原子级平整界面中的单接触问题：一种模拟方法
Single-Contact Problem in Atomically Flat Interfaces: a Simulation Approach
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中文总结 AI 辅助
研究晶体SiO₂/SiO₂界面单接触问题，结合原子模拟与改进连续介质模型，计算界面滑动势能面确定相关摩擦参数，扩展Mindlin模型描述粘滑转变，实验验证模型与实际微粗糙摩擦学相关。
中文摘要 AI 辅助
理解单粗糙接触处的摩擦对于弥合纳米级结构超润滑性与以赫兹接触几何为主导的实际摩擦学系统之间的差距至关重要。在这项工作中，我们结合原子模拟和改进的连续介质模型来研究晶体SiO₂/SiO₂界面处滑动的起始。计算界面滑动势能面以确定与载荷相关的剪切强度和最小尺度滑动（MSS）摩擦。这两个量在3 GPa以下对法向压力呈线性依赖，且在零压力下有非零值。纳入这些参数，我们扩展了经典Mindlin模型，包括粘附和纳米级载荷效应，以描述在实际赫兹应力分布下的粘滑转变。该模型表明非均匀压力分布会大幅降低有效静摩擦力，石墨烯钝化接触的振荡剪切实验再现了预测的刚度坍塌特征以及在钝化极限下从模拟获得的粘附限制剪切强度，支持了该模型与实际微粗糙摩擦学的相关性。
英文摘要
Understanding friction at single-asperity contacts is essential for bridging the gap between nanoscale structural superlubricity and realistic tribological systems dominated by Hertzian contact geometry. In this work, we combine atomistic simulations and a modified continuum model to investigate the onset of sliding at crystalline SiO$_2$/SiO$_2$ interfaces. Interfacial sliding potential energy surfaces (ISPES) are computed to determine the load-dependent shear strength and minimal-scale sliding (MSS) friction. Both quantities exhibit linear dependence on normal pressure below 3 GPa, and have non-zero values at zero pressure. Incorporating these parameters, we extend the classical Mindlin model by including adhesion and nanoscale load effects, allowing us to describe the stick to slip transition under realistic Hertzian stress distributions. The model shows that nonuniform pressure distributions substantially lower the effective static friction, and oscillatory-shear experiments on graphene-passivated contacts reproduce both the predicted stiffness-collapse signature and, in the passivated limit, the adhesion-limited shear strength obtained from simulation, supporting the model's relevance to real micro-asperity tribology.
