Evaluation of residual stress assessment methods using a repair weld benchmark

Abstract

A simple design of a letterbox-type repair weld on a plate is evaluated as a benchmark problem. Residual stresses are recorded using the non-destructive neutron diffraction technique and compared with predictions by full three-dimensional finite element modelling. The comparison is performed over a number of path lines in an attempt to evaluate both methods as potential residual stress assessment tools, for weld repairs. The proposed finite element methodology is based on uncoupled quasi-static thermoelasticity and incorporates the element activation–deactivation technique for simulating weld deposition. Sensitivity analysis indicates that the effect of heat loss due to radiation on predicted residual stresses is negligible, whereas incorporation of full annealing into the model is recommended. The diffractometer used, is STRESS-SPEC, located at the FRMII research reactor (Munich, Germany) and comprises a highly flexible monochromator arrangement and a two-dimensional position-sensitive 3He detector. The success of the repair weld benchmark design is illustrated by not only the satisfactory correlation between experimental and computational results in the form of residual stress but also temperature history data.