Fracture-mechanical analysis of an austenitic steel (X6CrNi1811) using two standard crack test plates under two-dimensional stress

In this study the fracture-mechanical stresses reaching far into the full plastic range are determined on the basis of the elastic-plastic fundamental equations with consideration to the material behaviour with its complete, highly accurate characteristics obtained from tension tests. The problems of alternative use of material laws with nominal and true tensions and elongations is discussed theoretically. By means of parallel calculations with the two forms of the material law the influence on the stresses is shown. The investigation is based on the numerical calculation with the finite elements of a centre cracked disc and a compact specimen with a crack depth ratio of a/b=0.6 each with consideration to the real material behaviour of the steel X6 CrNi 1811. (orig./MM)