| Frictional heating generated by sliding contact bodies causes thermoelastic distortion. This generated heat tends to modify the shape of the contact bodies, and this in turn, influences the contact pressure distribution between the components. When the sliding speed is sufficiently high, the system becomes unstable, and hot spots appear on the surface of the bodies where the pressure and temperature values are elevated. This phenomenon is known as thermoelastic instability (TEI), and the sliding speed that alters the stability of the system is called the critical sliding speed.; Three complementary approaches are used to study the TEI phenomenon of different models: a theoretical stability analysis, a transient numerical simulation, and a steady state numerical analysis.; In the first approach, an analytical method is used to determine the stability of a multi-layer system. A characteristic equation that determines the stability is derived utilizing relations for the displacement and temperature profiles in each layer, as well as the layer-to-layer contact pressure field. This model was validated by analyzing some special cases with known results. The outcome of this theoretical stability investigation suggests using a plane strain model for the layers in order to ensure conservative results.; To predict what happens above the critical speed, a transient finite element simulation is developed for a two-dimensional, three-layer thermoelastic model of a stationary layer placed between two sliding layers, with frictional heat generation. The results in the linear range, full contact regime are validated by comparison with the analytical predictions of Lee and Barber. In the nonlinear range, a separation occurs, and there is a non-monotonic transition to a steady state with a partial contact area. The migration speed falls to low values compared to the values that are obtained while the system is in the linear range. When several wavelengths are unstable, the final steady state generally corresponds to that of the longest unstable wavelength, even though some other modes may have more rapid growth rates in the linear regime.; It is observed from the transient simulations, that a prohibitively large number of time steps is required for the system to reach steady state. For this reason, a steady state finite element model is developed to directly obtain a steady state solution. First, a two-dimensional, two-layer model is built with a sliding speed acting out-of-plane to reduce the problem's complexity. This model shows that, through an iterative scheme, it is possible to efficiently find a steady state solution for each wavelength with an initial pressure perturbation applied to the system. A two-dimensional, three-layer model with a sliding speed applied in-plane is then investigated. The developed steady state solution of this more advanced model is also successfully validated in the linear range with the analytical solution of Lee and Barber, as well as with the results obtained from the corresponding transient simulation. Finally, the three-layer model is used to investigate the behavior of the system at various sliding speeds. |
