PHOTOELASTIC tests are a valuable tool for analyzing combined stresses in gears, where the calculations suitable for simple stresses become extremely complicated.
First, a plastic replica of the part is made of transparent material. Then, when this part is examined by means of polarized light as it is being stressed, a visible stress pattern is formed that can be evaluated.
The author discusses the different types of stresses found in gear teeth under load, presenting formulas, where they have been developed, and stress patterns obtained by means of photoelasticity in other cases