Experimental characterization of microscopic damage progress in AS4/PEEK cross-ply laminates under thermal cycling

Abstract

Microscopic damage progress in high temperature CFRP cross-ply laminates under thermal cycling was investigated. Two types of laminate configuration were tested to study the effect of ply thickness. Matrix cracks initiated in both 0° and 90° plies and the number of cracks increased as the number of cycles increased. The saturated number of cracks in 90° plies was twice as large as that in 0° plies. To discuss these experimental results, shear-lag analysis was used to evaluate both the energy release rate associated with matrix cracking and the thermal residual stress in cracked plies. It was implied that the effect of the maximum thermal residual stress as well as the energy release rate range were significant in the quantitative evaluation of the matrix cracking induced by the thermal cycling.

Keywords:

• Thermal cycling
• energy release rate
• shear-lag analysis
• modified Paris law