Effect of Surface Roughness on the Adhesion of Elastomers to Hard Surfaces

2010 ◽  
Vol 662 ◽  
pp. 39-51 ◽  
Author(s):  
Keith Fuller
Keyword(s):  
Surface Roughness ◽  
Rough Surfaces ◽  
Theoretical Work ◽  
Contact System ◽  
Contact Theory ◽  
Smooth Surfaces ◽  
Rigid Substrate ◽  
Recent Theoretical Work ◽  
Effect Of Surface

The work presented started with the aim of trying to explain why clean smooth surfaces of materials such as metals brought gently into contact show no adhesion. The observation by Johnson Kendall & Roberts of adhesion between smooth surfaces of an elastomeric hemisphere and a rigid substrate suggested a model contact system with which the effect of surface roughness could be investigated experimentally. Moreover the Johnson-Kendal-Roberts (JKR) contact theory could be used to predict the effect of roughness on adhesion. The observations and predictions obtained are compared, and the implications for the contact of two rigid materials outlined. The limitations of the validity of the predictions are mentioned. Further studies of the adhesion to rough surfaces, in particular the phenomenon of enhanced adhesion at low roughness, will be discussed. Finally, more recent theoretical work is briefly referred to.

Arachidonic Acid and Prostaglandin E2 Influence Human Osteoblast (MG63) Response to Titanium Surface Roughness

2008 ◽  
Vol 34 (6) ◽  
pp. 303-312 ◽  
Author(s):  
David D. Dean ◽  
Casey M. Campbell ◽  
Scott F. Gruwell ◽  
John W. M. Tindall ◽  
Hui-Hsiu Chuang ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Arachidonic Acid ◽  
Thymidine Incorporation ◽  
Specific Activity ◽  
Rough Surfaces ◽  
Cell Number ◽  
Smooth Surfaces ◽  
Implant Surface ◽  
Implant Placement ◽  
Effect Of Treatment

Abstract Prior studies have shown that implant surface roughness affects osteoblast proliferation, differentiation, matrix synthesis, and local factor production. Further, cell response is modulated by systemic factors, such as 1,25(OH)2D3 and estrogen as well as mechanical forces. Based on the fact that peri-implant bone healing occurs in a site containing elevated amounts of prostaglandin E2 (PGE2), the hypothesis of the current study is that PGE2 and arachidonic acid (AA), the substrate used by cyclooxygenase to form PGE2, influence osteoblast response to implant surface roughness. To test this hypothesis, 4 different types of commercially pure titanium (cpTi) disks with surfaces of varying roughness (smooth Ti, Ra 0.30 μm; smooth and acid etched Ti [SAE Ti], Ra 0.40 μm; rough Ti, Ra 4.3 μm; rough and acid etched Ti [RAE Ti], Ra 4.15μm) were prepared. MG63 osteoblasts were seeded onto the surfaces, cultured to confluence, and then treated for the last 24 hours of culture with AA (0, 0.1, 1, and 10 nM), PGE2 (0, 1, 10, 25, and 100 nM), or the general cyclooxygenase inhibitor indomethacin (0 or 100 nM). At harvest, the effect of treatment on cell proliferation was assessed by measuring cell number and [3H]-thymidine incorporation, and the effect on cell differentiation was determined by measuring alkaline phosphatase (ALP) specific activity. The effect of AA and PGE2 on cell number was somewhat variable but showed a general decrease on plastic and smooth surfaces and an increase on rough surfaces. In contrast, [3H]-thymidine incorporation was uniformly decreased with treatment on all surfaces. ALP demonstrated the most prominent effect of treatment. On smooth surfaces, AA and PGE2 dose-dependently increased ALP, while on rough surfaces, treatment dose-dependently decreased enzyme specific activity. Indomethacin treatment had either no effect or a slightly inhibitory effect on [3H]-thymidine incorporation on all surfaces. In contrast, indomethacin inhibited ALP on smooth surfaces and stimulated ALP on rough. Taken together, the results indicate that both AA and PGE2 influence osteoblast response by promoting osteoblast differentiation on smooth surfaces, while inhibiting it on rough surfaces. Because implants with rough surfaces are acknowledged to be superior to those with smooth surfaces, these results suggest that use of nonsterioidal anti-inflammatory drugs to block PGE2 production and reduce inflammation may be beneficial in the postoperative period after implant placement. They also indicate that manipulation of the AA metabolic pathway may offer a new therapeutic approach for modulating bone healing after implant placement. Because peri-implant healing takes place in a complex cellular environment quite different from the one used in the present study, additional work will be necessary to substantiate these possibilities.

Effect of Surface Roughness on Fouling of Calcium Carbonate: An Experimental Investigation

2010 ◽  
Author(s):  
M. Izadi ◽  
D. K. Aidun ◽  
P. Marzocca ◽  
H. Lee
Keyword(s):  
Surface Roughness ◽  
Calcium Carbonate ◽  
Rough Surface ◽  
Smooth Surface ◽  
Rough Surfaces ◽  
Operating Conditions ◽  
Tubular Heat Exchanger ◽  
Analytical Microscopy ◽  
Deposit Layer ◽  
Effect Of Surface

The effect of surface roughness on the fouling behavior of calcium carbonate is experimentally investigated. The real operating conditions of a tubular heat exchanger are simulated by performing prolonged experiments with duration of 3 to 7 days. The solution used is a mixture of sodium bicarbonate and calcium chloride in de-ionized water with the concentration of 0.4 g/l of each. An on-line fouling evaluation system was developed such that the fouling resistance for a selected solution could be measured in real time. The experiments are repeated with the same procedure for 90/10 Cu/Ni tubes with different internal surface roughness. After the experiment the surface is analyzed by analytical microscopy to investigate the morphology of the deposit layer. Comparison of the experimental results of smooth and rough surfaces shows that a combination of aragonite and calcite polymorphs are formed on rough surface while only dendritic porous aragonite crystals are formed on smooth surface. Accordingly, the deposit layer formed on rough surface is denser and has a higher thermal resistance comparing to that formed on smooth surface. The fouling factor-time curves of smooth and rough surfaces obtained by the current experimental study agree with the results found by the analytical microscopy of the surface and show higher fouling resistances for rough surface. Experimental data is significantly important for the design, and formulating operating, and cleaning schedules of the equipment.

Assessment of surface roughness for a ‘silent’ aircraft

2013 ◽  
Vol 117 (1189) ◽  
pp. 283-298
Author(s):  
Y. Liu
Keyword(s):  
Surface Roughness ◽  
Rough Surfaces ◽  
Aircraft Design ◽  
Theoretical Work ◽  
Roughness Height ◽  
Test Cases ◽  
Noise Sources ◽  
Airframe Noise ◽  
Trailing Edge Noise ◽  
Potential Contributor

AbstractBoundary-layer noise produced by rough surfaces is a potential contributor to airframe noise. In this paper, an attempt is made to assess the surface roughness noise for a conceptual Silent Aircraft design SAX-40 using a prediction model described in previous theoretical work (Liu and Dowling(12)). Estimates of three idealised test cases show that surface roughness could produce a relatively high noise level and enhance the trailing-edge noise somewhat. Roughness height and roughness density are two significant parameters which affect surface roughness noise, with roughness height having the more dominant effect. The distribution of roughness noise sources decreases in the streamwise direction on the SAX-40 surface. Two candidate rough surfaces are selected for SAX-40 to keep surface roughness noise at a negligible level and to meet an aggressive noise target.

The Effect of Surface Roughness in Polymers on X-Ray Fluorescence Intensity Measurements

1967 ◽  
Vol 11 ◽  
pp. 177-184
Author(s):  
J. Gianelos ◽  
C. E. Wilkes
Keyword(s):  
Surface Roughness ◽  
Matrix Effects ◽  
Rough Surfaces ◽  
Target Material ◽  
Wire Mesh ◽  
Coarse Mesh ◽  
X Ray ◽  
Intensity Measurements ◽  
Intensity Changes ◽  
Effect Of Surface

AbstractWe sought to determine how seriously surface roughness affects X-ray intensity measurements in polymers. Fourteen elements ranging from lead to silicon were added singly to fourteen batches of trans-1,4-polyisoprene. Smooth pressings of each batch were made, and intensity readings were taken (I0). Reproducibly rough surfaces were made from these by molding a square wire-mesh pattern into them, with the use of Tyler standard sieve screens. The amount of roughness was controlled by using screens of very fine to very coarse mesh. We studied the change in the X-ray intensity of the rough surfaces versus the smooth [(I/I0) × 100] with respect to: (1) the degree of roughness, (2) concentration of the added element, (3) emitted wavelength of the added element, (4) X-ray tube target material, and (5) correction for matrix effects on the intensity. We found that, at wavelengths emitted below 1 Å, intensity differences are small, regardless of which factors were varied. At wavelengths emitted above 1 Å, however, we found large differences. The intensity changes are highly dependent on roughness. Also, they become greater at the longer emitted wavelengths and with increasing concentration of added elements. Beginning with Ti Kα, losses are much higher with the use of chromium primary radiation than with tungsten. A technique of milling polyethylene into polymers with rough surfaces to provide a smooth surface is discussed.

scholarly journals Deterministic normal contact of rough surfaces with adhesion using a surface integral method

2020 ◽  
Vol 476 (2242) ◽  
pp. 20200281 ◽  
Author(s):  
Ali Ghanbarzadeh ◽  
Mostafa Faraji ◽  
Anne Neville
Keyword(s):  
Surface Roughness ◽  
Root Mean Square ◽  
Fundamental Problem ◽  
Rough Surfaces ◽  
Adhesive Contact ◽  
Mean Square ◽  
Surface Integral ◽  
Normal Contact ◽  
Surface Integration ◽  
Effect Of Surface

The fundamental problem of adhesion in the presence of surface roughness and its effect on the prediction of friction has been a hot topic for decades in numerous areas of science and engineering, attracting even more attention in recent years in areas such as geotechnics and tectonics, nanotechnology, high-value manufacturing and biomechanics. In this paper a new model for deterministic calculation of the contact mechanics for rough surfaces in the presence of adhesion is presented. The contact solver is an in-house boundary element method that incorporates fast Fourier transform for numerical efficiency. The adhesive contact model considers full Lennard-Jones potentials and surface integration at the asperity level and is validated against models in the literature. Finally, the effect of surface roughness on the adhesion between surfaces was studied, and it was shown that the root mean square gradient of surface roughness can change the adhesive pressures irrespective of the root mean square surface roughness. We have tested two adhesion parameters based on Johnson's modified criteria and Ciavarella's model. We showed that Civarella's model introduces the most reasonable criteria suggesting that the RMS roughness and large wavelength of surfaces roughness are the important parameters of adhesion between rough surfaces.

Surface Roughness Effects in Infinitely Long Porous Journal Bearings

1999 ◽  
Vol 121 (1) ◽  
pp. 139-147 ◽  
Author(s):  
K. Gururajan ◽  
J. Prakash
Keyword(s):  
Surface Roughness ◽  
Journal Bearing ◽  
Hydrodynamic Lubrication ◽  
Rough Surfaces ◽  
Stochastic Theory ◽  
Journal Bearings ◽  
Roughness Effects ◽  
Effect Of Surface

Christensen’s stochastic theory of hydrodynamic lubrication of rough surfaces is used to study the effect of surface roughness in an infinitely long porous journal bearing operating under steady conditions. It is shown that the surface roughness considerably influences the bearing performance; the direction of the influence depends on the roughness type.

Effect of surface roughness topography on percolation characteristic of contact interface

2020 ◽  
pp. 135065012097735
Author(s):  
Tong Zhang ◽  
Xiaojun Liu ◽  
Yan Zhang ◽  
Jiaxin Ye ◽  
Wei Wang ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Percolation Threshold ◽  
Critical Pressure ◽  
Rough Surfaces ◽  
Glass Plate ◽  
Peak Height ◽  
Elastic Contact ◽  
Contact Interface ◽  
Autocorrelation Length ◽  
Effect Of Surface

The contact geometry of rough surfaces markedly affects the functional properties such as sealing and lubrication. The effect of surface roughness on the percolation characteristic of elastic contact was studied. The elastic contact of randomly rough surfaces with a glass plate was performed using four different surface roughnesses of silicone rubber blocks as specimens. The results illustrate that the percolation threshold was significantly affected by the valley morphology of a surface. The increase in depth and void volume of valleys improved the connectivity between valleys, but impeded the coalescence of contact clusters, resulting in the extinction of the spanning void cluster allowing fluid flow when the relative contact area was large. Furthermore, the critical pressure and connectivity at the percolation threshold were related to the maximum peak height and autocorrelation length of a surface, respectively.

Effects of Surface Roughness on Rebound Strength in Particle-Wall Collisions in Air and Liquids

2005 ◽  
Author(s):  
Y. Q. Nguyen ◽  
John C. Wells
Keyword(s):  
Surface Roughness ◽  
Qualitative Agreement ◽  
Rough Surfaces ◽  
Tap Water ◽  
Stokes Number ◽  
Glass Beads ◽  
Smooth Surfaces ◽  
Sugar Water ◽  
Glass Plates ◽  
The Impact

Experiments to examine the effects of surface roughness on the strength of rebounds from particle-wall collisions, in liquids and in air, are presented. The target walls are glass plates and have three different values of surface roughness: less than 0.3 μm, 10.5 μm, and 40.1 μm. Particles are glass beads with diameters from 1.05mm to 2.35mm. The experiments are conducted in tap water, sugar-water, and in air. Pre-impact Stokes numbers in liquids are in the range 20–170. For impacts in air, no significant effect of the surface roughness on rebound velocity is observed. In liquids, rough surfaces yield stronger rebounds than smooth surfaces. For a given ratio of surface roughness/particle’s radius, the enhancement of the surface roughness on the rebound compared to the smooth one increases when the impact Stokes number decreases toward the “rebound threshold”. These observations are in qualitative agreement with suggestions in the literature.

Molecular investigation of the wettability of rough surfaces using molecular dynamics simulation

2018 ◽  
Vol 20 (34) ◽  
pp. 22308-22319 ◽  
Author(s):  
Hamzeh Yaghoubi ◽  
Masumeh Foroutan
Keyword(s):  
Molecular Dynamics ◽  
Surface Roughness ◽  
Molecular Dynamics Simulation ◽  
Rough Surfaces ◽  
Dynamics Simulation ◽  
Computational Investigation ◽  
Molecular Investigation ◽  
Effect Of Surface

In the present study, a computational investigation on the effect of surface roughness on the wettability behavior of water nanodroplets has been performed via molecular dynamics simulation.

Shear Stresses Below Asperities in Hertzian Contact as Measured by Photoelasticity

1973 ◽  
Vol 95 (3) ◽  
pp. 277-283 ◽  
Author(s):  
R. L. Leibensperger ◽  
T. M. Brittain
Keyword(s):  
Surface Roughness ◽  
Three Dimensional ◽  
Contact Fatigue ◽  
Hertzian Contact ◽  
Contact Theory ◽  
Shear Stresses ◽  
Asperity Contact ◽  
Surface Shear ◽  
Stress Theory ◽  
Effect Of Surface

The effect of surface roughness on shear stresses below the surface of an unlubricated Hertzian contact is analyzed using a three dimensional stress freezing photoelastic technique. The shear stresses in the micro-Hertzian contact in each asperity are shown to combine and form, at a greater depth below the surface, shear stresses generally associated with contact stress theory. These macro-Hertzian stresses are compared with the micro-Hertzian stresses in the asperities. The results are also correlated with an existing asperity contact theory and are discussed in relation to the contact fatigue phenomenon.

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