On the post-buckling behavior of bilaterally constrained plates

A combined experimental/analytical effort is carried out to elucidate the post-buckling response of bilaterally constrained columns and plates under monotonically increasing edge displacement. Real-time observations of the outward deformation of the plate via the shadow moire technique facilitate deep insight into the behavior of this class of problems. The lateral constraints lead to a sequential plate snapping process that arise from secondary buckling of a contact zone(s) in the plate. The critical load for mode transition is evaluated systematically as a function of the confining gap, the plate aspect ratio and other system parameters. The results generally exhibit significant scatter that is attributed to the inherent asymmetry of the deformation pattern in such systems. A large-deformation finite element analysis incorporating frictional contact algorithm is used to model the problem. The deformation patterns as well as the critical loads predicted from this analysis generally agree well with the experimental results. A simple analytic expression, based on the linear theory of beams, is developed for the critical loads. The experimental data are found to be well contained by lower and upper bounds from this analysis once the plate surface interacts with the two confining planes. The results of this work may serve as a basis for multilaminate design possessing unique mechanical response and superior energy absorption capability.