Evaluating the effect of particle roundness on three-body wear between polymers and metals

In tribological systems, hard particles trapped within the contact zone can induce substantial wear, adversely affecting system performance and durability. This type of wear, known as three-body wear, arises when these particles abrade the sliding surfaces, with their size and shape playing a pivotal role in the wear mechanisms. Although round particles are frequently employed in theoretical and numerical analyses due to their computational simplicity, this assumption may not accurately capture the full complexity of three-body wear dynamics. In this study, we critically examine the effect of particle roundness on three body wear between metals and polymers by systematically varying particle size, load, and sliding speed. Our findings show that particle roundness dominants rolling over sliding, irrespective of boundary conditions or particle dimensions, making round particle an unrealistic representation of real-world wear scenarios. This is explained as the roundness prevents particles from embedding deeply into the polymer, instead causing surface deformation. Numerical simulations confirm that sliding behavior occurs only under extremely low-friction conditions, which are not typical in practical applications. These results highlight the necessity of incorporating angular and irregularly shaped particles to accurately model the mechanics of three-body wear and its impact on tribological systems.