STUDY OF UNIFIED FAILURE CRITERIA

Abstract

Modeling composites structures with fidelity sufficient to provide increased utility to the design community depends on a robust predictive capability that is accurate across as wide of a range of scenarios as possible. Such a model should provide an equally accurate capability to predict the failure of anisotropic composite structures as simpler isotropic ones. Additionally, the accurate prediction of failure should be possible in a variety of scenarios ranging from pri samples up to and including specimens with cracks or other stress concentrating features. Any truly satisfactory model should also span the range of strain rates and apply with equal accuracy from low-rate quasi-static strain rates near 10E-4 s^-1 up to high-rate dynamic impacts at 10^5 s^-1. As a result of their inherently complex structure, any accurate composite failure theory necessitates a multi length scale perspective. As a result, the accurate modeling and prediction of failure for heterogeneous and anisotropic composites has been, thus far, an elusive goal. The work outlined here is an attempt to unite some of the previously separate theories of failure and to extend a newly developed, more unified failure theory, to a broad range of brittle materials. Although this is intended to be particularly useful for composite materials, the enhanced accuracy of such a theory will be shown to apply equally well to homogeneous, isotropic materials as heterogeneous, anisotropic ones.