Influence of Non-Gaussian-Distributed Surface Roughness on the Static Performance of Slider Bearings

An investigation on full fluid film lubrication assuming non-Gaussian-distributed surface roughness has been conducted. A typical slider bearing is chosen as the research object. Edgeworth expansion containing skewness and kurtosis is introduced to approximate the roughness density function. Using Christensen's stochastic roughness model, effects of roughness direction and non-Gaussian distribution properties on the working performance of slider bearings have been quantitatively analyzed. The results show that the variation range of working performance caused by skewness and kurtosis is up to 9.82%. Effects of skewness and kurtosis on the performance are nontrivial and should not be neglected. Compared to the Gaussian distribution, Edgeworth series can represent physical rough surfaces more accurately. Though the effects of skewness and kurtosis on the working performance are complicated, some laws can still be found. For example, large skewness decreases the load capacity, whereas large kurtosis reduces friction force. According to the results, we can choose certain machining processes that can produce the desired surface roughness.