Ply-Cracking Damage and Nonlinear Deformation of CFRP Cross-Ply Laminate

Abstract

This paper deals with progressive ply-cracking damage and nonlinear deformation of CFRP cross-ply laminate. Tensile tests in 0°-axis direction and in off-axis direction are carried out on five kinds of CFRP cross-ply laminates which are different in stacking lay-up. Under 0°-axis tension, initiation and evolution of the ply-cracking damage in 90° plies are observed, and corresponding stress-strain relation is slightly nonlinear after the damage. On the other hand, under off-axis tension, the stress-strain response exhibits nonlinear deformation, while the ply-cracking damage is not remarkable except for the specimen with large fracture strain. Therefore, it is concluded that the nonlinear deformation of the laminates under off-axis tension is mainly attributed to the nonelastic deformation of the matrix resin. Numerical analyses for the progressive ply-cracking damage and the nonlinear deformation of the CFRP cross-ply laminates are conducted based on a ply-cracking damage theory and a nonlinear lamination theory, respectively, and applicability of these theories are discussed based on the experimental and numerical results.