Quantitative Characterization of Surface Topography Using an Improved Deterministic Method

The characteristic parameters, such as curvature radius of asperity, height distribution, and asperity density play a decisive role when studying the contact characteristics of rough surfaces. A new method of asperity definition based on curve fitting and peak refit, named the deterministic method, is proposed in this paper. The real topography of the rough surface is described by the moving least-squares method. And the local maximum of the curve is defined as the asperity, and the local minimum is defined as the valley. To improve the stability of characteristic parameters of the rough surfaces, this method regenerates a new asperity when the asperities are gathered too closely. Both the characteristic parameters obtained by the deterministic method and the spectral moment method are used in two typical elastic-elastoplastic-plastic contact models, to analyze the contact characteristics of rough surfaces. Numerical calculation results show that, compared to the spectral moment method, the deterministic method demonstrates greater consistency across different sampling intervals, indicating lower sensitivity to sampling interval variations. This improves the accuracy and stability of contact performance parameters, validating the effectiveness of the proposed method, which can serve as a feasible approach for analyzing fine contact on rough surfaces.