Compression-after-impact effect on postbuckling behavior of thermoplastic composite laminated plates

This paper investigates the postbuckling behavior of carbon fiber reinforced thermoplastic composite (CFRTPC) laminated plates under uni-axial compression-after-impact (CAI). A physical model is proposed where both internal damage and local geometric imperfection of the plate caused by impact are taken into account. The distributed damage and impacted region of the plate are determined by using X-ray computed tomography analysis. An experiment-based approach is utilized to obtain the nonlinear constitutive law along with the stiffness degradation for the CFRTPC laminated plates. The experiments for two CFRTPC laminated plates under uni-axial compression-after-impact are carried out firstly. Then the experimental data are compared with finite element numerical results to validate the present method. The numerical results reveal that the postbuckling load-deflection curves of CFRTPC laminated plates under CAI are significantly influenced by the initial local geometric imperfection, impact point position, plate width-to-thickness ratio and boundary conditions. In contrast, the initial local geometric imperfection and impact point position only have a small effect on the postbuckling load-shortening curves of CFRTPC laminated plates under CAI.