SENSITIVITY ANALYSES OF FINITE ELEMENT METHOD FOR COMPUTING RESIDUAL STRESS OF DISSIMILAR METAL MULTI-PASS WELD

Recently the stress corrosion cracking cases of dissimilar metal welds are found in many nuclear power plants. Weld-induced residual stress is main factor for crack growth. Therefore exact estimation of residual stress is important for reliable operation. This paper presents residual stress computation performed by EU mock-up Nozzle. Based on ANSYS software, uncoupled thermal-mechanical three-dimensional (3D) and two-dimensional ax symmetric finite element models are developed. Based on 2 dimensional and 3 dimensional finite element analyses, effect of the welding sequence approaches for multi-pass weld such as lump, layer and ring etc. on residual stress variation is estimated for sensitivity analysis.