STRESSES IN THE CONTACT ZONE

The paper deals with the contact-stress problem with particular reference to adhesion in the rail-wheel contact situation. The methods of calculation of the size, shape and orientation of the contact area are described, and con-firmed by the results of frozen-stress photoelastic tests. The test results are confined to the contact surface, since sub-surface stresses are not directly relevant in the adhesion problem. The distributions of surface shear stress resulting from the application of tangential forces to different shapes of contact area are described for static and rolling conditions. Methods of calculating thc creep of rolling bodies are also considered. The problem of bodies rolling and spinning about an axis normal to the contact area is not so well under-stood, but a brief description is given. The effects of bending stresses in rails and of the size of the contact area in relation to the railhead are discussed briefly