Distinguishing the effects of adhesive wear and thermal degradation on the tribological characteristics of paper-based friction materials under dry environment: A theoretical study

• Adhesive wear and thermal degradation are major degradation sources of paper-based friction materials.
• The effects of both degradation sources on the tribological characteristics of such materials are theoretically investigated.
• Degradation models are derived based on understanding of the physics of the degradation mechanisms.
• The stochastic elasto-plastic GW-McCool contact model and the degradation models are employed to build a simulation framework.
• We reveal that the two degradation mechanisms have opposite effects on some contact parameters.

Adhesive wear and thermal degradation are the main aging mechanisms of paper-based friction materials. However, how these aging mechanisms affect the tribological characteristics of such materials is not fully understood. In this paper, the respective influences of the two aging mechanisms on the tribological characteristics of the friction materials are investigated through simulation. It is assumed that adhesive wear pre-dominantly affects the surface topography, while thermal degradation significantly affects the mechanical properties of the friction material. The simulation results show that the static friction coefficient and both normal and tangential contact stiffnesses increase due to adhesive wear, but decrease due to thermal degradation. These trends are qualitatively in agreement with experimental observations reported in the literature and our previous work.