Unified micromechanical model for the mechanical properties of two constituent composite materials. Part IV: Rubber-elastic behavior

Abstract

This series of papers reports a new, general, and unified micromechanical model for estimating the three-dimensional mechanical properties of a composite made from two constituent materials, i.e., continuous fiber and matrix. The present paper addresses the application of the model to rubber-based composites, with a focus on prediction of the entire stress-strain response characteristic of a composite having an elastomer matrix constituent material. For this purpose, an accurate constitutive theory has been developed for any incompressible rubber-like material. Its incremental stress-strain relationship at any given level is simply correlated by a load-dependent compliance matrix, similar to Hooke's law. The theory is consistent in that when the involved material parameters, i.e., the load-dependent Young's modulus and Poisson's ratio, are determined using a single type of test data such as uniaxial tension data, it is then able to predict precisely the material responses to other types of deformation conditions. Combining the incremental theory with the unified model developed in Parts I and II, an analysis procedure for the overall properties of elastomer-based composites follows. As an application, an interlock weft-knitted polyester-fiber fabric-reinforced polyurethane elastomer composite is investigated. Favorable correlation has been found between the theoretical and experimental results.