Simultaneous simulation of closure behavior and shape development of fatigue surface cracks

The shape development and crack closure behavior of a surface crack subjected to fatigue loadings are two important features studied by researchers in the fatigue community. In the current study, both features are considered in the finite element analysis, and closure behavior and shape development of surface cracks are obtained simultaneously. In the analysis, two types of finite element models are constructed, one developed for the closure analysis and the other for the stress intensity factor computation of surface cracks. In the closure analysis, a new node release scheme is developed and the crack front nodes are unnecessarily simultaneously released during a loading cycle. Hence, the closure analysis of a surface crack with an evolving front of arbitrary shape becomes possible. The calculated results show that the proposed two-finite element model approach can obtain reasonable opening stress levels and crack shapes.