Method for Calculating Normal Pressure Distribution of High Resolution and Large Contact Area

Abstract

The exact calculation of contact stresses below the surface is the basis for optimizing load capacity of heavily loaded rolling–sliding contacts. The level of stress is significantly influenced by the normal pressure distribution within the contact area, which occurs as a result of the transferred normal force and the contact geometry. In this paper, a new method for high resolution pressure calculation of large contact areas is presented. By this, measured surface topography can be taken into account. The basis of the calculation method is the half-space theory according to Boussinesq/Love. Instead of regular grids, optimized meshing strategies are applied to influence the calculation efforts for large contact areas. Two objectives are pursued with the targeted meshing strategy: on the one hand, the necessary resolution for measured surface structures can be realized; while on the other hand, the total number of elements is reduced by a coarse grid in the surrounding areas. In this way, rolling–sliding contacts with large contact areas become computable with conventional simulation computers. Using the newly developed “method of combined solutions,” the overall result is finally composed by the combination of section of separate solutions, which are calculated by consecutively shifting the finely meshed segment over the entire contact area. The vital advancement in this procedure is the introduction of irregular grids, through which the cross influences are not neglected and fully regarded for every separate calculation. The presented methodology is verified stepwise in comparison to the Hertzian theory. The influence of irregular grids on the calculation quality is examined in particular. Finally, the calculation approach is applied to a real disk-on-disk rolling contact based on measured surface topography.