LARGE-STRAIN ANALYSIS OF REINFORCED MEMBRANES

A theoretical formulation is developed for large-strain analysis of reinforced, multilayer membranes that contain nonlinear, viscoelastic materials and are subjected to unidirectional, in-plane loading. Regularity conditions, satisfied by the displacement fields of interest, allow the problem to be formulated in terms of a single, in-plane component of the displacement field, even when strains are large. The theory is implemented in a finite-element software package called REMA (reinforced membrane analysis), designed to run on a personal computer. An explicit stiffness matrix is used. The software is designed to investigate a wide range of membrane behaviors and to model the sequential stages of reinforcement and matrix subcomponent failure. Here, it is used to predict the load-deflection behavior and sequence of subcomponent failures produced by typical in situ loading of a reinforced roofing membrane. The predictions are compared with corresponding laboratory tests.