A consistent crack modelling and analysis of rectangular hollow section joints

Abstract

This paper proposes a flexible approach to model one or several cracks under the weld toe of a rectangular hollow section (RHS) joint by mapping the two-dimensional crack's curvature onto the three-dimensional crack surface. Based on this model, an automatic mesh technique is developed to generate the entire finite element mesh of the damaged joint. This method can generate the mesh of cracks with any length, position, quantity, shape, and type (surface crack or through-thickness crack). Because of the steep stress gradient at the stress concentration region, the mesh around the crack front is refined using several mesh refinement steps to capture the stress distribution accurately. The generated model is then applied to study the plastic collapse load and crack opening displacement (COD) of some cracked RHS T-joints. Comparison between the numerical results and experimental test data shows that a good agreement is obtained for a typical RHS T-joint specimen subjected to brace end tension load. Thus, it confirms the efficiency and reliability of the proposed modelling approach for any cracked RHS T-joints.