Characteristics of indentation cracking using cohesive zone finite element techniques for pyramidal indenters

During indentation of brittle materials, cracks may be generated around the impression, depending on load conditions, material and indenter geometry. We investigate the effect of indenter geometry (centerline-to-face angle and number of edges) on crack characteristics by indentation cracking test and finite element analysis (FEA). Considering conditions for crack initiation and propagation, an FE model is employed featuring cohesive interfaces in zones of potential crack formation. After verification of the FE model through comparison with experimental results for Vickers and three-sided pyramidal indentation, we study the crack morphology for diverse indenter geometries and establish a relation between the crack length cc and the number of indenter edges ncnc. Together with a relation between indenter angle ψ   and crack length cc, we can predict the length of the crack induced by other types of indenter from the crack size obtained with a reference indenter.