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

In this paper an algorithm is proposed for the analysis of cracks growing in a stable manner in ductile materials. This algorithm uses a recently 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 behaviour is modelled through the use of an approximation for the plastic component of the strain tenser on the region expected to yield. This region is discretized with internal quadratic, quadrilateral and/or triangular cells. This new algorithm for stable crack growth is based on the release of pairs of elements, which are assumed to be in contact prior to the formation of the crack. Crack-face contact is simulated by directly enforcing compatibility and equilibrium conditions between the surfaces of the crack. Elastoplastic fracture parameters, namely J-type integrals, can be calculated at all stages of the fatigue crack growth process. An example of the application of this technique is presented.