High-Performance Composite Materials for Vehicle Construction

A method for predicting the strength of a unidirectional composite material in terms of its micromechanical response to an applied stress. It accounts for elastoplastic material behavior, local failure that initiates a crack, and propagation of the crack to cause total failure of the composite. Because the relatively low transverse tensile strength of most high-performance unidirectional composites often limits the performance of the composite system, the analysis is applied to the case of transverse normal loading. The basic principles of the theory of plasticity are combined with a finite element numerical technique to produce a rigorous analysis procedure capable of accurately modeling the complex boundary-value problem under consideration, an initial step toward the ultimate goal of accurately predicting the strength of a material. The limited numerical results obtained are discussed in detail. Suggestions for refinements and extensions of the analysis are outlined.