Polycarbonate as a Model Material for Three-Dimensional Photoplasticity

Abstract

Polycarbonate is a polymer which exhibits extreme toughness, a pronounced yield behavior, and the ability to flow extensively prior to fracture. These characteristics coupled with its birefringent properties indicate its suitability as a model material for photoelastic analyses. This study treats the photoplastic response of polycarbonate which has been deformed well beyond the yield point and unloaded. The strain field associated with this permanent deformation is related to the birefringence by the conventional strain-optic law. The birefringence is permanently locked in the polycarbonate models on a molecular scale. The model can be sliced to isolate planes of interest and the method can be applied to study permanent strains in plastically deformed three-dimensional bodies.