Neutron diffraction analysis of the residual stress distribution in a bent bar

A well-characterized residual stress distribution resulting from four-point bending has been analysed using the neutron diffraction technique. Residual stresses were obtained from the strains measured at discrete positions through the bent bar on the (111) and (311) crystal planes of a nickel-based alloy using the appropriate diffraction elastic constants. In addition a profile refinement method was used to determine the residual stresses from average strains from all the diffraction peaks in the spectrum. The measured residual stress profiles have also been compared with strain gauge data and with analytical and finite element predictions. It has been established that the profile refinement approach gives stresses which most closely match those obtained by the non-diffraction techniques.