A multiscale model of friction considering the influence of third-body wear particles

Accurately predicting friction in sliding interfaces that contain third-body wear particles is critical for engineering applications such as sliding movement in pistons, bearings or metal forming. We present a hierarchical multiscale framework that links particle-scale mechanics to macroscopic friction in a strip-draw friction test. At the macroscale, a one-dimensional finite-element model reproduces the global stress state of the strip-draw setup and updates the local wear-particle density via Archard’s law. The local friction force at each node is then computed from mesoscale simulation results. At the mesoscale, a coupled discrete-element boundary-element approach resolves load sharing between rough surfaces and rigid oblate-spheroidal wear particles. The mesoscale solution returns to the macroscale solver a friction coefficient that depends on normal pressure, sliding velocity, surface geometry, and particle density, thereby closing the loop between scales. The simulated friction coefficient matches strip-draw experiments, capturing both the observed decrease in friction with increasing normal pressure and the influence of tool-pad size.