Determination of Principal-Stress Directions from Color Photoelastic Fringes Obtained with a Semicircular Polariscope

摘要

A method was developed for determining the directions of the principal stresses from color photoelastic fringes obtained in a semicircular polariscope. The semicircular polariscope was composed of a circular polarizer and an ordinary linear polarizer. A model was illuminated with circularly polarized light and the light transmitted from the model was analyzed with the rotating analyzer so that phase-stepped color photoelastic fringes were obtained. A four-step color phase-shifting technique was used for obtaining the principal-stress directions from color photoelastic fringes. The ability of the method was investigated with theoretical color photoelastic fringes of a circular disk under diametric compression. Results showed that the method is effective to determine the principal-stress directions.