Development of the integrated measuring system of strain distribution and defect using ESPI & shearography

Abstract

The non-destructive, non-contact measurement techniques of displacement and defect using laser speckle interferometry have the advantages of sensitivity, non-destructiveness and real-time measurement. ESPI (Electronic Speckle Pattern Interferometry) and Shearography are representative techniques using laser speckle interferometry. Both of them have been studied independently owing to physically different nature of optics and been tried to apply to the industrial field from 1970. But it is yet to be succeeded for the system volume and operation hardship. This paper presents the integrated system that can observe in-plane, out-of-plane displacement and defect on the surface using ESPI and Shearography. It is anticipated to apply this system usefully to the non-contact metrological field. And qualitative comparison shows acceptable agreement of experiments performed by this integrated system with the strain gauge.