COMPOSITE PLATES IN POSTBUCKLING: DUAL EXTREMAL VARIATIONAL PRINCIPLES, ENERGY FEATURES, STABILITY, LAY-UP OPTIMALITY CONDITIONS VIA COMPLEMENTARY ENERGY APPROACH

Abstract

In the present paper the composite plates in postbuckling are explored. The dual extremal variational principles are created. The principles generalize the stationary ones obtained earlier. The stability of the plate near the single-modal bifurcation point is proven. Some useful energy relations are established. It is also demonstrated that the total complementary energy may be considered as a measure of the compliance for the post-buckled composite plate. The latter measure leads to the same lay-up optimality conditions as obtained earlier via the maximization of the total potential energy. Basing on the complementary variational principle, a monotonic plate compliance minimization approach is proposed. The approach allows determining the stiffest lay-up.