Multi-wavelengths shearography for NDT and strain measurements

摘要

Non-destructive testing and the measurement of strain are key techniques in material characterization and structural testing. By using laser-based imaging techniques such as shearography the whole-field displacements of an object surface can be visualised. A multiwavelengths shearographic sensor with switchable shear directions was developed to measure planar strain distributions. In this paper we describe the experimental set-up and give examples of in-plane strain measurements during tensile testing. The comparison with strain gage measurements and an application to NDT are discussed.