XFEM simulation of fatigue crack growth in a welded joint of a pressure vessel with a reinforcement ring

Abstract

The numerical analysis of the behaviour of a pressure vessel with a reinforcement ring subjected to both static and dynamic load is presented in this paper. This research was based on a previous analysis which involved different reinforcement ring dimensions, and their influence on the stress distribution within the pressure vessel, assuming the presence of a crack (Sedmak et al., in: International Conference on Structural Integrity and Durability, 2017). The aim was to compare the numerical results for two models, one of which was a 2D model simulated with classic FEM, whereas the other included a 3D fatigue crack, and was simulated with extended finite element method, using Morfeo software. The numerical simulation was based on a pressure vessel which is typically used as a part of hydropower plants, containing a manhole which is supported by the reinforcement ring. The analysis focused on a crack that was located in the welded joint between the reinforcement ring and the pressure vessel mantle. The results obtained by the simulations have shown the differences in the stress magnitudes and in the consequences resulting from the crack growth in both cases, depending on the type of the load, wherein the second (fatigue) load case was noticeably more extreme.