scholarly journals Cylinder-Flat Contact Mechanics with Surface Roughness

2020 ◽  
Vol 69 (1) ◽  
Author(s):  
A. Tiwari ◽  
B. N. J. Persson
Keyword(s):  
Surface Roughness ◽  
Contact Pressure ◽  
Dimensionless Parameter ◽  
Elastic Half Space ◽  
Root Mean Square Roughness ◽  
Mean Square ◽  
Hertz Contact ◽  
Random Surface ◽  
Roughness Amplitude ◽  
Flat Contact

AbstractWe study the nominal (ensemble averaged) contact pressure p(x) acting on a cylinder squeezed in contact with an elastic half space with random surface roughness. The contact pressure is Hertzian-like for $$\alpha < 0.01$$ α < 0.01 and Gaussian-like for $$\alpha > 10$$ α > 10 , where the dimensionless parameter $$\alpha = h_{\rm rms}/\delta $$ α = h rms / δ is the ratio between the root-mean-square roughness amplitude and the penetration for the smooth surfaces case (Hertz contact).

The Influence of Surface Roughness on Elastohydrodynamic Traction

1987 ◽  
Vol 201 (2) ◽  
pp. 145-150 ◽  
Author(s):  
C R Evans ◽  
K L Johnson
Keyword(s):  
Surface Roughness ◽  
Film Thickness ◽  
Rheological Properties ◽  
Root Mean Square ◽  
Contact Pressure ◽  
Viscosity Index ◽  
Root Mean Square Roughness ◽  
Mean Square ◽  
Sliding Surfaces ◽  
The Mean

If the ratio λ of the nominal elastohydrodynamic film thickness h0 to the root-mean-square roughness is greater than about 5, the traction between two rolling and sliding surfaces is negligibly influenced by surface roughness. The traction is then primarily a function of the parameter α0[Formula: see text], as described in reference (4), where[Formula: see text] is the mean contact pressure and αo is the pressure–viscosity index of the lubricant. When λ lies in the range 0.5–6, it is shown that the effect of asperity interaction is for the traction to still be governed by the bulk rheological properties of the oil, but at a pressure corresponding to the mean contact pressure of the asperities.

Effects of Friction on Contact of Transverse Ground Surfaces

1994 ◽  
Vol 116 (3) ◽  
pp. 430-437 ◽  
Author(s):  
J. B. Mann ◽  
T. N. Farris ◽  
S. Chandrasekar
Keyword(s):  
Rough Surface ◽  
Contact Pressure ◽  
Smooth Surface ◽  
Bulk Material ◽  
Elastic Half Space ◽  
Material Surface ◽  
Asperity Contact ◽  
Hertz Contact ◽  
Effective Stresses ◽  
Subsurface Stress

The two-dimensional plane-strain sliding contact of a smooth rigid roller on a transverse ground rough surface is analyzed. The rough surface is idealized as an elastic half-space with periodic roughness modeled as cylindrical ridges oriented transverse to the sliding direction. The contact problem is solved using a numerical iterative method in which each asperity contact is treated as a micro-Hertz contact, and the exact treatment of asperity interaction is included. The subsurface stress field is calculated using Westergaard stress functions. The subsequent analysis compares the rough surface stress fields with the corresponding smooth Hertz contact to evaluate the influence of surface roughness and friction on the subsurface stress distributions. The results show that the real area of contact is less than the corresponding smooth surface Hertz contact area, and the magnitude of the actual localized maximum contact pressure is always greater than the corresponding smooth surface contact pressure. The asperity level subsurface effective stresses are greater in magnitude than the maximum subsurface stress due to the macro-Hertz contact for low coefficients of friction, and for high coefficients of friction the maximum effective stresses occur on the bulk material surface.

The Generating Mechanism of Surface Roughness by Random Cutting Edges

1978 ◽  
Vol 20 (4) ◽  
pp. 197-200
Author(s):  
M. Hasegawa ◽  
T. Tsukizoe
Keyword(s):  
Surface Roughness ◽  
Root Mean Square ◽  
Statistical Approach ◽  
Ground Surface ◽  
Root Mean Square Roughness ◽  
Mean Square ◽  
Two Dimensional ◽  
Dimensional Distribution

This paper describes a statistical approach for predicting the generating mechanism of the surface roughness produced by random cutting edges. The two-dimensional distribution of the generated surface roughness is derived by considering the distribution of the maxima of the cutting edges. The method is used to determine the root-mean-square roughness of the ground surface.

scholarly journals THE PREDICTION AND OPTIMIZATION OF SURFACE ROUGHNESS IN GRINDING OF S50C CARBON STEEL USING MINIMUM QUANTITY LUBRICATION OF VIETNAMESE PEANUT OIL

2021 ◽  
pp. 1-8
Author(s):  
Van Canh Nguyen ◽  
Tien Dung Hoang ◽  
Thuy Nguyen ◽  
Ngoc Hoanh Dao ◽  
Hien Do Minh ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Carbon Steel ◽  
Root Mean Square ◽  
Flow Rate ◽  
Feed Rate ◽  
Cutting Parameters ◽  
Peanut Oil ◽  
Root Mean Square Roughness ◽  
Depth Of Cut ◽  
Mean Square

This experimental research aimed to build the regression model of grinding S50C carbon steel based on a Regression Optimizer. The workpiece specimens were JIS S50C carbon steel that was hardened at 52HRC. Taguchi L27 orthogonal array was performed with 5 3-levels-factors. The studied factors were combining cutting parameters, such as cutting speed, feed rate, depth of cut, and lubricant parameters, including air coolant flow rate Q and air pressure P. The results show that cutting parameters includes workpiece velocity Vw, feed rate f, and depth of cut t, influence the most on surface roughness Ra, Root Mean Square Roughness Rq, and Mean Roughness Depth Rz,. By contrast, the influence of lubrication parameters is fuzzy. Therefore, this present work focused on predicting and optimizing Ra, Rz, Rq in surface grinding of JSI S50C carbon steel using MQL of peanut oil. In this work, combining of grinding parameters and lubrication parameters were considered as input factors. The regression models of Ra, Rz, and Rq were obtained using Minitab 19 by Regression Optimizer tool, and then the multi-object optimization problem was solved. The present findings have shown that Vietnamese vegetable peanut oil could be considered as the lubricant in the grinding process. The optimum grinding and lubricant parameters as following: the workpiece velocity Vw of 5 m/min, feed rate f of 3mm/stroke, depth of cut of 0.005mm and oil flow rate, air pressure of 91.94 ml/h, 1 MPa, respectively. Corresponding to the surface roughness Ra, Root Mean Square Roughness Rq, and Mean Roughness Depth Rz of 0.6512mm, 4.592mm, 0.8570mm, respectively.  

Effect of Surface Orientation and Off-Angle on Surface Roughness and Electrical Properties of p-Type Impurity Implanted 4H-SiC Substrate after High Temperature Annealing

2006 ◽  
Vol 527-529 ◽  
pp. 835-838 ◽  
Author(s):  
Akimasa Kinoshita ◽  
Makoto Katou ◽  
Miwa Kawasaki ◽  
Kazutoshi Kojima ◽  
Kenji Fukuda ◽  
...  
Keyword(s):  
Surface Roughness ◽  
High Temperature ◽  
Annealing Temperature ◽  
Surface Orientation ◽  
Free Carrier ◽  
Root Mean Square Roughness ◽  
Mean Square ◽  
High Temperature Annealing ◽  
P Type ◽  
Effect Of Surface

We investigate the effect of surface orientation and off-angle for Al-implanted 4H-SiC samples after high temperature annealing. The samples are obtained from a 4H-SiC (0001) substrate 8° off-angled (Si-face 8°off), and (000-1) substrates 8° (C-face 8°off), 4° (C-face 4°off) and less than 1° off-angled (C-face ~1°off). An n-type epitaxial layer is deposited on all substrates. Multiple implantations of Al+ (30~200keV) are carried out at 600°C. The total dose is 8.6 × 1015 cm-2. The Al-implanted samples are annealed in Ar ambient at 1580°C, 1700°C and 1800°C for 30s using the hybrid super rapid thermal annealing (HS-RTA) equipment. In this study, sheet resistance (Rs), free carrier concentration (Ns), Hall mobility (μ) and root-mean square roughness (Rrms) are used to evaluate the Al-implanted samples after high temperature annealing. Rs for all Al-implanted samples after annealing at 1800°C for 30s is around 18k/. Rrms for the Al-implanted C-face samples after annealing at 1800°C increases with increasing off-angle. Rrms for the Al-implanted Si-face 8°off sample after annealing increases with annealing temperature. Rrms for the C-face ~1°off Al-implanted sample after annealing at 1800°C is lower than that for the Si-face 8°off Al-implanted sample after annealing at 1700°C, moreover Rs for the C-face ~1°off sample after annealing at 1800°C is about 10% of that for the Si-face 8°off Al-implanted sample after annealing at 1700°C. It is shown that the C-face ~1°off sample is useful to fabricate a p+ region with low Rs and low Rrms. If C-face 4H-SiC is used to fabricate devices, devices made on C-face 4H-SiC with low off angle are expected to decrease any problems caused by increase of surface roughness after high temperature annealing (~1800°C).

Influence of Surface Roughness on Breakdown Voltage of 4H-SiC SBD with FLR Structure

2009 ◽  
Vol 615-617 ◽  
pp. 643-646 ◽  
Author(s):  
Akimasa Kinoshita ◽  
Takashi Nishi ◽  
Takasumi Ohyanagi ◽  
Tsutomu Yatsuo ◽  
Kenji Fukuda ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Breakdown Voltage ◽  
Room Temperature ◽  
Light Emission ◽  
Root Mean Square Roughness ◽  
Avalanche Breakdown ◽  
Mean Square ◽  
Electrical Field ◽  
Force Microscopy ◽  
Atomic Force

The Ti/4H-SiC Schottky barrier diodes with a field limiting ring (FLR) structure are fabricated. Two types of SBDs are prepared; one (SBD-A) is covered and another (SBD-B) isn’t covered with a carbon cap during high temperature annealing after ion implantation. The breakdown voltage at room temperature for SBD-A and SBD-B are 1400 V and 1000 V, respectively. The breakdown for both SBDs occurs due to an avalanche breakdown. The light emission images are obtained at the breakdown voltage by photo emission microscope (PEM). The light emission is observed along an FLR of the SBD-A as designed. On the other hand, the spot of light emission is observed on a FLR structure of the SBD-B. This light emission spot indicates that leakage current is concentrated because an electrical field concentration is generated at this one for the SBD-B. The root-mean-square roughness of the Al-implanted region on the FLR structure calculated from the atomic force microscopy (AFM) images for the SBD-A and the SBD-B are 0.697 nm and 5.58 nm, respectively. Therefore it is considered that large surface roughness on the FLR decreases breakdown voltage of SBD because an electrical field concentration is generated at a spot.

Surface Roughness Influence on O2 and Ar RIE Gas Treated Aluminum Surface

2014 ◽  
Vol 925 ◽  
pp. 92-95
Author(s):  
Zaliman Sauli ◽  
Vithyacharan Retnasamy ◽  
Uda Hashim ◽  
Steven Taniselass ◽  
Moganraj Palianysamy ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Atomic Force Microscopy ◽  
Design Of Experiment ◽  
Surface Characteristics ◽  
Aluminum Surface ◽  
Root Mean Square Roughness ◽  
Mean Square ◽  
Bias Power ◽  
Force Microscopy ◽  
Atomic Force

This study reports on the preliminary investigations on the effect of Reactive Ion Etch (RIE) parameters on the surface characteristics of Al bond pad. Investigation is done employing Design of Experiment (DOE) method. Quantity of Oxygen, Argon, ICP power and BIAS power were varied to get 16 sets of recipes. This provides 16 samples with different combination of RIE parameters. Surface characteristics of the samples were analyzed using Atomic Force Microscopy (AFM).Data collected were in terms of Surface Roughness (RA), Peak Vs Valley (P-V) and Surface Root-Mean-Square Roughness (RMS). Result shows that combination of these RIE parameters does not vastly affect the surface characteristics of the Al bond pad.

Experimental Analysis of Non-Uniform Surface Roughness Affecting to Flow Resistance

2010 ◽  
Author(s):  
A. Matsumoto ◽  
T. Ito ◽  
M. Motozawa ◽  
H. Kawashima ◽  
H. Ando ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Reynolds Number ◽  
Friction Coefficient ◽  
Density Distribution ◽  
Probability Density ◽  
Root Mean Square ◽  
Flow Resistance ◽  
Root Mean Square Roughness ◽  
Probability Density Distribution ◽  
Mean Square

Experimental investigation on non-uniform surface roughness affecting to flow resistance has been carried out. Experiment was performed with the concentric cylinder device. In this experiment, we evaluated non-uniform surface roughness of various surface by the optical method and measured friction coefficient in turbulent flow over each surface roughness. As an evaluation of non-uniform surface roughness, we measured surface roughness profiles of each surface by a laser displacement sensor. Based on this surface roughness profiles, we calculated some roughness parameters such as the root mean square roughness. One important result indicates the relationship between friction coefficient and roughness Reynolds number. The friction coefficient increases logarithmically with increasing roughness Reynolds number. Moreover, to discuss the effect of non-uniform roughness in detail, the Probability Density Function (PDF) of the roughness height and the spectrum of the surface roughness profiles were analyzed. As a result, the frictional drag over the rough surface can be mostly evaluated by the roughness Reynolds number which is defined by the root mean square roughness when the probability density distribution of the surface roughness profile has Gaussian distribution. However, if the probability density distribution does not have Gaussian distribution, kurtosis and skewness of surface roughness profile are also important parameter for the evaluation of the surface roughness.

ФОРМИРОВАНИЕ ПЕРЕХОДНОГО СЛОЯ ALN НА ТЕМПЛЕЙТАХ 3С-SIC/SI(111) МЕТОДОМ АММИАЧНОЙ МОЛЕКУЛЯРНО-ЛУЧЕВОЙ ЭПИТАКСИИ

2020 ◽  
Vol 96 (3s) ◽  
pp. 148-153
Author(s):  
С.Д. Федотов ◽  
А.В. Бабаев ◽  
В.Н. Стаценко ◽  
К.А. Царик ◽  
В.К. Неволин
Keyword(s):  
Crystal Structure ◽  
Growth Rate ◽  
Low Temperature ◽  
Surface Morphology ◽  
Single Crystal ◽  
Root Mean Square Roughness ◽  
Rate Variation ◽  
Mean Square ◽  
Nucleation Layer ◽  
Low Temperature Epitaxy

Представлены результаты изучения морфологии поверхности и структуры слоев AlN, сформированных аммиачной МЛЭ на темплейтах 3C-SiC/Si(111) on-axis- и 4° off-axis-разориентации. Опробован технологический режим низкотемпературной эпитаксии зародышевого слоя AlN на поверхности 3C-SiC(111). Среднеквадратичная шероховатость поверхности (5 х 5 мкм) слоев AlN толщиной 150 ± 50 нм составила 2,5-3,5 нм на темплейтах 3C-SiC/Si(111) on-axis и 3,3-3,5 нм на 4° off-axis. Показано уменьшение шероховатости смачивающего слоя AlN при изменении скорости роста. Получены монокристаллические слои AlN(0002) со значениями FWHM (ω-геометрия) 1,4-1,6°. The paper presents the surface morphology and crystal structure of AlN layers formed by ammonia MBE on 3C-SiC/Si(111) on-axis and 4° off-axis disorientation. It offers the technological approach of low-temperature epitaxy of the AlN nucleation layer on the 3C-SiC (111) surface. Root mean square roughness (5 х 5 |xm) of AlN layers with thickness of 150 ± 50 nm was 2,5-3,5 nm onto on-axis templates and 3.3-3.5 nm onto 4° off-axis. It appears that the RMS roughness of the AlN surface is changing with the growth rate variation. Single-crystal AlN(0002) layers with FWHM values (ω-geometry) of 1.4-1.6° have been obtained.

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