 巻：23, 号：2, 開始ページ：145, 終了ページ：151, 2023年06月, ［査読有り］, ［責任著者］
  日本語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.11395/jjsem.23.145
  DOI ID：10.11395/jjsem.23.145
• CFRPA6の結晶化処理方法が曲げ損傷挙動に及ぼす影響　　　　　　　　　　　　　　　
  坂井 建宣; Fei Chunhao; 蔭山 健介
  強化プラスチックス, 巻：69, 号：4, 開始ページ：167, 終了ページ：172, 2023年04月, ［査読有り］, ［筆頭著者］
  日本語, 研究論文（学術雑誌）
• Fabrication and characteristics of electret using fine silica powder and its application of ultrasonic sensor　　　　　　　　　　　　　　　
  Kensuke Kageyama; Kakeru Kobayashi; Yoshiaki Kawada; Takenobu Sakai
  ELECTRONICS AND COMMUNICATIONS IN JAPAN, 巻：105, 号：3, 2022年09月
  Electrets were prepared by spin-coating the dispersion of fine silica powders, and their charge retention characteristics were investigated. Finer silica aggregates were formed on the PTFE surface layer by spin-coating the dispersed solution of fine silica powder than those formed by spray-coating colloidal silica. Electrets using fine silica powder also showed better charge retention characteristics than those using colloidal silica. Such an improvement in the charge retention might be due to the suppression of discharge in the excessive gap caused by coarse silica aggregates. Then, ECSs were fabricated using the prepared electrets, and their transmitting and receiving characteristics of airborne ultrasound were also investigated. The peak sensitivity of the ECS using a spin coating of fine powdered silica dispersion was slightly improved from those using spray coating of colloidal silica. On the other hand, the peak frequency and frequency band were greatly improved using spin coating of fine powdered silica dispersion. Therefore, ECS using fine silica powder is expected to be applied as a broadband airborne ultrasonic sensor.
  WILEY, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1002/ecj.12372
  DOI ID：10.1002/ecj.12372, ISSN：1942-9533, eISSN：1942-9541, Web of Science ID：WOS:000840118200001
• CFRP積層構成とWavelet解析により得られたAEピーク周波数の関係　　　　　　　　　　　　　　　
  坂井建宣; 川口廉; 山田洋平; 蔭山 健介
  強化プラスチックス, 巻：68, 号：8, 開始ページ：315, 終了ページ：320, 2022年08月, ［査読有り］, ［筆頭著者］
  日本語, 研究論文（学術雑誌）
• ポリエチレンにおける時間–温度換算則の現象の解明
  元 師弘; 眞野彩子; 蔭山健介; 坂井建宣
  日本複合材料学会誌, 巻：48, 号：4, 開始ページ：149, 終了ページ：155, 2022年07月, ［査読有り］
  The Japan Society for Composite Materials, 日本語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.6089/jscm.48.149
  DOI ID：10.6089/jscm.48.149, ISSN：0385-2563, eISSN：1884-8559
• Evaluation of viscoelastic non-isochoric plastic behavior of PBT and PA6
  Yoshihiko Sato; Sayaka Masumizu; Kenichi Sakaue; Jun Koyanagi; Akio Ohtani; Takenobu Sakai
  Mechanics of Time-Dependent Materials, 2022年04月, ［最終著者］
  Springer Science and Business Media LLC, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1007/s11043-022-09552-1
  DOI ID：10.1007/s11043-022-09552-1, ISSN：1385-2000, eISSN：1573-2738
• A Possibility for Quantitative Detection of Mechanically-Induced Invisible Damage by Thermal Property Measurement via Entropy Generation for a Polymer Material　　　　　　　　　　　　　　　
  Takenobu Sakai; Naohiro Takase; Yutaka Oya; Jun Koyanagi
  Materials, 巻：15, 号：3, 開始ページ：737, 2022年01月, ［査読有り］, ［筆頭著者］
  英語, 研究論文（学術雑誌）
• CFRTPの曲げ特性に及ぼすひずみ速度依存性の粘弾性および結晶構造的考察　　　　　　　　　　　　　　　
  福嶋 遼太; 蔭山 健介; 坂井 建宣
  日本複合材料学会誌, 2021年09月, ［査読有り］, ［最終著者, 責任著者］
  日本語, 研究論文（学術雑誌）
• 大気中熱処理がCFRTPの動的粘弾性特性に及ぼす影響　　　　　　　　　　　　　　　
  福嶋 遼太; 蔭山 健介; 坂井 建宣
  実験力学, 巻：21, 号：2, 2021年07月, ［査読有り］, ［最終著者, 責任著者］
  日本語, 研究論文（学術雑誌）
• CFRPの破壊モード分類のための時間周波数解析法の選定　　　　　　　　　　　　　　　
  白石 知久; 蔭山 健介; 坂井 建宣
  強化プラスチックス, 巻：67, 号：4, 開始ページ：133, 終了ページ：134, 2021年04月, ［査読有り］
• Molecular Dynamics Simulation for Evaluating Fracture Entropy of a Polymer Material under Various Combined Stress States　　　　　　　　　　　　　　　
  Naohiro Takase; Jun Koyanagi; Kazuki Mori; Takenobu Sakai
  Materials, 巻：14, 号：8, 開始ページ：1884, 2021年04月, ［査読有り］, ［最終著者］
  英語, 研究論文（学術雑誌）
• Molecular Dynamics Simulation of Weak Bonds in Carbon Fiber Reinforced Plastic Adhesive Joints　　　　　　　　　　　　　　　
  Reimon Terazawa; Atsushi Tamura; Kensuke Kageyama; Takenobu Sakai
  Advanced Composite Materials, 2021年03月, ［査読有り］, ［最終著者, 責任著者］
  英語, 研究論文（学術雑誌）
• Effect of heat treatment on mechanical properties of carbon-fiber-reinforced themoplastic
  Ryota Fukushima; Yohei Yamada; Kensuke Kageyama; Takenobu Sakai
  Advanced Composite Materials, 巻：30, 号：6, 開始ページ：527, 終了ページ：543, 2021年03月
  Informa UK Limited, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1080/09243046.2021.1893886
  DOI ID：10.1080/09243046.2021.1893886, ISSN：0924-3046, eISSN：1568-5519
• Formulation of non-linear viscoelastic–viscoplastic constitutive equation for polyamide 6 resin　　　　　　　　　　　　　　　
  Jun Koyanagi; Kodai Hasegawa; Akio Ohtani; Takenobu Sakai; Kenichi Sakaue
  Heliyon, 巻：7, 号：2, 開始ページ：e06335, 終了ページ：e06335, 2021年02月
  Elsevier BV, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1016/j.heliyon.2021.e06335
  DOI ID：10.1016/j.heliyon.2021.e06335, ISSN：2405-8440
• Molecular dynamics simulation for the quantitative prediction of experimental tensile strength of a polymer material　　　　　　　　　　　　　　　
  Jun Koyanagi; Naohiro Takase; Kazuki Mori; Takenobu Sakai
  Composites Part C: Open Access, 巻：2, 開始ページ：100041, 終了ページ：100041, 2020年10月, ［査読有り］, ［最終著者］
  Elsevier BV, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1016/j.jcomc.2020.100041
  DOI ID：10.1016/j.jcomc.2020.100041, ISSN：2666-6820
• Effect of matrix crystallinity of carbon fiber reinforced polyamide 6 on static bending properties
  Takenobu Sakai; Nur Safiah Binti Shamsudim; Ryota Fukushima; Kensuke Kageyama
  Advanced Composite Materials, 開始ページ：1, 終了ページ：14, 2020年08月, ［査読有り］, ［筆頭著者, 責任著者］
  Informa UK Limited, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1080/09243046.2020.1802805
  DOI ID：10.1080/09243046.2020.1802805, ISSN：0924-3046, eISSN：1568-5519
• AEと環境の同時測定によるトマトの乾燥ストレス応答評価の検討　　　　　　　　　　　　　　　
  蔭山 健介; 林 由将; 菅野 アナム; 坂井 建宣
  Eco-Engineering, 巻：32, 号：1, 開始ページ：1, 終了ページ：5, 2020年02月, ［査読有り］, ［最終著者］
  研究論文（学術雑誌）
• Effect of Crystallization on Mechanical Properties of CFRTP　　　　　　　　　　　　　　　
  Takenobu Sakai; Nur Safiah Binti Shamsudim
  Conference Proceedings of the Society for Experimental Mechanics Series, 開始ページ：45, 終了ページ：46, 2020年
  Carbon fiber reinforced thermoplastics are consisted with the carbon fiber and thermos plastics such as PP, PA6, PI, and PC and so on. Mechanical properties, especially viscoelasticity, of CFRTP were depended on the matrix resin, therefore, if the mechanical properties of matrix resin has changed, CFRTP’s properties will be also changed. In this study, carbon fiber reinforced polyamide 6 was used for evaluate the effect of crystallization. The materials were heat treated for crystallization, and the crystallization was controlled by heat treatment time. As the result of dynamic mechanical analysis, storage modulus was decreased with the increase in the heat treatment time, however, longer heat treatment time made the storage modulus increased. As the results of DSC measurement, the peak shape of melting point was different each other. The double peak was observed with the longer heat treatment time, however, the single peak was observed with the short heat treatment time. This is because the mechanical properties of CFRTP was dominated by the peak shape and peak area of the melting point.
  Springer, 英語, 研究論文（国際会議プロシーディングス）
  DOI：https://doi.org/10.1007/978-3-030-29986-6_7
  DOI ID：10.1007/978-3-030-29986-6_7, ISSN：2191-5652, SCOPUS ID：85087179263
• Investigation of Drought Stress Response in Tomato Plants by Simultaneous Measurement of AE and Environment　　　　　　　　　　　　　　　
  Kensuke Kageyama; Yoshimasa Hayashi; Anamu Kanno; Takenobu Sakai
  ECO-ENGINEERING, 巻：32, 号：1, 開始ページ：1, 終了ページ：5, 2020年
  Simultaneous measurement system of AE at the stem and illuminance, temperature and humidity of the ground surface in greenhouse cultivation tomatoes was developed and the simultaneous measurement were carried out at two sites. AE occurrence rate tended to decrease in winter similar to humidity deficit HD. Most AE occurred in the daytime though the daily fluctuation behavior of HD and AE events differed by the site. The rank correlation coefficients, RV1h and RV6h using hourly differentials of AE events and HD, and those from 6h moving average values, respectively were derived. As the result, the strong correlation found between average value of RV1h of the whole period and yield Y, and there was also the weak correlation between monthly average value of RV1h and Y.
  SOC ECO-ENGINEERING, ENV SCI & TECH, GRAD SCH LIFE & ENV SCI, 日本語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.11450/seitaikogaku.32.1
  DOI ID：10.11450/seitaikogaku.32.1, ISSN：1347-0485, eISSN：1880-4500, Web of Science ID：WOS:000510837400001
• 一方向性CFRPの損傷発生挙動のひずみ速度・温度依存性　　　　　　　　　　　　　　　
  坂井 建宣; 安部 聡; 蔭山 健介
  日本複合材料学会誌, 巻：46, 号：2, 開始ページ：54, 終了ページ：61, 2020年, ［査読有り］, ［筆頭著者, 責任著者］
  研究論文（学術雑誌）
• Development of an Impulse Response Method for Assessing Knee Osteoarthritis at the Femorotibial Joint: Comparison Between Healthy Young Adults and Older Women with Clinical Knee Osteoarthritis
  Keita Aimoto; Susumu Ota; Kazunori Hase; Takenobu Sakai; Katsuya Kodama; Hiroaki Nakamura
  Journal of Medical and Biological Engineering, 巻：40, 号：1, 開始ページ：35, 終了ページ：40, 2019年, ［査読有り］
  © 2019, Taiwanese Society of Biomedical Engineering. Purpose: Because in patients with knee osteoarthritis (OA), the knee joint properties such as cartilage, meniscus, soft tissue and bone formation are assumed to degeneration change, the shock absorb might also decrease. The transmission of impulse from femur and tibia is thought to change in the knee joint. The purpose of the present study was to determine the differences between young healthy women and elderly women with knee OA using the impulse response method. Methods: Twenty-six older women with clinically diagnosed knee OA (OA group, age: 69 ± 6 years) and 26 young women without knee OA (young control [YC] group, age: 21 ± 1 years) participated in the study. The OA group fulfilled the knee OA classification criteria based on clinical findings. An input device provided an impulse to the subject while standing. The output value was measured using a single-axis accelerometer. The outcome measures were the input–output ratio and power spectrum. Results: The input–output ratio did not significantly differ between the groups. The power spectrum at 21–30 Hz was significantly greater (p = 0.036) in the OA group than in the control group. Additionally, the power spectrum at 21–30 Hz correlated with knee pain (r = 0.39, p = 0.049). At 21–30 Hz, transmission of impulse from femur and tibia in the knee joint was lower in the OA group than in the control group. Conclusion: The IR method used in the present study could detect the transmission of impulse in early knee OA.
  Springer Science and Business Media LLC, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1007/s40846-019-00484-9
  DOI ID：10.1007/s40846-019-00484-9, ISSN：1609-0985, eISSN：2199-4757, SCOPUS ID：85068919681
• 廃タイヤ強化ポリ乳酸複合材料の機械的特性評価　　　　　　　　　　　　　　　
  坂井建宣; 川井喬介; 蔭山健介; 立山耕平; 山田浩
  強化プラスチックス, 巻：64, 号：1, 開始ページ：31, 終了ページ：35, 2019年, ［査読有り］, ［筆頭著者, 責任著者］
  研究論文（学術雑誌）
• Estimating the creep behavior of glass-fiber-reinforced polyamide considering the effects of crystallinity and fiber volume fraction　　　　　　　　　　　　　　　
  Takenobu Sakai; Yuto Hirai; Satoshi Somiya
  Mechanics of Advanced Materials and Modern Processes, 巻：4, 号：5, 開始ページ：1, 終了ページ：9, 2019年, ［査読有り］, ［筆頭著者, 責任著者］
  研究論文（学術雑誌）
• 分子動力学シミュレーションによるポリカーボネートの体積クリープの静水圧依存性評価　　　　　　　　　　　　　　　
  坂井 建宣; 鈴木 将士; 蔭山 健介
  日本複合材料学会誌, 巻：45, 号：1, 開始ページ：26, 終了ページ：33, 2019年, ［査読有り］, ［筆頭著者, 責任著者］
• Experimental studies on the mechanical behavior of Mayan archeological rocks　　　　　　　　　　　　　　　
  V.J. Ley-Paredes; C.R. R?os-Soberanis; E. Perez-Pacheco; C. Vinajera-Reyna; S. Wakayama; T. Sakai
  DYNA Colombia, 巻：86, 号：208, 開始ページ：227, 終了ページ：233, 2019年, ［査読有り］, ［最終著者］
• 炭素繊維強化ポリアミドの結晶化が静的曲げ特性に及ぼす影響　　　　　　　　　　　　　　　
  坂井 建宣; Nur Safiah; Binti Shamsudim; 福嶋遼太; 蔭山健介
  日本複合材料学会誌, 巻：45, 号：6, 開始ページ：223, 終了ページ：229, 2019年, ［査読有り］, ［筆頭著者, 責任著者］
  研究論文（学術雑誌）
• Evaluation of Degradation State of Used Bedsore Preventing Mattress　　　　　　　　　　　　　　　
  Takenobu Sakai; Ryoichiro Ito; Kensuke Kageyama
  2018 IEEE 7th Global Conference on Consumer Electronics, GCCE 2018, 開始ページ：447, 終了ページ：450, 2018年12月
  Bedsore preventing mattress needs body pressure dispersibility, and this properties related to the mattress's viscoelasticity. In the hospital and rental shop of mattress, the judgement of the degradation of mattress was carried out by manual operation, however, there is no quantitative evaluation method of the degradation has existed. In this study, degradation state of used bedsore preventing mattress was evaluated using dynamic mechanical analysis (DMA) which can measure the material's viscoelasticity.
  Institute of Electrical and Electronics Engineers Inc., 英語, 研究論文（国際会議プロシーディングス）
  DOI：https://doi.org/10.1109/GCCE.2018.8574712
  DOI ID：10.1109/GCCE.2018.8574712, SCOPUS ID：85060271944
• Performance Evaluation of Flexible Electret Sensor Array for Ultrasonic Object Detection in Short Distance　　　　　　　　　　　　　　　
  Kensuke Kageyama; Tsubasa Okawa; Takenobu Sakai
  2018 IEEE 7TH GLOBAL CONFERENCE ON CONSUMER ELECTRONICS (GCCE 2018), 開始ページ：824, 終了ページ：825, 2018年
  Ultrasonic object detection in short distance could contribute the monitoring of human life activity and remote operation of home appliances. In this study, Ultrasonic sensor array using flexible electret elements were fabricated to detect objects in short distance. The reflection waves were clearly detected at short distance. The object (PVC pipe) detection was examined using the ultrasound generated by the ECS array. The estimated distance was good agreement with the true value though large errors were observed for the estimated angles because only three receivers were used for ECS array.
  IEEE, 英語, 研究論文（国際会議プロシーディングス）
  ISSN：2378-8143, Web of Science ID：WOS:000459859500291
• 超音波センサに適した極薄PTFE層を有するシリカ凝集体エレクトレットの製作と特性評価　　　　　　　　　　　　　　　
  蔭山健介; 折笠健; アハマド ザリフ; アフィック ビン; ジャマルディン; 坂井建宣
  電気学会論文誌E, 巻：138, 号：9, 開始ページ：441, 終了ページ：447, 2018年, ［査読有り］, ［最終著者］
• Accelerated creep and creep-rupture testing of transverse unidirectional carbon/epoxy lamina based on the stepped isostress method　　　　　　　　　　　　　　　
  Jonathon Tanks; Katherine Rader; Stephen Sharp; Takenobu Sakai
  COMPOSITE STRUCTURES, 巻：159, 開始ページ：455, 終了ページ：462, 2017年01月, ［査読有り］, ［最終著者］
  Accelerated methods for measuring long-term viscoelastic properties of fiber reinforced polymer (FRP) composites are important for reducing the time needed to characterize material behavior. Most of them are based on the time-temperature-stress superposition principle (TTSSP), or some variation. This paper investigates the applicability of the stepped isostress method (SSM) to study tensile creep of unidirectional carbon FRP (CFRP) lamina used in rehabilitating prestressed concrete structures. The SSM employs a load-stepping approach, typically with three to five steps for a single specimen resulting in creep-rupture. Theoretical analysis of the experimental method (previously lacking) is discussed and modifications to the testing and analysis protocol are shown to improve validity of the master curves compared to conventional creep curves and traditional TTSSP creep master curves at room temperature. Finally, three failure criteria are compared for predicting creep-rupture of CFRP laminates based on the accelerated testing method. (C) 2016 Elsevier Ltd. All rights reserved.
  ELSEVIER SCI LTD, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1016/j.compstruct.2016.09.096
  DOI ID：10.1016/j.compstruct.2016.09.096, ISSN：0263-8223, eISSN：1879-1085, Web of Science ID：WOS:000386759100043
• 平織炭素繊維強化熱可塑性ポリイミド複合材の曲げクリープにおける時間−温度依存性　　　　　　　　　　　　　　　
  岡田瑞生; 上田政人; 後藤健; 小林訓史; 坂井建宣; 荒井広明
  日本複合材料学会誌, 巻：43, 号：2, 開始ページ：41, 終了ページ：47, 2017年, ［査読有り］
  日本複合材料学会, 日本語
  ISSN：0385-2563, CiNii Articles ID：40021134702, CiNii Books ID：AN00196748
• フレキシブル基板を用いた胸部表面振動計測装置の開発　　　　　　　　　　　　　　　
  坂井建宣; 柴山正輝; 野方文雄; 蔭山健介
  実験力学, 巻：17, 号：1, 開始ページ：39, 終了ページ：44, 2017年, ［査読有り］, ［筆頭著者, 責任著者］
  日本実験力学会, 日本語
  ISSN：1346-4930, CiNii Articles ID：40021181929, CiNii Books ID：AA11822914
• 胸部表面の微細振動計測による心臓運動の可視化および心音源の位置標定　　　　　　　　　　　　　　　
  坂井建宣; 林和輝; 河村洋子; 横田康成; 野方文雄
  実験力学, 巻：17, 号：1, 開始ページ：45, 終了ページ：51, 2017年, ［査読有り］
  日本実験力学会, 日本語
  ISSN：1346-4930, CiNii Articles ID：40021181938, CiNii Books ID：AA11822914
• 廃棄CFRPを基とする炭素／炭素複合材料の高機能化の研究　　　　　　　　　　　　　　　
  高橋智彦; 坂井建宣; 宗宮詮
  強化プラスチックス, 巻：63, 号：5, 開始ページ：233, 終了ページ：238, 2017年, ［査読有り］
  強化プラスチック協会, 日本語
  ISSN：0452-9685, CiNii Articles ID：40021224117, CiNii Books ID：AN00058449
• AE測定による開繊ガラス繊維強化プラスチックの損傷挙動評価　　　　　　　　　　　　　　　
  喜多村竜太; 浅野忠明; 伊丹康人; 井口英明; 小泉浩二; 坂井建宣; 荻原慎二
  強化プラスチックス, 巻：63, 号：9, 開始ページ：451, 終了ページ：457, 2017年, ［査読有り］
  強化プラスチック協会, 日本語
  ISSN：0452-9685, CiNii Articles ID：40021339854, CiNii Books ID：AN00058449
• AE法を用いた炭素繊維強化熱可塑性ポリイミドの破壊過程の解明　　　　　　　　　　　　　　　
  坂井建宣; 安部聡; 後藤健; 小林訓史; 上田政人; 荻原慎二; 若山修一; 蔭山健介
  実験力学, 巻：17, 号：1, 開始ページ：27, 終了ページ：33, 2017年, ［査読有り］
  日本実験力学会, 日本語
  ISSN：1346-4930, CiNii Articles ID：40021181916, CiNii Books ID：AA11822914
• 樹木のアコースティック・エミッション測定を目的としたエレクトレットセンサの製作と特性評価　　　　　　　　　　　　　　　
  蔭山 健介; 魯 子暁; 菅原 拓也; 坂井 建宣
  実験力学, 巻：16, 号：4, 開始ページ：295, 終了ページ：300, 2017年, ［査読有り］
  <p> Electret condenser sensors (ECS) is suitable for detection of ultrasounds propagating air and soft materials because it has an air gap in the element. In this study, ECS were fabricated to detect artificial acoustic emission (AE) propagating a wood plate and AEs at a trunk of acerola. ECS demonstrated the higher S/N ratio from 40 to 100 kHz for the detection of the artificial AEs than a piezoelectric AE sensor (PS) and a wideband acceleration sensor (AC). The AEs detected by ECS showed several frequency peak from 50 to 200 kHz at the AE measurement at a trunk of acerola while the AE detected by PS also showed wide frequency from 100 to 500 kHz. Furthermore, the ECS had the same degree of sensitivity as PS at AE measurement at the trunk of acerola while AC hardly detected the AEs. The AE behavior of ES, however, did not partially coincide with the significant increase of AE events of PS. Hence, the long-term reliability of ES must be investigated for practical use of AE measurement of woody plants.</p>
  日本実験力学会, 日本語
  DOI：https://doi.org/10.11395/jjsem.16.295
  DOI ID：10.11395/jjsem.16.295, ISSN：1346-4930, CiNii Articles ID：130005300055, CiNii Books ID：AA11822914
• Sensitivity Enhancement of FBG Sensors for Acoustic Emission Using Waveguides　　　　　　　　　　　　　　　
  Takenobu Sakai; Satomi Suzuki; Shuichi Wakayama
  EXPERIMENTAL MECHANICS, 巻：56, 号：8, 開始ページ：1439, 終了ページ：1447, 2016年10月, ［査読有り］
  Sensors created from optical fibers are often used to measure strain due to their high accuracy. However, they are not used as often for higher frequency applications as a result of low sampling rates in their data acquisition systems. Recently, acquisition systems have been developed that satisfy the required specifications for use in acoustic emission (AE), but these types of sensors are not used due to their low signal-to-noise (S/N) ratios. However, there are many studies on the sensitivity enhancement conferred by the fiber Bragg grating sensor (FBG sensor). This sensor is easy to use and does not require specific reference fibers when sensing. In this study, acoustic waveguides, which are usually used in ultrasonic microscopes, were fabricated and used in FBG AE sensors to enhance the S/N ratio. Two types of waveguides were designed; the refraction type and the reflection type. FBG fibers were attached to the waveguides, which were then secured using adhesive to a thin aluminum plate. Impulses were inputted into the sensor by breaking pencil lead on the plate. The results showed that the amplitude of the first wave was increased using these waveguides. Using finite-element method (FEM) analysis, the enhancement of the wave amplitude was also evaluated such that the acoustic waveguide could be used for enhancement of the S/N ratio of FBG sensors.
  SPRINGER, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1007/s11340-016-0178-6
  DOI ID：10.1007/s11340-016-0178-6, ISSN：0014-4851, eISSN：1741-2765, Web of Science ID：WOS:000383599900011
• Fracture behavior of wasted activated carbon powder composites　　　　　　　　　　　　　　　
  Takenobu Sakai; Tomohiko Gushiken; C. R. Rios-Soberanis; Tomoki Masuko; Satoshi Matsushima; Satoshi Kobayashi; Satoru Yoneyama; Shuichi Wakayama
  ADVANCED COMPOSITE MATERIALS, 巻：25, 号：4, 開始ページ：375, 終了ページ：384, 2016年08月, ［査読有り］
  At the Waterworks Bureau (Tokyo Metropolitan Government), activated carbon has been used for filtering water. After being used for the filtering process, it is normally disposed or burned for thermal recycling. However, CO2 emissions occur during the thermal recycling. This work focuses on the identification of mechanical behavior of recycled wasted activated carbon (WAC) in order to elaborate smart materials having mechanical electrical functions. Acoustic emission technique (AE) was used intensively as characterization support in which sensors were attached to detect microdamage during bending tests. At first, the resonant frequencies of the specimens were measured using the through-transmission test. The resonant frequencies of the specimens containing low weight fractions of WAC powder were less in comparison to the frequencies of the specimens with higher volume fraction. The frequency analysis was carried out with the projected wavelet transform on the signals detected during bending tests. Obtained data showed that, typically, the first major peaks showed the resonant frequency of the sensors, while the second major peaks exhibited signals indicative of resin cracking. The surfaces of the fractured specimens were analyzed by optical microscopy in order to visualize the crack formation and propagation on the activated carbon composite under flexural stresses. Consequently, fractographic and AE analyses provide better understanding of the failure mechanisms involved.
  TAYLOR & FRANCIS LTD, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1080/09243046.2015.1011049
  DOI ID：10.1080/09243046.2015.1011049, ISSN：0924-3046, eISSN：1568-5519, Web of Science ID：WOS:000377425400006
• 熱可塑性樹脂を母材とした繊維不連続を有する一方向強化CF/PA6積層板の損傷挙動評価 (特集 複合材料)　　　　　　　　　　　　　　　
  小柳 興瑶; 喜多村 竜太; 松葉 朗; 河野 洋輔; 中谷 隼人; 坂井 建宣; 荻原 慎二
  材料, 巻：65, 号：8, 開始ページ：561, 終了ページ：566, 2016年08月, ［査読有り］
  ©2016 The Society of Materials Science. The tensile tests of the unidirectional CFRP laminate composites (CF/PA6) with fiber discontinuity were performed, and mechanical properties were obtained. The laminate stacking sequence of the specimens is [024], and the specimens have fiber discontinuity of 6, 12 and 18 layers. And, the damage growth behaviors were investigated by microscopic observation and acoustic emission (AE) monitoring. Furthermore, the delamination onset stresses were predicted by the simple analysis model. As a result, the stress-strain curves showed nonlinear behavior, and nonlinear starting points became early with increase of the fiber discontinuity layers. It is found that the initial damage of the specimen was the crack between fiber discontinuity end/resin interface by microscopic observation and AE monitoring. And, the delamination between continuous/discontinuous ply around the resin occurred. After that, the resin at the fiber discontinuity was broken at the time of maximum applied stress, then the delamination grew extensively in the specimen, finally the specimens was broken. In addition, the delamination onset stresses were predicted by analysis model using energy release rate, and these stresses were almost agree with experimental values.
  日本材料学会, 日本語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.2472/jsms.65.561
  DOI ID：10.2472/jsms.65.561, ISSN：1880-7488, CiNii Articles ID：40020938488, SCOPUS ID：84983606002
• Damage accumulation studied by acoustic emission in bone cement prepared with core-shell nanoparticles under fatigue　　　　　　　　　　　　　　　
  O. F. Pacheco-Salazar; Shuichi Wakayama; Takenobu Sakai; C. R. Rios-Soberanis; J. V. Cauich-Rodriguez; J. M. Cervantes-Uc
  JOURNAL OF MATERIALS SCIENCE, 巻：51, 号：12, 開始ページ：5635, 終了ページ：5645, 2016年06月, ［査読有り］
  Analysis of acoustic emission signals generated during the fatigue testing of core-shell nanoparticles filled acrylic bone cements is reported. Core-shell nanoparticles composed of a poly(butyl acrylate) rubbery core and a poly(methyl methacrylate-co-styrene) (P(MMA-co-St)) outer glassy shell with varying compositions (20/80, 30/70, 40/60, and 50/50) were incorporated into the solid phase of bone cement at 10 wt%. Acoustic emission data revealed that the damage accumulation process was discontinuous for all bone cement formulations, being less pronounced in formulations with higher fatigue resistance (20/80 and 30/70) which emitted a higher number of events before the final fracture. The capability of both 20/80 and 30/70 core-shell nanoparticles to hinder the microcracks or crazes propagation was attributed to their poor interfacial adhesion with the matrix in comparison with formulations with 40/60 and 50/50 core-shell nanoparticles. Based on the acoustic emission data and SEM micrographs, a crack propagation scheme for bone cements containing core-shell nanoparticles was proposed. In this regard, core-shell nanoparticles had a double role on the bone cement as reported for other systems; firstly, the nanoparticles promoted nucleation sites for crazes or microcracks, and secondly, they could also hinder the propagation of these defects, acting as a barrier to their growth. Crack propagation mechanism consisted mainly in crazing ahead of the cracks tip as well as the coalescence of these cracks which were responsible of the acoustic emission detected.
  SPRINGER, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1007/s10853-016-9865-z
  DOI ID：10.1007/s10853-016-9865-z, ISSN：0022-2461, eISSN：1573-4803, Web of Science ID：WOS:000373626000006
• 熱可塑性樹脂を母材とした繊維不連続有する一方向強化 CF/PA6積層板の損傷挙動評価　　　　　　　　　　　　　　　
  小柳興瑶; 喜多村竜太; 松葉 朗; 河野洋輔; 中谷隼人; 坂井建宣; 荻原慎二
  材料, 巻：54, 号：8, 開始ページ：555, 終了ページ：560, 2016年, ［査読有り］
• Preliminary study of optimal measurement location on vibroarthrography for classification of patients with knee osteoarthritis　　　　　　　　　　　　　　　
  Ota S; Ando S; Tozawa Y; Nakamura T; Okamoto S; Sakai T; Hase K
  J Phys Ther Sci., 巻：28, 開始ページ：2904, 終了ページ：2908, 2016年, ［査読有り］
• Spin test of three-dimensional composite rotor using polymer ring as a connection device for high-speed flywheel　　　　　　　　　　　　　　　
  Noboru HIROSHIMA; Hiroshi HATTA; Yuuichi NAGURA; Masashi KOYAMA; Takenobu SAKAI; Yasuo KOGO
  Mechanical Engineering Journal, 巻：3, 号：4, 開始ページ：1, 終了ページ：12, 2016年, ［査読有り］
  

  A method for connecting a driving shaft to a three-dimensional composite disk via a polymer ring was examined to achieve stable rotation at high rotation speeds. Polyoxymethylene (POM) was adopted as the polymer ring material. Compression test was conducted to determine the limit of linear viscoelasticity, and creep resistance of POM was examined to evaluate its long-term durability. Structural design using finite element analysis including long-term creep resistance has shown that this method was predicted to be effective up to a tip speed of 1210 m/s. A three-dimensional composite disk was reinforced to three directions in accordance with the cylindrical coordinates. A trial composite disk with outer and inner diameters of 304 and 41 mm, respectively, was manufactured and tested up to a tip speed of 908 m/s. Vibration amplitudes were measured using gap and laser sensors. The vibration phenomenon and methods of suppressing vibration were discussed for higher rotation speeds.

  
  一般社団法人 日本機械学会, 英語
  DOI：https://doi.org/10.1299/mej.16-00261
  DOI ID：10.1299/mej.16-00261, CiNii Articles ID：130005169886
• Detection of Cavitation in Stem of Miniature Tomato using Acceleration Sensor　　　　　　　　　　　　　　　
  Kageyama, K; Iman; B. A. H; Kimura, K; Sakai, T
  Advanced Experimental Mechanics, 巻：1, 開始ページ：214, 終了ページ：218, 2016年, ［査読有り］
• Charge Retention of Silica-Agglomerate Electret using Electrostatic Spraying at Elevated Temperatures　　　　　　　　　　　　　　　
  Chenye WU; Kensuke KAGEYAMA; Takenobu SAKAI
  Advanced Experimental Mechanics, 巻：1, 開始ページ：120, 終了ページ：125, 2016年, ［査読有り］
• Evaluation of Irrigation Response using AE Method for Management of High-Frequency Irrigation of Hydroponic Miniature-Tomato　　　　　　　　　　　　　　　
  Kensuke Kageyama; Takenobu Sakai
  Journal of Acoustic Emission, 巻：34, 開始ページ：65, 終了ページ：70, 2016年, ［査読有り］
• 樹木のアコースティック・エミッション測定を目的としたエレクとレットセンサの製作と特性評価　　　　　　　　　　　　　　　
  蔭山健介; 魯子 暁; 菅原拓也; 坂井建宣
  実験力学, 巻：16, 号：3, 開始ページ：9, 終了ページ：14, 2016年, ［査読有り］
• Estimation of creep and recovery behavior of a shape memory polymer　　　　　　　　　　　　　　　
  Takenobu Sakai; Takayuki Tao; Satoshi Somiya
  MECHANICS OF TIME-DEPENDENT MATERIALS, 巻：19, 号：4, 開始ページ：569, 終了ページ：579, 2015年11月, ［査読有り］
  The shape recovery and shape fixity properties of shape memory polymers (SMPs), advanced functional materials, were investigated in this study. Although the shape recovery behavior of these polymers has been examined from a viscoelastic point of view, questions remain with regard to quantifying the recovery behavior of SMPs. SMPs can recover their shape after the molding process; this recovery occurs via creep recovery and/or shape recovery; an estimation of SMP recovery requires a good understanding of both processes. In this study, the time-temperature superposition principle was applied to the creep and shape recovery behavior of SMPs. The creep behavior was estimated using an experimentally obtained master curve and time-temperature shift factors. Our estimated results were in good agreement with the experimental data. However, the estimation of the creep recovery with changing temperature below or above the glass transition temperature was not successful due to the lack of consideration of the shape recovery behavior. The time and temperature dependency of the shape recovery were confirmed for creep behavior, using the master curve for the recovery ratio and the corresponding shift factors for shape recovery. The values of the shape recovery shift factors differed from those for the time-temperature shift factors obtained for creep behavior. Therefore, these shape recovery shift factors were used in the estimation of creep and shape recovery behavior using the master curve for the creep tests. The estimated results were closer to the results obtained experimentally. Moreover, our results indicated that the recovery behavior above was dominated by shape recovery as a result of polymer viscoelasticity.
  SPRINGER, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1007/s11043-015-9279-3
  DOI ID：10.1007/s11043-015-9279-3, ISSN：1385-2000, eISSN：1573-2738, Web of Science ID：WOS:000365423600007
• Evaluation of damage progression and mechanical behavior under compression of bone cements containing core-shell nanoparticles by using acoustic emission technique　　　　　　　　　　　　　　　
  O. F. Pacheco-Salazar; Shuichi Wakayama; Takenobu Sakai; J. V. Cauich-Rodriguez; C. R. Rios-Soberanis; J. M. Cervantes-Uc
  JOURNAL OF THE MECHANICAL BEHAVIOR OF BIOMEDICAL MATERIALS, 巻：46, 開始ページ：137, 終了ページ：147, 2015年06月, ［査読有り］
  In this work, the effect of the incorporation of core-shell particles on the fracture mechanisms of the acrylic bone cements by using acoustic emission (AE) technique during the quasi-static compression mechanical test was investigated. Core-shell particles were composed of a poly(butyl acrylate) (PBA) rubbery core and a methyl methacrylate/styrene copolymer (P(MMA-co-St)) outer glassy shell. Nanoparticles were prepared with different core-shell ratio (20/80, 30/70, 40/60 and 50/50) and were incorporated into the solid phase of bone cement at several percentages (5, 10 and 15 wt%). It was observed that the particles exhibited a spherical morphology averaging ca. 125 nm in diameter, and the dynamic mechanical analysis (DMA) thermograms revealed the desired structuring pattern of phases associated with core-shell structures. A fracture mechanism was proposed taking into account the detected AE signals and the scanning electron microscopy (SEM) micrographs. In this regard, core-shell nanoparticles can act as both additional nucleation sites for microcracks (and crazes) and to hinder the microcrack propagation acting as a barrier to its growth; this behavior was presented by all formulations. Cement samples containing 15 wt% of core-shell nanoparticles, either 40/60 or 50/50, were fractured at 40% deformation. This fact seems related to the coalescence of microcracks after they surround the agglomerates of core-shell nanoparticles to continue growing up. This work also demonstrated the potential of the AE technique to be used as an accurate and reliable detection tool for quasi-static compression test in acrylic bone cements. (C) 2015 Elsevier Ltd. All rights reserved.
  ELSEVIER SCIENCE BV, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1016/j.jmbbm.2015.02.028
  DOI ID：10.1016/j.jmbbm.2015.02.028, ISSN：1751-6161, eISSN：1878-0180, Web of Science ID：WOS:000353752100014
• 実験‐数値ハイブリッド法を用いた繊維‐樹脂界面応力解析　　　　　　　　　　　　　　　
  坂井建宣; 飯原靖憲; 米山聡
  実験力学, 巻：15, 号：3, 開始ページ：169-174 (J-STAGE), 終了ページ：174, 2015年
  In this study, the single fiber composite was used to evaluate the stress transfer between a single fiber and a matrix. Single steel fiber was inserted to the epoxy resin, and the tensile load was applied to the steel fiber. Applied load was varied from 0N to 177N, and then the photoelastic images were taken by a digital CCD camera. On the photoelastic analysis, the stress separation was carried out using an experimental-numerical hybrid method. The boundary conditions for a local finite element model, that is, the tractions along boundaries were inversely determined from photoelastic fringes. After determining the boundary conditions for the local finite element model, the stresses could be obtained by finite element direct analysis. The maximum shear stress were placed on the side surface of the steel fiber near the end of fiber, and the maximum normal stress difference was measured near the surface of the end of fiber. The results of stress distribution on the interface between the fiber and the resin indicated that the stress concentration was observed on the middle part of the end of fiber and the side surface near the end of fiber.
  日本実験力学会, 日本語
  DOI：https://doi.org/10.11395/jjsem.15.169
  DOI ID：10.11395/jjsem.15.169, ISSN：1346-4930, J-Global ID：201502205211245825, CiNii Articles ID：130005102012, CiNii Books ID：AA11822914
• Improvement of heat resistance of silica-agglomerate electret using electrostatic spraying　　　　　　　　　　　　　　　
  Chenye WU; Kensuke KAGEYAMA; Takenobu SAKAI
  Mechanical Engineering Journal, 巻：2, 号：3, 開始ページ：1, 終了ページ：15, 2015年, ［査読有り］
  The silica-agglomerate electret could be obtained after spraying negatively charged solution of colloidal silica on a fluororesin film using an electrostatic spraying technique. The surface electric potential was measured after spraying to investigate which method was suitable for preparing the electret. As a result, the method in which a spray gun was installed to a conventional corona-charging setup delivered the electret with the amplitude of the electric surface potential over 0.8 kV. The silica agglomerates using an electrostatic spraying technique (ES electret) showed larger diameter D and lower point density N than those using conventional technique (corona-charging after spraying, CC electret). Furthermore, the prepared electrets were heated to examine the improvement of the heat resistivity by the electrostatic spraying. Then, the obtained silica-agglomerate electret showed better heat resistivity than the conventional silica-agglomerate electret. Then, the charge retention at 250°C R250 of ES electrets prepared in this study was higher than 57 % when the electrets suffered high temperature from 200 to 250 °C for 12.5 min at the heating test. Consequently, it can be concluded that the electrostatic spraying was excellent technique to obtain the silica-agglomerates electret with high heat resistance.
  The Japan Society of Mechanical Engineers, 英語
  DOI：https://doi.org/10.1299/mej.15-00064
  DOI ID：10.1299/mej.15-00064, ISSN：2187-9745, CiNii Articles ID：130005071473
• Characterization of crack growth resistance under thermal shock on silicon nitride with various microstructure　　　　　　　　　　　　　　　
  SAKAI Takenobu; WAKAYAMA Shuichi; KAMETANI Go; YOSHIDA Katsumi; AKATSU Takashi
  Mech Eng J (Web), 巻：1, 号：1, 開始ページ：SMM0002-SMM0002 (J-STAGE), 終了ページ：SMM0002, 2014年
  The crack growth resistance under thermal shock loading on silicon nitride was characterized using Disc-on-Rod test which was developed by the authors. The microdamage during thermal shock fracture was monitored by acoustic emission (AE) technique. Specimens were composed of β-Si₃N₄ with an acicular structure. Cylinders of silicon nitride with various microstructures were sintered at different temperatures. A pre-crack was introduced using Knoop indentation. In the Disc-on-Rod test, the specimens were uniformly heated to 850 ºC, and only the center of circular specimen was quenched by contacting with a copper rod. Within a fraction of a second after contacting, crack propagated in an unstable manner, at the same time, a high amplitude AE signal was detected. Subsequently, stable crack propagation was observed, and several low amplitude AE signals were generated corresponding to crack propagation. The specimen sintered at higher temperature showed lower crack growth resistance. From the results of microstructure observation and the fracture mechanical consideration, it is suggested that larger grains with > 1.5 μm in minor axes contribute to the toughening of materials. Consequently, the results of this study provide fundamental insights for the development of ceramic materials with high resistance to thermal shock fracture.
  The Japan Society of Mechanical Engineers, 英語
  DOI：https://doi.org/10.1299/mej.2014smm0002
  DOI ID：10.1299/mej.2014smm0002, ISSN：2187-9745, J-Global ID：201402248521643971, CiNii Articles ID：130003398611
• Evaluation of Mechanical Behaviour of Bone Cements by Using Acoustic Emission Technique　　　　　　　　　　　　　　　
  C. R. Rios-Soberanis; S. Wakayama; T. Sakai; J. M. Cervantes-Uc; A. May-Pat
  MATERIAL SCIENCE AND ENGINEERING TECHNOLOGY II, 巻：856, 開始ページ：246, 終了ページ：+, 2014年, ［査読有り］
  Biomaterials such as acrylic bone cements are widely applied in orthopaedic surgery for the fixation of artificial joints. Therefore, the mechanical behavior of such materials under external stresses is of special interest in order to achieve long-term in vivo performance. Fracture process can be attributed to diverse random microscopic damage modes. As the load increases, new damage modes appear and the existing ones can transition into others depending on the nature of the material. However, limitation exists in detailing the understanding of the micromanage initiation and development, and, consequently, in optimizing biomaterials performance. This paper focuses in the study of the emission of acoustic signals from bone cements in order to monitor the evolution of the internal defects that are believed to dominate in vivo failure.
  TRANS TECH PUBLICATIONS LTD, 英語, 研究論文（国際会議プロシーディングス）
  DOI：https://doi.org/10.4028/www.scientific.net/AMR.856.246
  DOI ID：10.4028/www.scientific.net/AMR.856.246, ISSN：1022-6680, Web of Science ID：WOS:000336337600047
• Photoelastic Stress Analysis of the Fiber/Matrix Interface in a Single-Fiber Composite　　　　　　　　　　　　　　　
  Takenobu SAKAI; Yasunori IIHARA; Satoru YONEYAMA
  2014 Special Issue of Journal of the Japanese Society for Experimental Mechanics,, 巻：14, 開始ページ：213, 終了ページ：216, 2014年, ［査読有り］
• シリカ凝集体を用いたPFAフィルムエレクトレットの耐熱性向上　　　　　　　　　　　　　　　
  蔭山 健介; 三村 昌平; 坂井 建宣
  電気学会論文誌, 巻：135, 号：4, 開始ページ：122, 終了ページ：128, 2014年, ［査読有り］
• Damage accumulation behavior of non-crimp fabric-reinforced epoxy composite under static and cyclic tensile loading
  T. Sakai; S. Wakayama; E. Pérez-Pacheco; J. Rodriguez-Laviada; C. R. Rios-Soberanis
  Advanced Composite Materials, 巻：22, 号：4, 開始ページ：281, 終了ページ：297, 2013年08月
  A non-crimp fabric with a stacking sequence of [0°,+45°,90°,- 45°] embedded in epoxy resin matrix was analyzed. Samples for mechanical test were obtained from laminates at different orientations depending on the textile architecture direction at 0°, 45°, and 90°in order to study the relationship between damage initiation and propagation with fabric geometry. Tension mode tests (static and cyclic) were carried out to evaluate the evolution of damage using as a main tool, the acoustic emission technique that allows monitoring the mechanical behavior of the materials during the test in real time. Results show that there is a remarkable mechanical influence of the reinforcement textile in the composite and that damage generation and progression (mechanisms of fracture) is highly dependent of the direction in which the stress is applied in relation with the architecture of the fabric. In static tensile mode, samples at 0°exhibited better mechanical parameters than samples at 90°, while at 45°orientation was lesser. The effect of textile geometry was demonstrated to have an influence in such mechanisms. In cyclic tensile mode, Kaiser effect is observed at low stresses, while the experimental results showed that the Felicity effect became clearer along with the increasing of stress level. © 2013 Japan Society for Composite Materials, Korean Society for Composite Materials and Taylor &
  Francis.
  英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1080/09243046.2013.809636
  DOI ID：10.1080/09243046.2013.809636, ISSN：0924-3046, SCOPUS ID：84879658619
• Mechanical evaluation and damage sequence identification of multiaxial textile reinforced composites　　　　　　　　　　　　　　　
  C. R. Rios-Soberanis; S. Wakayama; T. Sakai; E. Perez-Pacheco; J. Rodriguez-Laviada
  Annual Technical Conference - ANTEC, Conference Proceedings, 巻：1, 開始ページ：393, 終了ページ：397, 2013年01月
  Mechanical properties and damage pattern of a multiaxial textile reinforced epoxy composite was evaluated by tension and bending test. A non crimp fabric (NCF) of [0°,+45°, 90°, - 45°] stacking sequence was used as reinforcement. Through the identification of the initiation sites and the coalescence of cracks was possible to correlate the damage with the textile geometry and its effect on the mechanical properties. Fractography was used as a tool to identify governing mechanisms and link these to the material internal structure and the textile geometry. Acoustic emission technique was employed to identify the mechanisms of fracture by correlating the signals of mechanical waves produced my damage with fracture stages. Additionally the effect of textile architecture on the composite mechanical properties and damage pattern was correlated with its damage initiation and propagation. Through a combination of experimental work and theoretical studies the mechanisms controlling the mechanical behavior are explained.
  SCOPUS ID：84903544243
• Manufacture of partially biodegradable composite materials based on PLA-tires powder: Process and characterization　　　　　　　　　　　　　　　
  Carlos Rolando Rios-Soberanis; Shuchi Wakayama; Takenobo Sakai; José De Los Ángeles Rodriguez-Laviada; Emilio Pérez-Pacheco
  International Journal of Polymer Science, 巻：2013, 開始ページ：1, 終了ページ：8, 2013年, ［査読有り］
  This research work focuses on the processability and mechanical characterization of blends of polylactic acid (PLA) and tire (elastomeric part). Wasted tires used as filler in the PLA matrix were reduced by two different processes (thermal shock and pyrolysis) in order to acquire the solid residuals in powder to be characterized and compared. Elastomeric solids obtained from scraped tires were used as filler in the PLA matrix and mixed in a Brabender 60 cc mixer at different concentrations ranging from 0% to 60% of filler volume fraction. The blend was laminated, and then samples were obtained in order to undertake mechanical properties at tension and Izod impact tests. A fully detailed analysis on the solid powders by Differential Scanning Calorimeter (DSC), thermogravimetric analysis (TGA), infrared analysis (IR), and scanning electron microscopy analysis (SEM) identified them as a rich source of carbon. Blends were characterized thermally and mechanically showing a direct effect due to the tire nature (thermoset rubber) and concentration. Fracture mechanisms were also identified. © 2013 Carlos Rolando Rios-Soberanis et al.
  英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1155/2013/514951
  DOI ID：10.1155/2013/514951, ISSN：1687-9422, SCOPUS ID：84878694786
• Characterization of Damage Process of Rabbit Tendon by Acoustic Emission Technique in Vitro　　　　　　　　　　　　　　　
  Takenobu SAKAI; Satomi SUZUKI; Shuichi WAKAYAMA; Satoru YONEYAMA; Ei YAMAMOTO
  2013 Special Issue of Journal of the Japanese Society for Experimental Mechanics, 巻：13, 開始ページ：213, 終了ページ：216, 2013年, ［査読有り］
• Estimating the creep behavior of polycarbonate with changes in temperature and aging time　　　　　　　　　　　　　　　
  Takenobu Sakai; Satoshi Somiya
  MECHANICS OF TIME-DEPENDENT MATERIALS, 巻：16, 号：3, 開始ページ：241, 終了ページ：249, 2012年08月, ［査読有り］
  Thermoplastic resins are typically used without any kind of physical aging treatment. For such materials, creep behavior and physical aging, which depend on time and temperature, occur simultaneously. The effects of these processes are evident after quenching and are recorded in the material as a thermal history. This history strongly influences mechanical properties and creep behavior in particular. Thus, a more thorough understanding of the physical aging process is desirable. We examined the creep deformation of polycarbonate (PC) to reveal the effects of physical aging on creep behavior. The effects were dependent on both time and temperature. The relationship between physical aging and creep behavior exemplified superposition principles with regard to time and both pre-test aging time and pre-test aging temperature. The superposition principles allowed the calculation of creep deformations at a given temperature; the calculated results were corroborated by experimental data.
  SPRINGER, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1007/s11043-011-9154-9
  DOI ID：10.1007/s11043-011-9154-9, ISSN：1385-2000, Web of Science ID：WOS:000307555200001
• 炭素繊維強化PEEKの繊維体積含有率および樹脂の結晶化度を考慮したクリープ解析　　　　　　　　　　　　　　　
  坂井 建宣; 川畑 有紀子; 宗宮 詮
  実験力学 : journal of JSEM, 巻：12, 号：2, 開始ページ：94, 終了ページ：100, 2012年06月
  The Poly (ether-ether-ketone) (PEEK) resin is a kind of super engineering thermoplastics, and has good mechanical properties and high heat resistance. Recently it has been used for the matrix of Carbon Fiber Reinforced Plastics (CFRP) as a substitute material for thermosetting plastics at high temperature because of its fine moldability. For such occasion, it is very important for reliability of these materials to reveal the visco-elastic behavior of polymer materials. In this study, linearity for creep behavior of PEEK and CFRPEEKs were discussed, and the relationship between time and temperature, fiber volume fractions and crystallinity was revealed.<br>   Bending creep tests were performed on the crystallized PEEK resin and its CFRPs. It was found that master curves of creep compliance were obtained, and the Arrhenius type time -temperature superposition principle was applied for crystallized PEEK resin and its crystallized CFRPs. Effects of crystallinity and fiber volume fractions on creep behavior were considered by making grand master curves and great grand master curve.Great grand master curve and the shift factors for making great grand master curve were approximated with prony-series equation and quadratic expressions. Using these equations, the creep analyses were carried out. The results have a good agreement with the experimental data. And the estimation data was determined with great accuracy.
  The Japanese Society for Experimental Mechanics, 日本語
  DOI：https://doi.org/10.11395/jjsem.12.94
  DOI ID：10.11395/jjsem.12.94, ISSN：1346-4930, J-Global ID：201202206296603664, CiNii Articles ID：10030800757, CiNii Books ID：AA11822914
• NCFの曲げ挙動に及ぼすZ糸の影響　　　　　　　　　　　　　　　
  坂井 建宣; C-R Rios Rolando; 若山 修一
  材料システム, 巻：30, 開始ページ：35, 終了ページ：40, 2012年, ［査読有り］
  金沢工業大学材料システム研究所, 日本語
  ISSN：0286-6013, CiNii Articles ID：40019240282, CiNii Books ID：AN00027831
• 炭素繊維強化ポリエーテルエーテルケトンの繊維および結晶化を考慮したクリープ解析　　　　　　　　　　　　　　　
  坂井 建宣; 川畑 有紀子; 宗宮 詮
  実験力学, 巻：12, 号：2, 開始ページ：26, 終了ページ：32, 2012年, ［査読有り］
• Estimation of fatigue life of cortical bone considering viscoelastic properties and damage mechanics　　　　　　　　　　　　　　　
  Takenobu Sakai; Keita Yasui; Shuichi Wakayama
  Conference Proceedings of the Society for Experimental Mechanics Series, 巻：3, 開始ページ：289, 終了ページ：294, 2011年12月
  Recently, the Osteoporosis victims increase in the senior citizen. Therefore, the danger of the stress fracture due to the decrease in bone strength is pointed out. Especially, the damage accumulation behavior of the bone in the cyclic load becomes a problem for the fatigue of the bone. Moreover, it is necessary to consider the viscoelastic property for the prediction of the fatigue behavior, because the bone is a viscoelastic material. In this study, our objective is to estimate the fatigue behavior that considers the viscoelasticity behavior and the damage accumulation behavior as damage mechanics. The viscoelastic properties were revealed with the strain rate tests, and we calculated the 3-mode Maxwell parameters with these results. The damage accumulation behaviors were measured with the Acoustic Emission method. Using these results, we could estimate the fatigue behavior of cortical bone with the viscoelastic parameter and cumulative AE energy.
  ISSN：2191-5644, SCOPUS ID：84857852242
• Effect of fabric architecture (NCF) on bending and creep test of textile composites　　　　　　　　　　　　　　　
  T. Sakai; S. Wakayama; C. R. Rios-Soberanis; C. R. Rios-Soberanis; J. Rodriguez-Laviada; E. Pérez-Pacheco
  ICCM International Conferences on Composite Materials, 2011年12月, ［査読有り］
  SCOPUS ID：84875936059
• Analysis of damage progression in textile reinforced composite in tension (static and cyclic) mode using acoustic emission　　　　　　　　　　　　　　　
  T. Sakai; S. Wakayama; C. R. Rios-Soberanis; C. R. Rios-Soberanis; J. Rodriguez-Laviada; E. Pérez-Pacheco
  Annual Technical Conference - ANTEC, Conference Proceedings, 巻：1, 開始ページ：442, 終了ページ：446, 2011年08月
  A non crimp fabric (NCF) with a stacking sequence of [0°,+45°, 90°,-45°] embedded in epoxy resin matrix was analyzed. Samples for mechanical test were obtained from laminates at different orientations depending on the textile direction at 0°, 45° and 90° in order to identify the failure mechanisms. Tension mode tests (static and cyclic) were carried out to evaluate the evolution of damage using as a main tool the acoustic emission technique that allows monitoring the mechanical behavior of the materials during the test in "real time".
  SCOPUS ID：80051757622
• Analysis of creep behavior in thermoplastics based on visco-elastic theory　　　　　　　　　　　　　　　
  Takenobu Sakai; Satoshi Somiya
  MECHANICS OF TIME-DEPENDENT MATERIALS, 巻：15, 号：3, 開始ページ：293, 終了ページ：308, 2011年08月, ［査読有り］
  Plastics and fiber-reinforced plastics (FRP) are used in the aerospace industry because of their mechanical properties. However, despite their excellent high-temperature mechanical properties, plastics and FRP eventually deform visco-elastically at high temperatures. Most of the research has focused on the creep behavior of FRPs, but few studies have investigated the linear visco-elastic behavior. Linear visco-elastic behavior and non-linear visco-elastic behavior occur with physical aging in these plastics. In this study, the non-linear visco-elastic behavior of plastics and FRP was investigated based on the bending creep deformation of polycarbonate (PC) and polyoxymethylene (POM). Moreover, the effects of the fiber volume fraction on the creep characteristics were investigated using glass fiber-reinforced polycarbonate (GFRPC). The creep deformation was calculated using the linear visco-elastic theory based on these effects, and comparison between experimental and estimated data showed that the creep analysis sufficiently predicted the creep behavior.
  SPRINGER, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1007/s11043-011-9136-y
  DOI ID：10.1007/s11043-011-9136-y, ISSN：1385-2000, Web of Science ID：WOS:000293911800005
• ガラス繊維強化ポリアミドの繊維含有率及び結晶化度がクリープ挙動に及ぼす影響　　　　　　　　　　　　　　　
  坂井 建宣; 平井 悠斗; 宗宮 詮
  材料システム, 巻：29, 開始ページ：53, 終了ページ：59, 2011年01月
  金沢工業大学材料システム研究所, 日本語
  ISSN：0286-6013, J-Global ID：201102295123267680, CiNii Articles ID：40018708300, CiNii Books ID：AN00027831
• Effect of crystallinity and fiber volume fraction on creep behavior of glass fiber reinforced polyamide　　　　　　　　　　　　　　　
  Takenobu Sakai; Yuto Hirai; Satoshi Somiya
  Conference Proceedings of the Society for Experimental Mechanics Series, 巻：3, 開始ページ：159, 終了ページ：164, 2011年
  Thermoplastic Polyamide (PA) is known as Nylon®, and its FRP are one of the engineering plastics. It is very important for them to reveal accurately the visco-elastic behavior. Furthermore, PA is a crystalline polymer, and it is necessary to consider the effect of crystallization on mechanical properties. The purpose of this study was to make clear the effect of crystallization and fiber volume fraction on creep behavior of PA and its composites. The creep test was performed using the materials which adjusted crystallinity on each fiber volume fraction. As a result, these materials conformed to Arrhenius type of time-temperature superposition principle, and these effects on creep behavior had the time retardation effect. To compare the creep behavior on these effects, we made the grand master curves for crystallinity and fiber volume fraction. Obtained two grand master curves were compared each other, the shapes of these curves are similarly, and we can superposed them. It is therefore, the creep behavior including each conditions have the same behavior. Using these curves and shift factors, we can calculate the creep behavior, and be able to estimate the creep behavior with the effect of arbitrary time, temperature, crystallinity and fiber contents. ©2010 Society for Experimental Mechanics Inc.
  Springer New York LLC, 英語, 研究論文（国際会議プロシーディングス）
  DOI：https://doi.org/10.1007/978-1-4419-9794-4_25
  DOI ID：10.1007/978-1-4419-9794-4_25, ISSN：2191-5652, SCOPUS ID：79960304602
• AE Monitoring of Damage Accumulation in Transparent Conductive Oxide Film under the Mechanical Strain　　　　　　　　　　　　　　　
  WAKAYAMA Shuichi; TAKAGI Nobuyuki; SAKAI Takenobu; MIYASAKA Tsutomu; IKEGAMI Masashi
  J Solid Mech Mater Eng (Web), 巻：5, 号：12, 開始ページ：774-779 (J-STAGE), 終了ページ：779, 2011年
  In this study, tensile tests of the transparent conductive oxide (TCO) deposited on the polyethylene naphthalate (PEN) films (TCO + PEN films) used in dye-sensitized solar cells (DSCs) were carried out. In order to discriminate the AE signals in TCO from PEN films, PEN film specimens (TCO was removed by 17.5% hydrochloric acid) were also prepared. It was found from the tensile tests that many AE signals were detected in TCO + PEN films, while AE activity in PEN films was much lower. On the other hand, the electric resistance of TCO was also measured during tensile tests. The remarkable increase in AE event rate was recognized at the strain of ∼0.63%, while the electric resistance increased rapidly at the strain of 0.68%. These results demonstrated that the critical damage in TCO was detected by the measurement of AE signals more sensitively than the electric resistance measurement. To identify AE sources, in-situ observation of specimen during tensile test with AE measurement was carried out. During tensile test, cracks transverse to the loading direction in the TCO were found at the strain of 0.67%, and then saturated at the strain of ∼9%. Cracks parallel to the loading direction in TCO were initiated at the strain of 9.63%. On the other hand, the remarkable increase in AE event rate was recognized at the strain of ∼0.7%. It reached a peak at the strain of ∼2%, and then decreased, and increased again at the strain of ∼10%. It was then concluded that AE behavior corresponds to the cracking behavior in TCO. Consequently, it was suggested that AE technique could be a powerful technique for evaluating the damage accumulation process in DSCs.
  The Japan Society of Mechanical Engineers, 英語
  DOI：https://doi.org/10.1299/jmmp.5.774
  DOI ID：10.1299/jmmp.5.774, ISSN：1880-9871, J-Global ID：201202222804110860, CiNii Articles ID：130002072387
• Mechanical Properties of CNF Reinforced Ceramic Composites Sintered with SPS Technique　　　　　　　　　　　　　　　
  UMINO Kosuke; WAKAYAMA Shuichi; SAKAI Takenobu; UMEHARA Yuka; AKATSU Takashi
  J Solid Mech Mater Eng (Web), 巻：5, 号：12, 開始ページ：866-872 (J-STAGE), 終了ページ：872, 2011年
  Alumina matrix composites reinforced by carbon nanofibers (CNFs) of 0, 5, 10, 20 vol% were fabricated using a spark plasma sintering (SPS) technique. In this study, to disperse CNFs uniformly in ceramic matrix, an electrostatic adsorption technique was used to fabricate the mixed powder. The open porosity of the specimen increased and the mechanical properties decreased with the increase in CNF content. It might be resulted from the insufficient interfacial shear strength and CNFs worked as flaws in composites. In order to improve the interfacial shear strength, SiC particles were added into the interfacial phase between CNF and matrix so that the thermal mismatch and bonding between CNF and matrix were controlled. Consequently, it was demonstrated that mechanical properties were enhanced and the pull-out length decreased for the specimens with SiC addition. It was then suggested that the interfacial shear strength was successfully improved due to SiC addition.
  The Japan Society of Mechanical Engineers, 英語
  DOI：https://doi.org/10.1299/jmmp.5.866
  DOI ID：10.1299/jmmp.5.866, ISSN：1880-9871, J-Global ID：201202278506345907, CiNii Articles ID：130002072395
• Effect of Powder Contents on Viscoelastic Behavior of Glass Powder Filled Epoxy Resin　　　　　　　　　　　　　　　
  Takenobu SAKAI; Koichi OKABE; Satoru YONEYAMA
  2011 Special Issue of Journal of the Japanese Society for Experimental Mechanics, 巻：11, 開始ページ：187, 終了ページ：191, 2011年, ［査読有り］
• Effect of Viscoelastic Behavior on Electroconductivity of Recycled Activated Carbon Composites　　　　　　　　　　　　　　　
  Takenobu Sakai; Tomohiko Gushiken; Jun Koyanagi; Rolando Rios-Soberanis; Tomoki Masuko; Satoshi Matsushima; Satoshi Kobayashi; Satoru Yoneyama
  ADVANCES IN EXPERIMENTAL MECHANICS VIII, 巻：70, 開始ページ：231, 終了ページ：+, 2011年, ［査読有り］
  In the Waterworks Bureau, the activated carbon has been used for filtering water. After the life service of activated carbon, it is normally disposed. This work focuses on the processing of a composite material in order to recycle these wasted carbon particles. These activated carbons were used for the filler of composite materials, and a composite with carbon contents of 10% similar to 60% was manufactured and characterized. They exhibited electroconductive behavior because of the carbon particles used as fillers. The electroconductivity have an intimate relationship with the strain of the material. However, because of the composite viscoelasticity, the electroconductivity presented changes by their stress relaxation behavior with the same strain. In this study, it was revealed the relationship between the viscoelasticity and the electroconductivity of recycled activated carbon composites.
  TRANS TECH PUBLICATIONS LTD, 英語, 研究論文（国際会議プロシーディングス）
  DOI：https://doi.org/10.4028/www.scientific.net/.231
  DOI ID：10.4028/www.scientific.net/.231, ISSN：1660-9336, Web of Science ID：WOS:000303372700037
• Effect of crystallinity and fiber volume fraction on creep behavior of glass fiber reinforced polyamide　　　　　　　　　　　　　　　
  Takenobu Sakai; Yuto Hirai; Satoshi Somiya
  Society for Experimental Mechanics - SEM Annual Conference and Exposition on Experimental and Applied Mechanics 2010, 巻：1, 開始ページ：821, 終了ページ：826, 2010年
  Thermoplastic Polyamide (PA) is known as Nylon®, and its FRP are one of the engineering plastics. It is very important for them to reveal accurately the visco-elastic behavior. Furthermore, PA is a crystalline polymer, and it is necessary to consider the effect of crystallization on mechanical properties. The purpose of this study was to make clear the effect of crystallization and fiber volume fraction on creep behavior of PA and its composites. The creep test was performed using the materials which adjusted crystallinity on each fiber volume fraction. As a result, these materials conformed to Arrhenius type of time-temperature superposition principle, and these effects on creep behavior had the time retardation effect. To compare the creep behavior on these effects, we made the grand master curves for crystallinity and fiber volume fraction. Obtained two grand master curves were compared each other, the shapes of these curves are similarly, and we can superposed them. It is therefore, the creep behavior including each conditions have the same behavior. Using these curves and shift factors, we can calculate the creep behavior, and be able to estimate the creep behavior with the effect of arbitrary time, temperature, crystallinity and fiber contents. © 2010 Society for Experimental Mechanics Inc.
  英語, 研究論文（国際会議プロシーディングス）
  SCOPUS ID：78049450684
• 多段荷重下におけるポリカーボネートのクリープ挙動　　　　　　　　　　　　　　　
  坂井 建宣; 隅原 晋平; 宗宮 詮
  材料システム, 巻：28, 開始ページ：9, 終了ページ：14, 2010年, ［査読有り］
  金沢工業大学材料システム研究所, 日本語
  ISSN：0286-6013, CiNii Articles ID：40017038701, CiNii Books ID：AN00027831
• 炭素繊維強化熱可塑性ポリイミドのクリープ挙動に及ぼすフィジカルエージングの影響　　　　　　　　　　　　　　　
  坂井 建宣; 野溝 寿一; 宗宮 詮
  実験力学, 巻：10, 号：4, 開始ページ：401, 終了ページ：406, 2010年, ［査読有り］
• Analysis of creep behavior in thermoplastic based on visco-elastic theory　　　　　　　　　　　　　　　
  Takenobu Sakai; Satoshi Somiya
  Society for Experimental Mechanics - SEM Annual Conference and Exposition on Experimental and Applied Mechanics 2009, 巻：2, 開始ページ：1411, 終了ページ：1419, 2009年
  Although plastics with high mechanical properties are widely used in the fields including the aircraft and space industries, various types of FRP have been developed to improve the mechanical properties. Even though those plastics and FRPs are superior in the high-temperature mechanical properties, they are visco-elastically deformed by using at high temperature for a long time. It is, therefore, expected to elucidate the characteristics of visco-elastic phenomena of those materials in detail and improve the estimation technique of long-term life based on this elucidation result for enhancing the reliability of the materials and aiming at the high degree of utilization. Although many researches concerning the creep behavior of FRPs have been made, few researches have been made so far for investigating the linear visco-elastic behavior. And it is known that not only the linear visco-elastic behavior is occurred on the plastics, but also non-linear visco-elastic behavior. In this study, the non-linear visco-elastic behavior of plastics and the FRPs was investigated by making an experiment of the bending creep deformation of Polycarbonate (PC) and Polyacetal (Polyoxymethylene, POM). Moreover, the effects of the fiber volume fraction on the creep characteristics were investigated with glass fiber reinforced polycarbonate (GFRPC). After that, the creep analysis was made with containing these effects on the equation of linear visco-elastic theory. ©2009 Society for Experimental Mechanics Inc.
  英語, 研究論文（国際会議プロシーディングス）
  SCOPUS ID：73449093526
• Effect of Thermal History on the Creep Behavior of Polycarbonate　　　　　　　　　　　　　　　
  SAKAI Takenobu; SOMIYA Satoshi
  J Solid Mech Mater Eng (Web), 巻：3, 号：11, 開始ページ：1193-1201 (J-STAGE), 終了ページ：1201, 2009年
  Thermoplastic resin is often used to form molded material without post-curing or aging treatments. Creep and physical aging occur simultaneously in such material, and these effects are dependent on the time and temperature. The effects of physical aging after molding are also dependent on the thermal history of the material, and this has a large influence on the mechanical properties, especially creep. It is therefore necessary to control the progress of physical aging when designing materials. In this study, we examined the creep deformation of polycarbonate to determine the thermal history as the effect of physical aging on the creep behavior. The physical aging effects had a distinct time and temperature dependency that also affected the density of the material. Our findings showed that it was possible to calculate the effect of the thermal history on physical aging using only the relationship between physical aging and density.
  The Japan Society of Mechanical Engineers, 英語
  DOI：https://doi.org/10.1299/jmmp.3.1193
  DOI ID：10.1299/jmmp.3.1193, ISSN：1880-9871, J-Global ID：200902242961748360, CiNii Articles ID：130000127279
• Time-temperature dependence behavior of physical aging on creep behavior of PC　　　　　　　　　　　　　　　
  Takenobu Sakai; Satoshi Somiya
  Proceedings of the SEM Annual Conference and Exposition on Experimental and Applied Mechanics 2007, 巻：1, 開始ページ：531, 終了ページ：537, 2007年
  Thermoplastic resin and its FRTP were practically used without post cure treatment and aging treatment which is called "molded material". For such materials, it is known that creep behavior and physical aging occur simultaneously. And the effect of physical aging has the time and temperature dependency. The effect was occurred on the materials after molded, and the effect saved on the materials as the thermal history. This history has big influence on mechanical properties especially creep properties. Therefore, it is necessary to stay in control of the progress of the physical aging. In this report, the creep deformation of Polycarbonate (PC) was researched to grasp the effect of physical aging on creep behavior. It was clearly that the effect had the time and temperature dependency by two shift factors, and it had the same tendency as density. Using these relationships between the shift factors and density, it must be able to calculate the effect of thermal history as physical aging since the materials were molded by density.
  英語, 研究論文（国際会議プロシーディングス）
  SCOPUS ID：36148999517
• 2539 ポリウレタン系形状記憶ポリマー(DiARY)の曲げクリープ挙動の研究(J10-9 高分子・薄膜,J10 知的材料・構造システム)　　　　　　　　　　　　　　　
  田尾 隆幸; 坂井 建宣; 宗宮 詮
  年次大会講演論文集, 巻：2007, 開始ページ：279, 終了ページ：280, 2007年
  Shape Memory polymer (SMP) is known to have visco-elastic behavior. Shape recovery is considered to occur due to this visco-elastic behavior. On the other hand, creep and creep recovery may also occur that is known as one of visco-elastic behavior. It is important to understand creep and creep recovery behavior, because it effects on material's shape memory and shape recovery characteristics. This research examined the creep and creep recovery behavior by three point bending creep test. As a result, time and temperature dependence was confirmed, and also master curve can be drawn by superposing the creep compliance curves. Moreover, estimation of creep and creep recovery can be possible by master curve, shift factor and Boltzmann's superposition principle.
  一般社団法人日本機械学会, 日本語
  DOI：https://doi.org/10.1299/jsmemecjo.2007.6.0_279
  DOI ID：10.1299/jsmemecjo.2007.6.0_279, CiNii Articles ID：110007084743, CiNii Books ID：AA11461871
• Viscoelasticity of Shape Memory Polymer: Polyurethane series DiARY　　　　　　　　　　　　　　　
  SAKAI Takenobu; TAO Takayuki; SOMIYA Satoshi
  J Solid Mech Mater Eng (Web), 巻：1, 号：4, 開始ページ：480-489 (J-STAGE), 終了ページ：489, 2007年
  This study examined the creep behavior of DiARY^®, a shape-memory polymer (SMP), and the factors influencing the creep behavior. The creep test using the short term method obtained the master curve for the creep compliance, and confirmed the time-temperature superposition principle. Using this method, physical aging has little effect on the results of the creep test. To examine the effects of physical aging, we performed the creep test without using this method, which showed that physical aging alters the energy of activation of DiARY and the time-physical age time dependency at a specific temperature. The aging master curves were obtained as very smooth curves. In addition, the aging shift factors were attained when creating the aging master curves. The effect of physical aging depended on the time and temperature, confirming the time-physical aging time superposition principle, and achieved the effect of physical aging described as the aging shift rate. Using the master curve, time-temperature shift factor, and aging shift rate, it was possible to estimate the creep deformation, including the effect of physical aging on creep behavior.
  The Japan Society of Mechanical Engineers, 英語
  DOI：https://doi.org/10.1299/jmmp.1.480
  DOI ID：10.1299/jmmp.1.480, ISSN：1880-9871, J-Global ID：200902251784719710, CiNii Articles ID：130000078625
• ガラス繊維強化ポリカーボネートのクリープ挙動に及ぼすフィジカルエージングの影響　　　　　　　　　　　　　　　
  坂井 建宣; 宗宮 詮
  材料, 巻：56, 号：5, 開始ページ：399, 終了ページ：405, 2007年, ［査読有り］
• Estimating creep deformation of glass-fiber-reinforced polycarbonate　　　　　　　　　　　　　　　
  Takenobu Sakai; Satoshi Somiya
  MECHANICS OF TIME-DEPENDENT MATERIALS, 巻：10, 号：3, 開始ページ：185, 終了ページ：199, 2006年09月, ［査読有り］
  Thermoplastic resin and fiber-reinforced thermo-plastics (FRTPs) were used without post-cure treatment as "molded material." For such materials, creep behavior and physical aging occur simultaneously. This study examined the creep behavior of polycarbonate (PC) and glass-fiber-reinforced polycarbonate (GFRPC) injection moldings, including the effect of physical aging and fiber content, and determined that the time-temperature superposition principle could be applied to the creep behavior for different fiber contents. The effects of physical aging on creep behavior were evaluated quantitatively on pure resin and with various fiber contents without heat treatment. We found that the effect of physical aging could be evaluated with the proposed factor, "aging shift rate." To discuss the linearity of viscoelasticity in FRTPs, this study used two shift factors: time and modulus shift factors. The fiber content affected creep behavior by both retarding and restraining it through changing the elastic modulus. This was shown by generating a grand master curve of creep compliance, which included the effects of time, temperature, and fiber content. Using the grand master curve of creep compliance and shift factors, it was possible to estimate the creep deformation of molded materials under varying conditions and fiber contents. The estimated creep deformation gave a very good fit to the experimental creep deformation.
  SPRINGER, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1007/s11043-006-9017-y
  DOI ID：10.1007/s11043-006-9017-y, ISSN：1385-2000, Web of Science ID：WOS:000243768700002
• Estimation of creep deformation applying phased stress on GFRPC　　　　　　　　　　　　　　　
  Takenobu Sakai; Satoshi Somiya
  Proceedings of the 2006 SEM Annual Conference and Exposition on Experimental and Applied Mechanics 2006, 巻：2, 開始ページ：964, 終了ページ：970, 2006年
  Thermoplastic resin and its FRTP were practically used without post cure treatment and aging treatment which is called "molded material". For such materials, it is known that creep behavior and physical aging occur simultaneously. On the other hand, the creep test is usually carried out under a constant stress. Furthermore, it is known that nonlinear behavior appears under the phased stresses on creep behavior. In previous reports, the creep deformation of Polycarbonate (PC) and Glass fiber reinforced polycarbonate (GFRPC) was researched to estimate the creep deformation on the molded materials under the phased stresses. Using these results, the creep deformation under phased stresses was estimated with time-temperature superposition principle and the principle of superposition on each creep behavior. Using this estimation method, it was able to estimate the creep deformation of molded materials in arbitrary condition, time, temperature, fiber contents, and stress. Therefore, the results of estimation of creep deformation were very fit to the experimental creep deformation. Furthermore, this estimation method of creep behavior made it possible to estimate the creep behavior on pragmatic conditions.
  英語, 研究論文（国際会議プロシーディングス）
  SCOPUS ID：33750336182
• 2707 ポリウレタン系形状記憶ポリマー(DiARY)のクリープ挙動の研究(G04 機械材料・材料加工,G04 機械材料・材料加工)　　　　　　　　　　　　　　　
  田尾 隆幸; 坂井 建宣; 宗宮 詮
  年次大会講演論文集, 巻：2006, 開始ページ：143, 終了ページ：144, 2006年
  Shape Memory polymer (SMP) is known to have visco-elastic behaviour. Shape recovery is considered to occur due to this visco-elastic behaviour. On the other hand, creep behaviour may also occur that is known as one of visco-elastic behaviour. It is important to understand creep behaviour, because it effects on material's reliability. This research examined the creep behaviour using the SMP, and creep behaviour and influencing factor were investigated by three point bending creep test. As a result, time and temperature dependence was confirmed, and also physical aging has a large effects on creep behaviour. To be more precise, creep deflection was suppressed with increasing of physical aging treatment time. In physical aging time for 1000min, master curve can be drawn by superposing the creep compliance curves, and SMP conformed to Arrhenius type of time-temperature superposition principle.
  一般社団法人日本機械学会, 日本語
  DOI：https://doi.org/10.1299/jsmemecjo.2006.1.0_143
  DOI ID：10.1299/jsmemecjo.2006.1.0_143, CiNii Articles ID：110006634323, CiNii Books ID：AA11461871

• TiコーティングがFRPの物性に与える影響　　　　　　　　　　　　　　　
  小熊 広之; 白石 知久; 森田 寛之; 坂本 大輔; 坂井 建宣
  強化プラスチック協会誌, 巻：66, 号：9, 開始ページ：395, 終了ページ：400, 2020年09月, ［査読有り］, ［最終著者］
  記事・総説・解説・論説等（学術雑誌）
• 変形挙動予測によるプラスチックの寿命予測　　　　　　　　　　　　　　　
  坂井 建宣
  プラスチックス, 巻：2019, 号：10, 2019年10月, ［筆頭著者, 最終著者, 責任著者］
  記事・総説・解説・論説等（学術雑誌）
• 複合材料の寿命評価－時間－温度換算則－　　　　　　　　　　　　　　　
  坂井 建宣
  強化プラスチック協会誌, 巻：65, 号：8, 開始ページ：335, 終了ページ：338, 2019年08月, ［査読有り］, ［筆頭著者, 最終著者, 責任著者］
  記事・総説・解説・論説等（学術雑誌）
• Preparation and characteristic evaluation of silica-agglomerate electret with ultra-thin PTFE layer for ultrasonic sensor
  Kensuke Kageyama; Takeru Orikasa; Ahmad Zarif Afiq Bin Jamaludin; Takenobu Sakai
  IEEJ Transactions on Sensors and Micromachines, 巻：138, 開始ページ：441, 終了ページ：447, 2018年01月01日
  © 2018 The Institute of Electrical Engineers of Japan. Influence of formation of silica agglomerates on a ultra-thin fluororesin electret on the characteristics of the charge-retention and the aero-ultrasonic sensor was investigated. The ultra-thin PTFE layer (thickness was 2.8 μm) was obtained by spin-coating and silica agglomerates were formed by spraying droplets of colloidal silica. The formation of PTFE/silica agglomerate composite layer on PTFE layer resulted the larger and more flat agglomerates than the formation of single layer of silica agglomerates on the PTFE layer. The measurement of the charge retention of the obtained electrets after 24 h at RT and at 250°C revealed that the formation of PTFE/silica-agglomerate composite layer on the ultra-thin PTFE layer enhanced the charge retention. Furthermore, the electret condenser sensor (ECS) fabricated using the silica-agglomerate electret on the ultra-thin PTFE layer exhibited the excellent sensitivity and high resonance frequency compared with conventional ECS with PFA layer (thickness was 12.5 μm).
  DOI：https://doi.org/10.1541/ieejsmas.138.441
  DOI ID：10.1541/ieejsmas.138.441, ISSN：1341-8939, SCOPUS ID：85052660116
• Effect of temperature and strain rate on damage accumulation behavior of unidirectional CFRP　　　　　　　　　　　　　　　
  Takenobu Sakai; Satoru Abe; Kensuke Kageyama
  33rd Technical Conference of the American Society for Composites 2018, 巻：1, 開始ページ：439, 終了ページ：444, 2018年01月01日
  © Copyright© (2018) by DEStech Publications, Inc. All rights reserved. Carbon Fiber reinforced plastics (CFRP) is consisted with the carbon fiber and matrix resin. It has reported to consider that the matrix resin's properties also depends on CFRP's mechanical properties in the recent research. Matrix resin's considerable mechanical property is viscoelasticity that depends on time and temperature. In this study, we focused on the effect of temperature and strain rate on the damage accumulation behavior of unidirectional CFRP laminate, and tensile tests with acoustic emission technique were carried out at three different temperature with three different strain rate. As the results of tensile tests, lower temperature and higher strain rate showed higher tensile strength, that is, it is understood that tensile strength depended on the matrix's viscoelastic properties. Crack initiation behavior, which was defined at the point of rapid increase in cumulative AE energy, was depended on the temperature and strain rate. To understand the details of AE information, the frequency analysis was done. In the frequency analysis, the resonant frequency of AE sensors effects on the frequency properties of the detected signals, so we tried to erase the effect of sensors by deconvolution of AE sensor's frequency properties from detected signals. As the results of deconvolution, we could distinguished the failure modes as matrix cracking, fiber/matrix interfacial debonding and fiber breaking. Using these results, matrix cracking, fiber/matrix interfacial debonding were effected by temperature and strain rate, however, fiber breaking was not affected. Consequently, the crack accumulation behavior of each failure mode depended on the temperature and strain rate as the same tendency of matrix's viscoelastic properties.
  SCOPUS ID：85059307841
• Biomechanical contribution of elastin on wound skin of hairless mice　　　　　　　　　　　　　　　
  Takenobu Sakai; Miho Katsuragi; Kenske Kageyama; Ei Yamamoto
  巻：2017-, 開始ページ：1, 終了ページ：2, 2017年12月19日, ［査読有り］
  Dynamic mechanical analysis (DMA) was carried out to understand the effect of the application of elastin on wound skin of hairless mice. Wound group, placebo group, and elastin group were selected to evaluate that effect. As the results of DMA testing, the wound and the placebo groups showed lower storage and loss moduli than the elastin group. On the result of loss tangent, there is a small difference between these groups, and the elastin group showed the lowest value. Consequently, the application of elastin on the wounded skin showed the possibility for recovery the skins.
  英語
  DOI：https://doi.org/10.1109/GCCE.2017.8229323
  DOI ID：10.1109/GCCE.2017.8229323, SCOPUS ID：85045770977
• Acoustic Emission Technique Applied in Textiles Mechanical Characterization　　　　　　　　　　　　　　　
  Carlos Rolando Rios-Soberanis; Jose Rodriguez-Laviada; Emilio Perez-Pacheco; Takenobu Sakai; Shuichi Wakayama
  巻：95, 開始ページ：1, 終了ページ：4, 2017年, ［査読有り］
  The common textile architecture/geometry are woven, braided, knitted, stitch boded, and Z-pinned. Fibres in textile form exhibit good out-of-plane properties and good fatigue and impact resistance, additionally, they have better dimensional stability and conformability. Besides the nature of the textile, the architecture has a great role in the mechanical behaviour and mechanisms of damage in textiles, therefore damage mechanisms and mechanical performance in structural applications textiles have been a major concern. Mechanical damage occurs to a large extent during the service lifetime consequently it is vital to understand the material mechanical behaviour by identifying its mechanisms of failure such as onset of damage, crack generation and propagation. In this work, textiles of different architecture were used to manufacture epoxy based composites in order to study failure events under tensile load by using acoustic emission technique which is a powerful characterization tool due to its link between AE data and fracture mechanics, which makes this relation a very useful from the engineering point of view.
  英語
  DOI：https://doi.org/10.1051/matecconf/20179507016
  DOI ID：10.1051/matecconf/20179507016, ISSN：2261-236X, Web of Science ID：WOS:000406705800076
• 筋骨格系組織の動的な生体力学的特性の計測手法 : 動的粘弾性測定とアコースティック・エミッション法 (特集 生体計測およびその応用)　　　　　　　　　　　　　　　
  松岡 史都; 若山 修一; 坂井 建宣
  実験力学 : Journal of JSEM : Journal of the Japan Society for Experimental Mechanics, 巻：16, 号：4, 開始ページ：289, 終了ページ：294, 2016年12月
  日本実験力学会, 日本語
  ISSN：1346-4930, CiNii Articles ID：40021071551, CiNii Books ID：AA11822914
• PFAとコロイダルシリカとの濡れ性を改善したシリカ凝集体エレクトレットの作製と特性評価
  呉 シンク; 蔭山 健介; 坂井 建宣
  「センサ・マイクロマシンと応用システム」シンポジウム論文集 電気学会センサ・マイクロマシン部門 [編], 巻：33, 開始ページ：1, 終了ページ：6, 2016年10月02日
  Institute of Electrical Engineers of Japan, 日本語
  CiNii Articles ID：40021215456
• OS1405 関節音による変形性膝関節症診断システムの開発　　　　　　　　　　　　　　　
  中村 博明; 長谷 和徳; 林 祐一郎; 太田 進; 坂井 建宣
  日本機械学会関東支部総会講演会講演論文集, 巻：2016, 号：22, 開始ページ："OS1405, 終了ページ：1"-"OS1405-2", 2016年03月10日
  An articular sound arising from knee joint is known to be useful for diagnosis of knee osteoarthritis. However, measurement and evaluation method have been unsolved and it has not been implemented yet. This study aims to establish a simple, highly accurate and available in clinical diagnosis system of knee osteoarthritis using articular sound. The articular sound was measured by stethoscopes attached on the shank and the continuous wavelet transform was used for data processing. The discriminant formula was determined using discriminant analysis with parameters from the measurement data and then receiver operating characteristic (ROC) curve was obtained. As a result, the discriminant formula having the sensitivity of 0.778 and specificity of 0.792 was found.
  一般社団法人日本機械学会, 日本語
  CiNii Articles ID：110010050168, CiNii Books ID：AA11902161
• OS1001-322 ポリプロピレンの粘弾性特性係数と粘弾性試験の関係　　　　　　　　　　　　　　　
  坂井 建宣
  M&M材料力学カンファレンス, 巻：2015, 開始ページ："OS1001, 終了ページ：322-1"-"OS1001-322-3", 2015年11月21日
  By the linear viscoelastic theory in the textbook of viscoelasticity, the viscoelastic parameters obtained by different viscoelastic tests can be interconversion. However, this interconversion is based on that theory, the interconversion of the experimental data have not seen yet. In this study, the viscoelastic tests were carried out with different environment and same test conditions. And also we carried out the viscoelastic tests with the same testing apparatus and using the same materials. The results showed the difference in the environment on the viscoelastic tests, the silicon oil environment more progressed the creep behavior than the air environment. This is because that the silicon oil's thermal conductivity is one fourth of the air, and the heat generated with the deformation could not escape from the surface of the materials. In addition, the static bending tests were carried out with different strain rate and stress rate at elevated temperature. The results of static bending tests were converted to the creep compliances, then the results were compared with master curve of short term creep tests and 1 month long term creep tests. The results shows the good agreement between the master curve and long term creep tests. However the creep compliances obtained by static bending tests showed the different creep behaviors.
  一般社団法人日本機械学会, 日本語
  CiNii Articles ID：110010053538, CiNii Books ID：AA12322087
• 214 AE法を用いた引張負荷下の透明導電膜における破壊機構の力学的検討　　　　　　　　　　　　　　　
  松枝 剛広; 細山田 晃治; 會澤 修太郎; 湯澤 亮; 若山 修一; 坂井 建宣; 池上 和司; 宮坂 力
  機械材料・材料加工技術講演会講演論文集, 巻：2015, 号：23, 開始ページ："214, 終了ページ：1"-"214-4", 2015年11月14日
  Tensile test of Indium Tin Oxide (ITO) deposited on polyerhylene naphthalate (PEN) films used in solar cells were carried out. It was found from tensile tests that many AE signals were detected in ITO films. On the other hand, the electric resistance of ITO + PEN film was also measured later than first AE signal during tensile tests. In order to identify AE sources, in-situ observation of specimen and measurement of electricity resistance were also carried out. It was demonstrated that AE behavior shows good agreement with the cracking behavior in ITO. In addition to it, AE monitoring could be detected damages in ITO under mechanical strain earlier than were measurement of electricity resistance. Consequently, it was suggested that AE technique was extremely effective technique for damage detection and evaluating the damage accumulation process in films used in solar cells.
  一般社団法人日本機械学会, 日本語
  CiNii Articles ID：110010050354, CiNii Books ID：AA11902467
• よくわかる実験技術 動的粘弾性試験　　　　　　　　　　　　　　　
  坂井 建宣
  実験力学 : Journal of JSEM : Journal of the Japan Society for Experimental Mechanics, 巻：15, 号：3, 開始ページ：239, 終了ページ：241, 2015年09月29日
  日本実験力学会, 日本語
  ISSN：1346-4930, J-Global ID：201502201504093137, CiNii Articles ID：40020608038, CiNii Books ID：AA11822914
• PS4-8 Detection of Microdamage in Rabbit Patellar Tendon under Impact Tensile Load by Acoustic Emission(PS4: Poster Short Presentation IV,Poster Session)　　　　　　　　　　　　　　　
  Matsuoka Fumito; Wakayama Shuichi; Sakai Takenobu; Yamamoto Ei
  Proceedings of the ... Asian Pacific Conference on Biomechanics : emerging science and technology in biomechanics, 巻：2015, 号：8, 開始ページ：288, 終了ページ：288, 2015年09月16日
  一般社団法人日本機械学会, 英語
  CiNii Articles ID：110010043915, CiNii Books ID：AA12087919
• S0420102 引張負荷下の透明導電膜における損傷蓄積過程のAEモニタリング　　　　　　　　　　　　　　　
  若山 修一; 會澤 修太郎; 湯澤 亮; 坂井 建宣; 池上 和志; 宮坂 力
  年次大会 : Mechanical Engineering Congress, Japan, 巻：2015, 開始ページ："S0420102, 終了ページ：1"-"S0420102-3", 2015年09月13日
  Tensile tests of the transparent conductive films used in DSC (Dye-sensitized solar cell), consisting of ITO (Indium tin oxide) coating and PEN (Polyethylene naphthalate) substrate, were carried out and the damage accumulation process was monitored using acoustic emission technique. Damage initiation in ITO layer was detected earlier by AE technique than the electric resistance measurement during tensile tests. AE generation behavior was consistent with the result of in-situ observation of cracking behavior; initiation and saturation of transverse (perpendicular to tensile direction) cracking followed by the longitudinal (parallel to tensile direction) cracking due to buckling. Utilizing the principle of "fragmentation tests" for composite materials, interfacial shear strength for ITO/PEN interface was evaluated from experimental results for the critical strain at crack saturation and the spacing of saturated cracks. Finally, it was found that the shear strength was degraded by GBL (γ-Butyrolactone) used as electrolyte in DSC.
  一般社団法人日本機械学会, 日本語
  CiNii Articles ID：110010049345, CiNii Books ID：AA12588255
• J0230305 脱灰処理を施したウシ皮質骨の微視損傷蓄積過程のAE評価　　　　　　　　　　　　　　　
  金澤 孝悦; 若山 修一; 坂井 建宣
  年次大会 : Mechanical Engineering Congress, Japan, 巻：2015, 開始ページ："J0230305, 終了ページ：1"-"J0230305-4", 2015年09月13日
  Microdamage of healthy bovine cortical bone specimen and decalcified bone specimen during static compression tests was monitored by acoustic emission (AE) technique. Microdamage accumulation was successively monitored by AE technique. In static compression tests of healthy bone specimen, cracks were propagated due to microdamage accumulation, and cumulative AE events increased before final fracture. In static compression tests of decalcified bone specimen, macrocrack was observed with increasing in cumulative AE energy and cumulative AE events and decreasing in stress before fracture. Maximum stress and Young's modulus between healthy bone specimen and decalcified bone specimen had a significant difference. Those between specimen A (decalcified only specimen inside) and specimen B (decalcified specimen inside and outside) had no significant difference. Microdamage accumulation process of healthy bone specimen and decalcified bone specimen before leading to final fracture was shown by AE technique.
  一般社団法人日本機械学会, 日本語
  CiNii Articles ID：110010048687, CiNii Books ID：AA12588255
• J0230101 衝撃引張負荷下の家兎膝蓋腱の断裂過程のAEモニタリングと高速度カメラによるその場観察　　　　　　　　　　　　　　　
  松岡 史郎; 若山 修一; 坂井 建宣; 山本 衛
  年次大会 : Mechanical Engineering Congress, Japan, 巻：2015, 開始ページ："J0230101, 終了ページ：1"-"J0230101-4", 2015年09月13日
  Rabbit patellar tendon-bone complex specimens were subjected to impact tensile load to simulate the sports accident. During the tests, microdamage initiation and accumulation process in tendon was monitored using acoustic emission (AE) technique. In addition, in-situ observation from vertical and horizontal directions using two high-speed cameras was carried out to determine the strain distribution. The stress increased monotonically to the ultimate tensile stress (UTS), which was significantly higher than the static tests. Despite of the extremely short time, a number of AE signals were detected continuously before the UTS. Furthermore, AE signals were emitted in the area where the local strain increased significantly in the strain distribution of the surface. It is then demonstrated that AE technique enables not only the detection of invisible microdamage but the identification of the damage location. It is worth nothing that the amplitudes of detected AE signals were much higher than static tests. Since AE amplitude corresponds to the magnitude of individual microdamage, it is suggested that larger magnitude of individual microdamage is initiated under impact tensile load. Consequently, it is demonstrated that AE technique has a possibility of clarifying the detailed rupture mechanism of tendon or ligament under impact load.
  一般社団法人日本機械学会, 日本語
  CiNii Articles ID：110010048676, CiNii Books ID：AA12588255
• 廃タイヤのリサイクルのためのポリ乳酸複合材料の創製 (2015年度年次講演会)　　　　　　　　　　　　　　　
  坂井 建宣; 川井 喬介; 立山 耕平; Rios Soberanis C-R; Rodroguez-Laviada J.; Perez-Pacheco E.; 川田 良暁; 蔭山 健介; 山田 浩之
  日本実験力学会講演論文集 : 年次講演会 = Proceedings of JSEM : annual Conference on Experimental Mechanics, 号：15, 開始ページ：160, 終了ページ：162, 2015年
  日本実験力学会, 日本語
  ISSN：1346-4922, CiNii Articles ID：40020846819, CiNii Books ID：AA11910104
• Observation of Fiber-Matrix Interfacial Stresses Using Phase-Stepping Photoelasticity　　　　　　　　　　　　　　　
  Takenobu Sakai; Yasunori Iihara; Satoru Yoneyama
  開始ページ：215, 終了ページ：223, 2015年, ［査読有り］
  In this study, the single fiber composite was used to evaluate the stress transfer between a single fiber and a matrix. Single steel fiber was inserted to the epoxy resin, and it was applied the tensile load. Applied load was from 0 N to 177 N, and then the photoelastic images were taken by a digital CCD camera. In the photoelastic analysis, the phase-stepping and phase-unwrapping technique were used to measure the stress difference distribution more accurately. Obtained data were included the 3D information, therefore, we converted the stress difference data, including the 3D information to 2D photoelasticity using the geometrical information. The maximum shear stress was placed on the side surface of the steel fiber near the end of fiber, and the maximum normal stress difference was measured near the surface of the end of the fiber. The results of stress distribution on the interface between the fiber and the resin indicated that the stress concentration was observed in the middle part of the end of the fiber and the side surface near the end of the fiber.
  英語
  DOI：https://doi.org/10.1007/978-3-319-06986-9_24
  DOI ID：10.1007/978-3-319-06986-9_24, ISSN：2191-5644, Web of Science ID：WOS:000347773500024
• よくわかる学術用語 時間-温度換算則　　　　　　　　　　　　　　　
  坂井 建宣
  実験力学 : Journal of JSEM : Journal of the Japan Society for Experimental Mechanics, 巻：14, 号：4, 開始ページ：283, 終了ページ：285, 2014年12月28日
  日本実験力学会, 日本語
  ISSN：1346-4930, J-Global ID：201502241354952420, CiNii Articles ID：40020347961, CiNii Books ID：AA11822914
• S0420104 セラミックスにおける熱衝撃破壊特性の動的評価法の開発([S042-01]セラミックスおよびセラミックス系複合材料(1),機械材料・材料加工部門)　　　　　　　　　　　　　　　
  李 世亮; 塚田 隆允; 若山 修一; 坂井 建宣; 吉田 克己; 赤津 隆
  年次大会 : Mechanical Engineering Congress, Japan, 巻：2014, 開始ページ："S0420104, 終了ページ：1"-"S0420104-4", 2014年09月07日
  The experimental technique for the investigation of thermal shock fracture of ceramics under various stress ratios was developed. In order to determine the testing configurations, the thermal stress field in specimen was analyzed using FEM. It was found that the ellipse specimen and cooling rod with the specific aspect ratios yield the designated stress ratio which is constant during the test. The corresponding experiments were also carried out. The specimen was heated to 650 ℃ and quenched by means of contacting with a cool copper rod. The transient temperature on the ellipse specimen was measured by IR camera and the thermal stress was calculated by FEM. During thermal shocked fracture AE signals were detected by an AE sensor attached on the bottom of the copper rod. The constant thermal stress ratio was obtained corresponding to the result of FEM calculation. Consequently, the testing configuration, which enables the evaluation of thermal shock fracture behavior under various stress ratio, was developed.
  一般社団法人日本機械学会, 日本語
  CiNii Articles ID：110009945082, CiNii Books ID：AA12588255
• S0420103 微視破壊過程のAE評価に基づいたセラミックスの破壊シミュレーション([S042-01]セラミックスおよびセラミックス系複合材料(1),機械材料・材料加工部門)　　　　　　　　　　　　　　　
  若山 修一; 宮川 朋大; 脇本 陽介; 坂井 建宣; 池田 潤二; 宮路 史明
  年次大会 : Mechanical Engineering Congress, Japan, 巻：2014, 開始ページ："S0420103, 終了ページ：1"-"S0420103-4", 2014年09月07日
  Microfracture process in ceramics was analyzed using Monte-Carlo simulation. It was supposed in the simulation that the microfracture process consists of the maincrack formation resulted from the growth and coalescence of pre-existing microcracks, and the propagation of maincrack to final failure. To determine the crack growth parameters for simulation, microfracture process in alumina ceramics was characterized by acoustic emission technique, and the critical stress for maincrack formation and final strength were determined and compared with the results of simulation. The Monte-Carlo simulation assuming the 3 microcracks array with random size was adapted to the fracture analysis during the proof test with various proof stresses and holding times as well as residual strength measurements. The time-to-maincrack formation, yields and residual strength were calculated and it was found that they showed good agreement with the several experimental results. Consequently, the proof test with the wide range of proof stresses and holding times were examined and their influence on the yields, residual strength and lifetime was discussed.
  一般社団法人日本機械学会, 日本語
  CiNii Articles ID：110009945081, CiNii Books ID：AA12588255
• OS1719 形状記憶ポリマーの回復特性の時間-温度依存性　　　　　　　　　　　　　　　
  坂井 建宣; 田尾 隆幸; 宗宮 詮
  M&M材料力学カンファレンス, 巻：2014, 開始ページ："OS1719, 終了ページ：1"-"OS1719-2", 2014年07月19日
  As one of advanced functional materials, Shape Memory Polymer was studied on the shape recovery property, the shape fix property, and so on. However, it is difficult to comprehend the simple shape recovery behavior, because the viscoelastic and shape recover behaviors will occur simultaneously. Viscoelastic behavior is based on the entanglement effect on their polymeric chain, and the shape recovery behavior is based on the cross-link behavior. It is, therefore, necessary to divide these effects for understanding the viscoelastic and shape recovery behavior. The goal of this paper is to understand the viscoelastic and the simple shape recovery behavior, which depends on the cross-link, of the shape memory polymers.
  一般社団法人日本機械学会, 日本語
  CiNii Articles ID：110009939688, CiNii Books ID：AA12322087
• OS0511 スペックル干渉法による隣接結晶粒の変形挙動観察　　　　　　　　　　　　　　　
  有川 秀; 坂井 建宣; 小笠原 良助; 米山 聡
  M&M材料力学カンファレンス, 巻：2014, 開始ページ："OS0511, 終了ページ：1"-"OS0511-2", 2014年07月19日
  Deformation behavior of adjacent crystal grains of a metal is observed using speckle interferometry. Coarse grained aluminum specimens which have two crystal grains in the observation region are made by a thermo-mechanical treatment for the observation by speckle interferometry. Grain boundaries are arranged 0°, 45° and 90° for the loading direction. Crystal orientations are measured by electron backscatter diffraction. Tensile tests are performed and the in-plane and the out-of-plane deformation behaviors of the specimen surfaces are observed using speckle interferometry. As the results, strain maps of ε_x, ε_y, and γ_, are obtained and heterogenous deformation behaviors in each crystal grain can be observed. Various values of yield stresses and strains of each crystal grain in each specimen are obtained. The values depend on Schmidt factor obtained from the crystal orientation analysis. A tendency of the variation to decrease with decreasing the angles of the grain boundaries is obtained. Therefore, the experimental investigation of deformations of adjacent crystal grains is made possible by speckle interferometry.
  一般社団法人日本機械学会, 日本語
  CiNii Articles ID：110009939492, CiNii Books ID：AA12322087
• 10210 関節音による変形性膝関節症診断手法に関する基礎的研究　　　　　　　　　　　　　　　
  戸沢 優介; 長谷 和徳; 太田 進; 坂井 建宣
  日本機械学会関東支部総会講演会講演論文集, 巻：2014, 号：20, 開始ページ："10210, 終了ページ：1"-"10210-2", 2014年03月14日
  The articular sound arising from the knee joint is useful for the diagnosis of knee osteoarthritis. However, measurement and evaluation methods are unsolved, so that a standard diagnosis technique has not been established at present. This study aims to establish of the diagnostic method by the articular sound. The articular sound was measured by four stethoscopes attached to the knee joint. The location and status of the disease from the articular sound were quantitatively evaluated by introducing a signal processing techniques such as AIC (akaike's information criterion) and continuous wavelet transform. As a result, the sound frequency to be produced by knee osteoarthritis patient tended to be higher than that by healthy person.
  一般社団法人日本機械学会, 日本語
  CiNii Articles ID：110009949289, CiNii Books ID：AA11902161
• 使用済活性炭強化ポリプロピレンの曲げ損傷挙動 (2014年度年次講演会)　　　　　　　　　　　　　　　
  坂井 建宣; 具志堅 智彦; Soberanis C-R Rios
  日本実験力学会講演論文集, 号：14, 開始ページ：247, 終了ページ：249, 2014年
  日本実験力学会, 日本語
  ISSN：1346-4922, CiNii Articles ID：40020212692, CiNii Books ID：AA11910104
• ウェアラブルな心音・呼吸音評価装置の開発　　　　　　　　　　　　　　　
  坂井 建宣
  研究助成金受給者研究報告集, 巻：33, 開始ページ：153, 終了ページ：157, 2014年
  日揮・実吉奨学会, 日本語
  CiNii Articles ID：40020772224, CiNii Books ID：AN10192980
• 413 微視き裂の相互作用を考慮したシミュレーションによるセラミックスの寿命予測　　　　　　　　　　　　　　　
  若山 修一; 脇本 陽介; 坂井 建宣; 池田 潤二; 宮路 史明
  機械材料・材料加工技術講演会講演論文集, 巻：2013, 号：21, 開始ページ："413, 終了ページ：1"-"413-3", 2013年11月08日
  一般社団法人日本機械学会, 日本語
  CiNii Articles ID：110009935909, CiNii Books ID：AA11902467
• 127 廃タイヤ粉末強化複合材料の機械的特性　　　　　　　　　　　　　　　
  坂井 建宣; 若山 修一; Rolando Soberanis C-R; Rodroguez-Laviada J.; Perez-Pacheco E.
  機械材料・材料加工技術講演会講演論文集, 巻：2013, 号：21, 開始ページ："127, 終了ページ：1"-"127-3", 2013年11月08日
  一般社団法人日本機械学会, 日本語
  CiNii Articles ID：110009935814, CiNii Books ID：AA11902467
• OS0707 ウシ皮質骨の圧縮変形における粘弾性挙動および損傷蓄積挙動　　　　　　　　　　　　　　　
  坂井 建宣; 吉屋 英理; 安井 慶太; 若山 修一
  M&M材料力学カンファレンス, 巻：2013, 開始ページ："OS0707, 終了ページ：1"-"OS0707-3", 2013年10月12日
  Recently, the osteoporosis victims increase in the senior people. Therefore, the danger of the stress fracture due to the decrease in bone strength is pointed out. Especially, the damage accumulation behavior of the bone in the cyclic load becomes a problem for the fatigue of the bone. Moreover, it is necessary to consider the viscoelastic property for the prediction of the fatigue behavior, because the bone is a viscoelastic material. In this study, our objective is to estimate the fatigue behavior that considers the viscoelasticity behavior and the damage accumulation behavior as damage mechanics. The viscoelastic properties were revealed with the strain rate tests, and we calculated the 3-mode Maxwell parameters with these results. The damage accumulation behaviors were measured with the Acoustic Emission method. Using these results, we could estimate the fatigue behavior of cortical bone with the viscoelastic parameter and cumulative AE energy.
  一般社団法人日本機械学会, 日本語
  CiNii Articles ID：110009936609, CiNii Books ID：AA12322087
• S042013 微視構造を制御した窒化ケイ素のき裂進展挙動の動的評価([S042]セラミックスおよびセラミックス系複合材料)　　　　　　　　　　　　　　　
  坂井 建宣; 亀谷 豪; 若山 修一; 吉田 克己
  年次大会 : Mechanical Engineering Congress, Japan, 巻：2013, 開始ページ："S042013, 終了ページ：1"-"S042013-3", 2013年09月08日
  The microdamage in silicon nitride during thermal shock fracture was monitored by acoustic emission (AE) technique. Disc-on-Rod test was used to evaluate thermal shock fracture process. Cylinders with different microstructures were fabricated by sintering at different temperatures. In the Disc-on-Rod test, a pre-crack introduced specimen was heated, and only the center of circular specimen was quenched. Crack growth behavior under thermal shock loading can be monitored by using AE technique. The crack extension length was measured by the Digital Microscope. The crack growth resistance was calculated using Virtual Crack Closure Method and the FEM software. The crack growth resistance curves showed the rising R-curve behaviors for each material; therefore, it is assumed that the materials showed toughening mechanisms during the Disc-on Rod tests. As sintering temperature increased, crack growth resistance increased under the thermal shock loading.
  一般社団法人日本機械学会, 日本語
  CiNii Articles ID：110009933997, CiNii Books ID：AA12588255
• 21208 フレキシブル太陽電池の外力による損傷のAE法およびロックインサーモグラフィを用いた評価(OS4-2【機械工学が支援する微細加工技術(2)】)　　　　　　　　　　　　　　　
  田澤 博幸; 坂井 建宣; 若山 修一
  日本機械学会関東支部総会講演会講演論文集, 巻：2013, 号：19, 開始ページ：549, 終了ページ：550, 2013年03月14日
  In this study, the tensile test has been carried out to the flexible solar cells, and there failure processes have been characterized by the acoustic emission (AE) technique and the lock-in thermography. At the same time, the dark I-V curve has been measured during the test, and the leak current at-2 V has been used as a measure of degradation. The cumulative AE energy and the leak current began to increase at the strain of 〜0.8% and 〜1.2%, respectively. Accordingly the AE technique can detect mechanical damages earlier than the leak current increases. It is demonstrated by the lock-in thermography that the mechanical damages at holes contribute to performance degradation.
  一般社団法人日本機械学会, 日本語
  CiNii Articles ID：110009954666, CiNii Books ID：AA11902161
• 10513 家兎膝蓋腱の擬似生体環境下における損傷挙動のAE法による評価(OS2-4【バイオエンジニアリング(4)】)　　　　　　　　　　　　　　　
  鈴木 仁己; 坂井 建宣; 若山 修一; 山本 衛
  日本機械学会関東支部総会講演会講演論文集, 巻：2013, 号：19, 開始ページ：87, 終了ページ：88, 2013年03月14日
  AE monitoring of damage process of rabbit patellar tendon under static tensile load was carried out. Considering strong viscoelasticity of tendon, load was applied at various loading rate (10, 1, 0.1 mm/min) until the complete rupture in physiological saline at 37°C. The displacement of the specimen was monitored by a digital video camera, and acquired images were used for determining the displacement distribution in tendon by the digital image correlation (DIC) technique. It was found that the average failure stress increased as loading rate increased, and the differences in maximum stress were considered to be statistically significant. AE signals were detected before the maximum load and AE source locations corresponded to the locally elongated area, which indicates that fascicle failure takes place before the maximum load. Consequently, the fundamental insights for the damage monitoring technique which are indispensable for the optimization of programs of sports training or rehabilitation are obtained.
  一般社団法人日本機械学会, 日本語
  CiNii Articles ID：110009954435, CiNii Books ID：AA11902161
• 20312 窒化ケイ素の熱衝撃破壊におけるき裂進展抵抗のAE法による評価(GS-12【耐久性】)　　　　　　　　　　　　　　　
  亀谷 豪; 坂井 建宣; 若山 修一; 吉田 克己
  日本機械学会関東支部総会講演会講演論文集, 巻：2013, 号：19, 開始ページ：277, 終了ページ：278, 2013年03月14日
  The microdamage in silicon nitride during thermal shock fracture was monitored by acoustic emission (AE) technique. Disc-on-Rod test, which was developed by the authors, was used to evaluate thermal shock fracture process. Specimens were composed of β-Si_3N_4 with acicular structure. Cylinders with different microstructures were fabricated by sintering at different temperatures. A pre-crack was introduced using knoop indentation. In the Disc-on-Rod test, specimen was uniformly heated to 850 ℃, and only the center of circular specimen was quenched. After contacting, crack propagated in an unstable manner, at the same time, one relatively high amplitude AE signal was detected. Subsequently, stable crack propagation was observed, and several relatively low amplitude AE signals were generated corresponding to crack propagation. As sintering temperature increased, crack growth resistance decreased under the both thermal shock and mechanical loading. Furthermore, crack growth resistance sunder thermal shock loading were higher than those under mechanical loading.
  一般社団法人日本機械学会, 日本語
  CiNii Articles ID：110009954530, CiNii Books ID：AA11902161
• J022024 種々のひずみ速度下における家兎膝蓋腱の損傷過程のAE法による評価　　　　　　　　　　　　　　　
  鈴木 仁己; 坂井 建宣; 若山 修一; 山本 衛
  年次大会 : Mechanical Engineering Congress, Japan, 巻：2012, 開始ページ："J022024, 終了ページ：1"-"J022024-3", 2012年09月09日
  AE monitoring of damage process of rabbit patellar tendon under static tensile load was carried out. Considering strong viscoelasticity of tendon, load was applied at various loading rate (10, 1, 0.1 mm/min) until the complete rupture in physiological saline at 37℃. The displacement of the specimen was monitored by a digital video camera, and acquired images were used for determining the displacement distribution in tendon by the digital image correlation (DIC) technique. It was found that AE signals were detected before the maximum load and AE source locations corresponded to the locally elongated area, which indicates that fascicle failure takes place before the maximum load. The average failure stress increased as loading rate increased, and the differences in average failure stress were considered to be statistically significant. Consequently, the fundamental insights for the damage monitoring technique which are indispensable for the optimization of programs of sports training or rehabilitation are obtained.
  一般社団法人日本機械学会, 日本語
  CiNii Articles ID：110009993276, CiNii Books ID：AA12588255
• S042021 人工関節用ATZ複合セラミックスのAE法による微視損傷検出および長期信頼性評価　　　　　　　　　　　　　　　
  坂井 建宣; 風間 岳; 若山 修一; 池田 潤二; 宮路 史明
  年次大会 : Mechanical Engineering Congress, Japan, 巻：2012, 開始ページ："S042021, 終了ページ：1"-"S042021-3", 2012年09月09日
  The microdamages in ATZ composite ceramics during 4-point bending test were monitored by acoustic emission (AE) technique, and the rapid increase in cumulative AE energy prior to the final fracture was observed, which could be related with the maincrack formation as the origin of final fracture. The critical stress for maincrack formation σ_c was determined as the stress at rapid increasing point of AE signals. The stress increased with decreasing in Alumina weight fraction without 0% By increasing in ZrO_2, the growth grain size of Al_2O_3 was restrained and the flaw size turned smaller, since σ_c depends on the dispersion in the size and the distribution of initial failure.
  一般社団法人日本機械学会, 日本語
  CiNii Articles ID：110009993393, CiNii Books ID：AA12588255
• 特集「時間依存性材料」の編集にあたって　　　　　　　　　　　　　　　
  坂井 建宣
  実験力学 : journal of JSEM, 巻：12, 号：2, 開始ページ：70, 終了ページ：70, 2012年06月25日
  日本語
  ISSN：1346-4930, CiNii Articles ID：10030800702, CiNii Books ID：AA11822914
• 首都大学東京大学院 理工学研究科 機械工学専攻材料力学研究室　　　　　　　　　　　　　　　
  坂井 建宣; 若山 修一
  実験力学 : journal of JSEM, 巻：12, 号：1, 開始ページ：55, 終了ページ：55, 2012年03月28日
  日本語
  ISSN：1346-4930, CiNii Articles ID：10030556144, CiNii Books ID：AA11822914
• 第18回国際複合材料会議報告　　　　　　　　　　　　　　　
  荻原 慎二; 横関 智弘; 本田 真也; 小林 訓史; 黄木 景二; 胡 寧; 中村 理恵; 松崎 亮介; 上田 政人; 島村 佳伸; 中田 政之; 北條 正樹; 合田 公一; 斉藤 博嗣; 坂井 建宣; 中谷 隼人; 廣瀬 康夫; 河井 昌道; 水口 周; 小山 昌志; 野田 淳二; 佐々木 元; 倉敷 哲生; 尾崎 毅志; 加藤 久弥; 武田 真一; 吉村 彰記; 石田 雄一; 小柳 潤; 平野 義鎭; 仲井 朝美
  日本複合材料学会誌 = Journal of the Japan Society for Composite Materials, 巻：38, 号：2, 開始ページ：67, 終了ページ：84, 2012年03月15日
  日本複合材料学会, 日本語
  ISSN：0385-2563, CiNii Articles ID：10030825480, CiNii Books ID：AN00196748
• 使用済活性炭複合材料の導電性と粘弾性特性の関係 (2012年度年次講演会)　　　　　　　　　　　　　　　
  坂井 建宣; 具志堅 智彦; 増子 知樹
  日本実験力学会講演論文集, 号：12, 開始ページ：161, 終了ページ：164, 2012年
  日本実験力学会, 日本語
  ISSN：1346-4922, CiNii Articles ID：40019492486, CiNii Books ID：AA11910104
• 511 ポリ乳酸-PBATブレンド材における成形条件と圧縮特性(固体ポリマーの動的力学特性,衝撃負荷に対する材料・構造の応答,オーガナイスドセッション9)　　　　　　　　　　　　　　　
  具志堅 智彦; 大宮 正毅; 坂井 建宣
  学術講演会講演論文集, 巻：61, 開始ページ：121, 終了ページ：122, 2012年
  日本材料学会, 日本語
  CiNii Articles ID：110009484906, CiNii Books ID：AA11881527
• 実験力学に関する将来構想 : 今後の実験力学会における材料力学　　　　　　　　　　　　　　　
  坂井 建宣
  実験力学 : journal of JSEM, 巻：11, 号：4, 開始ページ：340, 終了ページ：340, 2011年12月28日
  日本語
  ISSN：1346-4930, CiNii Articles ID：10030287004, CiNii Books ID：AA11822914
• A110 皮質骨における疲労損傷のAE法による評価(A1-2 硬組織のバイオメカニクス)　　　　　　　　　　　　　　　
  安井 慶太; 坂井 建宣; 若山 修一
  バイオフロンティア講演会講演論文集, 巻：2011, 号：22, 開始ページ：19, 終了ページ：20, 2011年10月06日
  一般社団法人日本機械学会, 日本語
  ISSN：1348-2939, CiNii Articles ID：110009663310, CiNii Books ID：AA11902434
• A114 腱組織の損傷過程のAE法による評価(A1-3 軟組織のバイオメカニクス1)　　　　　　　　　　　　　　　
  鈴木 仁己; 坂井 建宣; 若山 修一; 山本 衛
  バイオフロンティア講演会講演論文集, 巻：2011, 号：22, 開始ページ：27, 終了ページ：28, 2011年10月06日
  一般社団法人日本機械学会, 日本語
  ISSN：1348-2939, CiNii Articles ID：110009663314, CiNii Books ID：AA11902434
• S042034 不連続繊維強化セラミック複合材料の作製および機械的特性の評価([S04203]セラミックスおよびセラミックス系複合材料(3))　　　　　　　　　　　　　　　
  海野 孝祐; 秋山 裕介; 若山 修一; 坂井 建宣; 梅原 由佳; 赤津 隆
  年次大会 : Mechanical Engineering Congress, Japan, 巻：2011, 開始ページ："S042034, 終了ページ：1"-"S042034-4", 2011年09月11日
  40 vol% SiC whisker reinforced alumina matrix composites (SiCw/Al_2O_3) were fabricated using a spark plasma sintering (SPS) technique. In this study, to decrease the thermal mismatch between SiCw and Al_2O_3, SiC particle (SiCp) was added into Al203 matrix (SiCw/SiCp/Al_2O_3). The relative density of the fabricated specimens was more than 99%, so that the sufficient densification was accomplished. Then, the mechanical properties and fracture morphology were examined. It was found that the mechanical properties of composites were increased from the monolithic Al203 and SiCw/Al_2O_3 composites. SEM observation of fracture surface after bending test showed that the amount of pull-out SiCw and the pull-out length in SiCw/SiCp/Al_2O_3 composites was larger than SiCw/Al_2O_3 composites. Therefore, the interfacial shear strength was successfully reduced due to SiCp addition. Consequently, it was suggested that the improvement of mechanical properties of SiCw/SiCp/Al_2O_3 composites may be accomplished by optimizing the interfacial shear strength due to SiCp addition.
  一般社団法人日本機械学会, 日本語
  CiNii Articles ID：110009759847, CiNii Books ID：AA12588255
• S042024 透明導電酸化膜の引張試験における損傷蓄積過程のAEモニタリング([S04202]セラミックスおよびセラミックス系複合材料(2))　　　　　　　　　　　　　　　
  高木 信幸; 若山 修一; 坂井 建宣; 池上 和志; 宮坂 力
  年次大会 : Mechanical Engineering Congress, Japan, 巻：2011, 開始ページ："S042024, 終了ページ：1"-"S042024-5", 2011年09月11日
  In this study, tensile tests of indium tin oxide (ITO) deposited on polyethylene naphthalate (PEN) films (ITO + PEN films) used in dye-sensitized solar cells (DSCs) were carried out. ITO + PEN films are fabricated at 150℃. Therefore, to clarify the influence of heat treatment on mechanical properties of ITO + PEN, the specimens with heat treatment were prepared. In order to discriminate AE signals in ITO from PEN films, PEN film specimens (ITO was removed by 17.5% hydrochloric acid) were also prepared. It was found from tensile tests that many AE signals were detected in ITO + PEN films, while few AE signals were detected in PEN films. On the other hand, the electric resistance of ITO was also measured during tensile tests. These results suggested that the critical damage in ITO was detected by the AE measurement more sensitively than the electric resistance. To identify AE sources, in-situ observation of specimen during tensile test with AE measurement was carried out. It was emphasized that AE behavior shows good agreement with the cracking behavior in ITO. Damages in ITO under mechanical strain were successfully monitored by AE technique in the present study. Consequently, it was suggested that AE technique could be a powerful technique for evaluating the damage accumulation process in DSCs.
  一般社団法人日本機械学会, 日本語
  CiNii Articles ID：110009759843, CiNii Books ID：AA12588255
• 119206 使用済活性炭強化ポリプロピレン複合材料の変形特性と導電性に関する研究(OS06 高分子材料および高分子系複合材料,オーガナイズド・セッション)　　　　　　　　　　　　　　　
  坂井 建宣; 具志堅 智彦; 増子 知樹; 松島 聡; 小林 諭史; 米山 聡
  日本機械学会関東支部総会講演会講演論文集, 巻：2011, 号：17, 開始ページ：95, 終了ページ：96, 2011年03月17日
  In the Waterworks Bureau, the activated carbon was used for filtering the water. After use the activated carbon, they were disposed. In this work, we tried to make that composite to recycle these carbons. These wasted activated carbons were used for the filler of composite materials, and we got the composite with the carbon contents of 10%〜60%. To evaluate of mechanical behavior of these composites, tensile test and stress relaxation test were carried out. The results show the powder contents dependency on tensile strength and Young's modulus. As seen in the results of stress relaxation test, the effect of powder contents on stress relaxation was revealed. To evaluate the electric property, the electric resistance was measured by 4-terminal method during tensile test and stress relaxation test. By the measurement of electric resistance, these composites can be used as smart materials.
  一般社団法人日本機械学会, 日本語
  CiNii Articles ID：110009663766, CiNii Books ID：AA11902161
• 220304 透明導電酸化膜における機械的損傷蓄積のAE法を用いた評価(OS16 東京ブロック・山梨ブロック共同企画 機械工学が支援する微細加工技術(半導体・MEMS・NEMS)1(半導体・MEMS・NEMS),オーガナイズド・セッション)　　　　　　　　　　　　　　　
  高木 信幸; 若山 修一; 水谷 彰宏; 坂井 建宣; 宮坂 力; 池上 和志
  日本機械学会関東支部総会講演会講演論文集, 巻：2011, 号：17, 開始ページ：567, 終了ページ：568, 2011年03月17日
  In this study, tensile tests of transparent conductive oxide (TCO) deposited on polyerhylene naphthalate (PEN) films (TCO + PEN films) used in dye-sensitized solar cells (DSCs) were carried out. In order to discriminate AE signals in TCO from PEN films, PEN film specimens (TCO was removed by 17.5% acidum hydrechloricum) were also prepared. It was found from tensile tests that many AE signals were detected in TCO + PEN films, while few AE signals were detected in PEN films. On the other hand, the electric resistance of TCO was also measured during tensile tests. These results suggested that the critical damage in TCO was detected by the measurement of AE signals more sensitively than the electric resistance measurement. To identify AE sources, in-situ observation of specimen during tensile test with AE measurement was carried out. It was emphasized that AE behavior shows good agreement with the cracking behavior in TCO. Damages in TCO under mechanical strain were successfully monitored by AE technique in the present study. Consequently, it was suggested that AE technique could be a powerful technique for evaluating the damage accumulation process in DSCs.
  一般社団法人日本機械学会, 日本語
  CiNii Articles ID：110009664001, CiNii Books ID：AA11902161
• 8E-01 擬似生体環境下の異なる周波数における皮質骨の疲労損傷のAE法による評価(OS-4 硬組織のバイオメカニクス(1))　　　　　　　　　　　　　　　
  安井 慶太; 若山 修一; 坂井 建宣
  バイオエンジニアリング講演会講演論文集, 巻：2010, 号：23, 開始ページ：77, 終了ページ：78, 2011年01月07日
  一般社団法人日本機械学会, 日本語
  CiNii Articles ID：110008744030, CiNii Books ID：AA11903175
• NCFの積層構成とクリープ挙動の関係 ([日本実験力学会]2011年度年次講演会)　　　　　　　　　　　　　　　
  坂井 建宣; Soberanis C. R. Rios; 若山 修一
  日本実験力学会講演論文集, 号：11, 開始ページ：450, 終了ページ：454, 2011年
  日本実験力学会, 日本語
  ISSN：1346-4922, CiNii Articles ID：40019017304, CiNii Books ID：AA11910104
• 特集「複合材料」の編集にあたって　　　　　　　　　　　　　　　
  坂井 建宣
  実験力学 : journal of JSEM, 巻：10, 号：4, 開始ページ：386, 終了ページ：386, 2010年12月25日
  日本語
  ISSN：1346-4930, CiNii Articles ID：10027692944, CiNii Books ID：AA11822914
• 111 静電交互吸着法を利用した高含有率カーボンナノファイバー強化アルミナ複合材料の破壊挙動(セラミックス/セラミックス基複合材料(2),ものづくりにおける基礎研究と先端技術の融合)　　　　　　　　　　　　　　　
  海野 孝祐; 若山 修一; 赤津 隆; 坂井 建宣; 梅原 由佳
  機械材料・材料加工技術講演会講演論文集, 巻：2010, 号：18, 開始ページ："111, 終了ページ：1"-"111-4", 2010年11月27日
  In this study, carbon nanofiber (CNF) reinforced Al_2O_3 composites were fabricated. To fabricate uniformly-dispersed CNF/Al_2O_3 powder, electrostatic adsorption, which could increase the surface potential of CNFs, was applied. Al203 sol was then adsorbed onto the surface of CNFs uniformly. The mixed powder was sintered by spark plasma sintering under the pressure of 50 MPa at 1600℃ in Ar atmosphere. Fracture behavior of the specimen was evaluated by bending test, indentation test and fracture-surface observation. The results showed that the bending strength of specimen was lower than monolithic Al_2O_3. It might be because there were many pores and the interface between CNF and Al_2O_3 were relatively weak. However, a large number of pull-out and bridging of CNFs were observed by the fracture surface observation with a scanning electron microscope. This suggests that CNFs could improve the fracture toughness of the CNF reinforced Al_2O_3 composites.
  一般社団法人日本機械学会, 日本語
  CiNii Articles ID：110008742944, CiNii Books ID：AA11902467
• フィジカルエージング　　　　　　　　　　　　　　　
  坂井 建宣
  実験力学 : journal of JSEM, 巻：10, 号：1, 開始ページ：120, 終了ページ：121, 2010年03月25日
  日本語
  ISSN：1346-4930, CiNii Articles ID：10026406397, CiNii Books ID：AA11822914
• よくわかる学術用語 フィジカルエージング
  坂井建宣
  実験力学, 巻：10, 号：1, 開始ページ：120, 終了ページ：121, 2010年03月25日
  日本語
  ISSN：1346-4930, J-Global ID：201002230071759367
• 2009 International Conference of Experimental Mechanics in Singapore 参加報告 : 2009 Asian Conference of Experimental Mechanics　　　　　　　　　　　　　　　
  坂井 建宣
  実験力学 : journal of JSEM, 巻：10, 号：1, 開始ページ：124, 終了ページ：124, 2010年03月25日
  日本語
  ISSN：1346-4930, CiNii Articles ID：10026406405, CiNii Books ID：AA11822914
• 生体適合性を有するモノマーを添加した骨セメントの粘弾性評価 ([日本実験力学会]2010年度年次講演会)　　　　　　　　　　　　　　　
  坂井 建宣; 若山 修一; Rios-Soberanis C. R.
  日本実験力学会講演論文集, 号：10, 開始ページ：41, 終了ページ：45, 2010年
  日本実験力学会, 日本語
  ISSN：1346-4922, CiNii Articles ID：40017284647, CiNii Books ID：AA11910104
• ポリアセタールの結晶状態を考慮したクリープ解析　　　　　　　　　　　　　　　
  坂井 建宣; 上野 宗一郎; 山田 幸市; 宗宮 詮
  実験力学 : journal of JSEM, 巻：9, 号：4, 開始ページ：388, 終了ページ：394, 2009年12月25日
  日本実験力学会, 日本語
  ISSN：1346-4930, CiNii Articles ID：10026406130, CiNii Books ID：AA11822914
• OS0516 生分解性プラスチックの引張変形が結晶化度に及ぼす影響(微視構造を有する材料の変形と破壊,オーガナイズドセッション)　　　　　　　　　　　　　　　
  坂井 建宣; 中曽根 祐司
  M&M材料力学カンファレンス, 巻：2009, 開始ページ：607, 終了ページ：608, 2009年07月24日
  The crystal condition of the poly lactic acid that was a crystalline polymer was changed (degree of crystallization etc.), and the tensile test was done. Then the influence of crystal condition on the mechanical attribute was examined. Therefore, heat-treatment was first given to the material based on the melting point and the crystallization temperature of the material requested from differential scanning calorimetry (DSC), and the material that changed the degree of crystallization was made. Next, when the change in the degree of crystallization in the extensional deformation was confirmed because the crystallinity dependence was seen in the extensional deformation as a result of doing the tensile test and having examined it, it was understood that the degree of crystallization had changed by the extensional deformation.
  一般社団法人日本機械学会, 日本語
  CiNii Articles ID：110008065013, CiNii Books ID：AA12322087
• PS25 ポリ乳酸ブレンド材の圧縮特性評価(ポスターセッション)　　　　　　　　　　　　　　　
  山村 俊貴; 大宮 正毅; 坂井 建宣; VIOT Philippe
  M&M材料力学カンファレンス, 巻：2009, 開始ページ：485, 終了ページ：487, 2009年07月24日
  Biodegradable polymers, Polylactide(PLA) have a potential to be engineering plastics because of energy and environmental reasons. Conventional polymers are made from the petroleum, but PLA is made from the starch whose source is plants. Thus, PLA is carbon-neutral because the carbon of the starch is from carbon dioxide in the air. PLA is brittle. So, it limits the use of PLA. To improve this brittleness, PLA have been blended with other flexible polymers. In this study, we use Poly butylene adipate-co-terephthalate(PBAT) as the blending polymer. PBAT is fully biodegradable and flexible, though its Young's modulus and tensile strength are inferior to PLA, breaking strain is much higher than PLA PBAT distributes evenly in the PLA matrix. By now, PLA and blended PLA were conducted static tensile tests, but not done compressive tests. So, we evaluated properties in the static and dynamic compressive tests. In result, addition 40 wt % PBAT to PLA, Young's modulus and yielding stress decrease, but maximum strain and the strain energy at crack initiation get larger. In addition, Young's modulus and yielding stress of neat PLA and blended PLA increase with the strain rate rising.
  一般社団法人日本機械学会, 日本語
  CiNii Articles ID：110008064965, CiNii Books ID：AA12322087
• 熱可塑性樹脂およびその複合材料の線形粘弾性理論に基づくクリープ解析 ([日本実験力学会]2009年度年次講演会)　　　　　　　　　　　　　　　
  坂井 建宣; 宗宮 詮
  日本実験力学会講演論文集, 号：9, 開始ページ：220, 終了ページ：225, 2009年
  日本実験力学会, 日本語
  ISSN：1346-4922, CiNii Articles ID：40016842731, CiNii Books ID：AA11910104
• ポリ乳酸ブレンド材の圧縮特性評価 ([日本実験力学会]2009年度年次講演会)　　　　　　　　　　　　　　　
  山村 俊貴; 大宮 正毅; 坂井 建宣
  日本実験力学会講演論文集, 号：9, 開始ページ：151, 終了ページ：156, 2009年
  日本実験力学会, 日本語
  ISSN：1346-4922, CiNii Articles ID：40016842717, CiNii Books ID：AA11910104
• ポリカーボネートのクリープ挙動に及ぼす熱履歴の影響とその測定　　　　　　　　　　　　　　　
  坂井建宣
  第40回応力 ひずみ測定と強度評価シンポジウム講演論文集, 2009, 開始ページ：137, 終了ページ：142, 2009年
  CiNii Articles ID：80020343962
• OS0618 結晶性高分子材料の力学的特性に及ぼす結晶状態の影響(OS06-04 力学特性の発現機構,OS06 微視構造を有する材料の変形と破壊(2))　　　　　　　　　　　　　　　
  坂井 建宣; 中曽根 祐司
  M&M材料力学カンファレンス, 巻：2008, 開始ページ："OS0618, 終了ページ：1"-"OS0618-2", 2008年09月16日
  結晶性高分子であるポリアセタールの結晶状態(結晶化度など)を変化させて、引張試験および硬さ試験等を行い、力学的特性に及ぼす結晶状態の影響を調べた。そのため、まず、示差走査熱量測定(DSC)から求めた供試材の融点および結晶化温度に基づいて、供試材に熱処理を施し、結晶化度を変化させた供試材を作製した。次に、引張試験を行い、結晶化処理を施した材料と受入材の引張挙動の相違を調べた。また、予ひずみを与えた材料について硬さ試験を行い、硬さに及ぼす予ひずみの影響を調べ、結晶化度の変化が結晶性高分子材料の引張強度特性に及ぼす影響を明らかにした。
  一般社団法人日本機械学会, 日本語
  CiNii Articles ID：110008697364, CiNii Books ID：AA12322087
• ポリアセタールのクリープ挙動に及ぼす結晶状態の影響 ([日本実験力学会]2008年度年次講演会)　　　　　　　　　　　　　　　
  坂井 建宣; 上野 宗一郎; 山田 幸市
  日本実験力学会講演論文集, 号：8, 開始ページ：267, 終了ページ：270, 2008年
  日本実験力学会, 日本語
  ISSN：1346-4922, CiNii Articles ID：40016856061, CiNii Books ID：AA11910104
• 2007 Society for Experimental Mechanics Annual Conference in Springfield 参加報告　　　　　　　　　　　　　　　
  坂井 建宣
  実験力学 : journal of JSEM, 巻：7, 号：3, 開始ページ：297, 終了ページ：297, 2007年09月25日
  日本語
  ISSN：1346-4930, CiNii Articles ID：10019954481, CiNii Books ID：AA11822914
• OS15-3-1 Estimation Corresponding to Temperature Change of Creep Behavior on Glass Fiber Reinforced-Polycarbonate　　　　　　　　　　　　　　　
  Sakai Takenobu; Somiya Satoshi
  Abstracts of ATEM : International Conference on Advanced Technology in Experimental Mechanics : Asian Conference on Experimental Mechanics, 巻：2007, 号：6, 開始ページ："OS15, 終了ページ：3-1-1"-"OS15-3-1-5", 2007年09月12日
  Thermoplastic resin was practically used without post cure treatment and physical aging treatment which is called "molded material". For such materials, it is known that creep behavior and physical aging occur simultaneously. And the effect of physical aging has the time and temperature dependency. The effect was occurred on the materials after molded, and the effect saved on the materials as the thermal history. This history has big influence on mechanical properties, especially creep properties. Therefore, it is necessary to understand the progress of the physical aging. In this report, the creep deformation of polycarbonate (PC) was researched to grasp the effect of physical aging on creep behavior. Two types of materials were prepared. One was "molded material", and another was pre-physical aged material. It was confirmed that the effect had the time and temperature dependency, and it had been able to apply the time-pre-aging time superposition principle and time-pre-aging temperature superposition principle of physical aging on creep behavior. The estimation corresponding to temperature change of creep deformation became possible using this superposition principle. The estimation result of the creep deformation of glass fiber reinforced polycarbonate (GFRPC) with temperature change during a creep test had the tendency similar to the experimental data. Therefore, it should be able to estimate the creep behavior with arbitrary thermal history since the materials reached to the saturated state of physical aging.
  一般社団法人日本機械学会, 英語
  CiNii Articles ID：110009969382, CiNii Books ID：AA11902310
• E-18 Visco-Elasticity of Shape Memory Polymer : Polyurethane series(Session: Contact strength/Mechanical)　　　　　　　　　　　　　　　
  Sakai Takenobu; Tao Takayuki; Somiya Satoshi
  ASMP : proceedings of Asian Symposium on Materials and Processing, 巻：2006, 開始ページ：110, 終了ページ：110, 2006年11月08日
  In this research, the creep behavior of shape memory polymer (SMP) was researched. On this material, master curve of creep compliance was obtained, and time-temperature superposition principle was confirmed. The effect of physical aging on creep behavior was researched, too. The effect of physical aging on creep behavior was described on the aging shift factors, and the effect was depended on the change of time and temperature. From this result, time-physical aged time superposition principle was confirmed. Using the master curve and the shift factors of time, temperature and physical aging, it makes to be able to estimate the creep deformation including the effect of physical aging on creep behavior.
  一般社団法人日本機械学会, 英語
  CiNii Articles ID：110006781508, CiNii Books ID：AA12251091
• ガラス繊維強化ポリカーボネートのクリープ挙動に関する材料設計法　　　　　　　　　　　　　　　
  坂井 建宣; 楠本 晃史; 宗宮 詮
  日本複合材料学会研究発表講演会予稿集, 巻：2003, 開始ページ：71, 終了ページ：72, 2003年05月01日
  日本語
  CiNii Articles ID：10010717047, CiNii Books ID：AA11644747
• 103 ディーゼルエンジン用ばねの機械的特性に及ぼすクリープ処理の影響　　　　　　　　　　　　　　　
  金子 堅司; 小島 正敏; 坂井 建宣
  講演論文集, 巻：2002, 開始ページ：5, 終了ページ：6, 2002年10月10日
  A creep tempering is done in production process of a spring designed for a fuel-injection nozzle of diesel engine. It is because that creep deformation occurs during use at high temperature and mechanical properties may change. But, conditions (temperature, time) in the creep tempering depend on empirical data that are not necessarily reasonable. In this study, effects of creep tempering on mechanical properties and residual stress of spring are investigated experimentally and theoretically. It is found that shear residual stress increases and spring constant does not so change after creep tempering process. Calculation methods of both shear residual stress and shear creep constitutive expressions of spring are proposed.
  一般社団法人日本機械学会, 日本語
  CiNii Articles ID：110002480844, CiNii Books ID：AN00360626

• 高分子の残留応力対策　　　　　　　　　　　　　　　
  ［共著］
  2016年
• 動的粘弾性チャートの解釈事例集　　　　　　　　　　　　　　　
  ［共著］
  2016年
• よくわかる実験技術・学術用語 第２版　　　　　　　　　　　　　　　
  ［共著］
  2010年

• Effect of temperature and strain rate on damage accumulation behavior of unidirectional CFRP　　　　　　　　　　　　　　　
  Takenobu Sakai; Satoru Abe; Kensuke Kageyama
  33rd Technical Conference of the American Society for Composites 2018, 2018年01月
  2018年01月 - 2018年01月
  © Copyright© (2018) by DEStech Publications, Inc. All rights reserved. Carbon Fiber reinforced plastics (CFRP) is consisted with the carbon fiber and matrix resin. It has reported to consider that the matrix resin's properties also depends on CFRP's mechanical properties in the recent research. Matrix resin's considerable mechanical property is viscoelasticity that depends on time and temperature. In this study, we focused on the effect of temperature and strain rate on the damage accumulation behavior of unidirectional CFRP laminate, and tensile tests with acoustic emission technique were carried out at three different temperature with three different strain rate. As the results of tensile tests, lower temperature and higher strain rate showed higher tensile strength, that is, it is understood that tensile strength depended on the matrix's viscoelastic properties. Crack initiation behavior, which was defined at the point of rapid increase in cumulative AE energy, was depended on the temperature and strain rate. To understand the details of AE information, the frequency analysis was done. In the frequency analysis, the resonant frequency of AE sensors effects on the frequency properties of the detected signals, so we tried to erase the effect of sensors by deconvolution of AE sensor's frequency properties from detected signals. As the results of deconvolution, we could distinguished the failure modes as matrix cracking, fiber/matrix interfacial debonding and fiber breaking. Using these results, matrix cracking, fiber/matrix interfacial debonding were effected by temperature and strain rate, however, fiber breaking was not affected. Consequently, the crack accumulation behavior of each failure mode depended on the temperature and strain rate as the same tendency of matrix's viscoelastic properties.
• Preparation and characteristic evaluation of silica-agglomerate electret with ultra-thin PTFE layer for ultrasonic sensor　　　　　　　　　　　　　　　
  Kensuke Kageyama; Takeru Orikasa; Ahmad Zarif Afiq Bin Jamaludin; Takenobu Sakai
  IEEJ Transactions on Sensors and Micromachines, 2018年01月
  2018年01月 - 2018年01月
  © 2018 The Institute of Electrical Engineers of Japan. Influence of formation of silica agglomerates on a ultra-thin fluororesin electret on the characteristics of the charge-retention and the aero-ultrasonic sensor was investigated. The ultra-thin PTFE layer (thickness was 2.8 μm) was obtained by spin-coating and silica agglomerates were formed by spraying droplets of colloidal silica. The formation of PTFE/silica agglomerate composite layer on PTFE layer resulted the larger and more flat agglomerates than the formation of single layer of silica agglomerates on the PTFE layer. The measurement of the charge retention of the obtained electrets after 24 h at RT and at 250°C revealed that the formation of PTFE/silica-agglomerate composite layer on the ultra-thin PTFE layer enhanced the charge retention. Furthermore, the electret condenser sensor (ECS) fabricated using the silica-agglomerate electret on the ultra-thin PTFE layer exhibited the excellent sensitivity and high resonance frequency compared with conventional ECS with PFA layer (thickness was 12.5 μm).
• CFRP の損傷蓄積挙動に及ぼすひずみ速度の影響　　　　　　　　　　　　　　　
  坂井建宣; 安部聡; 上田政人; 小林訓史; 荻原慎二; 若山修一; 蔭山健介
  日本機械学会M&M2016 材料力学カンファレンス講演論文集, 2016年10月
  2016年10月 - 2016年10月, 日本語
• OS1405 関節音による変形性膝関節症診断システムの開発　　　　　　　　　　　　　　　
  中村 博明; 長谷 和徳; 林 祐一郎; 太田 進; 坂井 建宣
  日本機械学会関東支部総会講演会講演論文集, 2016年03月, 一般社団法人日本機械学会
  2016年03月 - 2016年03月, 日本語
  An articular sound arising from knee joint is known to be useful for diagnosis of knee osteoarthritis. However, measurement and evaluation method have been unsolved and it has not been implemented yet. This study aims to establish a simple, highly accurate and available in clinical diagnosis system of knee osteoarthritis using articular sound. The articular sound was measured by stethoscopes attached on the shank and the continuous wavelet transform was used for data processing. The discriminant formula was determined using discriminant analysis with parameters from the measurement data and then receiver operating characteristic (ROC) curve was obtained. As a result, the discriminant formula having the sensitivity of 0.778 and specificity of 0.792 was found.
• An experimental-numerical hybrid approach to analysis of fiber-matrix interfacial stresses　　　　　　　　　　　　　　　
  Takenobu Sakai; Yasunori Iihara; Satoru Yoneyama
  Conference Proceedings of the Society for Experimental Mechanics Series, 2016年, Springer New York LLC
  2016年 - 2016年, 英語
  In this study, the single fiber composite was used to evaluate the stress transfer between a single fiber and a matrix. Single steel fiber was inserted to the epoxy resin, and it was applied the tensile load. Applied load was from 0 N to 177 N, and then the photoelastic images were taken by a digital CCD camera. On the photoelastic analysis, the stress separation was carried out using an experimental-numerical hybrid method. The boundary conditions for a local finite element model, that is, the tractions along boundaries are inversely determined from photoelastic fringes. After determining the boundary conditions for the local finite element model, the stresses can be obtained by finite element direct analysis. Using this input data and the finite element model of analysis region, not only the stress but also the strain distributions were obtained. Consequently, by using the photoelasticity data and geometric data for input data of finite element analysis, accurate data was obtained by the hybrid method for stress separation.
• ポリプロピレンの粘弾性特性係数と粘弾性試験の関係　　　　　　　　　　　　　　　
  坂井建宣
  日本機械学会M&M材料力学カンファレンス(CD-ROM), 2015年11月
  2015年11月 - 2015年11月, 日本語
• 214 AE法を用いた引張負荷下の透明導電膜における破壊機構の力学的検討　　　　　　　　　　　　　　　
  松枝 剛広; 細山田 晃治; 會澤 修太郎; 湯澤 亮; 若山 修一; 坂井 建宣; 池上 和司; 宮坂 力
  機械材料・材料加工技術講演会講演論文集, 2015年11月, 一般社団法人日本機械学会
  2015年11月 - 2015年11月, 日本語
  Tensile test of Indium Tin Oxide (ITO) deposited on polyerhylene naphthalate (PEN) films used in solar cells were carried out. It was found from tensile tests that many AE signals were detected in ITO films. On the other hand, the electric resistance of ITO + PEN film was also measured later than first AE signal during tensile tests. In order to identify AE sources, in-situ observation of specimen and measurement of electricity resistance were also carried out. It was demonstrated that AE behavior shows good agreement with the cracking behavior in ITO. In addition to it, AE monitoring could be detected damages in ITO under mechanical strain earlier than were measurement of electricity resistance. Consequently, it was suggested that AE technique was extremely effective technique for damage detection and evaluating the damage accumulation process in films used in solar cells.
• J0230101 衝撃引張負荷下の家兎膝蓋腱の断裂過程のAEモニタリングと高速度カメラによるその場観察　　　　　　　　　　　　　　　
  松岡 史郎; 若山 修一; 坂井 建宣; 山本 衛
  年次大会 : Mechanical Engineering Congress, Japan, 2015年09月, 一般社団法人日本機械学会
  2015年09月 - 2015年09月, 日本語
  Rabbit patellar tendon-bone complex specimens were subjected to impact tensile load to simulate the sports accident. During the tests, microdamage initiation and accumulation process in tendon was monitored using acoustic emission (AE) technique. In addition, in-situ observation from vertical and horizontal directions using two high-speed cameras was carried out to determine the strain distribution. The stress increased monotonically to the ultimate tensile stress (UTS), which was significantly higher than the static tests. Despite of the extremely short time, a number of AE signals were detected continuously before the UTS. Furthermore, AE signals were emitted in the area where the local strain increased significantly in the strain distribution of the surface. It is then demonstrated that AE technique enables not only the detection of invisible microdamage but the identification of the damage location. It is worth nothing that the amplitudes of detected AE signals were much higher than static tests. Since AE amplitude corresponds to the magnitude of individual microdamage, it is suggested that larger magnitude of individual microdamage is initiated under impact tensile load. Consequently, it is demonstrated that AE technique has a possibility of clarifying the detailed rupture mechanism of tendon or ligament under impact load.
• J0230305 脱灰処理を施したウシ皮質骨の微視損傷蓄積過程のAE評価　　　　　　　　　　　　　　　
  金澤 孝悦; 若山 修一; 坂井 建宣
  年次大会 : Mechanical Engineering Congress, Japan, 2015年09月, 一般社団法人日本機械学会
  2015年09月 - 2015年09月, 日本語
  Microdamage of healthy bovine cortical bone specimen and decalcified bone specimen during static compression tests was monitored by acoustic emission (AE) technique. Microdamage accumulation was successively monitored by AE technique. In static compression tests of healthy bone specimen, cracks were propagated due to microdamage accumulation, and cumulative AE events increased before final fracture. In static compression tests of decalcified bone specimen, macrocrack was observed with increasing in cumulative AE energy and cumulative AE events and decreasing in stress before fracture. Maximum stress and Young's modulus between healthy bone specimen and decalcified bone specimen had a significant difference. Those between specimen A (decalcified only specimen inside) and specimen B (decalcified specimen inside and outside) had no significant difference. Microdamage accumulation process of healthy bone specimen and decalcified bone specimen before leading to final fracture was shown by AE technique.
• S0420102 引張負荷下の透明導電膜における損傷蓄積過程のAEモニタリング　　　　　　　　　　　　　　　
  若山 修一; 會澤 修太郎; 湯澤 亮; 坂井 建宣; 池上 和志; 宮坂 力
  年次大会 : Mechanical Engineering Congress, Japan, 2015年09月, 一般社団法人日本機械学会
  2015年09月 - 2015年09月, 日本語
  Tensile tests of the transparent conductive films used in DSC (Dye-sensitized solar cell), consisting of ITO (Indium tin oxide) coating and PEN (Polyethylene naphthalate) substrate, were carried out and the damage accumulation process was monitored using acoustic emission technique. Damage initiation in ITO layer was detected earlier by AE technique than the electric resistance measurement during tensile tests. AE generation behavior was consistent with the result of in-situ observation of cracking behavior; initiation and saturation of transverse (perpendicular to tensile direction) cracking followed by the longitudinal (parallel to tensile direction) cracking due to buckling. Utilizing the principle of "fragmentation tests" for composite materials, interfacial shear strength for ITO/PEN interface was evaluated from experimental results for the critical strain at crack saturation and the spacing of saturated cracks. Finally, it was found that the shear strength was degraded by GBL (γ-Butyrolactone) used as electrolyte in DSC.
• 衝撃引張負荷下の家兎膝蓋腱の断裂過程のAEモニタリングと高速度カメラによるその場観察　　　　　　　　　　　　　　　
  松岡史都; 若山修一; 坂井建宣; 山本衛
  日本機械学会年次大会講演論文集(CD-ROM), 2015年09月
  2015年09月 - 2015年09月, 日本語
• 引張負荷下の透明導電膜における損傷蓄積過程のAEモニタリング　　　　　　　　　　　　　　　
  若山修一; 會澤修太郎; 湯澤亮; 坂井建宣; 池上和志; 宮坂力
  日本機械学会年次大会講演論文集(CD-ROM), 2015年09月
  2015年09月 - 2015年09月, 日本語
• 脱灰処理を施したウシ皮質骨の微視損傷蓄積過程のAE評価　　　　　　　　　　　　　　　
  金澤孝悦; 若山修一; 坂井建宣
  日本機械学会年次大会講演論文集(CD-ROM), 2015年09月
  2015年09月 - 2015年09月, 日本語
• 周波数解析による変形性膝関節症の診断　　　　　　　　　　　　　　　
  坂井建宣; 児玉勝也; 川田良暁; 蔭山健介; 戸沢優介; 長谷和徳; 若山修一; 安藤聡子; 中村拓也; 太田進
  応力・ひずみ測定と強度評価シンポジウム講演論文集, 2015年01月
  2015年01月 - 2015年01月, 日本語
• OS1001-322 ポリプロピレンの粘弾性特性係数と粘弾性試験の関係　　　　　　　　　　　　　　　
  坂井 建宣
  M&M材料力学カンファレンス, 2015年, 一般社団法人 日本機械学会
  2015年 - 2015年, 日本語
  By the linear viscoelastic theory in the textbook of viscoelasticity, the viscoelastic parameters obtained by different viscoelastic tests can be interconversion. However, this interconversion is based on that theory, the interconversion of the experimental data have not seen yet. In this study, the viscoelastic tests were carried out with different environment and same test conditions. And also we carried out the viscoelastic tests with the same testing apparatus and using the same materials. The results showed the difference in the environment on the viscoelastic tests, the silicon oil environment more progressed the creep behavior than the air environment. This is because that the silicon oil's thermal conductivity is one fourth of the air, and the heat generated with the deformation could not escape from the surface of the materials. In addition, the static bending tests were carried out with different strain rate and stress rate at elevated temperature. The results of static bending tests were converted to the creep compliances, then the results were compared with master curve of short term creep tests and 1 month long term creep tests. The results shows the good agreement between the master curve and long term creep tests. However the creep compliances obtained by static bending tests showed the different creep behaviors.
• 廃タイヤのリサイクルのためのポリ乳酸複合材料の創製 (2015年度年次講演会)　　　　　　　　　　　　　　　
  坂井 建宣; 川井 喬介; 立山 耕平; Rios Soberanis C-R; Rodroguez-Laviada J; Perez-Pacheco E; 川田 良暁; 蔭山 健介; 山田 浩之
  日本実験力学会講演論文集 : 年次講演会 = Proceedings of JSEM : annual Conference on Experimental Mechanics, 2015年, 日本実験力学会
  2015年 - 2015年, 日本語
• AE法を用いた引張負荷下の透明導電膜における破壊機構の力学的検討　　　　　　　　　　　　　　　
  松枝剛広; 細山田晃治; 會澤修太郎; 湯澤亮; 若山修一; 坂井建宣; 池上和司; 宮坂力
  日本機械学会機械材料・材料加工技術講演会論文集(CD-ROM), 2015年
  2015年 - 2015年, 日本語
• 炭素繊維強化熱可塑性ポリイミド(AURUM)の曲げクリープにおける時間‐温度依存性　　　　　　　　　　　　　　　
  岡田瑞生; 上田政人; 後藤健; 小林訓史; 坂井建宣; 荒井広明
  宇宙科学技術連合講演会講演集(CD-ROM), 2015年
  2015年 - 2015年, 日本語
• 関節音による変形性膝関節症診断手法に関する基礎的研究―ウェーブレット変換による評価と音源位置推定精度検証―　　　　　　　　　　　　　　　
  戸沢優介; 長谷和徳; 太田進; 安藤聡子; 坂井建宣
  バイオメカニズム学術講演会予稿集, 2014年11月
  2014年11月 - 2014年11月, 日本語
• S0420103 微視破壊過程のAE評価に基づいたセラミックスの破壊シミュレーション([S042-01]セラミックスおよびセラミックス系複合材料(1),機械材料・材料加工部門)　　　　　　　　　　　　　　　
  若山 修一; 宮川 朋大; 脇本 陽介; 坂井 建宣; 池田 潤二; 宮路 史明
  年次大会 : Mechanical Engineering Congress, Japan, 2014年09月, 一般社団法人日本機械学会
  2014年09月 - 2014年09月, 日本語
  Microfracture process in ceramics was analyzed using Monte-Carlo simulation. It was supposed in the simulation that the microfracture process consists of the maincrack formation resulted from the growth and coalescence of pre-existing microcracks, and the propagation of maincrack to final failure. To determine the crack growth parameters for simulation, microfracture process in alumina ceramics was characterized by acoustic emission technique, and the critical stress for maincrack formation and final strength were determined and compared with the results of simulation. The Monte-Carlo simulation assuming the 3 microcracks array with random size was adapted to the fracture analysis during the proof test with various proof stresses and holding times as well as residual strength measurements. The time-to-maincrack formation, yields and residual strength were calculated and it was found that they showed good agreement with the several experimental results. Consequently, the proof test with the wide range of proof stresses and holding times were examined and their influence on the yields, residual strength and lifetime was discussed.
• S0420104 セラミックスにおける熱衝撃破壊特性の動的評価法の開発([S042-01]セラミックスおよびセラミックス系複合材料(1),機械材料・材料加工部門)　　　　　　　　　　　　　　　
  李 世亮; 塚田 隆允; 若山 修一; 坂井 建宣; 吉田 克己; 赤津 隆
  年次大会 : Mechanical Engineering Congress, Japan, 2014年09月, 一般社団法人日本機械学会
  2014年09月 - 2014年09月, 日本語
  The experimental technique for the investigation of thermal shock fracture of ceramics under various stress ratios was developed. In order to determine the testing configurations, the thermal stress field in specimen was analyzed using FEM. It was found that the ellipse specimen and cooling rod with the specific aspect ratios yield the designated stress ratio which is constant during the test. The corresponding experiments were also carried out. The specimen was heated to 650 ℃ and quenched by means of contacting with a cool copper rod. The transient temperature on the ellipse specimen was measured by IR camera and the thermal stress was calculated by FEM. During thermal shocked fracture AE signals were detected by an AE sensor attached on the bottom of the copper rod. The constant thermal stress ratio was obtained corresponding to the result of FEM calculation. Consequently, the testing configuration, which enables the evaluation of thermal shock fracture behavior under various stress ratio, was developed.
• 使用済活性炭強化ポリプロピレンの曲げ損傷挙動　　　　　　　　　　　　　　　
  坂井建宣; 具志堅智彦; SOBERANIS C‐R Rios; 増子知樹; 松島聡; 小林訓史; 米山聡; 若山修一
  日本実験力学会講演論文集, 2014年08月
  2014年08月 - 2014年08月, 日本語
• OS1719 形状記憶ポリマーの回復特性の時間-温度依存性　　　　　　　　　　　　　　　
  坂井 建宣; 田尾 隆幸; 宗宮 詮
  M&M材料力学カンファレンス, 2014年07月, 一般社団法人日本機械学会
  2014年07月 - 2014年07月, 日本語
  As one of advanced functional materials, Shape Memory Polymer was studied on the shape recovery property, the shape fix property, and so on. However, it is difficult to comprehend the simple shape recovery behavior, because the viscoelastic and shape recover behaviors will occur simultaneously. Viscoelastic behavior is based on the entanglement effect on their polymeric chain, and the shape recovery behavior is based on the cross-link behavior. It is, therefore, necessary to divide these effects for understanding the viscoelastic and shape recovery behavior. The goal of this paper is to understand the viscoelastic and the simple shape recovery behavior, which depends on the cross-link, of the shape memory polymers.
• OS0511 スペックル干渉法による隣接結晶粒の変形挙動観察　　　　　　　　　　　　　　　
  有川 秀; 坂井 建宣; 小笠原 良助; 米山 聡
  M&M材料力学カンファレンス, 2014年07月, 一般社団法人日本機械学会
  2014年07月 - 2014年07月, 日本語
  Deformation behavior of adjacent crystal grains of a metal is observed using speckle interferometry. Coarse grained aluminum specimens which have two crystal grains in the observation region are made by a thermo-mechanical treatment for the observation by speckle interferometry. Grain boundaries are arranged 0°, 45° and 90° for the loading direction. Crystal orientations are measured by electron backscatter diffraction. Tensile tests are performed and the in-plane and the out-of-plane deformation behaviors of the specimen surfaces are observed using speckle interferometry. As the results, strain maps of ε_x, ε_y, and γ_<xy>, are obtained and heterogenous deformation behaviors in each crystal grain can be observed. Various values of yield stresses and strains of each crystal grain in each specimen are obtained. The values depend on Schmidt factor obtained from the crystal orientation analysis. A tendency of the variation to decrease with decreasing the angles of the grain boundaries is obtained. Therefore, the experimental investigation of deformations of adjacent crystal grains is made possible by speckle interferometry.
• 形状記憶ポリマーの回復特性の時間‐温度依存性　　　　　　　　　　　　　　　
  坂井建宣; 田尾隆幸; 宗宮詮
  日本機械学会M&M材料力学カンファレンス(CD-ROM), 2014年07月
  2014年07月 - 2014年07月, 日本語
• スペックル干渉法による隣接結晶粒の変形挙動観察　　　　　　　　　　　　　　　
  有川秀一; 坂井建宣; 小笠原良助; 米山聡
  日本機械学会M&M材料力学カンファレンス(CD-ROM), 2014年07月
  2014年07月 - 2014年07月, 日本語
• 変形性膝関節症患者における膝関節音の信号特性について　　　　　　　　　　　　　　　
  太田進; 安藤聡子; 中村拓也; 岡本正吾; 長谷和徳; 戸沢優介; 坂井建宣
  JOSKAS, 2014年07月
  2014年07月 - 2014年07月, 日本語
• 家兎膝蓋腱における引張損傷のAE評価　　　　　　　　　　　　　　　
  若山修一; 松岡史都; 坂井建宣; 山本衛
  日本非破壊検査協会講演大会講演概要集, 2014年06月
  2014年06月 - 2014年06月, 日本語
• 10210 関節音による変形性膝関節症診断手法に関する基礎的研究　　　　　　　　　　　　　　　
  戸沢 優介; 長谷 和徳; 太田 進; 坂井 建宣
  日本機械学会関東支部総会講演会講演論文集, 2014年03月, 一般社団法人日本機械学会
  2014年03月 - 2014年03月, 日本語
  The articular sound arising from the knee joint is useful for the diagnosis of knee osteoarthritis. However, measurement and evaluation methods are unsolved, so that a standard diagnosis technique has not been established at present. This study aims to establish of the diagnostic method by the articular sound. The articular sound was measured by four stethoscopes attached to the knee joint. The location and status of the disease from the articular sound were quantitatively evaluated by introducing a signal processing techniques such as AIC (akaike's information criterion) and continuous wavelet transform. As a result, the sound frequency to be produced by knee osteoarthritis patient tended to be higher than that by healthy person.
• 関節音による変形性膝関節症診断手法に関する基礎的研究　　　　　　　　　　　　　　　
  戸沢優介; 長谷和徳; 太田進; 坂井建宣
  日本機械学会関東支部総会・講演会講演論文集(CD-ROM), 2014年03月
  2014年03月 - 2014年03月, 日本語
• 使用済活性炭強化ポリプロピレンの曲げ損傷挙動 (2014年度年次講演会)　　　　　　　　　　　　　　　
  坂井 建宣; 具志堅 智彦; Soberanis C-R Rios
  日本実験力学会講演論文集, 2014年, 日本実験力学会
  2014年 - 2014年, 日本語
• 廃タイヤ粉末強化複合材料の機械的特性　　　　　　　　　　　　　　　
  坂井 建宣; 若山 修一; Soberanis C-R Rolando
  機械材料・材料加工技術講演会 M&P, 2013年11月, 日本機械学会
  2013年11月 - 2013年11月, 日本語
• 微視き裂の相互作用を考慮したシミュレーションによるセラミックスの寿命予測　　　　　　　　　　　　　　　
  若山 修一; 脇本 陽介; 坂井 建宣
  機械材料・材料加工技術講演会 M&P, 2013年11月, 日本機械学会
  2013年11月 - 2013年11月, 日本語
• 127 廃タイヤ粉末強化複合材料の機械的特性　　　　　　　　　　　　　　　
  坂井 建宣; 若山 修一; Rolando Soberanis C-R; Rodroguez-Laviada J; Perez-Pacheco E
  機械材料・材料加工技術講演会講演論文集, 2013年11月, 一般社団法人日本機械学会
  2013年11月 - 2013年11月, 日本語
• 413 微視き裂の相互作用を考慮したシミュレーションによるセラミックスの寿命予測　　　　　　　　　　　　　　　
  若山 修一; 脇本 陽介; 坂井 建宣; 池田 潤二; 宮路 史明
  機械材料・材料加工技術講演会講演論文集, 2013年11月, 一般社団法人日本機械学会
  2013年11月 - 2013年11月, 日本語
• 微視き裂の相互作用を考慮したシミュレーションによるセラミックスの寿命予測　　　　　　　　　　　　　　　
  若山修一; 脇本陽介; 坂井建宣; 池田潤二; 宮路史明
  日本機械学会機械材料・材料加工技術講演会論文集(CD-ROM), 2013年11月
  2013年11月 - 2013年11月, 日本語
• 廃タイヤ粉末強化複合材料の機械的特性　　　　　　　　　　　　　　　
  坂井建宣; 若山修一; SOBERANIS C‐R Rolando; RODROGUEZ‐LAVIADA J; PEREZ‐PACHECO E
  日本機械学会機械材料・材料加工技術講演会論文集(CD-ROM), 2013年11月
  2013年11月 - 2013年11月, 日本語
• OS0707 ウシ皮質骨の圧縮変形における粘弾性挙動および損傷蓄積挙動　　　　　　　　　　　　　　　
  坂井 建宣; 吉屋 英理; 安井 慶太; 若山 修一
  M&M材料力学カンファレンス, 2013年10月, 一般社団法人日本機械学会
  2013年10月 - 2013年10月, 日本語
  Recently, the osteoporosis victims increase in the senior people. Therefore, the danger of the stress fracture due to the decrease in bone strength is pointed out. Especially, the damage accumulation behavior of the bone in the cyclic load becomes a problem for the fatigue of the bone. Moreover, it is necessary to consider the viscoelastic property for the prediction of the fatigue behavior, because the bone is a viscoelastic material. In this study, our objective is to estimate the fatigue behavior that considers the viscoelasticity behavior and the damage accumulation behavior as damage mechanics. The viscoelastic properties were revealed with the strain rate tests, and we calculated the 3-mode Maxwell parameters with these results. The damage accumulation behaviors were measured with the Acoustic Emission method. Using these results, we could estimate the fatigue behavior of cortical bone with the viscoelastic parameter and cumulative AE energy.
• ウシ皮質骨の圧縮変形における粘弾性挙動および損傷蓄積挙動　　　　　　　　　　　　　　　
  坂井建宣; 吉屋英理; 安井慶太; 若山修一
  日本機械学会M&M材料力学カンファレンス(CD-ROM), 2013年10月
  2013年10月 - 2013年10月, 日本語
• S042013 微視構造を制御した窒化ケイ素のき裂進展挙動の動的評価([S042]セラミックスおよびセラミックス系複合材料)　　　　　　　　　　　　　　　
  坂井 建宣; 亀谷 豪; 若山 修一; 吉田 克己
  年次大会 : Mechanical Engineering Congress, Japan, 2013年09月, 一般社団法人日本機械学会
  2013年09月 - 2013年09月, 日本語
  The microdamage in silicon nitride during thermal shock fracture was monitored by acoustic emission (AE) technique. Disc-on-Rod test was used to evaluate thermal shock fracture process. Cylinders with different microstructures were fabricated by sintering at different temperatures. In the Disc-on-Rod test, a pre-crack introduced specimen was heated, and only the center of circular specimen was quenched. Crack growth behavior under thermal shock loading can be monitored by using AE technique. The crack extension length was measured by the Digital Microscope. The crack growth resistance was calculated using Virtual Crack Closure Method and the FEM software. The crack growth resistance curves showed the rising R-curve behaviors for each material; therefore, it is assumed that the materials showed toughening mechanisms during the Disc-on Rod tests. As sintering temperature increased, crack growth resistance increased under the thermal shock loading.
• 微視構造を制御した窒化ケイ素のき裂進展挙動の動的評価　　　　　　　　　　　　　　　
  坂井建宣; 亀谷豪; 若山修一; 吉田克己
  日本機械学会年次大会講演論文集(CD-ROM), 2013年09月
  2013年09月 - 2013年09月, 日本語
• 引張負荷下における家兎膝蓋腱の損傷蓄積過程のAE法による評価　　　　　　　　　　　　　　　
  坂井建宣; 鈴木仁己; 若山修一; 山本衛
  日本非破壊検査協会講演大会講演概要集, 2013年06月
  2013年06月 - 2013年06月, 日本語
• 10513 家兎膝蓋腱の擬似生体環境下における損傷挙動のAE法による評価(OS2-4【バイオエンジニアリング(4)】)　　　　　　　　　　　　　　　
  鈴木 仁己; 坂井 建宣; 若山 修一; 山本 衛
  日本機械学会関東支部総会講演会講演論文集, 2013年03月, 一般社団法人日本機械学会
  2013年03月 - 2013年03月, 日本語
  AE monitoring of damage process of rabbit patellar tendon under static tensile load was carried out. Considering strong viscoelasticity of tendon, load was applied at various loading rate (10, 1, 0.1 mm/min) until the complete rupture in physiological saline at 37°C. The displacement of the specimen was monitored by a digital video camera, and acquired images were used for determining the displacement distribution in tendon by the digital image correlation (DIC) technique. It was found that the average failure stress increased as loading rate increased, and the differences in maximum stress were considered to be statistically significant. AE signals were detected before the maximum load and AE source locations corresponded to the locally elongated area, which indicates that fascicle failure takes place before the maximum load. Consequently, the fundamental insights for the damage monitoring technique which are indispensable for the optimization of programs of sports training or rehabilitation are obtained.
• 20312 窒化ケイ素の熱衝撃破壊におけるき裂進展抵抗のAE法による評価(GS-12【耐久性】)　　　　　　　　　　　　　　　
  亀谷 豪; 坂井 建宣; 若山 修一; 吉田 克己
  日本機械学会関東支部総会講演会講演論文集, 2013年03月, 一般社団法人日本機械学会
  2013年03月 - 2013年03月, 日本語
  The microdamage in silicon nitride during thermal shock fracture was monitored by acoustic emission (AE) technique. Disc-on-Rod test, which was developed by the authors, was used to evaluate thermal shock fracture process. Specimens were composed of β-Si_3N_4 with acicular structure. Cylinders with different microstructures were fabricated by sintering at different temperatures. A pre-crack was introduced using knoop indentation. In the Disc-on-Rod test, specimen was uniformly heated to 850 ℃, and only the center of circular specimen was quenched. After contacting, crack propagated in an unstable manner, at the same time, one relatively high amplitude AE signal was detected. Subsequently, stable crack propagation was observed, and several relatively low amplitude AE signals were generated corresponding to crack propagation. As sintering temperature increased, crack growth resistance decreased under the both thermal shock and mechanical loading. Furthermore, crack growth resistance sunder thermal shock loading were higher than those under mechanical loading.
• 21208 フレキシブル太陽電池の外力による損傷のAE法およびロックインサーモグラフィを用いた評価(OS4-2【機械工学が支援する微細加工技術(2)】)　　　　　　　　　　　　　　　
  田澤 博幸; 坂井 建宣; 若山 修一
  日本機械学会関東支部総会講演会講演論文集, 2013年03月, 一般社団法人日本機械学会
  2013年03月 - 2013年03月, 日本語
  In this study, the tensile test has been carried out to the flexible solar cells, and there failure processes have been characterized by the acoustic emission (AE) technique and the lock-in thermography. At the same time, the dark I-V curve has been measured during the test, and the leak current at-2 V has been used as a measure of degradation. The cumulative AE energy and the leak current began to increase at the strain of 〜0.8% and 〜1.2%, respectively. Accordingly the AE technique can detect mechanical damages earlier than the leak current increases. It is demonstrated by the lock-in thermography that the mechanical damages at holes contribute to performance degradation.
• 家兎膝蓋腱の擬似生体環境下における損傷挙動のAE法による評価　　　　　　　　　　　　　　　
  鈴木仁己; 坂井建宣; 若山修一; 山本衛
  日本機械学会関東支部総会講演会講演論文集, 2013年03月
  2013年03月 - 2013年03月, 日本語
• フレキシブル太陽電池の外力による損傷のAE法およびロックインサーモグラフィを用いた評価　　　　　　　　　　　　　　　
  田澤博幸; 坂井建宣; 若山修一
  日本機械学会関東支部総会講演会講演論文集, 2013年03月
  2013年03月 - 2013年03月, 日本語
• 窒化ケイ素の熱衝撃破壊におけるき裂進展抵抗のAE法による評価　　　　　　　　　　　　　　　
  亀谷豪; 坂井建宣; 若山修一; 吉田克己
  日本機械学会関東支部総会講演会講演論文集, 2013年03月
  2013年03月 - 2013年03月, 日本語
• a‐Siフレキシブル太陽電池セルの単軸引張による損傷のAE法とロックインサーモグラフィを用いた評価　　　　　　　　　　　　　　　
  田澤博幸; 坂井建宣; 若山修一
  応用物理学会春季学術講演会講演予稿集(CD-ROM), 2013年03月
  2013年03月 - 2013年03月, 日本語
• 使用済タイヤ‐PLA複合材料のタイヤ粉砕方法が機械的挙動に及ぼす影響　　　　　　　　　　　　　　　
  坂井建宣; 森清卓也; SOBERANIS C‐R Rdando; 若山修一; 米山聡
  応力・ひずみ測定と強度評価シンポジウム講演論文集, 2013年01月
  2013年01月 - 2013年01月, 日本語
• 微視損傷蓄積挙動および粘弾性挙動を考慮したウシ皮質骨の圧縮変形評価　　　　　　　　　　　　　　　
  坂井建宣; 吉屋英理; 安井慶太; 若山修一
  アコースティック・エミッション総合コンファレンス論文集, 2013年
  2013年 - 2013年, 日本語
• Effect of crushing method of wasted tire on mechanical behavior on PLA composites　　　　　　　　　　　　　　　
  Takenobu Sakai; Takuya Morikiyo; C. R. Rios-Soberanis; Satoru Yoneyama; Shuichi Wakayama
  Conference Proceedings of the Society for Experimental Mechanics Series, 2013年
  2013年 - 2013年, 英語
  Poly Lactic Acid (PLA) is one of the Biodegradable Materials which has excellent mechanical properties. However, PLA is not wasted for the structural materials because of its brittleness. For improvement in the brittleness, the wasted tire was chosen as the reinforcement. On the other hand, wasted tires are a huge problem in terms of health and contamination due to bad disposal. There are many mechanisms to deal with this problem but they still have inconveniences. In this study, we made the wasted tire powder reinforced PLA. The wasted tire powder was crushed by two ways. One is frost shattering method, and the other is thermal shock process. The composites based on PLA were made with these two powders. To investigate the effect of crush method of wasted tire, fracture mechanics were investigated. And the viscoelastic behavior was investigated with the Dynamic Mechanical Analysis. And for impact tests, Split Hopkinson Pressure Bar tests were carried out. As the results of static and impact test, thermal shocked powder composites have the good impact resistance. © The Society for Experimental Mechanics, Inc. 2013.
• Mechanical evaluation and damage sequence identification of multiaxial textile reinforced composites　　　　　　　　　　　　　　　
  C. R. Rios-Soberanis; S. Wakayama; T. Sakai; E. Perez-Pacheco; J. Rodriguez-Laviada
  Annual Technical Conference - ANTEC, Conference Proceedings, 2013年01月
  2013年01月 - 2013年01月
  Mechanical properties and damage pattern of a multiaxial textile reinforced epoxy composite was evaluated by tension and bending test. A non crimp fabric (NCF) of [0°,+45°, 90°, - 45°] stacking sequence was used as reinforcement. Through the identification of the initiation sites and the coalescence of cracks was possible to correlate the damage with the textile geometry and its effect on the mechanical properties. Fractography was used as a tool to identify governing mechanisms and link these to the material internal structure and the textile geometry. Acoustic emission technique was employed to identify the mechanisms of fracture by correlating the signals of mechanical waves produced my damage with fracture stages. Additionally the effect of textile architecture on the composite mechanical properties and damage pattern was correlated with its damage initiation and propagation. Through a combination of experimental work and theoretical studies the mechanisms controlling the mechanical behavior are explained.
• 粒径制御した窒化ケイ素のディスクオンロッド試験による熱衝撃破壊過程の評価　　　　　　　　　　　　　　　
  亀谷豪; 坂井建宣; 若山修一; 吉田克己
  日本セラミックス協会秋季シンポジウム講演予稿集(CD-ROM), 2012年09月
  2012年09月 - 2012年09月, 日本語
• J022024 種々のひずみ速度下における家兎膝蓋腱の損傷過程のAE法による評価　　　　　　　　　　　　　　　
  鈴木 仁己; 坂井 建宣; 若山 修一; 山本 衛
  年次大会 : Mechanical Engineering Congress, Japan, 2012年09月, 一般社団法人日本機械学会
  2012年09月 - 2012年09月, 日本語
  AE monitoring of damage process of rabbit patellar tendon under static tensile load was carried out. Considering strong viscoelasticity of tendon, load was applied at various loading rate (10, 1, 0.1 mm/min) until the complete rupture in physiological saline at 37℃. The displacement of the specimen was monitored by a digital video camera, and acquired images were used for determining the displacement distribution in tendon by the digital image correlation (DIC) technique. It was found that AE signals were detected before the maximum load and AE source locations corresponded to the locally elongated area, which indicates that fascicle failure takes place before the maximum load. The average failure stress increased as loading rate increased, and the differences in average failure stress were considered to be statistically significant. Consequently, the fundamental insights for the damage monitoring technique which are indispensable for the optimization of programs of sports training or rehabilitation are obtained.
• S042021 人工関節用ATZ複合セラミックスのAE法による微視損傷検出および長期信頼性評価　　　　　　　　　　　　　　　
  坂井 建宣; 風間 岳; 若山 修一; 池田 潤二; 宮路 史明
  年次大会 : Mechanical Engineering Congress, Japan, 2012年09月, 一般社団法人日本機械学会
  2012年09月 - 2012年09月, 日本語
  The microdamages in ATZ composite ceramics during 4-point bending test were monitored by acoustic emission (AE) technique, and the rapid increase in cumulative AE energy prior to the final fracture was observed, which could be related with the maincrack formation as the origin of final fracture. The critical stress for maincrack formation σ_c was determined as the stress at rapid increasing point of AE signals. The stress increased with decreasing in Alumina weight fraction without 0% By increasing in ZrO_2, the growth grain size of Al_2O_3 was restrained and the flaw size turned smaller, since σ_c depends on the dispersion in the size and the distribution of initial failure.
• 種々のひずみ速度下における家兎膝蓋腱の損傷過程のAE法による評価　　　　　　　　　　　　　　　
  鈴木仁己; 坂井建宣; 若山修一; 山本衛
  日本機械学会年次大会講演論文集(CD-ROM), 2012年09月
  2012年09月 - 2012年09月, 日本語
• 人工関節用ATZ複合セラミックスのAE法による微視損傷検出および長期信頼性評価　　　　　　　　　　　　　　　
  坂井建宣; 風間岳; 若山修一; 池田潤二; 宮路史明
  日本機械学会年次大会講演論文集(CD-ROM), 2012年09月
  2012年09月 - 2012年09月, 日本語
• 使用済活性炭複合材料の導電性と粘弾性特性の関係　　　　　　　　　　　　　　　
  坂井建宣; 具志堅智彦; 増子知樹; 松島聡; 小林諭史; 米山聡; 若山修一
  日本実験力学会講演論文集, 2012年07月
  2012年07月 - 2012年07月, 日本語
• 511 ポリ乳酸-PBATブレンド材における成形条件と圧縮特性(固体ポリマーの動的力学特性,衝撃負荷に対する材料・構造の応答,オーガナイスドセッション9)　　　　　　　　　　　　　　　
  具志堅 智彦; 大宮 正毅; 坂井 建宣
  学術講演会講演論文集, 2012年05月, 社団法人日本材料学会
  2012年05月 - 2012年05月, 日本語
• ポリ乳酸‐PBATブレンド材における成形条件と圧縮特性　　　　　　　　　　　　　　　
  具志堅智彦; 大宮正毅; 坂井建宣
  日本材料学会学術講演会講演論文集, 2012年05月
  2012年05月 - 2012年05月, 日本語
• 胸部表面の振動解析による心臓運動の可視化　　　　　　　　　　　　　　　
  坂井建宣; 林和輝; 横田康成; 若山修一; 野方文雄
  応力・ひずみ測定と強度評価シンポジウム講演論文集, 2012年01月
  2012年01月 - 2012年01月, 日本語
• 使用済活性炭複合材料の導電性と粘弾性特性の関係 (2012年度年次講演会)　　　　　　　　　　　　　　　
  坂井 建宣; 具志堅 智彦; 増子 知樹
  日本実験力学会講演論文集, 2012年, 日本実験力学会
  2012年 - 2012年, 日本語
• AE Evaluation of Thermal Shock Fracture Process in Silicon Nitride with Controlled Grain Size　　　　　　　　　　　　　　　
  KAMETANI Go; SAKAI Takenobu; WAKAYAMA Shuichi; YOSHIDA Katsumi
  Prog Acoust Emiss, 2012年
  2012年 - 2012年, 英語
• AE Studies on Effect of Viscoelasticity of Bovine Cortical Bone on Microdamage Accumulation Behavior　　　　　　　　　　　　　　　
  SAKAI Takenobu; MIYAGAWA Tomohiro; YOSHIYA Eri; YASUI Keita; WAKAYAMA Shuichi
  Prog Acoust Emiss, 2012年
  2012年 - 2012年, 英語
• AE Monitoring of Damage Process of Rabbit Patellar Tendon under Various Strain Rate　　　　　　　　　　　　　　　
  SUZUKI Satomi; SAKAI Takenobu; WAKAYAMA Shuichi; YAMAMOTO Ei
  Prog Acoust Emiss, 2012年
  2012年 - 2012年, 英語
• Visualization of Heart Motion Based on Micro-vibration of the Chest Surface　　　　　　　　　　　　　　　
  F. Nogata; Y. Yokota; Y. Kawamura; H. Morita; Y. Uno; W. R. Walsh; T. Sakai
  5TH EUROPEAN CONFERENCE OF THE INTERNATIONAL FEDERATION FOR MEDICAL AND BIOLOGICAL ENGINEERING, PTS 1 AND 2, 2012年, SPRINGER
  2012年 - 2012年, 英語
  A new technique for imaging heart motion to assist in the understanding of heart diseases for both clinical doctors and patients has been developed. The technique is based on the measurement of micro-vibration of the chest surface using 64 sensors (63- acceleration sensor and one ECG) as a multiple-auscultator to show global and simultaneous heart motion. The results showed clear and simultaneous image of heart motion; contraction/expansion of atrioventricular and ventricle, location of four valves. The measurement time was five minutes approximately using a new mount plate with 64-sensor to fix skin of the chest quickly, which allows to clinical use easily. It was also found that heart vibration has four-frequency bands including one band that is inaudible sound using auscultation. It is concluded that the technique could be applied to inspect heart disease in visual and the digital database management of the auscultation examination. We think that it is needed to introduce new digital management for examining and diagnosing heart disease in a traditional auscultation technique.
• Effect of fabric architecture (NCF) on bending and creep test of textile composites　　　　　　　　　　　　　　　
  T. Sakai; S. Wakayama; C. R. Rios-Soberanis; J. Rodriguez-Laviada; E. Pérez-Pacheco
  ICCM International Conferences on Composite Materials, 2011年12月
  2011年12月 - 2011年12月
• Study on crystallinity dependency of creep deformation on GFRTP of polyoxythlene (POM)　　　　　　　　　　　　　　　
  S. Somiya; K. Yamada; T. Sakai
  Conference Proceedings of the Society for Experimental Mechanics Series, 2011年12月
  2011年12月 - 2011年12月
  It has clarified that the viscoelastic property of some kind of thermoplastic resin is dependent on crystallinity in until now. Concretely, it was confirmed that "Time-temperature superposition principle" was established on the creep deformation in them. And also, in various FRTP, in making fiber volume fraction to be a factor for creep deformation, it was clarified that "Time-temperature-fiber volume fraction superposition principle" was established. In this paper on the effect of crystal on creep deformation, the crystallinity was made to be a factor, and it clarified that "Time - temperature -crystallinity superposition principle" was established in POM resin and GFRPOM.
• Estimation of fatigue life of cortical bone considering viscoelastic properties and damage mechanics　　　　　　　　　　　　　　　
  Takenobu Sakai; Keita Yasui; Shuichi Wakayama
  Conference Proceedings of the Society for Experimental Mechanics Series, 2011年12月
  2011年12月 - 2011年12月
  Recently, the Osteoporosis victims increase in the senior citizen. Therefore, the danger of the stress fracture due to the decrease in bone strength is pointed out. Especially, the damage accumulation behavior of the bone in the cyclic load becomes a problem for the fatigue of the bone. Moreover, it is necessary to consider the viscoelastic property for the prediction of the fatigue behavior, because the bone is a viscoelastic material. In this study, our objective is to estimate the fatigue behavior that considers the viscoelasticity behavior and the damage accumulation behavior as damage mechanics. The viscoelastic properties were revealed with the strain rate tests, and we calculated the 3-mode Maxwell parameters with these results. The damage accumulation behaviors were measured with the Acoustic Emission method. Using these results, we could estimate the fatigue behavior of cortical bone with the viscoelastic parameter and cumulative AE energy.
• 窒化ケイ素セラミックスにおける熱衝撃破壊過程のAE法による評価　　　　　　　　　　　　　　　
  亀谷豪; 坂井建宣; 若山修一; 吉田克己
  日本非破壊検査協会講演大会講演概要集, 2011年10月
  2011年10月 - 2011年10月, 日本語
• A110 皮質骨における疲労損傷のAE法による評価(A1-2 硬組織のバイオメカニクス)　　　　　　　　　　　　　　　
  安井 慶太; 坂井 建宣; 若山 修一
  バイオフロンティア講演会講演論文集, 2011年10月, 一般社団法人日本機械学会
  2011年10月 - 2011年10月, 日本語
• A114 腱組織の損傷過程のAE法による評価(A1-3 軟組織のバイオメカニクス1)　　　　　　　　　　　　　　　
  鈴木 仁己; 坂井 建宣; 若山 修一; 山本 衛
  バイオフロンティア講演会講演論文集, 2011年10月, 一般社団法人日本機械学会
  2011年10月 - 2011年10月, 日本語
• 皮質骨における疲労損傷のAE法による評価　　　　　　　　　　　　　　　
  安井慶太; 坂井建宣; 若山修一
  日本機械学会バイオフロンティア講演会講演論文集, 2011年10月
  2011年10月 - 2011年10月, 日本語
• 腱組織の損傷過程のAE法による評価　　　　　　　　　　　　　　　
  鈴木仁己; 坂井建宣; 若山修一; 山本衛
  日本機械学会バイオフロンティア講演会講演論文集, 2011年10月
  2011年10月 - 2011年10月, 日本語
• S042024 透明導電酸化膜の引張試験における損傷蓄積過程のAEモニタリング([S04202]セラミックスおよびセラミックス系複合材料(2))　　　　　　　　　　　　　　　
  高木 信幸; 若山 修一; 坂井 建宣; 池上 和志; 宮坂 力
  年次大会 : Mechanical Engineering Congress, Japan, 2011年09月, 一般社団法人日本機械学会
  2011年09月 - 2011年09月, 日本語
  In this study, tensile tests of indium tin oxide (ITO) deposited on polyethylene naphthalate (PEN) films (ITO + PEN films) used in dye-sensitized solar cells (DSCs) were carried out. ITO + PEN films are fabricated at 150℃. Therefore, to clarify the influence of heat treatment on mechanical properties of ITO + PEN, the specimens with heat treatment were prepared. In order to discriminate AE signals in ITO from PEN films, PEN film specimens (ITO was removed by 17.5% hydrochloric acid) were also prepared. It was found from tensile tests that many AE signals were detected in ITO + PEN films, while few AE signals were detected in PEN films. On the other hand, the electric resistance of ITO was also measured during tensile tests. These results suggested that the critical damage in ITO was detected by the AE measurement more sensitively than the electric resistance. To identify AE sources, in-situ observation of specimen during tensile test with AE measurement was carried out. It was emphasized that AE behavior shows good agreement with the cracking behavior in ITO. Damages in ITO under mechanical strain were successfully monitored by AE technique in the present study. Consequently, it was suggested that AE technique could be a powerful technique for evaluating the damage accumulation process in DSCs.
• S042034 不連続繊維強化セラミック複合材料の作製および機械的特性の評価([S04203]セラミックスおよびセラミックス系複合材料(3))　　　　　　　　　　　　　　　
  海野 孝祐; 秋山 裕介; 若山 修一; 坂井 建宣; 梅原 由佳; 赤津 隆
  年次大会 : Mechanical Engineering Congress, Japan, 2011年09月, 一般社団法人日本機械学会
  2011年09月 - 2011年09月, 日本語
  40 vol% SiC whisker reinforced alumina matrix composites (SiCw/Al_2O_3) were fabricated using a spark plasma sintering (SPS) technique. In this study, to decrease the thermal mismatch between SiCw and Al_2O_3, SiC particle (SiCp) was added into Al203 matrix (SiCw/SiCp/Al_2O_3). The relative density of the fabricated specimens was more than 99%, so that the sufficient densification was accomplished. Then, the mechanical properties and fracture morphology were examined. It was found that the mechanical properties of composites were increased from the monolithic Al203 and SiCw/Al_2O_3 composites. SEM observation of fracture surface after bending test showed that the amount of pull-out SiCw and the pull-out length in SiCw/SiCp/Al_2O_3 composites was larger than SiCw/Al_2O_3 composites. Therefore, the interfacial shear strength was successfully reduced due to SiCp addition. Consequently, it was suggested that the improvement of mechanical properties of SiCw/SiCp/Al_2O_3 composites may be accomplished by optimizing the interfacial shear strength due to SiCp addition.
• 透明導電酸化膜の引張試験における損傷蓄積過程のAEモニタリング　　　　　　　　　　　　　　　
  高木信幸; 若山修一; 坂井建宣; 池上和志; 宮坂力
  日本機械学会年次大会講演論文集(CD-ROM), 2011年09月
  2011年09月 - 2011年09月, 日本語
• 不連続繊維強化セラミック複合材料の作製および機械的特性の評価　　　　　　　　　　　　　　　
  海野孝祐; 秋山裕介; 若山修一; 坂井建宣; 梅原由佳; 赤津隆
  日本機械学会年次大会講演論文集(CD-ROM), 2011年09月
  2011年09月 - 2011年09月, 日本語
• NCFの積層構成とクリープ挙動の関係　　　　　　　　　　　　　　　
  坂井建宣; RIOS‐SOBERANIS C. R; 若山修一
  日本実験力学会講演論文集, 2011年08月
  2011年08月 - 2011年08月, 日本語
• Analysis of damage progression in textile reinforced composite in tension (static and cyclic) mode using acoustic emission　　　　　　　　　　　　　　　
  T. Sakai; S. Wakayama; C. R. Rios-Soberanis; J. Rodriguez-Laviada; E. Pérez-Pacheco
  Annual Technical Conference - ANTEC, Conference Proceedings, 2011年08月
  2011年08月 - 2011年08月
  A non crimp fabric (NCF) with a stacking sequence of [0°,+45°, 90°,-45°] embedded in epoxy resin matrix was analyzed. Samples for mechanical test were obtained from laminates at different orientations depending on the textile direction at 0°, 45° and 90° in order to identify the failure mechanisms. Tension mode tests (static and cyclic) were carried out to evaluate the evolution of damage using as a main tool the acoustic emission technique that allows monitoring the mechanical behavior of the materials during the test in "real time".
• Effect of crystallinity and fiber volume fraction on creep behavior of glass fiber reinforced polyamide　　　　　　　　　　　　　　　
  Takenobu Sakai; Yuto Hirai; Satoshi Somiya
  Conference Proceedings of the Society for Experimental Mechanics Series, 2011年07月
  2011年07月 - 2011年07月
  Thermoplastic Polyamide (PA) is known as Nylon®, and its FRP are one of the engineering plastics. It is very important for them to reveal accurately the visco-elastic behavior. Furthermore, PA is a crystalline polymer, and it is necessary to consider the effect of crystallization on mechanical properties. The purpose of this study was to make clear the effect of crystallization and fiber volume fraction on creep behavior of PA and its composites. The creep test was performed using the materials which adjusted crystallinity on each fiber volume fraction. As a result, these materials conformed to Arrhenius type of time-temperature superposition principle, and these effects on creep behavior had the time retardation effect. To compare the creep behavior on these effects, we made the grand master curves for crystallinity and fiber volume fraction. Obtained two grand master curves were compared each other, the shapes of these curves are similarly, and we can superposed them. It is therefore, the creep behavior including each conditions have the same behavior. Using these curves and shift factors, we can calculate the creep behavior, and be able to estimate the creep behavior with the effect of arbitrary time, temperature, crystallinity and fiber contents. ©2010 Society for Experimental Mechanics Inc.
• 胸部振動計測による心臓内部血流の可視化　　　　　　　　　　　　　　　
  坂井建宣; 野方文雄; 横田康成; 若山修一
  日本非破壊検査協会講演大会講演概要集, 2011年05月
  2011年05月 - 2011年05月, 日本語
• 119206 使用済活性炭強化ポリプロピレン複合材料の変形特性と導電性に関する研究(OS06 高分子材料および高分子系複合材料,オーガナイズド・セッション)　　　　　　　　　　　　　　　
  坂井 建宣; 具志堅 智彦; 増子 知樹; 松島 聡; 小林 諭史; 米山 聡
  日本機械学会関東支部総会講演会講演論文集, 2011年03月, 一般社団法人日本機械学会
  2011年03月 - 2011年03月, 日本語
  In the Waterworks Bureau, the activated carbon was used for filtering the water. After use the activated carbon, they were disposed. In this work, we tried to make that composite to recycle these carbons. These wasted activated carbons were used for the filler of composite materials, and we got the composite with the carbon contents of 10%〜60%. To evaluate of mechanical behavior of these composites, tensile test and stress relaxation test were carried out. The results show the powder contents dependency on tensile strength and Young's modulus. As seen in the results of stress relaxation test, the effect of powder contents on stress relaxation was revealed. To evaluate the electric property, the electric resistance was measured by 4-terminal method during tensile test and stress relaxation test. By the measurement of electric resistance, these composites can be used as smart materials.
• 220304 透明導電酸化膜における機械的損傷蓄積のAE法を用いた評価(OS16 東京ブロック・山梨ブロック共同企画 機械工学が支援する微細加工技術(半導体・MEMS・NEMS)1(半導体・MEMS・NEMS),オーガナイズド・セッション)　　　　　　　　　　　　　　　
  高木 信幸; 若山 修一; 水谷 彰宏; 坂井 建宣; 宮坂 力; 池上 和志
  日本機械学会関東支部総会講演会講演論文集, 2011年03月, 一般社団法人日本機械学会
  2011年03月 - 2011年03月, 日本語
  In this study, tensile tests of transparent conductive oxide (TCO) deposited on polyerhylene naphthalate (PEN) films (TCO + PEN films) used in dye-sensitized solar cells (DSCs) were carried out. In order to discriminate AE signals in TCO from PEN films, PEN film specimens (TCO was removed by 17.5% acidum hydrechloricum) were also prepared. It was found from tensile tests that many AE signals were detected in TCO + PEN films, while few AE signals were detected in PEN films. On the other hand, the electric resistance of TCO was also measured during tensile tests. These results suggested that the critical damage in TCO was detected by the measurement of AE signals more sensitively than the electric resistance measurement. To identify AE sources, in-situ observation of specimen during tensile test with AE measurement was carried out. It was emphasized that AE behavior shows good agreement with the cracking behavior in TCO. Damages in TCO under mechanical strain were successfully monitored by AE technique in the present study. Consequently, it was suggested that AE technique could be a powerful technique for evaluating the damage accumulation process in DSCs.
• 透明導電酸化膜における機械的損傷蓄積のAE法を用いた評価　　　　　　　　　　　　　　　
  高木信幸; 若山修一; 水谷彰宏; 坂井建宣; 宮坂力; 池上和志
  日本機械学会関東支部総会講演会講演論文集, 2011年03月
  2011年03月 - 2011年03月, 日本語
• 使用済活性炭強化ポリプロピレン複合材料の変形特性と導電性に関する研究　　　　　　　　　　　　　　　
  坂井建宣; 具志堅智彦; 増子知樹; 松島聡; 小林諭史; 米山聡
  日本機械学会関東支部総会講演会講演論文集, 2011年03月
  2011年03月 - 2011年03月, 日本語
• 使用済活性炭強化ポリプロピレン複合材料の変形特性と導電性の関係　　　　　　　　　　　　　　　
  具志堅智彦; 米山聡; 坂井建宣; 小林訓史; SOBERANIS Rolando Rios; 増子知樹; 松島聡
  応力・ひずみ測定と強度評価シンポジウム講演論文集, 2011年01月
  2011年01月 - 2011年01月, 日本語
• 8E-01 擬似生体環境下の異なる周波数における皮質骨の疲労損傷のAE法による評価(OS-4 硬組織のバイオメカニクス(1))　　　　　　　　　　　　　　　
  安井 慶太; 若山 修一; 坂井 建宣
  バイオエンジニアリング講演会講演論文集, 2011年01月, 一般社団法人日本機械学会
  2011年01月 - 2011年01月, 日本語
• 擬似生体環境下の異なる周波数における皮質骨の疲労損傷のAE法による評価　　　　　　　　　　　　　　　
  安井慶太; 若山修一; 坂井建宣
  バイオエンジニアリング講演会講演論文集, 2011年01月
  2011年01月 - 2011年01月, 日本語
• NCFの積層構成とクリープ挙動の関係 ([日本実験力学会]2011年度年次講演会)　　　　　　　　　　　　　　　
  坂井 建宣; Soberanis C. R. Rios; 若山 修一
  日本実験力学会講演論文集, 2011年, 日本実験力学会
  2011年 - 2011年, 日本語
• 使用済タイヤ粉含有率がポリ乳酸複合材料の損傷に及ぼす影響　　　　　　　　　　　　　　　
  坂井建宣; RIOS‐SOBERANIS C. R; 若山修一
  アコースティック・エミッション総合コンファレンス論文集, 2011年
  2011年 - 2011年, 日本語
• 111 静電交互吸着法を利用した高含有率カーボンナノファイバー強化アルミナ複合材料の破壊挙動(セラミックス/セラミックス基複合材料(2),ものづくりにおける基礎研究と先端技術の融合)　　　　　　　　　　　　　　　
  海野 孝祐; 若山 修一; 赤津 隆; 坂井 建宣; 梅原 由佳
  機械材料・材料加工技術講演会講演論文集, 2010年11月, 一般社団法人日本機械学会
  2010年11月 - 2010年11月, 日本語
  In this study, carbon nanofiber (CNF) reinforced Al_2O_3 composites were fabricated. To fabricate uniformly-dispersed CNF/Al_2O_3 powder, electrostatic adsorption, which could increase the surface potential of CNFs, was applied. Al203 sol was then adsorbed onto the surface of CNFs uniformly. The mixed powder was sintered by spark plasma sintering under the pressure of 50 MPa at 1600℃ in Ar atmosphere. Fracture behavior of the specimen was evaluated by bending test, indentation test and fracture-surface observation. The results showed that the bending strength of specimen was lower than monolithic Al_2O_3. It might be because there were many pores and the interface between CNF and Al_2O_3 were relatively weak. However, a large number of pull-out and bridging of CNFs were observed by the fracture surface observation with a scanning electron microscope. This suggests that CNFs could improve the fracture toughness of the CNF reinforced Al_2O_3 composites.
• 静電交互吸着法を利用した高含有率カーボンナノファイバー強化アルミナ複合材料の破壊挙動　　　　　　　　　　　　　　　
  海野孝祐; 若山修一; 赤津隆; 坂井建宣; 梅原由佳
  日本機械学会機械材料・材料加工技術講演会論文集(CD-ROM), 2010年11月
  2010年11月 - 2010年11月, 日本語
• Effect of crystallinity and fiber volume fraction on creep behavior of glass fiber reinforced polyamide　　　　　　　　　　　　　　　
  Takenobu Sakai; Yuto Hirai; Satoshi Somiya
  Society for Experimental Mechanics - SEM Annual Conference and Exposition on Experimental and Applied Mechanics 2010, 2010年11月
  2010年11月 - 2010年11月
  Thermoplastic Polyamide (PA) is known as Nylon®, and its FRP are one of the engineering plastics. It is very important for them to reveal accurately the visco-elastic behavior. Furthermore, PA is a crystalline polymer, and it is necessary to consider the effect of crystallization on mechanical properties. The purpose of this study was to make clear the effect of crystallization and fiber volume fraction on creep behavior of PA and its composites. The creep test was performed using the materials which adjusted crystallinity on each fiber volume fraction. As a result, these materials conformed to Arrhenius type of time-temperature superposition principle, and these effects on creep behavior had the time retardation effect. To compare the creep behavior on these effects, we made the grand master curves for crystallinity and fiber volume fraction. Obtained two grand master curves were compared each other, the shapes of these curves are similarly, and we can superposed them. It is therefore, the creep behavior including each conditions have the same behavior. Using these curves and shift factors, we can calculate the creep behavior, and be able to estimate the creep behavior with the effect of arbitrary time, temperature, crystallinity and fiber contents. © 2010 Society for Experimental Mechanics Inc.
• 種々のひずみ速度下における生体骨の疲労損傷のAE法による評価　　　　　　　　　　　　　　　
  安井慶太; 若山修一; 坂井建宣
  日本非破壊検査協会講演大会講演概要集, 2010年10月
  2010年10月 - 2010年10月, 日本語
• 生体適合性を有するモノマーを添加した骨セメントの粘弾性評価　　　　　　　　　　　　　　　
  坂井建宣; 若山修一; RIOS‐SOBERANIS C. R; CERVANTES‐UC J. M; MAY‐PAT A; FLORES‐GALLARDO S
  日本実験力学会講演論文集, 2010年08月
  2010年08月 - 2010年08月, 日本語
• 生体適合性を有するモノマーを添加した骨セメントの粘弾性評価 ([日本実験力学会]2010年度年次講演会)　　　　　　　　　　　　　　　
  坂井 建宣; 若山 修一; Rios-Soberanis C. R
  日本実験力学会講演論文集, 2010年, 日本実験力学会
  2010年 - 2010年, 日本語
• EVALUATION OF MECHANICAL BEHAVIOR OF ACTIVATED CARBON COMPOSITES BY 4-POINT FLEXURAL TEST USING ACOUSTIC EMISSION TECHNIQUE　　　　　　　　　　　　　　　
  SAKAI Takenobu; SOBERANIS C‐R Rios; MASUKO Tomoki; MATSUSHIMA Satoshi; KOBAYASHI Satoshi; WAKAYAMA Shuichi
  Prog Acoust Emiss, 2010年
  2010年 - 2010年, 英語
• Effect of Powder Contents on Stress Relaxation of Glass Powder Reinforced Epoxy　　　　　　　　　　　　　　　
  T. Sakai; K. Okabe; S. Yoneyama
  FOURTH INTERNATIONAL CONFERENCE ON EXPERIMENTAL MECHANICS, 2010年, SPIE-INT SOC OPTICAL ENGINEERING
  2010年 - 2010年, 英語
  Glass powder reinforced epoxy was used in the fields of plastic sealing of semiconductor devices. In such environment, the materials were exposed in the high temperature, and the stress relaxation behavior must occur in the materials. Therefore, the analysis of stress relaxation behavior was needed. The stress relaxation behaviors of epoxy composites filled with different amounts of glass powder were investigated. Master curves of stress relaxation were obtained, and time-temperature superposition principle was observed on perpetrated epoxy composites. The slopes of time-temperature shift factors were changed depended on the amount of glass powder. It is therefore, we can calculate the time-temperature shift factors by using this relationship. The effect of amounts of glass powder on stress relaxation was investigated, too. Comparing the master curves of stress relaxation with the different amount of glass powder, it is understood that the stress relaxation behaviors of both materials are the same. And it is explained that the effect of glass powder contents on stress relaxation behavior is the effect of reinforcement and heat resistance.
• Analysis of creep behavior in thermoplastic based on visco-elastic theory　　　　　　　　　　　　　　　
  Takenobu Sakai; Satoshi Somiya
  Society for Experimental Mechanics - SEM Annual Conference and Exposition on Experimental and Applied Mechanics 2009, 2009年12月
  2009年12月 - 2009年12月
  Although plastics with high mechanical properties are widely used in the fields including the aircraft and space industries, various types of FRP have been developed to improve the mechanical properties. Even though those plastics and FRPs are superior in the high-temperature mechanical properties, they are visco-elastically deformed by using at high temperature for a long time. It is, therefore, expected to elucidate the characteristics of visco-elastic phenomena of those materials in detail and improve the estimation technique of long-term life based on this elucidation result for enhancing the reliability of the materials and aiming at the high degree of utilization. Although many researches concerning the creep behavior of FRPs have been made, few researches have been made so far for investigating the linear visco-elastic behavior. And it is known that not only the linear visco-elastic behavior is occurred on the plastics, but also non-linear visco-elastic behavior. In this study, the non-linear visco-elastic behavior of plastics and the FRPs was investigated by making an experiment of the bending creep deformation of Polycarbonate (PC) and Polyacetal (Polyoxymethylene, POM). Moreover, the effects of the fiber volume fraction on the creep characteristics were investigated with glass fiber reinforced polycarbonate (GFRPC). After that, the creep analysis was made with containing these effects on the equation of linear visco-elastic theory. ©2009 Society for Experimental Mechanics Inc.
• ポリ乳酸ブレンド材の圧縮特性評価　　　　　　　　　　　　　　　
  山村俊貴; 大宮正毅; 坂井建宣; VIOT Philippe
  日本実験力学会講演論文集, 2009年08月
  2009年08月 - 2009年08月, 日本語
• 熱可塑性樹脂およびその複合材料の線形粘弾性理論に基づくクリープ解析　　　　　　　　　　　　　　　
  坂井建宣; 宗宮詮
  日本実験力学会講演論文集, 2009年08月
  2009年08月 - 2009年08月, 日本語
• PS25 ポリ乳酸ブレンド材の圧縮特性評価(ポスターセッション)　　　　　　　　　　　　　　　
  山村 俊貴; 大宮 正毅; 坂井 建宣; VIOT Philippe
  M&M材料力学カンファレンス, 2009年07月, 一般社団法人日本機械学会
  2009年07月 - 2009年07月, 日本語
  Biodegradable polymers, Polylactide(PLA) have a potential to be engineering plastics because of energy and environmental reasons. Conventional polymers are made from the petroleum, but PLA is made from the starch whose source is plants. Thus, PLA is carbon-neutral because the carbon of the starch is from carbon dioxide in the air. PLA is brittle. So, it limits the use of PLA. To improve this brittleness, PLA have been blended with other flexible polymers. In this study, we use Poly butylene adipate-co-terephthalate(PBAT) as the blending polymer. PBAT is fully biodegradable and flexible, though its Young's modulus and tensile strength are inferior to PLA, breaking strain is much higher than PLA PBAT distributes evenly in the PLA matrix. By now, PLA and blended PLA were conducted static tensile tests, but not done compressive tests. So, we evaluated properties in the static and dynamic compressive tests. In result, addition 40 wt % PBAT to PLA, Young's modulus and yielding stress decrease, but maximum strain and the strain energy at crack initiation get larger. In addition, Young's modulus and yielding stress of neat PLA and blended PLA increase with the strain rate rising.
• OS0516 生分解性プラスチックの引張変形が結晶化度に及ぼす影響(微視構造を有する材料の変形と破壊,オーガナイズドセッション)　　　　　　　　　　　　　　　
  坂井 建宣; 中曽根 祐司
  M&M材料力学カンファレンス, 2009年07月, 一般社団法人日本機械学会
  2009年07月 - 2009年07月, 日本語
  The crystal condition of the poly lactic acid that was a crystalline polymer was changed (degree of crystallization etc.), and the tensile test was done. Then the influence of crystal condition on the mechanical attribute was examined. Therefore, heat-treatment was first given to the material based on the melting point and the crystallization temperature of the material requested from differential scanning calorimetry (DSC), and the material that changed the degree of crystallization was made. Next, when the change in the degree of crystallization in the extensional deformation was confirmed because the crystallinity dependence was seen in the extensional deformation as a result of doing the tensile test and having examined it, it was understood that the degree of crystallization had changed by the extensional deformation.
• ポリ乳酸ブレンド材の圧縮特性評価 ([日本実験力学会]2009年度年次講演会)　　　　　　　　　　　　　　　
  山村 俊貴; 大宮 正毅; 坂井 建宣
  日本実験力学会講演論文集, 2009年07月, 日本実験力学会
  2009年07月 - 2009年07月, 日本語
• 生分解性プラスチックの引張変形が結晶化度に及ぼす影響　　　　　　　　　　　　　　　
  坂井建宣; 中曽根祐司
  日本機械学会M&M材料力学カンファレンス(CD-ROM), 2009年07月
  2009年07月 - 2009年07月, 日本語
• 熱可塑性樹脂およびその複合材料の線形粘弾性理論に基づくクリープ解析 ([日本実験力学会]2009年度年次講演会)　　　　　　　　　　　　　　　
  坂井 建宣; 宗宮 詮
  日本実験力学会講演論文集, 2009年, 日本実験力学会
  2009年 - 2009年, 日本語
• ポリカーボネートのクリープ挙動に及ぼす熱履歴の影響とその測定　　　　　　　　　　　　　　　
  坂井建宣; 宗宮詮
  応力・ひずみ測定と強度評価シンポジウム講演論文集, 2009年
  2009年 - 2009年, 日本語
• Time-temperature and humidity superposition principle on creep of PBS　　　　　　　　　　　　　　　
  Satoshi Somiya; Yujin Lee; Takenobu Sakai
  Society for Experimental Mechanics - 11th International Congress and Exhibition on Experimental and Applied Mechanics 2008, 2008年12月
  2008年12月 - 2008年12月
  For dissolve the environmental problem, the application of bio-degradable polymer to the engineering field, might be able to dissolve. Polybutylene Succinate (PBS) is a typical engineering plastics and it is well known that this polymer has good mechanical properties as well as a popular engineering such as polycarbonate. But, because the glassy temperature of PBS resin is lower than normal engineering polymers and shows high water absorption, this resin has problem for the practical using as an engineering polymer. In previous report, water absorption phenomenon of PBS at 50°C was measured and the effect of humidity on mechanical properties and creep compliance deformation were researched. For creep behavior, it was confirmed the amount of absorbed water affected creep deformation as same as the change of temperature. The purpose of this research is to make clear the application of "Time-temperature- humidity superposition principle" on PBS resin under some temperature condition from 30°C to 60°C. © 2008 Society for Experimental Mechanics Inc.
• Effect of crystallization on creep behavior of glass fiber reinforced polyacetal　　　　　　　　　　　　　　　
  Takenobu Sakai; Koichi Yamada; Satoshi Somiya
  Society for Experimental Mechanics - 11th International Congress and Exhibition on Experimental and Applied Mechanics 2008, 2008年12月
  2008年12月 - 2008年12月
  Thermoplastic Polyoxymethylene (Polyacetal / POM) is one of the engineering plastics. It is very important for POM and its FRP to grasp accurately the viscoelastic behavior. Furthermore, POM is a crystalline polymer with very high crystallinity. Therefore, it is necessary to consider the effect of crystallization. The purpose of this study was to make clear the effect of crystallization on bending creep behavior of POM and glass fiber reinforced POM (GFRPOM). It is considered that there are two factors for polymer crystallization. One is crystallinity which is calculated by ratio of crystal and amorphous part, the other is crystal grain size which represents interior morphology. The creep test was performed using the materials which adjusted crystal grain size and crystallinity. As a result, these materials conformed to Arrhenius type of time-temperature superposition principle, and the effect of crystallinity on creep behavior had the time retardation effect. The effect of crystal grain size made the shape of master curves different every crystal grain size. Therefore, the different crystal grain size makes the different creep behavior. Only considering the effect of same crystal grain size, it was able to estimate the long term creep behavior on materials of arbitrary time, temperature and crystallinity. © 2008 Society for Experimental Mechanics Inc.
• OS0618 結晶性高分子材料の力学的特性に及ぼす結晶状態の影響(OS06-04 力学特性の発現機構,OS06 微視構造を有する材料の変形と破壊(2))　　　　　　　　　　　　　　　
  坂井 建宣; 中曽根 祐司
  M&M材料力学カンファレンス, 2008年09月, 一般社団法人日本機械学会
  2008年09月 - 2008年09月, 日本語
  結晶性高分子であるポリアセタールの結晶状態(結晶化度など)を変化させて、引張試験および硬さ試験等を行い、力学的特性に及ぼす結晶状態の影響を調べた。そのため、まず、示差走査熱量測定(DSC)から求めた供試材の融点および結晶化温度に基づいて、供試材に熱処理を施し、結晶化度を変化させた供試材を作製した。次に、引張試験を行い、結晶化処理を施した材料と受入材の引張挙動の相違を調べた。また、予ひずみを与えた材料について硬さ試験を行い、硬さに及ぼす予ひずみの影響を調べ、結晶化度の変化が結晶性高分子材料の引張強度特性に及ぼす影響を明らかにした。
• 結晶性高分子材料の力学的特性に及ぼす結晶状態の影響　　　　　　　　　　　　　　　
  坂井建宣; 中曽根祐司
  日本機械学会M&M材料力学カンファレンス(CD-ROM), 2008年09月
  2008年09月 - 2008年09月, 日本語
• ポリアセタールのクリープ挙動に及ぼす結晶状態の影響　　　　　　　　　　　　　　　
  坂井建宣; 上野宗一郎; 山田幸市; 宗宮詮
  日本実験力学会講演論文集, 2008年06月
  2008年06月 - 2008年06月, 日本語
• ポリアセタールのクリープ挙動に及ぼす結晶状態の影響 ([日本実験力学会]2008年度年次講演会)　　　　　　　　　　　　　　　
  坂井 建宣; 上野 宗一郎; 山田 幸市
  日本実験力学会講演論文集, 2008年, 日本実験力学会
  2008年 - 2008年, 日本語
• Time-temperature dependence behavior of physical aging on creep behavior of PC　　　　　　　　　　　　　　　
  Takenobu Sakai; Satoshi Somiya
  Proceedings of the SEM Annual Conference and Exposition on Experimental and Applied Mechanics 2007, 2007年11月
  2007年11月 - 2007年11月
  Thermoplastic resin and its FRTP were practically used without post cure treatment and aging treatment which is called "molded material". For such materials, it is known that creep behavior and physical aging occur simultaneously. And the effect of physical aging has the time and temperature dependency. The effect was occurred on the materials after molded, and the effect saved on the materials as the thermal history. This history has big influence on mechanical properties especially creep properties. Therefore, it is necessary to stay in control of the progress of the physical aging. In this report, the creep deformation of Polycarbonate (PC) was researched to grasp the effect of physical aging on creep behavior. It was clearly that the effect had the time and temperature dependency by two shift factors, and it had the same tendency as density. Using these relationships between the shift factors and density, it must be able to calculate the effect of thermal history as physical aging since the materials were molded by density.
• 2539 ポリウレタン系形状記憶ポリマー(DiARY)の曲げクリープ挙動の研究(J10-9 高分子・薄膜,J10 知的材料・構造システム)　　　　　　　　　　　　　　　
  田尾 隆幸; 坂井 建宣; 宗宮 詮
  年次大会講演論文集 : JSME annual meeting, 2007年09月, 一般社団法人日本機械学会
  2007年09月 - 2007年09月, 日本語
  Shape Memory polymer (SMP) is known to have visco-elastic behavior. Shape recovery is considered to occur due to this visco-elastic behavior. On the other hand, creep and creep recovery may also occur that is known as one of visco-elastic behavior. It is important to understand creep and creep recovery behavior, because it effects on material's shape memory and shape recovery characteristics. This research examined the creep and creep recovery behavior by three point bending creep test. As a result, time and temperature dependence was confirmed, and also master curve can be drawn by superposing the creep compliance curves. Moreover, estimation of creep and creep recovery can be possible by master curve, shift factor and Boltzmann's superposition principle.
• ポリウレタン系形状記憶ポリマー(DiARY)の曲げクリープ挙動の研究　　　　　　　　　　　　　　　
  田尾隆幸; 坂井建宣; 宗宮詮
  日本機械学会年次大会講演論文集, 2007年09月
  2007年09月 - 2007年09月, 日本語
• Estimation of creep deformation applying phased stress on GFRPC　　　　　　　　　　　　　　　
  Takenobu Sakai; Satoshi Somiya
  Proceedings of the 2006 SEM Annual Conference and Exposition on Experimental and Applied Mechanics 2006, 2006年10月
  2006年10月 - 2006年10月
  Thermoplastic resin and its FRTP were practically used without post cure treatment and aging treatment which is called "molded material". For such materials, it is known that creep behavior and physical aging occur simultaneously. On the other hand, the creep test is usually carried out under a constant stress. Furthermore, it is known that nonlinear behavior appears under the phased stresses on creep behavior. In previous reports, the creep deformation of Polycarbonate (PC) and Glass fiber reinforced polycarbonate (GFRPC) was researched to estimate the creep deformation on the molded materials under the phased stresses. Using these results, the creep deformation under phased stresses was estimated with time-temperature superposition principle and the principle of superposition on each creep behavior. Using this estimation method, it was able to estimate the creep deformation of molded materials in arbitrary condition, time, temperature, fiber contents, and stress. Therefore, the results of estimation of creep deformation were very fit to the experimental creep deformation. Furthermore, this estimation method of creep behavior made it possible to estimate the creep behavior on pragmatic conditions.
• 2707 ポリウレタン系形状記憶ポリマー(DiARY)のクリープ挙動の研究(G04 機械材料・材料加工,G04 機械材料・材料加工)　　　　　　　　　　　　　　　
  田尾 隆幸; 坂井 建宣; 宗宮 詮
  年次大会講演論文集 : JSME annual meeting, 2006年09月, 一般社団法人日本機械学会
  2006年09月 - 2006年09月, 日本語
  Shape Memory polymer (SMP) is known to have visco-elastic behaviour. Shape recovery is considered to occur due to this visco-elastic behaviour. On the other hand, creep behaviour may also occur that is known as one of visco-elastic behaviour. It is important to understand creep behaviour, because it effects on material's reliability. This research examined the creep behaviour using the SMP, and creep behaviour and influencing factor were investigated by three point bending creep test. As a result, time and temperature dependence was confirmed, and also physical aging has a large effects on creep behaviour. To be more precise, creep deflection was suppressed with increasing of physical aging treatment time. In physical aging time for 1000min, master curve can be drawn by superposing the creep compliance curves, and SMP conformed to Arrhenius type of time-temperature superposition principle.
• ポリウレタン系形状記憶ポリマー(DiARY)のクリープ挙動の研究　　　　　　　　　　　　　　　
  田尾隆幸; 坂井建宣; 宗宮詮
  日本機械学会年次大会講演論文集, 2006年09月
  2006年09月 - 2006年09月, 日本語
• ガラス繊維強化ポリカーボネートのクリープ挙動予測方法の開発　　　　　　　　　　　　　　　
  坂井建宣; 宗宮詮
  FRPシンポジウム講演論文集, 2006年
  2006年 - 2006年, 日本語
• 繊維強化プラスチックのクリープ挙動に関する材料設計　　　　　　　　　　　　　　　
  坂井建宣; 楠本晃史; 宗宮詮
  FRP CON-EX講演要旨集, 2003年10月
  2003年10月 - 2003年10月, 日本語
• ガラス繊維強化ポリカーボネートのクリープ挙動に関する材料設計法　　　　　　　　　　　　　　　
  坂井 建宣; 楠本 晃史; 宗宮 詮
  日本複合材料学会研究発表講演会予稿集, 2003年05月
  2003年05月 - 2003年05月, 日本語
• ディーゼルエンジン用ばねの機械的特性に及ぼすクリープ処理の影響　　　　　　　　　　　　　　　
  金子堅司; 小島正敏; 坂井建宣
  日本機械学会中国四国支部地方講演会講演論文集, 2002年10月
  2002年10月 - 2002年10月, 日本語
• 103 ディーゼルエンジン用ばねの機械的特性に及ぼすクリープ処理の影響　　　　　　　　　　　　　　　
  金子 堅司; 小島 正敏; 坂井 建宣
  講演論文集, 2002年10月, 一般社団法人日本機械学会
  2002年10月 - 2002年10月, 日本語
  A creep tempering is done in production process of a spring designed for a fuel-injection nozzle of diesel engine. It is because that creep deformation occurs during use at high temperature and mechanical properties may change. But, conditions (temperature, time) in the creep tempering depend on empirical data that are not necessarily reasonable. In this study, effects of creep tempering on mechanical properties and residual stress of spring are investigated experimentally and theoretically. It is found that shear residual stress increases and spring constant does not so change after creep tempering process. Calculation methods of both shear residual stress and shear creep constitutive expressions of spring are proposed.

• 2024年09月 - 現在
  材料力学Ⅰ, 埼玉大学
• 2015年04月 - 現在
  機械工学セミナー, 埼玉大学
• 2014年12月 - 現在
  材料評価工学特論, 埼玉大学
• 2014年04月 - 現在
  機械工学実験Ⅰ, 埼玉大学
• 2014年04月 - 現在
  高分子材料工学, 埼玉大学
• 2019年04月 - 2023年09月
  数値解析Ⅰ, 埼玉大学
• 2015年04月 - 2023年09月
  材料工学Ⅱ, 埼玉大学

• 2016, 学士課程, 指導学生数計：4
• 2015, 学士課程, 指導学生数計：3
• 2014, 学士課程, 指導学生数計：5
• 2018, 学士課程, 指導学生数計：4, 指導学生数(内留学生)：2
• 2016, 博士前期(専門職学位)課程, 指導学生数計：6
• 2015, 博士前期(専門職学位)課程, 指導学生数計：2
• 2018, 博士前期(専門職学位)課程, 指導学生数計：4, 指導学生数(内留学生)：1

• 米国実験力学会
• 日本非破壊検査協会
• 日本材料学会
• 日本機械学会
• 日本実験力学会
• 日本複合材料学会

• ミクロとマクロの力学特性を繋ぐマルチレイヤーインデンテーション法の開発　　　　　　　　　　　　　　　
  日本学術振興会, 科学研究費助成事業, 基盤研究(B), 2021年04月01日 - 2024年03月31日
  山田 浩之; 洞出 光洋; 小笠原 永久; 樋口 理宏; 坂井 建宣, 防衛大学校(総合教育学群、人文社会科学群、応用科学群、電気情報学群及びシステム工学群)
  配分額（総額）：17420000, 配分額（直接経費）：13400000, 配分額（間接経費）：4020000
  本研究では，変形レイヤーのワンパス横断によりミクロからマクロの力学特性を連続的に評価できる「マルチレイヤーインデンテーション法」を開発し，ミクロとマクロを繋ぐことで真のマルチスケール材料力学の学理基盤を作ることを目的としている。初年度は，試験装置の開発，評価対象の材料選定などを行った。
  マルチレイヤーインデンテーション法の基礎となる試験装置の開発は，速度域で2種類に分けることとした。準静的から動的ひずみ速度範囲は，ステッピングモーターを利用して広範囲の速度環境に対応させた装置を試作した。また，今後，X線分析などのその場観察も対応可能な形状とした。ロードセルは付け替えることで最大5Nに対応しており，マイクロからミリスケールのレイヤー横断と，荷重が急増する2段インデンターにも対応させた。一方，衝撃インデンテーション試験には，高感度に対応するMEME半導体ひずみゲージが必要であり，試作を行った。ゲージ長を40μm以下を目標として，数パターン試作しており，今後，その性能評価が必要である。
  材料は，高密度ポリエチレンを対象とすることとした。準静的から衝撃のひずみ速度範囲の圧縮特性を評価し，変形中の微視構造の変化をSPring-8において評価を開始した。一方で，マイクロインデンテーション試験を開始し，基礎的な速度依存性評価を行った。同時に，ナノインデンテーション試験も行っているが，こちらは結果が安定せず，今後改善を行っていく。同時にナノインデンテーション試験の分子動力学による解析も開始した。
  課題番号：21H01221
• 膝関節音の周波数解析を用いた変形性膝関節症重症度分類法の開発　　　　　　　　　　　　　　　
  日本学術振興会, 科学研究費助成事業 挑戦的研究(萌芽), 挑戦的研究(萌芽), 2019年06月28日 - 2022年03月31日
  太田 進; 坂井 建宣, 星城大学
  配分額（総額）：6240000, 配分額（直接経費）：4800000, 配分額（間接経費）：1440000
  中高年の変形性膝関節症の罹患率は高いものの，初期には症状の出現が少ない．しかし，健康診断や人間ドックには関節などの運動器の検査が含まれることが少ない．
  本年度は，変形膝関節症初期に膝で音がするという現象を客観的に検討するものである．１）計測システムのプロトタイプ完成から臨床応用可能なシステムに修正，２）新型コロナウイルス感染症に伴い，人を対象に研究が実施できず，既存データをもとに信号処理法（アリの行動や植物根系アルゴリズムなどの群知能と呼ばれる手法）の検討を行った．研究実施に伴い，波及した研究として加振器を用い，膝関節を振動が通過する時の周波数特性や減衰から膝関節の状態を予測する基礎研究も加える．
  課題番号：19K22783
• 分子構造からみた時間－温度換算則の妥当性とMD解析による長期寿命予測法の開発　　　　　　　　　　　　　　　
  日本学術振興会, 科学研究費助成事業 国際共同研究加速基金(国際共同研究強化(A)), 国際共同研究加速基金(国際共同研究強化(A)), 2020年 - 2022年
  坂井 建宣, 埼玉大学
  配分額（総額）：15210000, 配分額（直接経費）：11700000, 配分額（間接経費）：3510000
  リュブリャナ大学（スロベニア）において、分子量の異なるポリエチレンを対象として、熱物性を調べるための示差走査熱量測定および、粘弾性特性を明らかにするための動的粘弾性試験による低温から高温までの特性評価を行った。分子量と結晶化度の調整が難しく、結晶化度が同じで分子量が異なる試料の作製が困難であることが明らかとなった。
  チャルマース工科大学（スウェーデン）においては、リュブリャナ大学で得られた動的粘弾性試験結果をもとに、時間－温度換算則の適用を試みた。その結果、すべての材料において時間－温度換算則が適用でき、さらに時間－温度換算則適用の際に得られるシフトファクターは、分子量に依らず一定となることが明らかとなった。また、原子間力顕微鏡を用いてナノサイズのインデンテーション試験を行う予定だったが、事情により困難となり、ナノインデンテーション試験を行った。その結果、分子動力学シミュレーション（MD解析）によるナノインデンテーション解析のサイズの10倍程度の圧痕を打つことができたが、MD解析結果と比較するためには大きすぎるため、様々な押し込み荷重における実験を行い、より小さい圧痕の条件を予測できるようにした。
  MD解析においては、ポリエチレンを対象としてクリープ解析を行い、さらに時間－温度換算則の適用を試みたところ、いかなる温度条件・分子量条件においても時間－温度換算則が適用できることが明らかとなった。またその時のポテンシャルエネルギーの推移から、ポテンシャルエネルギーについても時間－温度換算則が適用可能であることが明らかとなり、その時に得られる活性化エネルギーの評価によって、特定のポテンシャルエネルギーが時間－温度換算則に大きな影響を及ぼしていることが明らかとなった。
  課題番号：19KK0363
  論文ID：49832622
• アコースティック・エミッション法を用いたCGLガスワイピング音の周波数解析　　　　　　　　　　　　　　　
  JFEスチール株式会社, 共同研究費, 2020年04月 - 2021年03月
  坂井 建宣, 研究代表者
• 高分子材料の分子構造と寿命の関係の解明　　　　　　　　　　　　　　　
  日本学術振興会, 科学研究費助成事業 若手研究(A), 若手研究(A), 2017年04月01日 - 2020年03月31日
  坂井 建宣, 埼玉大学
  配分額（総額）：21970000, 配分額（直接経費）：16900000, 配分額（間接経費）：5070000
  側鎖が粘弾性特性に及ぼす影響を定量的に評価するために、側鎖が付いていないPE、メチル基が付いたPP、塩素が付いたPVC、ベンゼン環が付いたPSを対象として応力緩和解析を行った。はじめにおおよその分子の動きを把握するために重合度を10とした一本鎖モデルを作成し、応力緩和解析を行った。その結果、応力緩和挙動に対して非結合エネルギの影響が支配的であることが明らかとなった。またその理由として、側鎖同士の相互作用の強さが影響を及ぼしていることが明らかとなった。また非結合エネルギの時間変化については、側鎖の分子量と相関関係があることが明らかとなった。これより側鎖が大きい方が応力緩和挙動を発現しやすいことが示唆された。また重合度を50、本数を100本導入したバルクモデルについても同様の解析を行った。その結果、一本鎖モデルと同様に側鎖の分子量が大きいほど、総ポテンシャルエネルギーの変化が大きい結果が得られた。しかしバルクモデルでは非結合エネルギだけでなく、ねじり角にも側鎖の分子量と相関関係が見られた。また側鎖の大きさが大きいポリスチレンについては、一本鎖モデルとは異なる挙動を示すことが明らかとなった。バルクモデルにおいてはベンゼン環の大きさ故に、分子鎖の移動が妨げられたと考えられる。今後はベンゼン環に注目して動き解析を行うことも検討に入れる必要がある。
  また、PE・PP・PVCを対象として引張解析を行った。その結果、引張解析中に密度が低い部分が発生した。密度が低い部分を定量的に評価するために、全体の1/10の密度になった部分（空孔）が発生したときの発生応力をまとめた。ひずみ速度が高い・温度が低い場合において、空孔発生応力が高くなる傾向が見られた。また、側鎖の有無・種類によって分子鎖の配向度の変化が異なること、また非結合エネルギが増加することによって空孔部が発生することが明らかとなった。
  課題番号：17H04897
  論文ID：43551308
• 時間－温度換算則を活用した樹脂の寿命予測　　　　　　　　　　　　　　　
  日立化成株式会社, 奨学寄附金, 2019年04月 - 2020年03月
  坂井 建宣, 研究代表者
• 時間－温度換算則を活用した樹脂の寿命予測　　　　　　　　　　　　　　　
  日立化成株式会社, 奨学寄附金, 2018年04月 - 2019年03月
  坂井 建宣, 研究代表者
• 膝関節から生じる振動信号の解析による変形性膝関節症の早期診断方法の確立　　　　　　　　　　　　　　　
  日本学術振興会, 科学研究費助成事業 基盤研究(B), 基盤研究(B), 2015年04月01日 - 2018年03月31日
  太田 進; 長谷 和徳; 坂井 建宣; 酒井 忠博; 伊東 保志; 平岩 秀樹; 福山 篤司; 後藤 基志; 大古 拓史, 星城大学
  配分額（総額）：16380000, 配分額（直接経費）：12600000, 配分額（間接経費）：3780000
  本研究では，簡易的かつ非侵襲的に早期変形性膝関節症（膝OA)を鑑別することを目的に，膝を動かした時の膝から生じる音（振動）の特徴を膝OA,高齢者，健常成人と比較することで明らかにすることである．研究で明らかになったことは，１）健常と膝OAの比較において，センサ（加速度計）は，脛骨に貼付すると鑑別能力が高い．２）立ち上がり動作では，完全に膝が伸びる0-45度の範囲内で平均約180Hzの振動が生じる特徴が膝OAにあった．３）MRIによる軟骨変性（T2mapping)との関節音の関連は見いだせなかった．４）膝上に殴打刺激を入れた場合，膝OAでは20-30Hzの振動吸収が低下していた．
  課題番号：15H03047
• 『疲労骨折はミクロ損傷蓄積による骨質劣化の末路』の着想に基づく骨折リスク音響診断　　　　　　　　　　　　　　　
  日本学術振興会, 科学研究費助成事業 挑戦的萌芽研究, 挑戦的萌芽研究, 2015年04月01日 - 2017年03月31日
  若山 修一; 山本 衛; 坂井 建宣, 首都大学東京
  配分額（総額）：3640000, 配分額（直接経費）：2800000, 配分額（間接経費）：840000
  ラットに卵巣摘出手術を施し、術後13週および19週後に摘出した大腿骨を骨粗鬆症モデル試験片とした。曲げ試験、圧縮試験で機械的特性を評価するとともに、AE(アコースティック・エミッション)計測でミクロ損傷の蓄積過程をモニタリングした。また、マイクロX線ＣＴ画像解析で骨量(骨密度)を評価するとともに、超音波伝播特性計測、動的粘弾性測定（DMA）で骨質を評価した。その結果、骨幹部よりも骨端部で卵巣摘出の効果が顕著であることが明らかになり、今後の研究に有意義な結果が得られた。
  課題番号：15K12516
• 高分子材料の15年連続クリープ試験計画　　　　　　　　　　　　　　　
  日本学術振興会, 科学研究費助成事業 若手研究(B), 若手研究(B), 2014年04月01日 - 2017年03月31日
  坂井 建宣, 埼玉大学
  配分額（総額）：4030000, 配分額（直接経費）：3100000, 配分額（間接経費）：930000
  ポリプロピレン材を対象として長期クリープ試験を行った．また様々な温度における短時間クリープ試験，等ひずみ速度試験および等負荷速度試験からクリープコンプライアンスを算出し，時間－温度換算則を適用することによりマスター曲線を作成し，長期クリープ試験結果と比較した．短期クリープ試験結果は長期クリープ試験と良い一致を示し，ポリプロピレン材はW.L.F式による時間－温度換算則が最も適していることが明らかとなった．また等ひずみ速度試験，等負荷速度試験結果は一部のみが長期クリープ試験結果と一致したが，それ以外では一致しなかった，これは非線形粘弾性挙動の発現が原因であることが明らかとなった．
  課題番号：26820013
• CFRP接着層における弱接着状態検出法の開発　　　　　　　　　　　　　　　
  JAXA, JAXA航空技術イノベーションチャレンジ, 奨学寄附金, 2016年10月 - 2017年03月
  坂井 建宣, 埼玉大学, 研究代表者
• 炭素繊維強化複合材料の疲労特性への時間－温度換算則の適用　　　　　　　　　　　　　　　
  スガウェザリング技術振興財団, 研究助成, 奨学寄附金, 2015年04月 - 2016年03月
  坂井 建宣, 埼玉大学, 研究代表者
• ウェアラブルな心音・呼吸音評価装置の開発　　　　　　　　　　　　　　　
  公益財団法人 日揮・実吉奨学会, 日揮・実吉奨学金研究助成金, 奨学寄附金, 2014年10月 - 2015年09月
  坂井 建宣, 埼玉大学, 研究代表者
• 音響情報を利用した腱の断裂機序の解明と損傷治癒過程評価のための基礎的研究　　　　　　　　　　　　　　　
  日本学術振興会, 科学研究費助成事業 挑戦的萌芽研究, 挑戦的萌芽研究, 2012年04月01日 - 2014年03月31日
  若山 修一; 山本 衛; 坂井 建宣, 首都大学東京
  配分額（総額）：3900000, 配分額（直接経費）：3000000, 配分額（間接経費）：900000
  腱や靭帯に発生する微視損傷は、完全断裂の起点となる一方、腱組織の再生のトリガーになるとも考えられており、微視損傷の検出及び同定を行う技術の開発はリハビリテーションやスポーツトレーニングの最適化に有用である。
  本研究では、日本白色家兎から採取した膝蓋骨－膝蓋腱－脛骨複合体の疑似生体環境下（37℃生理食塩水中）で引張試験を行い、微視損傷の発生・蓄積過程をAEモニタリングした。応力は単調に増加し、最大応力以前に多くのAE信号が検出された。また、負荷速度が大きいほど高振幅のAEが検出され、高負荷速度では発生する個々の微視損傷の程度が大きいことが示唆された。
  課題番号：24650267
• 時間－温度換算則を活用した樹脂の寿命予測　　　　　　　　　　　　　　　
  新神戸電機株式会社, 奨学寄附金, 2013年04月 - 2014年03月
  坂井 建宣, 研究代表者
• 使用済タイヤ強化ポリ乳酸の粘弾性特性と衝撃特性　　　　　　　　　　　　　　　
  公益財団法人 LIXIL住生活財団, 若手研究助成（若手研究者）, 奨学寄附金, 2012年04月 - 2013年03月
  坂井 建宣, 首都大学東京, 研究代表者
• 使用済みタイヤを用いた生分解性プラスチック複合材料の創製　　　　　　　　　　　　　　　
  スズキ財団, 科学技術研究助成, 奨学寄附金, 2010年04月 - 2011年03月
  坂井 建宣, 首都大学東京, 研究代表者
• プラスチックの高温耐久性を考慮した構造設計手法の開発　　　　　　　　　　　　　　　
  みずほ学術振興財団, 第50回工学研究助成, 奨学寄附金, 2007年04月 - 2008年03月
  坂井 建宣, 慶應義塾大学, 研究代表者

• 膝関節症診断システム　　　　　　　　　　　　　　　
  太田 進; 長谷 和徳; 戸沢 優介; 坂井 建宣, 特許権