The Fatigue Growth of Internal Delaminations Under Compressive Loading of Cross-Ply Composite Plates

摘要

This study focuses on the mode dependence of delamination growth under cyclic compressive loads in corss-ply composite plates. The model proposed makes use of an initial postbukling solution derived from a perturbation procedure. A mode-dependent crack groth criterion is introduced. Expressions describing the fatigue crack growth are derived in terms of the distribution of the mode adjusted enegy release rate. The resulting crack growth laws are numerically intergrated to produce delamination growth versus number of cycles diagrmas. The model does not impose any restrictive assumptions on the relative thickness of the delaminated and the base plates, although transverse shear stress effects are not considered. Experimental reslts are presented for cross-ply graphite/epoxy specimens, and the results are compared with experimental results for unidirectional speciments. The test data are obtianed for different delamination locations and for different vaues of applied compressive strain.