Parametric evaluation of progressive damage in polymer concretes: Size effect and statistics

Fracture and effective stress-strain graphs in two-dimensional random composites subjected to a uni-axial in-plane uniform strain are characterized. The inclusions are arranged randomly in the matrix. Both inclusions and matrix are isotropic and elastic-brittle. We conduct this analysis numerically using a very fine two-dimensional triangular spring network and simulate the crack initiation and propagation by sequentially removing of the bonds, which exceed a local fracture criterion. In particular, the focus of this paper is on effects of scale (size of inclusion) and geometric randomness in such composites. We consider several "windows of observation" (scales) and study crack patterns, types of constitutive responses, and statistics of the corresponding scale-dependent effective elastic stiffness and strength of such composites. Parametric study is conducted to cover a wide range of material combinations defined by the stiffness ratio and the strain-to-failure ratio and a damage plane in terms of these two parameters to illustrate the results is employed.