scholarly journals A Simple Analysis of Texture-Induced Friction Reduction Based on Surface Roughness Ratio

2021 ◽  
Vol 69 (2) ◽  
Author(s):  
Jiaxin Ye ◽  
Jiazhou Xuan ◽  
Yongliang Qiao ◽  
Yifan Zhang ◽  
Haiyang Zhang ◽  
...  
2021 ◽  
Author(s):  
Jiaxin Ye ◽  
Jiazhou Xuan ◽  
Yongliang Qiao ◽  
Yifan Zhang ◽  
Haiyang Zhang ◽  
...  

Abstract The effect of surface texture on friction reduction under fluid lubrication has been broadly acknowledged in the tribology community. However, the lack of understanding of the underlying mechanisms remains a challenge for the advancement of textured enhanced lubrication. Numerous models have been proposed, but they are almost all based on the hydrodynamic effect alone and have proven cumbersome, system specific and unreflective of the beneficial secondary lubrication provided by the residual lubricants within the texture. This paper presents a simple analysis of texture induced friction reduction based on the actual liquid-solid interface area and the secondary lubrication hypothesis. A simple model based on the surface roughness ratio (the ratio between the actual and projected solid surface area) of the textured surface was proposed which 1) is simple, intuitive, quantitative and sensitive to texture shape and area fraction; 2) directly reflects proposed secondary lubrication mechanisms; 3) reflects the general data trend in the collected literature. By focusing on the variations of key texture parameters, the proposed model combined with a sampling of independent studies in literature has demonstrated that 1) the effect of increased pit depth-to-diameter ratio (d/D) on friction reduction is most significant between 0.01 and 0.2; 2) further increase in d/D only marginally affects the friction coefficient; 3) texture’s area fraction plays a much weaker role than the depth/diameter ratio in friction reduction. By quantitatively isolating the secondary lubrication effects, this model may help to link disparate studies in the literature while providing defensible quantitative insights into texture induced lubrication mechanisms.


2010 ◽  
Vol 1 ◽  
pp. 163-171 ◽  
Author(s):  
W Merlijn van Spengen ◽  
Viviane Turq ◽  
Joost W M Frenken

We have replaced the periodic Prandtl–Tomlinson model with an atomic-scale friction model with a random roughness term describing the surface roughness of micro-electromechanical systems (MEMS) devices with sliding surfaces. This new model is shown to exhibit the same features as previously reported experimental MEMS friction loop data. The correlation function of the surface roughness is shown to play a critical role in the modelling. It is experimentally obtained by probing the sidewall surfaces of a MEMS device flipped upright in on-chip hinges with an AFM (atomic force microscope). The addition of a modulation term to the model allows us to also simulate the effect of vibration-induced friction reduction (normal-force modulation), as a function of both vibration amplitude and frequency. The results obtained agree very well with measurement data reported previously.


Tribologia ◽  
2016 ◽  
Vol 267 (3) ◽  
pp. 195-204
Author(s):  
Sławomir WOŚ ◽  
Waldemar KOSZELA ◽  
Paweł PAWLUS

Various machining methods are currently used to obtain the best co-action of sliding surfaces. Application of two-process surfaces led to a decrease of frictional resistance. Textured surfaces after abrasive jest machining are practical examples of two-process topographies. The results of the application of textured discs with the same array of oil pockets of similar sizes, but with different roughness in areas free of dimples, are presented in this paper. It was determined that after this type of machining, the effect of the friction force decrease was caused by surface texturing.


Author(s):  
I. H. Musselman ◽  
R.-T. Chen ◽  
P. E. Russell

Scanning tunneling microscopy (STM) has been used to characterize the surface roughness of nonlinear optical (NLO) polymers. A review of STM of polymer surfaces is included in this volume. The NLO polymers are instrumental in the development of electrooptical waveguide devices, the most fundamental of which is the modulator. The most common modulator design is the Mach Zehnder interferometer, in which the input light is split into two legs and then recombined into a common output within the two dimensional waveguide. A π phase retardation, resulting in total light extinction at the output of the interferometer, can be achieved by changing the refractive index of one leg with respect to the other using the electrooptic effect. For best device performance, it is essential that the NLO polymer exhibit minimal surface roughness in order to reduce light scattering. Scanning tunneling microscopy, with its high lateral and vertical resolution, is capable of quantifying the NLO polymer surface roughness induced by processing. Results are presented below in which STM was used to measure the surface roughness of films produced by spin-coating NLO-active polymers onto silicon substrates.


Author(s):  
H. Kinney ◽  
M.L. Occelli ◽  
S.A.C. Gould

For this study we have used a contact mode atomic force microscope (AFM) to study to topography of fluidized cracking catalysts (FCC), before and after contamination with 5% vanadium. We selected the AFM because of its ability to well characterize the surface roughness of materials down to the atomic level. It is believed that the cracking in the FCCs occurs mainly on the catalysts top 10-15 μm suggesting that the surface corrugation could play a key role in the FCCs microactivity properties. To test this hypothesis, we chose vanadium as a contaminate because this metal is capable of irreversibly destroying the FCC crystallinity as well as it microporous structure. In addition, we wanted to examine the extent to which steaming affects the vanadium contaminated FCC. Using the AFM, we measured the surface roughness of FCCs, before and after contamination and after steaming.We obtained our FCC (GRZ-1) from Davison. The FCC is generated so that it contains and estimated 35% rare earth exchaged zeolite Y, 50% kaolin and 15% binder.


Author(s):  
Amritpal Singh ◽  
Rakesh Kumar

In the present study, Experimental investigation of the effects of various cutting parameters on the response parameters in the hard turning of EN36 steel under the dry cutting condition is done. The input control parameters selected for the present work was the cutting speed, feed and depth of cut. The objective of the present work is to minimize the surface roughness to obtain better surface finish and maximization of material removal rate for better productivity. The design of experiments was done with the help of Taguchi L9 orthogonal array. Analysis of variance (ANOVA) was used to find out the significance of the input parameters on the response parameters. Percentage contribution for each control parameter was calculated using ANOVA with 95 % confidence value. From results, it was observed that feed is the most significant factor for surface roughness and the depth of cut is the most significant control parameter for Material removal rate.


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