Separation of isochromatic and isoclinic patterns of a slice optically isolated in a 3-D photoelastic medium

Abstract

We show a nondestructive experimental method which gives the isochromatic and isostatic patterns of slice optically isolated in a three dimensional photoelastic model. We used a nondestructive method of optical slicing developed in our laboratory. In this method, the photoelastic model is optically sliced by two plane laser beams. The analyze of the scattered light gives fringes equivalent to the ones obtained in a plane polariscope (isochromatic and isoclinic fringes). In order to separate the isochromatic and the isoclinic fringes, we recorded several images for different polarization orientations and we separated the isoclinic and isochromatic fringes using the Fourier transform. Then the isostatics pattern is plotted. We show a test of a punctual loading on the top of a prismatic specimen and the possibilities of our method in an industrial case of a model realized by stereolithography technique.