Abstract:

A 4 node plate element based on Mindlin first order shea ring theory is presented to analyze the pre postbuckling behavior of composite laminates with circle delamination damage. For the configuration analyzed, moder ate strain levels, and without including delamination front contact effect, alth ough the local buckling load decreases greatly because of the presence of the th in delamination, the laminate can sustain a high postbuckling load. It is to say that pre buckling analysis is not sufficient to model the residual strength of laminate with delamination and post buckling analysis is necessary. The post buckling load of the laminate with all clamped boundary edges is much higher tha n that of the laminate with all simply supported edges. The stiffness of laminat e changes so slightly after local buckling that local buckling load can not be i dentified from the load displacement curve.

Key words: no nlinear it y, finite element method, buckling, delam inatio n damag e