Abstract In complex operational environments, random shocks change the contact behavior of rough surfaces, resulting in time-dependent and uncertain characteristics, which further affect their friction, wear, and lubrication properties. However, in the currently available impact models, only deterministic shocks are considered at surfaces in contact and the evolution of contact behavior over time is ignored, which is detrimental in many engineering applications. Therefore, in the current study, a model based on elastic–plastic deformation and the loading/unloading contact theory is proposed to analyze the time-dependent behavior of contacting asperities; this model is affected by two characteristic parameters of random shocks, viz. shock magnitude and interarrival time. The corresponding contact variables of surfaces were deduced using the multiscale Jackson and Streator model while individual asperities were assumed to be power law hardening materials under stick contact conditions to comply better with physical reality. Furthermore, experimental results on AISI 1045 steel ring contact pairs considering the shock effect were compared with predictions made by the theoretical model; the reasonable difference between the two sets of results illustrates the effectiveness of the current approach. In addition, the impact of the strain hardening exponent, shock properties, and sample size on the time-dependent surface load is discussed. These insights can potentially help in analyzing the time-dependent wear behavior of multiscale rough surfaces.

中文翻译：

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随机冲击作用下多尺度粗糙表面瞬态接触行为的建模与分析

摘要 在复杂的运行环境中，随机冲击会改变粗糙表面的接触行为，导致具有时间依赖性和不确定性的特性，从而进一步影响其摩擦、磨损和润滑性能。然而，在当前可用的冲击模型中，仅考虑接触表面的确定性冲击，而忽略了接触行为随时间的演变，这在许多工程应用中是不利的。因此，在目前的研究中，提出了一种基于弹塑性变形和加载/卸载接触理论的模型来分析接触粗糙的时间相关行为；该模型受随机冲击的两个特征参数的影响，即。冲击强度和到达间隔时间。表面的相应接触变量是使用多尺度 Jackson 和 Streator 模型推导出来的，而在棒状接触条件下，假设个别凹凸是幂律硬化材料，以更好地符合物理现实。此外，将考虑冲击效应的AISI 1045钢环接触副的实验结果与理论模型的预测进行了比较；两组结果之间的合理差异说明了当前方法的有效性。此外，还讨论了应变硬化指数、冲击特性和样本大小对随时间变化的表面载荷的影响。这些见解可能有助于分析多尺度粗糙表面的时间相关磨损行为。