A New Method for Measuring Stress Inside Movable Element in Contact

Subsurface stress plays an important role in the damage of a movable contact element, but subsurface stresses are usually obtained with numerical calculation according to the theory of contact mechanics. In the present paper, a new method to measure the subsurface stress of the movable element is proposed with using photoelastic technology. Although the technology has been widely used in measuring the stress in the static state, it is seldom used in a moving body because the observed point is moving. After the experimental tester is introduced in detail, the principles of the photoelastic technology are presented. The tester is designed to be able to working in three conditions, the static, the rolling, and the sliding, in the line or surface contacts. The experimental results, that is, the interference fringes, of the three states are then presented in different loads and rotational speeds. Because the fringe figure indicates the maximum shear stress distribution in the body of the moving element, we can find what the real stress distribution in the rolling or sliding element is alike.