Fracture energy and tensile strength depending on stress triaxiality along a running crack front in three-dimensional cohesive modeling

Abstract

It is known that the critical fracture energy value decreases with specimen thickness, whereas the local tensile strength of the material increases with the stress triaxiality. In the present work, the critical fracture energy and the tensile strength depending on stress triaxiality are experimentally investigated and identified with the help of finite element computations. It is found that the fracture energy distributes in a running crack front very differently from that in a straight through-crack. The maximum crack driving force appears near the free surface in the plane stress state, whereas the maximum tensile stress is in the specimen middle. The local fracture energy is monotonically decreasing in the form of an exponential function, while the local tensile strength linearly increases with the stress triaxiality.