Finite element analysis of temperatures and stresses in a single‐pass butt‐welded pipe—influence of mesh density and material modelling

Abstract

Single‐pass girth butt welding of a carbon‐manganese pipe is studied numerically using the finite element codes ADINAT/ADINA. A rotationally symmetric finite element model is employed in both the thermal and mechanical analysis. This model is used to investigate the influence on the residual stress state of pipe geometry, mesh density and material modelling. The results from the present study are compared with previous results from two different FE analyses and an experimental investigation. One of the FE analyses was fully three dimensional and the other employed shell elements. The calculated residual stresses were found to differ significantly only when different material models were employed. The thermal strain seemed to be the material parameter with the largest influence on the residual stress state. Especially the changes in thermal strain during phase transformations seemed to have a great influence. This means that the temperature field should be determined accurately enough to predict when and where the different phase transformations occur. Almost the same residual stresses were obtained for two pipes with different pipe geometries and weld parameters.