A MICROMECHANICAL MODEL FOR NONLINEAR VISCOELASTIC BEHAVIOR OF PARTICLE-REINFORCED RUBBER WITH DISTRIBUTED DAMAGE

A model based on micromechanics for predicting effective viscoelastic stress-strain equations and microcrack growth in particle-reinforced rubber (or other relatively soft viscoelastic matrix) is described. Geometric idealization of the microstructure follows that of the composite spheres assemblage and generalized self-consistent scheme originally used for linear elastic composites without damage. The approach combines a perturbation analysis of the matrix, which becomes more accurate as the particle volume fraction is increased, with the Rayleigh-Ritz energy method for predicting mechanical response of the composite. Results for linear elastic behavior with crack growth are first obtained, and then extensions to linear and nonlinear viscoelastic behavior are discussed.