Elastoplastic dual boundary elements: Application to crack-face contact

Abstract

The elastoplastic dual boundary element method (EPDBEM) is extended to the analysis of elastoplastic fracture mechanics (EPFM) problems in which crack-face contact occurs. The dual equations of the method are the displacement and the traction boundary integral equations. The use of these dual equations allows the solution of general mixed-mode crack problems with a single-region formulation. The elastoplastic behaviour is modelled through the use of an approximation for the plastic component of the strain tensor on the region expected to yield. This region is discretized with internal quadratic, quadrilateral and/or triangular cells. The contact conditions between the surfaces of the crack are introduced by directly enforcing compatibility and equilibrium conditions. Three examples of plates subjected to reversed bending are analysed, namely: an edge-cracked plate; a straight crack at a hole at the edge of a plate; and a kinked crack at a hole at the edge of a plate. The method is used to determine J-integrals, the extent of the contact region, the deformed shapes and the contact stresses, and where possible, these results are compared with others available in the literature.