带涂层干摩擦阻尼器的分子动力学仿真

从纳米级微凸体间的剪切运动出发研究干摩擦阻尼器摩擦机理。采用更加精确的多体势,建立描述两个可变形半球状微凸体剪切运动过程的分子动力学模型。应用该模型分析了单晶铜微凸体剪切运动过程中切向力和法向力随相对位移、干涉深度和微凸体半径的变化规律,同时研究了剪切过程结束后剩余变形能的变化。通过多尺度分析和统计学工具,建立了干摩擦模型的微凸体模型,并与实验结果进行对比。研究表明:单晶铜在真空中发生干摩擦时,结合面的表面法向接触刚度与法向载荷成正比,滑动摩擦因数只与表面粗糙度参数有关。计算结果与纯铜摩擦实验结果相吻合,证明该方法可准确地分析覆盖涂层的干摩擦阻尼器工作面干摩擦特性,对于已知微观参数的表面,能够准确地预测滑动摩擦因数。 

Molecular dynamics simulations of dry friction dampers with coating

To study and simulate its mechanical characteristics of dry friction process, the shear movement of nanoscale asperities was studied. A molecular dynamics model was created. This model predicted shear movement of two hemispherical deformable asperities by adopting a suitable potential. Shear and normal forces during shear movement of two single-crystal copper asperities were analyzed. The residual deformation energy after the movement was also studied. A dry friction model based on nanoscale asperities was developed through multi-scale analysis and statistical methods. And its results were compared with experimental results. The following conclusions were summarized. In case of dry friction of single-crystal copper in vacuum, the normal contact stiffness on joint surfaces and normal load were in direct proportion, while sliding coefficient of friction was only relevant with surface roughness. The results of simulation were coincident with the results from pure copper friction experiments. This method was proved to be able to analyze dry frictional characteristic of dry friction damper working surfaces covered by wear-resistant coating accurately. For surfaces with known micro parameters, this method can predict the sliding coefficient of friction accurately.