Evaluation of Ductile Crack Propagation Behavior for Subsurface Crack in Cladded Plates Using XFEM

In petrochemical and nuclear power plants, inner surface of components, such as pressure vessels and piping, which are made of carbon steels or low-alloy steels, is often cladded by austenitic stainless steels to improve the corrosion resistance of those components. In the evaluation of a crack postulated near the inner surface of cladded components, the following two different kinds of cracks are often assumed: One is a surface crack penetrated through cladding and the other is a subsurface crack under cladding. In order to evaluate the structural integrity of those components in a rational manner, it is important to investigate the crack propagation behavior. In particular, it should be evaluated whether a subsurface crack penetrates through cladding or is arrested at the interface between cladding and base metal. In this study, ductile crack propagation analysis for a subsurface elliptical crack in cladded plates was performed using elastic-plastic XFEM, which can model the crack independent of finite elements.