Three-dimensional multiparticle cell simulations of deformation and damage in sphere-reinforced composites

The tensile loading of an elasto–plastic matrix reinforced with elastic spheres was studied by means of the three-dimensional finite element analysis of periodic multiparticle cells containing a random dispersion of thirty identical spheres. Damage in the form of void nucleation, growth and coalescence in the matrix was included with the aid of the modified Gurson model. It was found that damage was early localized in regions between spheres closely packed along the deformation axis: the strain concentration in these regions nucleates voids, which grew driven by the tensile hydrostatic stresses. The stress relaxation induced by void nucleation and growth reduced significantly the flow stress of the composite, and eventually a maximum in the stress–strain curves was observed. The multiparticle cell results were compared with those obtained from single-particle axisymmetric simulations, and the effect of reinforcement volume fraction was analyzed as well as that of the matrix damage parameters on the composite behavior.