Abstract
Photoplasticity is a full-field technique that is based on the interpretation of optical patterns in transparent birefringent materials that have been stressed beyond their elastic limit. Polycarbonate resin, a photoplastic model material, has been subjected to much study. In this study, we attempted to investigate the dependence of the stress-strain curves of polycarbonate resin on temperature and tensile speed at high temperature, to find the best temperature for plastic strain freezing. We also considered whether the theoretical equation of Ramberg-Osgood could be applied to the stress-strain curve that was obtained by photoplastic experimentation.
Therewith, the aim of next study is an examination of the possibilities of the plastic strain freezing method in comparison with the elastic stress freezing method. First, we attempted to determine the best temperature for plastic strain freezing. Further, it became apparent from systematic experimental results that it is 'strain' and not 'stress' which is frozen in plastic regions. In other words, it was made clear that the Birefringence N in strain freezing was proportional to the difference in the principal strains (ε1-ε2).
