Fast computable residual stress analysis for welded pipe joint based on iterative substructure method

Residual stress caused by welding is one of the most influential factors on stress corrosion cracking (SCC) to occur in vessels and piping of nuclear power plants. Among various evaluation methods of welding residual stress, numerical simulation is effective for complement of measured data and systematic study on dominant factors. However, an application for actual size components frequently makes it difficult to analyze the residual stress because of extremely long calculation time depending on the structural size and welding conditions. In this paper, a development of an efficient and reliable technique for welding residual stress analysis is reported. The analysis technique to calculate the residual stress using iterative substructure method was developed and compared with conventional one using a commercial finite element analysis code concerning the analysis accuracy and the computational speed for the residual stress of welded pipe joint. The residual stress distributions obtained by the both methods agreed well with each other. Moreover, it has been clear that the developed technique can calculate the residual stress with less computing time. From the results, it is concluded that the analysis technique using the iterative substructure method can also calculate the residual stress distribution much faster with nearly same accuracy as the conventional methods when the size of welding structure is larger. (author)