Emphasizing the accuracy of the uncertainty of residual stress determination using neutron diffraction

Abstract

The execution of residual strain measurements using neutron diffraction in order to determine the residual stress state in a material or component is now a well-established method. The analysis of the uncertainty of the resultant strain and stress is a topic that is frequently brought into discussion. There are many sources, some obvious and some not so obvious that can contribute to the overall uncertainty and each should be considered carefully. The potential uncertainties could be simulated using a model that closely represents the experimental set-up and the particular sample that is being measured. A suggested form could be the use of a finite element model of the sample within one of the many neutron scattering simulation programs. The interaction between the properties of the sample and the instrument and/or set-up that is measuring the strain is something that can vary substantially. Taking this into account, the accuracy of the final uncertainty of the measurement is revisited and reassessed in this discussion.