Multi-inclusion unit cell models for metal matrix composites with randomly oriented discontinuous reinforcements

A multi-inclusion unit cell approach is employed to study the elastic and elastoplastic behavior of metal matrix composites reinforced by randomly oriented short fibers. Periodic arrangements of 15 identical fibers of spheroidal or cylindrical shape with an aspect ratio of 5 and a reinforcement volume fraction of 15% are generated by a random sequential adsorption algorithm. The overall responses of the resulting unit cells under uniaxial tensile loading and the corresponding microscale stress and strain fields are evaluated via the finite element method. In addition, a microgeometry containing 15 identical spherical particles at the same volume fraction is studied for comparison. s of the reinforcement types and shapes in the elastic and elastoplastic ranges are studied and the predicted microfields are discussed in terms of their phase averages and the corresponding standard deviations. Weibull-type fracture probabilities are used to assess the vulnerability of the fibers or particles to brittle fracture.