Microscopic observation of voids and transverse crack initiation in CFRP laminates |
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Authors: | Shigeki Aratama Ryosuke Hashizume Kazuya Takenaka Koushi Koga Yusuke Tsumura Takushi Miyake |
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Affiliation: | 1. Aerospace Company, Kawasaki Heavy Industries, Ltd., Kakamigahara, Japan;2. Department of Mechanical Engineering and Science, Kyoto University, Kyoto, Japanaratama_shigeki@khi.co.jp;4. Department of Mechanical Engineering and Science, Kyoto University, Kyoto, Japan;5. Department of Mechanical Engineering, Gifu University, Gifu, Japan |
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Abstract: | In situ three-point bending tests under observation using scanning electron microscopy were performed for specimens including voids to investigate the effect of voids on transverse crack initiation in carbon fiber-reinforced plastic (CFRP) laminates. First, initial failure load (i.e. applied load at the first transverse crack initiation) was investigated. Microscopic strain distributions were then measured by digital image correlation analysis using SEM pictures taken before and during loading in the in situ tests. In addition, specimens including voids and transverse cracks after the in situ tests were observed using X-ray computed tomography to clarify transverse crack onset locations with respect to void shapes and distributions. These experiment results suggested that voids actually caused strain concentration and corresponding local plastic deformation, and finally resulted in reduction of macroscopic initial failure strains in CFRP laminates. |
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Keywords: | CFRP void transverse cracking scanning electron microscopy (SEM) microscopic strain image analysis strain distribution X-ray computed tomography (CT) |
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