Modeling of Fracture Propagation in Random Composites Coupling Virtual Elements and Interface Elements

In this paper, the fracture propagation process in polycrystalline random composites is investigated by using a coupled virtual element-interface element model. Each crystal, also referred to as grain, is discretized with a single low-order virtual element with constant strain interpolation over the element, while the interaction between grains is described by means of interface finite elements. These latter are characterized by a nonlinear constitutive law accounting for damage, unilateral contact, and friction, thus allowing to model the typical intergranular crack growth. Numerical applications are performed to investigate the tensile and shear response of Alumina/Zirconia specimens, a pragmatic example of ceramic matrix composite widely used in many engineering fields. The investigation is conducted at the level of the representative volume element, whose size is derived from the results of a statistical homogenization procedure tailored for random composites.