Micro-Mechanical Modeling of Polymer Based Unidirectional Composites: Use of Bulk Properties of Matrix with the Smeared Crack Model

Abstract

Traditional approach to micro-mechanical modeling uses in situ properties of ingredients, which are so fitted as to match predictions of the micromechanical analysis with the experimental in-plane shear response of a lamina for a particular value of fiber volume fraction. In situ properties thus derived, cannot, in general, be used with a different fiber volume fraction or a different micromechanical model. The study presented here is based on the premise that micromechanical models should be transparent and rational tools for obtaining composite properties. Therefore, an attempt is made to characterize the composite from the actual properties of the ingredients and accounting for the presence of thermal residual stresses, shear softening and micro cracking in the matrix throughout the loading history. Experimental comparisons show that a micro-mechanical model with a realistic representative volume element (RVE) and diligent accounting of matrix behavior provides good bounds on experimental response with consistent accuracy, when bulk material properties are used.