Influence Of Rough Surface Pattern Parameters On Lubricating Performance

The contact fatigue life of machine parts and its lubricating state are closely-related.The current lubricating design is based on smooth surface contact,while absolutely smooth surface doesn't exist in industry.The rough troughs exist in surface of all machine parts.How does the pattern parameters of rough surface influence on lubricating performance? Searching the answer is main research content in this paper.Taking into account the effect of thermal and characters of non-Newtonian fluid and using the direct iteration method,this paper numerically analyzes line contact thermo-elastohydrodynamic lubrication problem.With the method,a great number of solutions have obtained to investigate the influence of amplitude,wavelength and phase on lubricating performance.After the analysis and summary for solutions,the significant results are gained as follows:(1)In the small wavelength part,the influences of wavelength on maximum film thickness,maximum pressure value and maximum film temperature are significant.The pressure distribution and film profile fluctuate obviously.With the increase of the wavelength,the number of pressure spikes decreases and the position of contraction gradually moves towards the exit direction.(2)In the large wavelength part,with the increase of the wavelength,film profile,film thickness and pressure distribution gradually tend to steady state.At the same time,the film maximum film temperature and maximum pressure value decrease with the increase of the wavelength. (3)The influences of amplitude parameter on pressure distribution and film thickness are the most obvious.As the increases of peak height the number of pressure peaks and amplitude both decrease.The average film thickness(?)_avis up slightly,when amplitude parameter(?)_b＜0.1;when 0.1＜(?)_b＜0.2,average film thickness decreases with the increase of peak height.On a condition of smaller wavelength,tiny changes of peak height can lead drastic increasing of maximum film temperature.However,the larger wavelength is not highly sensitive to changes of peak height.(4)Phase of roughness can lead drastic changes of the film profile,the pressure distribution and temperature distribution.Different phases can generate different values of cosine roughness function,which has a strong impact on the position of wave crest and wave trough.In the small wavelength part,the variety of phase can lead drastic changes of minimum film thickness,maximum pressure value and maximum film temperature.In the large wavelength part, phase influences weakly on them.(5)For the machining teeth surface of grinding generally is transverse surface.The results indicate that the average film thickness formed by the transverse surface was obvious deeper than that of the smooth surface.In addition,the corresponding results of both are almost the same in the large wavelength part.This paper focuses on the influence of surface pattern parameters on lubricating performance.Due to the effect of roughness increases the difficulty of computing convergence,therefore the scope of amplitude variety is limited. In addition,applying direct iteration method to solve heavy-duty problem is difficulty.It will be one of the research objectives to resolve these issues.