Influence of microstructure on the fracture induced by a hard cutting indenter

The process of indentation of brittle and quasi-brittle materials has been investigated both from the experimental and the theoretical point of view. Quite surprisingly, only a few studies have tried to explain the mechanics of cutting due to an indenter which penetrates inside the material. In this paper, an attempt is made to find some general relations for the cutting process in brittle and quasi-brittle materials, under different hypotheses for the microscopic failure behaviour. Fracture patterns in homogeneous brittle solids are obtained by the Finite Element Method in the framework of Linear Elastic Fracture Mechanics (LEFM). On the other hand, microstructural heterogeneities are taken into account by the Lattice Model simulation. Although the reality is often much more complex than its theoretical model, the study provides interesting hints for improving performance of cutting tools.