FINITE ELEMENT SIMULATION OF WELDING IN PIPES: A SENSITIVITYANALYSIS

摘要

Thermal cycling, high heating rates, high temperature peaks and inter-pass and post weld cooling are parameters that largelyaffect residual stress generation in and around welds.A multi-pass weld joining two pipes made of different materials issimulated using 2-D axi-symmetric finite element analysis.The proposed methodology for weld simulation incorporates thewell-known birth of elements technique and follows the prescribed temperature approach for heat input modeling.The effect ofvarious aspects of modeling, on the accuracy of predicted residual strains, is investigated through a series of sensitivity tests,using a 2-D axi-symmetric model.Radiation, creep and heat input model selection, have a significant impact on results, butphase change, convective cooling and pipe contact are not as important.Results are also compared to neutron diffractionmeasurements obtained from the literature.Welding electrode start/stop effects on predicted residual strains are found to besignificant, after a limited 3-D analysis, which justifies further investigation.