Non-linear dynamic stability analysis of composite laminates under periodic in-plane compressive loads

This work deals with the investigation of the non-linear instability behavi our of the composite laminates subjected to periodic in-plane/axial load, t hrough the finite element formulation with dynamic response analysis. Here, C-1 eight-noded shear-flexible plate element, based on a new kind of kinem atics which allows to exactly ensure the continuity conditions for displace ments and stresses at the interfaces between the layers of the laminate, an d also the boundary conditions at the top and bottom surfaces of the lamina te, is employed. The non-linear governing equations obtained are solved usi ng the Newmark direct integration method coupled with a modified Newton-Rap hson iteration procedure. The analysis brings out various characteristic fe atures of the dynamic stability such as existence of beats, their dependenc y on the forcing frequency, and the typical character of vibrations in the different regions. Numerical results are also presented to highlight the in fluence of ply-angle and lay-up of the laminate on dynamic stability behavi our of the composite laminates. Copyright (C) 1999 John Whey & Sons, Ltd.