基于分子动力学-格林函数法的微凸体接触数值分析
发布时间：2019-02-15 17:20
【摘要】：表面接触是摩擦的先决条件,其真实接触面积、压应力大小、空间分布等一直是接触力学关注的核心问题.采用分子动力学-格林函数法(GFMD)模拟粗糙面的接触过程,验证了其在大规模接触分析中的高效及准确性,同时探讨了由微球体组成的粗糙面的接触力学特性,并分析了分子尺度下的结果和传统力学模型计算结果的差异.结果表明,单个微凸体接触结果和分子动力学-格林函数法模拟所得非常接近,误差在5%以内.数值模拟发现,在微凸体高度符合高斯分布的情况下,接触面积和接触力成线性关系;在相同接触面积下,微凸体模型得出的接触力偏高,是上限值.微凸体模型没有考虑微凸体间的相互影响,实际是高估了弹性体的刚度;实际接触过程中微凸体相互影响,微凸体对临域形变影响尤其大,使接触区域更加离散.GFMD模型可以准确计算数十亿量级别分子、原子接触过程中真实接触面积及分布,为后续摩擦、滑移等分析提供可靠的参考.
[Abstract]:Surface contact is a prerequisite for friction, and its real contact area, compressive stress and spatial distribution are always the core problems of contact mechanics. The contact process of rough surface is simulated by molecular dynamics Green function method (GFMD), which verifies its high efficiency and accuracy in large-scale contact analysis. At the same time, the contact mechanical properties of rough surface composed of microspheres are discussed. The difference between the results of molecular scale and that of traditional mechanical model is analyzed. The results show that the contact results of a single microconvex body are very close to those obtained by the molecular dynamics-Green function method, and the error is less than 5%. The numerical simulation shows that the contact area is linear with the contact force when the height of the convex body accords with Gao Si's distribution, and the contact force obtained by the model is the upper limit under the same contact area. The interaction between the microconvex bodies is not considered in the model, and the stiffness of the elastomer is overestimated. In the actual contact process, the microconvex body affects each other, and the microconvex body has a great effect on the deformation of the adjacent region, which makes the contact region more discrete. The GFMD model can accurately calculate the real contact area and distribution of billions of molecules in atomic contact. It provides a reliable reference for the subsequent analysis of friction and slip.
【作者单位】： 华南理工大学土木与交通学院;清华大学摩擦学国家重点实验室;华南农业大学水利与土木工程学院;
【基金】：国家自然科学基金(11202080,11672108) 清华大学摩擦学国家重点实验室开放基金(SKLTKF15B05) 交通运输部建设科技项目基金(2014318363230)资助项目
【分类号】：O343.3
本文编号：2423559
[Abstract]:Surface contact is a prerequisite for friction, and its real contact area, compressive stress and spatial distribution are always the core problems of contact mechanics. The contact process of rough surface is simulated by molecular dynamics Green function method (GFMD), which verifies its high efficiency and accuracy in large-scale contact analysis. At the same time, the contact mechanical properties of rough surface composed of microspheres are discussed. The difference between the results of molecular scale and that of traditional mechanical model is analyzed. The results show that the contact results of a single microconvex body are very close to those obtained by the molecular dynamics-Green function method, and the error is less than 5%. The numerical simulation shows that the contact area is linear with the contact force when the height of the convex body accords with Gao Si's distribution, and the contact force obtained by the model is the upper limit under the same contact area. The interaction between the microconvex bodies is not considered in the model, and the stiffness of the elastomer is overestimated. In the actual contact process, the microconvex body affects each other, and the microconvex body has a great effect on the deformation of the adjacent region, which makes the contact region more discrete. The GFMD model can accurately calculate the real contact area and distribution of billions of molecules in atomic contact. It provides a reliable reference for the subsequent analysis of friction and slip.
【作者单位】： 华南理工大学土木与交通学院;清华大学摩擦学国家重点实验室;华南农业大学水利与土木工程学院;
【基金】：国家自然科学基金(11202080,11672108) 清华大学摩擦学国家重点实验室开放基金(SKLTKF15B05) 交通运输部建设科技项目基金(2014318363230)资助项目
【分类号】：O343.3
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