photoelasticiteetissä

Photoelasticite is a translucent polymer composite developed for use in photoelastic stress analysis. The material was first formulated in the early 2000s by a consortium of polymer scientists at the Danish Technical University and the Massachusetts Institute of Technology. Photoelasticite combines a polycarbonate backbone with a high concentration of micron‑sized glass spheres that provide a residual birefringence response to mechanical loads.

In unladen conditions, the refractive indices of photoelasticite are isotropic, but under tension or compression the induced strain aligns with the polymer chains. This strain‑induced birefringence produces colorful fringe patterns when observing the material through crossed polarizers, allowing precise measurement of principal stress directions and magnitudes. The silk‑like translucency of photoelasticite also makes it resistant to fraying or tearing, which distinguishes it from earlier materials such as PMMA or polyimide films.

Manufacturing involves melt extrusion followed by a heat‑setting step that aligns the microscopic glass spheres. Subsequent cryogenic cooling locks the alignment in place, and the final product can be machined into lenses, plates, or curved surfaces. Commercial suppliers offer stock sheets of various thicknesses, and some research groups have developed custom molds for specific experimental geometries.

Applications of photoelasticite span civil engineering, biomechanics, and aerospace testing. Engineers routinely use it to model stress distributions in bridge components and aircraft fuselage sections, while biomechanical laboratories use the material to examine load pathways in simulated bone grafts and joint prostheses. Studies published in the Journal of Applied Elasticity and the International Journal of Photoelasticity report the high accuracy of stress predictions when using photoelasticite compared with finite‑element analysis.