THE EFFECT OF PARTICLE-SIZE, SHAPE, DISTRIBUTION AND THEIR EVOLUTION ON THE CONSTITUTIVE RESPONSE OF NONLINEARLY VISCOUS COMPOSITES .2. EXAMPLES

Part I of this work was concerned with the development of constitutive models for nonlinearly viscous and perfectly plastic composites, whic h are capable of accounting for the evolution of microstructure when t he composites are subjected to finite deformation. This involved the d erivation of instantaneous constitutive relations for the composites d epending on appropriate microstructural variables, as well as of evolu tion equations for these variables. As an application of the general t heory, in this part of the work, use is made of the models to analyse the response of porous materials and of two-phase composites with perf ectly plastic phases under axisymmetric loading conditions (with fixed axes). Attention is focused on the effect of the evolution of the dis tribution of the inclusions (or voids) on the overall response of the composites. It is found that for porous materials, or for more general classes of composites where the inclusions are softer than the matrix , the effect of changes in the distribution of the inclusions is not v ery significant relative to the effect of changes in the size and shap e of the inclusions. On the other hand, for composites with inclusions that are sufficiently harder than the matrix, the deformation is conc entrated in the matrix, and the effect of changes in the distribution function of the inclusions can become quite significant.