Transverse crack growth in the width direction of CFRP laminates under fatigue loadings

摘要

The damage behavior of transverse cracks in cross-ply and quasi-isotropic toughened CFRP laminates under cyclic loadings is studied. Coupon specimens with ranges of specimen width and transverse ply thickness are tested. Detailed observations of both crack density and crack length suggest that there are consecutive three-stage damage processes of edge crack initiation, edge crack growth, and crack propagation across the width in quasi-isotropic laminates, whereas simultaneous inward crack propagation and edge crack growth takes place in cross-ply laminates. Energy release rates associated with crack propagation in the width direction are derived using the two-dimensional analytical model including both mechanical and thermal problems. Transverse crack propagation behavior under fatigue loadings can be estimated using the power law of the associated energy release rates.