A numerical study of the size effect in fracture mechanical bending tests with the cohesive zone method

Abstract A finite element crack growth model is presented which is based on the cohesive zone method and which handles crack initiation and crack growth with a prescribed traction–separation law. In this two parameter approach, the fracture behaviour is determined by the cohesive strength and the separation energy. The model is applied to simulate three-point bending tests of unirradiated reduced-activation ferritic–martensitic steels. The specimen size is varied from nearly standard to miniaturized dimensions to investigate its influence on the crack resistance curve. Additionally, the effect of side grooving on crack initiation and the early stage of crack growth is studied with the presented numerical method.