Research on thermoelastic instability and temperature-pressure perturbation characteristics of friction pairs in disc clutches

ObjectiveThe finite element model under symmetric (friction disc)-antisymmetric (steel disc) was established to investigate the thermoelastic instability (TEI) and perturbation field distribution of multi-layer material friction pairs, which was based on the Galerkin method.MethodsThe radial distribution of critical speed and perturbation growth rate variation were obtained through coordinate transformation and Matlab numerical model analysis. A transient perturbation field calculation model for sliding surfaces was proposed based on the perturbation method and finite element model, and the distribution of temperature and pressure perturbation field on the sliding surface was obtained.ResultsThe results indicate that the wave number corresponding to the minimum critical speed is the main characteristic wave number at which the perturbation growth rate increases the fastest. Thermoelastic instability first occurs at the outer diameter of the friction pair, and then gradually expands towards the inner diameter as the angular speed increases. The temperature and pressure perturbation fields are periodically distributed along the circumference of the friction pair, but the amplitude of perturbation at the outer diameter side is higher than that at the inner diameter side due to the difference in radial distribution of the linear speed. The amplitude of perturbation will rapidly increase with the relative sliding time due to the exponential growth effect when the relative sliding speed exceeds the critical speed. The results provide a basis for further research on the formation mechanism of hot spots and the distribution of temperature and pressure fields.