Strain Dependent Variations in the Frictional Properties of Bovine Articular Cartilage

2004 ◽  
Author(s):  
Ramaswamy Krishnan ◽  
Monika Kopacz ◽  
Michael J. Carter ◽  
Gerard A. Ateshian
Keyword(s):  
Friction Coefficient ◽  
Interstitial Fluid ◽  
Compressive Strain ◽  
Compression Stress ◽  
Unconfined Compression ◽  
Temporal Response ◽  
Bovine Articular Cartilage ◽  
Frictional Properties ◽  
Fluid Load ◽  
Strain Dependent

This study investigates the hypothesis that the equilibrium friction coefficient of cartilage decreases with increasing compressive strain. Furthermore, when accounting for this strain-dependence, it is hypothesized that the temporal response of the friction coefficient correlates linearly with interstitial fluid load support, in the configuration of unconfined compression stress-relaxation. Both hypotheses were confirmed from theory and experiment.

scholarly journals Cartilage interstitial fluid load support in unconfined compression

2003 ◽  
Vol 36 (12) ◽  
pp. 1785-1796 ◽  
Author(s):  
Seonghun Park ◽  
Ramaswamy Krishnan ◽  
Steven B. Nicoll ◽  
Gerard A. Ateshian
Keyword(s):  
Interstitial Fluid ◽  
Unconfined Compression ◽  
Fluid Load

Cartilage Interstitial Fluid Load Support in Unconfined Compression

2002 ◽  
Author(s):  
Seonghun Park ◽  
Ramaswamy Krishnan ◽  
Steven B. Nicoll ◽  
Gerard A. Ateshian
Keyword(s):  
Articular Cartilage ◽  
Interstitial Fluid ◽  
Articular Surface ◽  
Surface Zone ◽  
Unconfined Compression ◽  
Tissue Samples ◽  
Fluid Load ◽  
Tension And Compression ◽  
Fluid Pressurization ◽  
Theoretical Analyses

Under physiological conditions of loading, articular cartilage is subjected to both compressive strains, normal to the articular surface, and tensile strains, tangential to the articular surface. Previous studies have shown that articular cartilage exhibits a much higher modulus in tension than compression. Theoretical analyses have suggested that this tension-compression nonlinearity enhances the magnitude of interstitial fluid pressurization during loading in unconfined compression, above a theoretical threshold of 33% of the average applied stress. The first hypothesis of this experimental study is that the peak fluid load support in unconfined compression is significantly greater than the 33% theoretical limit predicted for porous permeable tissues modeled with equal moduli in tension and compression [1]. The second hypothesis is that the peak fluid load support is higher at the articular surface side of the tissue samples than near the deep zone, because the disparity between the tensile and compressive moduli is greater at the surface zone.

scholarly journals Frictional Response of Bovine Articular Cartilage Under Creep Loading Following Proteoglycan Digestion With Chondroitinase ABC

2005 ◽  
Vol 128 (1) ◽  
pp. 131-134 ◽  
Author(s):  
Ines M. Basalo ◽  
Faye Hui Chen ◽  
Clark T. Hung ◽  
Gerard A. Ateshian
Keyword(s):  
Articular Cartilage ◽  
Friction Coefficient ◽  
Treated Group ◽  
Time Dependent ◽  
Knee Joints ◽  
Control Group ◽  
Unconfined Compression ◽  
Chondroitinase Abc ◽  
Bovine Articular Cartilage ◽  
Creep Loading

The specific aim of this study was to investigate the effect of chondroitinase ABC treatment on the frictional response of bovine articular cartilage against glass, under creep loading. The hypothesis is that chondroitinase ABC treatment increases the friction coefficient of bovine articular cartilage under creep. Articular cartilage samples (n=12) harvested from two bovine knee joints (1-3months old) were divided into a control group (intact specimens) and a treated group (chondroitinase ABC digestion), and tested in unconfined compression with simultaneous continuous sliding (±4mm at 1mm∕s) under a constant applied stress of 0.5MPa, for 2500s. The time-dependent response of the friction coefficient was measured. With increasing duration of loading, treated samples exhibited a significantly higher friction coefficient than control samples as assessed by the equilibrium value (treated: μeq=0.19±0.02; control: μeq=0.12±0.03; p=0.002), though the coefficient achieved immediately upon loading did not increase significantly (treated: μmin=0.0053±0.0025; control: μmin=0.037±0.0013; p=0.19). Our results demonstrate that removal of the cartilage glycosaminoglycans using chondroitinase ABC significantly increases the overall time-dependent friction coefficient of articular cartilage. These findings strengthen the motivation for developing chondroprotective strategies by increasing cartilage chondroitin sulfate content in osteoarthritic joints.

Effect of Enzymatic Degeneration on the Frictonal Property of Articular Cartilage

2013 ◽  
Author(s):  
Shota Mochizuki ◽  
Shun Yanagida ◽  
Hiromichi Fujie
Keyword(s):  
Articular Cartilage ◽  
Collagen Fiber ◽  
Unconfined Compression ◽  
Cartilage Sample ◽  
Bovine Articular Cartilage ◽  
Frictional Properties ◽  
Friction Tester ◽  
Articular Cartilage Surface ◽  
The Coefficient Of Friction ◽  
Loaded Area

Articular cartilage is consisted of the chondrocyte, collagen fibers and proteoglycan, and interstitial fluid. Basalo et al reported that the coefficient of friction of bovine articular cartilage on a glass surface measured in unconfined compression fashion was increased by the degeneration of proteoglycan [1]. In their friction test, it was difficult to test a small cartilage sample having undulation while the loaded area in cartilage specimen was almost unchanged during friction. For the assessment of frictional properties of enzymatically degenerated cartilage in more physiological condition, we developed a friction tester that allows for performing friction tests of articular cartilage surface against a spherical indenter. With the tester, the loaded area in cartilage specimen translated along with frictional motion while the compressive stress exceeded more than 1 MPa. In the present study, the effect of enzymatic degeneration of proteoglycan and collagen fiber on property of articular cartilage using the friction tester.

scholarly journals Cartilage Interstitial Fluid Load Support in Unconfined Compression Following Enzymatic Digestion

2004 ◽  
Vol 126 (6) ◽  
pp. 779-786 ◽  
Author(s):  
Ines M. Basalo ◽  
Robert L. Mauck ◽  
Terri-Ann N. Kelly ◽  
Steven B. Nicoll ◽  
Faye H. Chen ◽  
...  
Keyword(s):  
Interstitial Fluid ◽  
Enzymatic Digestion ◽  
Solid Matrix ◽  
Unconfined Compression ◽  
Support Mechanism ◽  
Before And After ◽  
Fluid Load ◽  
Wet Weight ◽  
Cartilage Biomechanics ◽  
Fluid Pressurization

Interstitial fluid pressurization plays an important role in cartilage biomechanics and is believed to be a primary mechanism of load support in synovial joints. The objective of this study was to investigate the effects of enzymatic degradation on the interstitial fluid load support mechanism of articular cartilage in unconfined compression. Thirty-seven immature bovine cartilage plugs were tested in unconfined compression before and after enzymatic digestion. The peak fluid load support decreased significantly p<0.0001 from 84±10% to 53±19% and from 80±10% to 46±21% after 18-hours digestion with 1.0 u/mg-wet-weight and 0.7 u/mg-wet-weight of collagenase, respectively. Treatment with 0.1 u/ml of chondroitinase ABC for 24 hours also significantly reduced the peak fluid load support from 83±12% to 48±16%p<0.0001. The drop in interstitial fluid load support following enzymatic treatment is believed to result from a decrease in the ratio of tensile to compressive moduli of the solid matrix.

The Frictional Coefficient of Bovine Articular Cartilage Correlates With Interstitial Fluid Load Support in Creep

2002 ◽  
Author(s):  
Ramaswamy Krishnan ◽  
Gerard A. Ateshian
Keyword(s):  
Articular Cartilage ◽  
Friction And Wear ◽  
Interstitial Fluid ◽  
Load Transfer ◽  
Frictional Coefficient ◽  
Fluid Phase ◽  
Constant Load ◽  
Low Friction ◽  
Bovine Articular Cartilage ◽  
Fluid Load

Articular cartilage functions as the bearing material in joints and provides low friction and wear over a lifetime. The cartilage lubrication mechanism has not yet been fully characterized though several theories have been proposed. In previous studies [1–3] it was hypothesized that interstitial fluid load support contributes significantly to the reduction of the frictional coefficient due to load transfer from the solid to the fluid phase of the tissue. This study provides experimental verification for a theoretical model based on this hypothesis [1,4]. The specific aim of this study is to experimentally investigate the correlation between the frictional response of bovine articular cartilage, and its interstitial fluid load support during sliding against glass under a constant load.

A Discussion on natural strain and geological structure - Fold shapes as functions of progressive strain

1976 ◽  
Vol 283 (1312) ◽  
pp. 129-138 ◽  
Keyword(s):  
Boundary Conditions ◽  
Mechanical Behaviour ◽  
Finite Strain ◽  
Geological Structure ◽  
Stages Of Development ◽  
Rock System ◽  
Frictional Properties ◽  
Natural Strain ◽  
Progressive Strain ◽  
Strain Dependent

The folding of the components (layers or texture) of a rock system is viewed as an unstable strain-dependent process. The folds undergo successive stages of development, including initiation, amplification, propagation and decay. Fold shapes are functions of (i) initial morphology, (ii) mechanical behaviour of the rock, including stiffness contrasts and frictional properties of adjacent components, (in) overall finite strain. The folded components may or may not adopt periodic waveforms, depending on (i) the relative rates of propagation versus amplification of the folds and (n) the boundary conditions of the rock system.

scholarly journals Frictional Properties and Seismogenic Potential of Caprock Shales

Energies ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 6275
Author(s):  
Bahman Bohloli ◽  
Magnus Soldal ◽  
Halvard Smith ◽  
Elin Skurtveit ◽  
Jung Chan Choi ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
North Sea ◽  
Co2 Storage ◽  
Test Procedure ◽  
Shear Velocity ◽  
Frictional Properties ◽  
The North ◽  
Slip Event ◽  
The North Sea ◽  
Direct Shear Apparatus

Fractures and faults are critical elements affecting the geomechanical integrity of CO2 storage sites. In particular, the slip of fractures and faults may affect reservoir integrity and increase potential for breach, may be monitored via the resulting seismicity. This paper presents an experimental study on shale samples from Draupne and Rurikfjellet formations from the North Sea and Svalbard, Norway, using a laboratory test procedure simulating the slip of fractures and faults under realistic stress conditions for North Sea CO2 storage sites. The motivation of the study is to investigate whether the slip along the fractures within these shales may cause detectable seismic events, based on a slip stability criterion. Using a direct shear apparatus, frictional properties of the fractures were measured during shearing, as a function of the shear velocity and applied stress normal to the fracture. We calculated the friction coefficient of the fractures during the different stages of the shear tests and analysed its dependency on shear velocity. Information on velocity-dependent friction coefficient and its evolution with increasing slip were then used to assess whether slip was stable (velocity-strengthening) or unstable (velocity-weakening). Results showed that friction coefficient for both Draupne and Rurikfjellet shales increased when the shear velocity was increased from 10 to 50 µm/s, indicating a velocity-strengthening behaviour. Such a behaviour implies that slip on fractures and faults within these formations may be less prone to producing detectable seismicity during a slip event. These results will have implications for the type of techniques to be used for monitoring reservoir and caprock integrity, for instance, for CO2 storage sites.

scholarly journals Anisotropy of Graphene Nanoflake Diamond Interface Frictional Properties

Materials ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1425 ◽  
Author(s):  
Ji Zhang ◽  
Ehsan Osloub ◽  
Fatima Siddiqui ◽  
Weixiang Zhang ◽  
Tarek Ragab ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Friction Force ◽  
Md Simulations ◽  
Equilibrium Distance ◽  
Sliding Angle ◽  
Stick Slip ◽  
Single Crystalline ◽  
Frictional Properties ◽  
Diamond Substrate ◽  
Graphene Nanoflake

Using molecular dynamics (MD) simulations, the frictional properties of the interface between graphene nanoflake and single crystalline diamond substrate have been investigated. The equilibrium distance between the graphene nanoflake and the diamond substrate has been evaluated at different temperatures. This study considered the effects of temperature and relative sliding angle between graphene and diamond. The equilibrium distance between graphene and the diamond substrate was between 3.34 Å at 0 K and 3.42 Å at 600 K, and it was close to the interlayer distance of graphite which was 3.35 Å. The friction force between graphene nanoflakes and the diamond substrate exhibited periodic stick-slip motion which is similar to the friction force within a graphene–Au interface. The friction coefficient of the graphene–single crystalline diamond interface was between 0.0042 and 0.0244, depending on the sliding direction and the temperature. Generally, the friction coefficient was lowest when a graphene flake was sliding along its armchair direction and the highest when it was sliding along its zigzag direction. The friction coefficient increased by up to 20% when the temperature rose from 300 K to 600 K, hence a contribution from temperature cannot be neglected. The findings in this study validate the super-lubricity between graphene and diamond and will shed light on understanding the mechanical behavior of graphene nanodevices when using single crystalline diamond as the substrate.

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