Calibration Test in Photo-Rheological Stress Analysis for Variable Rate of Principal Stress Difference

Abstract

Calibration test for photo-rheological stress analysis in a plastically deforming body is performed by using a softened celluloid specimen heated at 55.5°C and subjected to a combined stress which consists of uniaxial tension and hydrostatic pressure under the variable stress rate and principal stress ratio. The relation between the principal stress and strain differences and the relation between the fringe order and the principal stress and strain differences established under the constant stress rate are proved to be useful also for the variable stress rate in the test. The value of principal stress difference obtained by the photo-rheological stress analysis using the above mentioned relation according to the fringe order obtained from the test agreed well with the assigned value of principal stress difference.