The effects of three-dimensional multi-particle arrangements on the mechanical behavior and damage initiation of particle-reinforced MMCs

A study of particle-reinforced metal-matrix composites (MMCs) by three-dime nsional multi-inclusion unit cells is presented. It employs cube-shaped cel ls containing some 20 randomly positioned spherical inclusions to approxima te statistically homogeneous arrangements of elastic particles embedded in an elastoplastic matrix. Three-dimensional simple periodic arrays as well a s two-dimensional arrangements of particles in a matrix are considered for comparison. Uniaxial tensile loading is modeled and results for the macrosc ale and microscale mechanical responses are evaluated in terms of ensemble and phase averages. To assess damage initiation by particle fracture the ma ximum principal stresses in the elastic inclusions are used to calculate fr acture probabilities by using Weibull statistics. Clear differences between multi-particle models and simple periodic arrangements as well as between planar and three-dimensional models are found in terms of the overall modul i, of the phase averages and standard deviations of the microscale stress a nd strain fields, and of the particle fracture probabilities. (C) 2001 Else vier Science Ltd. All rights reserved.