A plastic damage model for finite element analysis of cracking of silicon under indentation

A modified plastic damage model that accounts for tensile damage and compressive plasticity as well as interactions among them is adopted to simulate the indentation-induced cracking of silicon under Berkovich, cube corner, and Vickers indenters. Simulations with this model capture not only the well-known cracking geometries in indented ceramics, such as radial, median, lateral, and half penny (Vickers indenter) cracks, but also the recent experimentally discovered quarter penny cracks under Berkovich and cube corner pyramidal indenters. The quarter penny cracks are found to be formed by the coalescence of radial and median cracks for the first time in the simulation. Loads at which radial and half penny cracks are initiated in silicon are generally close to the experimental values reported in the literature, and the crack lengths on the sample surface agree well with both the current experimental measurements and analytical results by fracture mechanics.