CONTACT OF NOMINALLY FLAT SURFACES
CONTACT OF NOMINALLY FLAT SURFACES
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DOI：
10.1098/rspa.1966.0242
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发表时间：
1966-01-01
影响因子：
--
通讯作者：
WILLIAMSON, JB
中科院分区：
文献类型：
--
作者：
GREENWOOD, JA;WILLIAMSON, JB
通常假定两个名义上平坦的金属表面之间的真实的接触面积由它们的最高凸体的塑性变形决定。这立即导致这样的结果，即接触的真实的面积与载荷成正比，而与表观面积无关--这一结果在电接触和摩擦理论中有许多应用。Archard指出，塑性变形不可能是普遍的规则，并介绍了一个模型，该模型表明，与早期的想法相反，即使是纯弹性接触，接触面积也可能与载荷成正比。本文介绍了一种新的弹性接触理论，它比以前的理论更接近于真实的表面。我们展示了如何接触变形取决于表面的形貌，并建立了区分接触弹性的表面从那些接触塑性的标准。该理论还表明存在“弹性接触硬度”，这是一个取决于弹性特性和地形的复合量，它在弹性接触中起着与塑性接触中的常规硬度相同的作用。研制了一种新的表面形貌测量仪，用它可以对表面接触理论所示的各种参数进行实验测量。测量了表面微凸体的典型半径。他们被发现，令人惊讶的是，是数量级大于凹凸不平的高度。更一般地说，我们已经能够研究粗糙高度的分布和其他表面特征的各种表面制备的标准技术。利用这些数据，我们发现，表面之间的接触经常是塑性的，正如通常假设的那样，但弹性接触的表面在工程实践中并不罕见。
It is usually assumed that the real area of contact between two nominally flat metal surfaces is determined by the plastic deformation of their highest asperities. This leads at once to the result that the real area of contact is directly proportional to the load and independent of the apparent area—a result with many applications in the theories of electric contacts and friction. Archard pointed out that plastic deformation could not be the universal rule, and introduced a model which showed that, contrary to earlier ideas, the area of contact could be proportional to the load even with purely elastic contact. This paper describes a new theory of elastic contact, which is more closely related to real surfaces than earlier theories. We show how the contact deformation depends on the topography of the surface, and establish the criterion for distinguishing surfaces which touch elastically from those which touch plastically. The theory also indicates the existence of an ‘elastic contact hardness’, a composite quantity depending on the elastic properties and the topography, which plays the same role in elastic contact as the conventional hardness does in plastic contact. A new instrument for measuring surface topography has been built; with it the various parameters shown by the theory to govern surface contact can be measured experimentally. The typical radii of surface asperities have been measured. They were found, surprisingly, to be orders of magnitude larger than the heights of the asperities. More generally we have been able to study the distributions of asperity heights and of other surface features for a variety of surfaces prepared by standard techniques. Using these data we find that contact between surfaces is frequently plastic, as usually assumed, but that surfaces which touch elastically are by no means uncommon in engineering practice.