The computer simulation of multiple layering of welds is necessary to determine the distortion and residual stresses arising from the welding process. The welding simulation requires thermal and structural solutions, which are usually carried out in two simulations. Once solved, the thermal transient model temperature results are read in to the structural model to solve for component stresses.
This paper describes the application of the Abaqus Weld Interface (AWI) plug-in for 2D axisymmetric simulation of the residual stresses generated in a Dissimilar Metal Weld (DMW) nozzle to pipe joint comprising of an Alloy 600 nozzle girth weld to a 316 LN Stainless Steel (SS) safe-end pipe. The test piece was manufactured for an ongoing programme within Rolls-Royce PLC. A mechanised Tungsten Inert Gas (TIG) welding process was employed depositing 83 weld bead passes. The weld filler material was Alloy 82.
The AWI Graphical User Interface (GUI) simplifies and saves a large amount of time towards generating the Finite Element Models (FEMs). By using the AWI plug-in within Abaqus/CAE, the FEMs take approximately a month to generate and solve with significant time savings associated with setting up the surfaces for the welding bead sequences and matching the heat input to the actual specimen. The GUI rapidly creates both the thermal and structural input files for the Abaqus/Standard solver. However, modifications were made to the thermal and structural FEM model input files to suit the analysis pre-processing requirements for idealised conditions to match the test piece pipework conditions.
FEM predictions captured the characteristic through-wall Weld Residual Stress (WRS) profiles measured by Deep Hole Drilling (DHD). The weld shrinkage was under estimated.