Prediction of post-buckling and ultimate compressive strength of composite plates by semi-analytical methods

An efficient, semi-analytical method is developed for estimating the ultimate strength of simply supported, rectangular plates of laminated composite material subjected to uniaxial in-plane compression. The method is based on large deflection theory combined with first order shear deformation theory. Two degradation models have been developed, where instantaneous material degradation has been applied either to the entire failed ply or to the affected regions of a failed ply. Further, two different types of in-plane displacement fields have been examined, and their influence on the strength predictions is found to be significant for some of the cases.