Contact surfaces are widely used in precision machines for transmitting force and torque, whose characteristics are crucial. The onset of plasticity during contact at microscale is different from macroscopic behavior. Taking α-Fe as the paradigm material, inelastic behaviors of nanosized single-asperity and multi-asperity contact on the α-Fe surface were investigated using molecular dynamics (MD) simulations. The results show that (i) the macroscopic single-asperity model limits to accurately describe the nano-sized contact behavior, especially the estimation of the onset plasticity, (ii) the offset distance can delay the onset plasticity, (iii) compared with the MD simulation, the Greenwood-Williamson (GW) elastic model has a higher estimation on the contact force, while the Chang-Etsion-Bogy (CEB) and other revised-CEB elastoplastic models underestimate the contact force.

接触面广泛用于精密机械中传递力和扭矩，其特性至关重要。微尺度接触过程中可塑性的开始与宏观行为不同。以α-Fe为范式材料，使用分子动力学（MD）模拟研究了α-Fe表面上纳米尺寸的单粗糙和多粗糙接触的非弹性行为。结果表明，(i) 宏观单粗糙模型限制了对纳米尺寸接触行为的准确描述，尤其是对起始塑性的估计，(ii) 偏移距离可以延迟起始塑性，(iii) 与MD 模拟，Greenwood-Williamson (GW) 弹性模型对接触力有更高的估计，