Compos.Sci.Technol. 61, 1581-1590

THE EFFECTS OF THREE-DIMENSIONAL MULTI-PARTICLE ARRANGEMENTS ON THE MECHANICAL BEHAVIOR AND DAMAGE INITIATION OF PARTICLE-REINFORCED MMCs

W. Han, A. Eckschlager and H.J. Böhm

CDL Functionally Oriented Materials Design,
Institute of Lightweight Structures and Aerospace Engineering,
TU Wien, Vienna, Austria


Abstract - A study of particle reinforced metal matrix composites (MMCs) by three-dimensional multi-inclusion unit cells is presented. It employs cube shaped cells containing some 20 randomly positioned spherical inclusions to approximate statistically homogeneous arrangements of elastic particles embedded in an elastoplastic matrix. Three-dimensional simple periodic arrays as well as two-dimensional arrangements of particles in a matrix are considered for comparison. Uniaxial tensile loading is modeled and results for the macroscale and microscale mechanical responses are evaluated in terms of ensemble and phase averages. To assess damage initiation by particle fracture the maximum principal stresses in the elastic inclusions are used to calculate fracture probabilities 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 moduli, of the phase averages and standard deviations of the microscale stress and strain fields, and of the particle fracture probabilities.

Thermal residual stresses in metal matrix composites are studied by three-dimensional multi-inclusion unit cell models that employ a limited number of randomly positioned spherical inclusions embedded in the ductile matrix. The residual stresses due to cooling down are evaluated and predictions of their effects on the mechanical response under unidirectional tensile loading are compared with corresponding results for the initially stress free (virgin) material. The same load cases are studied by planar unit cell models and the results are compared in terms of the predicted overall material properties and the microscale stress and strain fields.


(hjb,010828)