Buckling of delaminated composites re-examined

Composite laminates under in-plane compression can fail prematurely because of the presence of existing delaminations. A concise buckling analysis is performed to determine the commencement of buckling. A commonly adopted plane-section assumption in the classical beam theory is examined and found to overestimate the strength of the composite laminates. Relaxation of the assumption results in a lower bound solution for the buckling load and thus a useful parameter for design purposes. This simple yet accurate analysis can be adapted to multi-delamination problems. The ultimate strength of the composite laminate is obtained through several simple post-buckling analyses.