Stress Analysis of Viscoelastic Composite Materials

Abstract

This paper deals with foundations and methods of linear visco elastic analysis of anisotropic composites, including temperature effects. Earlier work on mathematical and thermodynamic bases of constitutive equations and the corresponding principle is re viewed. This principle is then used to relate effective viscoelastic moduli for composites to constituent properties. It is shown that all results from elasticity theory, including upper and lower bounds on moduli, are applicable to viscoelastic materials. Three ap proximate methods of viscoelastic analysis are reviewed and ap plied to three problems: pressurization of an orthotropic cylinder, cooling of a glass fiber embedded in resin, and upper and lower bounds on operational and relaxation shear moduli for a fiber- reinforced composite. Although realistic material properties are used, these methods enable explicit solutions to be derived with out difficulty.