Analysis of heat induced strain in transparent samples using digital shearography

Abstract

Digital shearography, an interferometric technique, which describes the spatial derivative of the deformation in a material, has been demonstrated to be suitable for strain analysis in transparent samples. This study demonstrates the use of the technique in the inspection of transparent samples deformed through the application of heat. It is shown that the technique can resolve strains in the order of 20 micro strains. It is also shown that the phase shifting method utilized in the technique is able to resolve the transient states brought about by small temperature differences.