Numerical generation of arbitrarily oriented non-Gaussian three-dimensional rough surfaces

The roughness of the contacting asperities in an EHD contact has a significant influence on its load carrying capacity. The use of deterministic models for the simulation of rough contacts has made it possible to quantify the effect that certain roughness parameters have on its behaviour. These models set forth the need for artificially generated rough profiles that have specific prescribed properties. Rough surfaces that are produced by various manufacturing processes are most of the times non-Gaussian and have an arbitrary orientation. Therefore a numerical procedure is needed that would allow the generation of rough surfaces that exhibit the aforementioned properties. In this paper, a numerical method is proposed which allows the creation of rough surfaces whose heights follow a general statistical distribution and a given autocorrelation function. The method employs the non-linear Conjugate Gradient Method (NCGM) as well as Fast Fourier Transforms (FFT) in order to cope with storage and time limitations. The results show that the method can adequately produce rough surfaces whose statistical and spectral characteristics match the prescribed values.