Interaction Analysis of Non-aligned Cracks Using Extended Finite Element Method

Abstract

Abstract Multiple flaws are frequently occurred in actual components, such as pressure vessels and power plants. These flaws will in some circumstances lead to more severe effects than single flaw alone. Assessment of the interaction behavior is based on the evaluation of alignment and combination of these multiple flaws. In the current standards, multiple cracks are treated as an equivalent single crack if the distance between two cracks satisfies a prescribed criterion. First, this study introduces the current alignment and combination rules for through-wall cracks. Following, to investigate the effects of the interaction of cracks, brittle fracture of a plate containing two offset cracks is simulated. The effect of cracks distances and crack lengths on stress intensity factors is evaluated. In addition, crack growth behavior is simulated based on linear elastic fracture mechanics approach. The extended finite element method has been utilized to model the problem. This method enables the domain to be modeled by finite elements without explicitly meshing the crack surfaces, and hence crack propagation simulations can be carried out without remeshing. Based on the results, a new alignment and combination rule is proposed.

Keywords

• crack interaction
• crack growth
• extended finite element method
• brittle fracture