Use of Full Field of Strains Found By Grating Shearography to Determine Residual Stress

Abstract : A new method combining grating shearography and the incremental hole drilling method has been developed to determine the residual stress distribution in depth. Grating shearography is a technique designed to determine directly the strain field with a high level of sensitivity and a very high spatial resolution. The hole drilling method is one of the most popular methods used in mechanical engineering to determine the residual stress locked into a structure. This new optical method enables the strain to be measured while taking into account the entire strain field around the hole. The finite element method is used to calibrate the method. The method was tested on an ultrasonic shot-peened aluminium specimen.