粗糙表面确定性接触模型中峰的再定义

Re-Definition of Asperity-Peak for Deterministic Contact Model on Rough Surfaces

为了解决目前不同微凸峰确定准则所等效的接触模型中可能存在峰的不连续、重叠、丢失而造成接触过程中缺失基准,从而导致粗糙表面在相互作用过程中不能进行有效计算等问题,在3点峰和3点谷的基础上,定义当3个连续峰的中间峰高于相邻峰时为真峰、当3个连续谷的中间谷低于相邻谷时为真谷,并对其进行匹配得到"谷-峰-谷"模式的微凸峰。通过一组粗糙表面,分析了不同的采样间隔和粗糙度对峰数量、平均峰半径和峰高度的影响,并与文献中不同的准则进行了对比。结果表明:不同微凸峰确定准则所等效的模型具有很大的不确定性;随着采样间隔的增加,峰数量明显减少,平均峰半径和峰高度增大,当采样间隔小于0.5μm时,不同的确定准则影响减小;随着粗糙度的降低,峰数量略微增多,平均峰半径增大,平均峰高度减小。该模式的微凸峰为接触特性的演化提供了一个基准。

No baseline exists to evaluate the contact characteristics for deterministic contact model owing to the discontinuity, overlapping and missing of the asperity-peak. Based on the criteria of 3-point peak and 3-point valley, the middle higher peak or lower valley can be firstly identified as the true one in the three continuous peaks or valleys, and then a new asperity-peak of ＂valley- peak-valley＂ mode is defined. The proposed criterion is validated through a set of different surface profiles, and compared with other criteria found in the literature. The results show the huge influence obtained after using these different criteria. The number of asperity peaks decreases obviously with the increasing sampling interval, however, the mean asperity-peak radii and heights increase. The effects of different criteria on the calculated asperity-peak properties become almost negligible when the sampling interval is below 0.5 μm. The number of asperity peaks increases slightly with the decreasing surface roughness, and a similar tendency is found for the mean radii while the mean heights have an opposite effect. This criterion can provide a baseline for the evolution of the contact characteristics.