Contact Interaction of a Ball Piston and a Running Track in a Hydrovolumetric Transmission with Intermediate Deformable Surface Layers

Abstract

The properties of surface layers need to be accounted for in the analysis of contact interaction of complex-shaped bodies. Surface roughness, films, and coatings provide an additional response to the contact tractions. These microscopic deformations are generally nonlinear. To constitute the relationship between the contact pressure and normal compression of the intermediate layers, an ad hoc model is proposed. It consists of two superimposed layers on one side of the contact. Each layer has a different elasticity modulus and stiffness. As a result, the thicker later gets into contact sooner than the thinner one, which only comes into play after a certain loading level. This approach makes it possible to model an arbitrary bilinear response of the contact interface effectively using the finite element method. This model is applied to the analysis of contact interaction in radial hydrovolumetric drive with spherical pistons. The effect of layer stiffness parameters on the contact pressure distribution and the local stresses in the bodies is studied. The ability of additional compliance to reduce the stresses is found to be useful for further improvement of the strength of the pistons, which is crucial for the design.