Routine FE determination of stress intensity factors at curved crack fronts using an influence function technique

Abstract

A remarkably simple and accurate one-step application of the finite element (FE) method is suggested as a means for the engineer's routine determination of stress intensity factors in linear fracture mechanics for complicated non-symmetric geometries with three-dimensional states of stress and curved crack fronts. The vector-valued influence functions (Green functions) used here are a special kind of weight functions. Mode separation is inherent to the present procedure. Numerical examples demonstrate the versatility of the method. Accuracies within 1% are easily achieved. Detailed guidance to the design of the FE mesh at the crack front is given. Any standard FE code can be used, without requirements for special finite or boundary elements. In retrospect, the present method can be seen as a rather trivial calculation technique which has been made feasible and attractive by the capabilities of today's computers and softwares.