New formulation of the Ritchie, Knot and Rice Hypothesis

摘要

In the paper the RKR (Ritchie-Knot-Rice) hypothesis on the local fracture criterion has been reconsidered utilizing resultsof the finite element stress analysis in front of the crack.The numerical analysis was carried out using the finite strainformulation.In such a case the characteristic features of the stress field – the opening stress maximum and its location –were used to propose the local fracture criterion and to derive the analytical relation concerning the distance from thecrack tip where the maximum opening stress is located.Both the new version of the RKR hypothesis and the relations derived were utilized in the analysis of the in-plane-constraint influence on fracture toughness.