Wear is well known for causing material loss in a sliding interface. Available macroscopic approaches are bound to empirical fitting parameters, which range several orders of magnitude. Major advances in tribology have recently been achieved via Molecular Dynamics, although its use is strongly limited by computational cost. Here, we propose a study of the physical processes that lead to wear at the scale of the surface roughness, where adhesive junctions are formed between the asperities on the surface of the materials. Using a brittle formulation of the variational phase-field approach to fracture, we demonstrate that the failure mechanisms of an adhesive junction can be linked to its geometry. By imposing specific couplings between the damage and the elastic energy, we further investigate the triggering processes underlying each failure mechanism. We show that a large debris formation is mostly triggered by tensile stresses while shear stresses lead to small or no particle formation. We also study groups of junctions and discuss how microcontact interactions can be favored in some geometries to form macro-particles. This leads us to propose a classification in terms of macroscopic wear rate. Although based on a continuum approach, our phase-field calculations are able to effectively capture the failure of adhesive junctions, as observed through discrete Molecular Dynamics simulations.

中文翻译：

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变分相场连续介质模型揭示了粗糙连接处的粘着磨损机制

众所周知，磨损会导致滑动界面中的材料损失。可用的宏观方法与经验拟合参数有关，其范围在几个数量级。最近通过分子动力学取得了摩擦学的重大进展，尽管它的使用受到计算成本的强烈限制。在这里，我们建议在表面粗糙度的尺度上研究导致磨损的物理过程，其中在材料表面的凹凸不平之间形成粘合连接。使用变分相场断裂方法的脆性公式，我们证明了粘合剂连接的失效机制可以与其几何形状相关联。通过在损伤和弹性能量之间施加特定的耦合，我们进一步研究了每个故障机制背后的触发过程。我们表明，大碎片的形成主要是由拉伸应力引发的，而剪切应力会导致形成小颗粒或没有颗粒形成。我们还研究了连接组，并讨论了如何在某些几何形状中支持微接触相互作用以形成宏观粒子。这导致我们根据宏观磨损率提出分类。虽然基于连续方法，但我们的相场计算能够有效地捕获粘合剂连接的故障，如通过离散分子动力学模拟所观察到的。我们还研究了连接组，并讨论了如何在某些几何形状中支持微接触相互作用以形成宏观粒子。这导致我们根据宏观磨损率提出分类。虽然基于连续方法，但我们的相场计算能够有效地捕获粘合剂连接的故障，如通过离散分子动力学模拟所观察到的。我们还研究了连接组，并讨论了如何在某些几何形状中支持微接触相互作用以形成宏观粒子。这导致我们根据宏观磨损率提出分类。虽然基于连续方法，但我们的相场计算能够有效地捕获粘合剂连接的故障，如通过离散分子动力学模拟所观察到的。