The buckling and postbuckling behaviors were analyzed numerically and experimentally for composite plates with a hole. In the finite element analysis, the updated Lagrangian formulation and the eight-node degenerated shell element were used. For the progressive failure analysis, the maximum stress criterion was applied to the average stress in each layer of all the finite elements and then stiffness and stress corresponding to failure mode were reduced to zero for the failed layers of all the elements. In the experiments, the shadow moire technique was used to monitor the out-of-plane deformation. The piezoelectric sensor was also used for detecting damage event globally. The major finding in experiments was that when a plate has lower bending stiffness in axial direction, local disturbances caused mode shape changes in postbuckling range. Experiments showed good agreement with the finite element results on buckling load and postbuckling compression strength. The influence of the hole size and the stacking sequence was investigated. The buckling and postbuckling behaviors were largely dependent on the hole size and the stacking sequence. The postbuckling compression strength was dominated by the bending stiffness in axial direction.
