Effect of Wear on Frictionally Excited Thermoelastic Instability 2020-01-1629
A finite element model for the effect of wear on frictionally excited Thermoelastic Instability (TEI) is developed by combining the equations of thermoelasticity, the classical Reye-Archard-Khrushchov wear law, along with the conforming contact conditions. The method is based on a two-dimensional, frictional sliding model with a bimaterial interface and a simplified geometry of finite thickness. An assumption of the solution in the perturbation form leads to a second-order eigenvalue problem, with the eigenvalue being the exponential growth rate of perturbation. The existing analytical solutions using two infinite half planes are used to validate the numerical solutions in several representative scenarios, including a limiting case in the absence of wear. In general, good agreements between the numerical and analytical approaches have been obtained. However, the discrepancies exist when the wear rates of the two materials are close to each other and when the wear rates are significantly greater than the critical rate. This is largely induced by the numerical errors in the nonlinear eigenvalue equation, as well as the convergence issue in the analytical solution when it drastically oscillates across the thickness. It has been confirmed through this study that wear may suppress or amplify the effect of TEI depending on the thermomechanical properties of the materials, which is consistent with the recent research findings on the same topic via an analytical approach. The model developed in this research can be extended to deal with more complex geometries and boundary conditions at higher dimensions.