The subsurface stress plays an important role in the damage of the movable contact element, but most subsurface stresses are obtained with numerical calculations according to the 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 of the static elements, it is seldom used in the 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 the 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 the different loads and the rotational speeds. Because the fringe figures indicate 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.

The subsurface stress plays an important role in the damage of the movable contact element, but most subsurface stresses are obtained with numerical calculations according to the 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 of the static elements, it is seldom used in the 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 the 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 the different loads and the rotational speeds. Because the fringe figures indicate 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.