Elastic-plastic finite-element (FE) analyses of a pressurized cylinder with a deep inner surface flaw were done to study the effect of different loading conditions, i.e., axial forces and crack-face loading. The local energy-release rate was calculated by the method of virtual crack extension including a correction term if pressure acts on the crack faces. The numerical results are compared with a small-scale yielding generalization of the Newman-Raju approximation.
The FE analysis reveals that the highest triaxiality of the stress state does not coincide with the point of maximumJ. Thus, an explanation might be found for the experimentally observed canoe shape of stable crack propagation.