Thermo-Mechanical Analysis Approach for Prediction of Weld Distorion and Residual Stresses on Hydro Form Structure

Residual stresses and thermal distortion are a common phenomenon observed in any welding method. This is a result of non-uniform stresses generated due to highly localized heating at the joint edges, which fuses the base material and leads to considerable amount of changes in mechanical properties. Thus, it is very important to evaluate these effects in any welded structural members before designing for actual loading condition. Therefore, accurate prediction of these stresses and distortion is of critical importance to ensure the in-service structural integrity of welded structures. The recent advancement in Computational simulation and numerical techniques helps in evaluating the weld distortion and residual stresses. The moving heat flux approach and Element birth/death method makes it easier to analyze the weld distortion. This is done with the use of ANSYS^® Commercial FE software. In this study, cylindrical vessels which are connected through circumferential butt weld (V groove type) are considered for evaluating the residual stress and thermal distortion induced due to welding process. The present work is focused on simulating the weld distortion by thermo mechanical analysis in a realistic approach from the above said methods and is aimed in measuring the induced imperfections in the welded structures. It has been observed from the results that the Element birth/death method is a more realistic and precise method for predicting the thermal distortion and residual stresses in the structure.