Applications of the method of caustics to studies of rolling contact fatigue (Part1): for measuring normal contact force in disk-to-disk contact

摘要

The method of caustics was applied to several problems of rolling contact fatigue, which is one of the causes of damage in machines and mechanical components. The method of caustics allows continuous determination of contact traction and stress concentration factors without actual physical contact. The following is the first part in a two-part series; a method for measuring the vertical forces in disk-to-disk contact is described. Next, two analytical methods called the "method of contact width modification" and the "fan-shaped body approximation" were used to derive a relational expression for disk-to disk contact. The expression was used to develop a caustic simulation program for two-dimensional Hertzian contact, which has more general applications. Disks and plates of an acrylic resin (PMMA) were used. The results of the caustic experiments and of a simulation matched well. A relational expression was developed that uses Dx, the diameter of the image in disk-to-disk contact, to estimate the normal force P.