Determination of time-dependent fringe order and principal birefringence direction using tricolor photoviscoelasticity

Abstract

The authors propose a new method for simultaneous determination of both fringe order and principal direction of birefringence in practical photoviscoelastic analysis using a white incident light with a set of the three primary colors. When using this method, not only fringe order but principal birefringence direction are successfully and easily determined from a single color image through a plane polariscope. Utilizing this method together with photoviscoelastic constitutive equations, time -dependent principal stress and strain difference, also their directions are obtained. In this paper, the fundamental of the tricolor photoviscoelastic technique is described briefly, then a successful application of the method to the analysis of an example of viscoelastic problem is shown.