Elastic-plastic adhesive contact of fractal microparts surfaces with low adhesion parameters

The elastic-plastic adhesive contact model of microparts surfaces with low adhesion parameters is developed based on the fractal rough surfaces description. The critical transition area from elastic to plastic deformation of single asperity contact is determined by the plastic deformation condition. Based on this, the relation between the applied load and the real contact area of rough surfaces are deduced. It has been shown that the fractal dimensions whichever are less or larger than 1.5 have similar effect on the load-area relations. Small applied loads are needed to achieve the same real contact area for the larger fractal dimension in each case duo to the rough surfaces become smoother with the increase of fractal dimensions. The effect of elastic adhesion index on the relation is more remarkable at high load. For the plastic adhesion index, the effect is also prominent at high loads, but the effect trend is contrary to the elastic adhesion one. This is for the index indicates the ration of hardness to the surface adhesion work.