Fatigue behavior of CFRP cross-ply laminates under on-axis and off-axis cyclic loading
✍ Scribed by Keiichiro Tohgo; Shuji Nakagawa; Kazuro Kageyama
- Publisher
- Elsevier Science
- Year
- 2006
- Tongue
- English
- Weight
- 473 KB
- Volume
- 28
- Category
- Article
- ISSN
- 0142-1123
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✦ Synopsis
This paper focuses on the damage and fracture process of CFRP cross-ply laminates under on-axis and off-axis cyclic loading. On the semi-log S-N curves obtained by fatigue tests, fatigue fracture is described by a straight line and the fatigue limit is not recognized clearly. In the on-axis fatigue tests, fiber-peeling damage in 0°plies develops in addition to ply-cracking damage in 90°plies. The fiber-peeling damage was described by peeling-off of fiber bundles from the specimen surface after micro-scale damage of matrix resin and fiber-matrix interface. Most of the ply-cracking damage develops at an early stage of stress cycles, and slightly increases during fatigue, while the fiber-peeling damage in 0°plies initiates from the edges of 0°plies and evolves in the whole area of laminates with an increase in stress cycles. The fatigue fracture seems to occur when the 0°plies lose their load carrying capacity by the evolution of the fiber-peeling damage. In the off-axis fatigue tests, the fatigue fracture is caused by the initiation and evolution of ply-cracking damage and succeeding delamination. It is concluded that the fatigue strength is governed by the fiber-peeling damage in 0°plies under on-axis cyclic loading and by the ply-cracking damage and delamination under off-axis cyclic loading.