PSI - Issue 2_B

Koji Fujimoto et al. / Procedia Structural Integrity 2 (2016) 182–189 Koji Fujimoto, Masahiro Hojo, Akira Fujita / Structural Integrity Procedia 00 (2016) 000 – 000

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(3) We observed much longer fatigue life in the four-point-bending fatigue test than in the flatwise tension fatigue test. However, the effects of the residual stress and the biaxial loading should be considered and evaluated properly in the four-point-bending fatigue test. Regarding the flatwise tension fatigue test, stress concentration may occur at the boundary between the straight part of the specimen and the non-uniform cross sectional part adjacent to the stainless grip. Further, we should consider the possibility of the effect of the bending stress due to misalignment of the loading axis. (4) On the fracture surface at the curved section of the four-point-bending fatigue test specimen, we could observe toughened interlayer regions. However, regarding the fracture surface of the flatwise tension fatigue test specimen or the fracture surface at the straight section of the four-point-bending fatigue test specimen, fracture in the CF/epoxy layer was predominant. Designation: D 6415/D 6415M - 06a, Standard Test Method for Measuring the Curved Beam Strength of a Fiber-Reinforced Polymer-Matrix Composite, ASTM International, 2006, pp. 1-10. Designation: D 7291/D 7291M - 07, Standard Test Method for Through- Thickness “Flatwise” Tensile Strength and Elastic Modulus of a Fiber Reinforced Polymer Matrix Composite Material, ASTM International, 2007, pp. 1-10. Hojo, M., Matsuda, S., Tanaka, M., Ochiai, S., Murakami, A., 2006, Mode I Delamination Fatigue Properties of Interlayer-Toughened CF/epoxy Laminates, Composites Science and Technology 66, 665-675. Hojo, M., Kono, M., Morimoto, T., Fujimoto, K., 2012, Flexure Strength of Curved CFRP Laminate and Interlaminar Tensile Strength, Proceedings of the 3rd Japan Conference on Composite Materials (USB Memory), Kyoto, The Japan Society for Composite Materials, Paper No. 3202 (in Japanese). Hojo, M., Fukuda, S., Morimoto, T., Fujimoto, K., Uenishi, K., 2013, Study on Improvement of Interlaminar Tensile Strength Test Using Curved CFRP Laminate Specimen, Proceedings of the 4th Japan Conference on Composite Materials (USB Memory), Tokyo, The Japan Society for Composite Materials, Paper No. 1C-15 (in Japanese). Hojo, M., Morimoto, T., Kono, M., Fukuda, S., Fujimoto, K., 2015, Strength Evaluation of Curved CFRP Laminated Composite, Proceedings of M&M2015 (CD-ROM), Materials and Mechanics Division, The Japan Society of Mechanical Engineers, Paper No. OS1105-342 (in Japanese). Morimoto, T., Sugimoto, S., Katoh, H., Hara, E., Yasuoka, T., Iwahori, Y., Ogasawara, T., Ito, S., 2015, JAXA Advanced Composites Database, JAXA Research and Development Memorandum, JAXA-RM-14-004, ISSN 1349-1121 (in Japanese). Shigemori, K., Hosoi, A., Fujita, Y., Kawada, H., 2014. Fatigue Strength Properties of Interlaminar Toughened CFRP Laminates under Cyclic Loading in the Out-of-Plane Direction, Transactions of the JSME 80, DOI: 10.1299/transjsme.2014smm0087 (in Japanese). References