He was an expert on stress analysis and Photoelasticity. He received a Ph.D. at the Sorbonne as a physicist on a subject of photoelasticity. So the present section deals with photoelasticity in a plane stress system. Dynamic photoelasticity integrated with high-speed photography is utilized to investigate fracture behavior in materials. The experiments use high-speed photography, full-field photoelasticity, and laser velocimetry as diagnostics. However, examining photoelasticity in three-dimensional systems is more involved than two-dimensional or plane-stress system. Dentistry utilizes photoelasticity to analyze strain in denture materials. Photoelasticity describes changes in the optical properties of a material under mechanical deformation. Photoelasticity can describe both three-dimensional and two-dimensional states of stress. This effect is called photoelasticity, and can be used to reveal stresses in structures.