Inelastic Analysis of a Unidirectional Composite Subjected to Transverse Normal Loading

Abstract

Composite material behavior is divisible into three distinct re gimes, linear elastic response up to the elastic limit, inelastic be havior beyond the elastic limit and up to that point at which first failure occurs locally, and subsequent crack propagation and total composite failure. The first regime has been thoroughly explored in previous investigations, while the second is the main topic of the present paper. The third is briefly discussed and is a subject under investigation. Utilizing a finite element analysis, numerical results are obtained for composite behavior beyond the elastic limit and up to first failure. Examples representative of several actual material systems are presented and discussed in detail. Results indicate that extensive local yielding and redistribution of stresses can occur in a composite with very little indication of such behavior being apparent by observation of the total stress- strain response of the composite alone. Thus, the establishment and interpretation of design criteria and theories of failure should be evaluated in light of these results and their implications with re spect to such phenomena as fatigue life and fracture behavior, among others.