| In recent years,surface texture technology has attracted wide attention because of its characteristics of reducing friction,reducing wear and improving load-carrying capacity.At present,most of the studies on surface texture are based on hard materials,while the studies on the surface microstructures of friction pairs of soft materials,such as PDMS,are relatively scarce.Therefore,it is the key to master and enrich the theory of surface texture technology to study the influence of lubricant flow on friction characteristics caused by contact elastic deformation of surface texture of flexible materials.Based on Reynolds equation,a mathematical model of hydrodynamic lubrication with regular surface micro-groove structure is established under hydrodynamic lubrication condition.The finite difference method is used to realize numerical simulation.The variation of hydrodynamic lubrication characteristics caused by the change of micro-groove structure size and arrangement mode is analyzed.ANSYS finite element analysis software was used to simulate the stress distribution of the friction pair surface in the process of boundary lubrication.Finally,the tribological properties of PDMS materials were analyzed by experiments.The main conclusions obtained in this paper are as follows:1.Under the condition of fluid lubrication,the lubrication film pressure of single micro-groove of PDMS-structural steel friction pair increases with the increase of micro-groove depth,and the pressure-free zone decreases with the increase of micro-groove depth;the lubrication film pressure increases with the increase of micro-groove width,and the pressure-free zone increases with the increase of micro-groove depth.With the increase of initial oil film thickness,the change of oil film shape disappears gradually,and the pressure of lubricating oil film decreases gradually.The difference between the pressure of lubricating oil film and that of single groove which neglects the elastic deformation of material surface decreases gradually,and the final state is basically the same.2.The hydrodynamic lubrication characteristics of the whole surface layer of friction pairs with micro-groove texture were studied.With the increase of width,the maximum oil film surface pressure first decreases and increases,the friction factorgradually decreases,and the higher the speed,the faster the friction factor decreases;with the increase of depth,the maximum oil film surface pressure gradually decreases;the maximum oil film surface pressure decreases with the increase of angle,and the friction factor increases with the increase of angle.3.Considering that the friction pair is in boundary lubrication state and the contact condition exists on the surface of the friction pair,the optimum microgroove width is 200 um,the optimum microgroove depth is 5-20 um and the optimum depth-width ratio is 0.15 on PDMS.When other parameters of the microgroove structure remain unchanged,the maximum equivalent stress of the sample on PDMS decreases gradually with the increase of texture area ratio.4.Under different speed conditions,the pairs made of PDMS specimens and PDMS specimens have larger friction factor than PDMS-steel pairs,and the higher the speed,the greater the friction factor.Among PDMS-PDMS and PDMS-steel pairs,PDMS specimens with different width and micro-groove structure showed good antifriction effect,while PDMS specimens with different depth and micro-groove structure showed different trend of antifriction effect under two pair conditions.Under different working conditions,the micro-groove structure with the best friction reduction characteristics has different aspect ratios.Figure [55] table [5] reference [55]... |
PDF Full Text Request