Feasibility analysis of the replacement of the actual machining surface by 3D numerical simulation rough surface

摘要

Most of the current studies on the surface morphology only focus the Gaussian random rough surfaces, however, there are many non-Gaussian random rough surfaces with some skewness and kurtosis in practical engineering. In this paper, a theoretical simulation method of the non-Gauss surface is built considering the surface morphology characteristics of the actual parts. Firstly, a three-dimension (3D) surface profilometer is used to measure the surface profile of the actual grinding and milling parts, and the morphology characteristics for the surface profile are obtained by the data representation. Secondly, the non-Gauss simulation surface is generated by the Fast Fourier Transform (FFT), the Johnson conversion system, and the autocorrelation function, which correspond to the surface features of the actual machined surface. Thirdly, the reverse engineering technology is used to generate the surface model and the interface contact models by taking into account the morphology features of actual machined surface and non-Gauss simulated surface, respectively. Finally, the contact models of actual surface and non-Gaussian simulated surface are analyzed by the finite element technique. Results show that the change laws of the fitting curve for the pressure-displacement and the displacement-contact area percentage between the actual machined surface and the non-Gaussian simulated surface are almost the same. At the same time, the mean errors of the contact pressure for the non-Gauss simulated surface and the actual machined surface are 7.57% (grinding) and 8.56% (milling), respectively, and the mean errors of the contact area percentage in different contact states are 8.84%, 9.38%, 7.99% (grinding) and 9.13%, 5.21%, 7.99% (milling), respectively. Because the comparison errors of the two angles are within 10%, the contact performance of the non-Gauss numerical simulation surface and the actual machined surface of the parts is almost equal, which certifies the feasibility of the substitution between the two kinds of surfaces. This paper provides an effective method for the digital characterization and simulation of the surface morphology of parts.