Effects of particle shape on the thermoelastoplastic behavior of particle reinforced composites

Abstract

Particle shape effects in thermoelastoplastic ductile matrix composites are evaluated systematically. This is done by studying generic, periodic, multi-inhomogeneity volume elements that contain 20 volume percent of randomly positioned and, where applicable, randomly oriented, identical particles taking the form of spheres, regular octahedra, cubes, or regular tetrahedra. The Finite Element method is used for obtaining the responses of the initially stress-free volume elements to single, stress controlled loading cycles at four fixed macroscopic stress triaxialities, viz., loading by shear, uniaxial, in-plane hydrostatic, and hydrostatic applied stresses. In addition, a thermal loading cycle and the effects of residual stresses on shear loading are considered. Results are evaluated as ensemble averages over five phase arrangements of each type. They are presented in terms of macroscopic responses as well as the evolution of the phase-level averages and standard deviations of the microscopic stress and strain fields. Consistent shape effects are predicted for all load cases considered, with the responses of cube-shaped and octahedral particles being fairly similar and lying between the predictions obtained for spherical and tetrahedral inhomogeneities. Among the shapes studied, tetrahedral particles are found to give rise to the stiffest responses under mechanical loading.