Influence of surface wear and asperity deformation on transient deterministic mixed lubrication simulations

We propose a full-scale deterministic transient mixed-lubrication model for nominally flat rough surfaces. The framework couples a moving topography with an inter-asperity mass-conserving cavitation algorithm and a DC-FFT elastoplastic half-space solver for dry contact. We assess how wear-induced topography changes and material behaviour influence mixed-lubrication predictions by considering new and worn cylinder-liner surfaces. In the hydrodynamic regime, new and worn surfaces generate similar hydrodynamic pressures, indicating little effect of wear on global load support. In the boundary regime, elastic and elastoplastic models produce comparable hydrodynamic pressures but different asperity responses. In the elastoplastic model, the worn surface generates higher hydrodynamic pressure and lower asperity pressure due to plateau smoothing, which reduces cavitation and improves lubricant flow. Observed film thickness ratio thresholds for defining lubrication regimes differ from traditional classifications, which may not capture mixed-regime transitions. This framework may support local-scale simulations for multiscale transient homogenization models and tribological system design.