Nonlinear mathematical models of weakly loaded contact joints

The paper presents nonlinear mathematical models describing the properties of dry and lubricated contact joints loaded in normal direction. The energy dissipation coefficient $\psi$ is expressed as a function of the load amplitude. The structure of the models is defined on the basis of the experimentally determined spectral-response characteristics of relative displacements of the contact surfaces, and of contact load in the normal direction. The form of the functional factors of models is estimated of the linear regression analysis.