Definition - What does Photoelasticity mean?
Photoelasticity refers to a physical property exhibited by solids that are transparent and isotropic in which they become doubly refracting. Either tensile or compressive stress can be applied to a solid's surface to enable a detailed study of the stress distribution from the patterns observed in a polariscope.
Corrosionpedia explains Photoelasticity
The property of photoelasticity is used to support an empirical determination of the material stress distribution of an object by placing it under a polarized light. This generates stress concentration data for irregular geometries and critical stress points in a material. In certain applications where mathematical methods are lacking, photoelasticity is incorporated to optimize an optomechanical property called birefringence, which is the property of a material possessing a refractive index that is dependant on polarization and light direction.