<title>Whole-field automatic measurements of isochromatics and isoclinics in photoelastic coatings</title>

Abstract

Digital approaches for determination of fringe order and principal stress direction in photoelastic coatings are presented. The relationships between the intensity values and the fringe orders of two wavelengths, and relevant theory and explicit conditions for directly determining the principal stress angles in the range z/2 are derived. The scheme developed allows for the automatic determination of the fringe orders with or without zero-order fringes in the fringe patterns. Test results are reported.