ELASTOPLASTIC SIMULATION OF FATIGUE-CRACK GROWTH - DUAL BOUNDARY-ELEMENT FORMULATION

In this paper an algorithm is proposed for the analysis of cracks grow ing in a stable manner in ductile materials. This algorithm uses a rec ently presented formulation of the elastoplastic dual boundary element method (EPDBEM) by Leitao et al., which allows for crack problems to be modelled within a single-region formulation. The elastoplastic beha viour is modelled through the use of an approximation for the plastic component of the strain tenser on the region expected to yield. This r egion is discretized with internal quadratic, quadrilateral and/or tri angular cells. This new algorithm for stable crack growth is based on the release of pairs of elements, which are assumed to be in contact p rior to the formation of the crack. Crack-face contact is simulated by directly enforcing compatibility and equilibrium conditions between t he surfaces of the crack. Elastoplastic fracture parameters, namely J- type integrals, can be calculated at all stages of the fatigue crack g rowth process. An example of the application of this technique is pres ented.