【摘要】：表面接觸是摩擦的先決條件,其真實接觸面積、壓應力大小、空間分布等一直是接觸力學關(guān)注的核心問題.采用分子動力學-格林函數(shù)法(GFMD)模擬粗糙面的接觸過程,驗證了其在大規(guī)模接觸分析中的高效及準確性,同時探討了由微球體組成的粗糙面的接觸力學特性,并分析了分子尺度下的結(jié)果和傳統(tǒng)力學模型計算結(jié)果的差異.結(jié)果表明,單個微凸體接觸結(jié)果和分子動力學-格林函數(shù)法模擬所得非常接近,誤差在5%以內(nèi).數(shù)值模擬發(fā)現(xiàn),在微凸體高度符合高斯分布的情況下,接觸面積和接觸力成線性關(guān)系;在相同接觸面積下,微凸體模型得出的接觸力偏高,是上限值.微凸體模型沒有考慮微凸體間的相互影響,實際是高估了彈性體的剛度;實際接觸過程中微凸體相互影響,微凸體對臨域形變影響尤其大,使接觸區(qū)域更加離散.GFMD模型可以準確計算數(shù)十億量級別分子、原子接觸過程中真實接觸面積及分布,為后續(xù)摩擦、滑移等分析提供可靠的參考.
[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.
【作者單位】： 華南理工大學土木與交通學院;清華大學摩擦學國家重點實驗室;華南農(nóng)業(yè)大學水利與土木工程學院;
【基金】：國家自然科學基金(11202080,11672108) 清華大學摩擦學國家重點實驗室開放基金(SKLTKF15B05) 交通運輸部建設科技項目基金(2014318363230)資助項目
【分類號】：O343.3

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