Thermomechanical Instabilities in Metal-Free Friction Materials Using a Nonlinear Transient Simulation Approach

The invention of metal-free friction materials is gaining popularity in the manufacturing of brake pads and clutch friction discs because of the negative factors associated with metals such as copper. To gain more insight into the failure mechanism of the recent invention during brake or clutch applications, a nonlinear transient thermomechanical model is established using Finite Element Code. The model is based on a two-dimensional configuration for an investigation on the onset of TMI (Thermo-Mechanical Instability) during sliding contact in such material. The model is validated by comparing the transient simulation results for a full-contact regime to the result from the existing eigenvalue method. A parametric study is carried out to examine how the thermal conductivities and the elastic moduli influence TMI. The simulation results show that the thermal conductivities in the transverse direction and elastic moduli in the longitudinal direction can stabilize the system. Conversely, the elastic moduli in the transverse direction and thermal conductivity in the longitudinal direction were found to enhance TMI formation. Overall, the elastic moduli and thermal conductivities in the longitudinal direction tend to play a minor role in TMI.