POSTBUCKLING COMPRESSIVE STRENGTH OF GRAPHITE-EPOXY LAMINATED CYLINDRICAL PANELS LOADED IN COMPRESSION

The postbuckling compressive strength and collapse phenomena of compos ite laminated cylindrical panels with various fiber angles and width-t o-length ratios are characterized by the nonlinear finite element meth od. For the iteration and load increment along the postbuckling equili brium path, a modified art-length method in which the effect of stress unloading due to failure can be considered is introduced. In the prog ressive failure analysis, the maximum stress criterion and complete un loading model are used. Validity of present finite element results are verified by experiment for [0(3)/90](S) cylindrical panel and [0/90//-45](S) plate. The postbuckling compressive strength of composite lam inated cylindrical panels is independent of the initial buckling stres s but high in the panel with large value of the bending stiffness in a xial direction. In several of the cylindrical panels, it is observed t hat the prebuckling compressive failures occur and directly result in collapse before buckling.