scholarly journals Effect of CoCr Counterface Roughness on the Wear of UHMWPE in the Noncyclic RandomPOD Simulation

2016 ◽  
Vol 139 (2) ◽  
Author(s):  
Vesa Saikko ◽  
Vesa Vuorinen ◽  
Hannu Revitzer
Keyword(s):  
Wear Mechanisms ◽  
Wear Test ◽  
Test System ◽  
Random Motion ◽  
Wear Particles ◽  
Knee Prostheses ◽  
Ultrahigh Molecular Weight ◽  
Computer Controlled ◽  
Pin On Disk ◽  
Counterface Roughness

With the random motion and load pin-on-disk (RandomPOD) wear test system, conventional and highly crosslinked ultrahigh molecular weight polyethylenes (UHMWPE) were run against CoCr counterfaces with different surface roughnesses. The unique 16-station, computer-controlled pin-on-disk device produced noncyclic motion and load. With appropriate specimen shapes, simulations of wear mechanisms of both hip and knee prostheses were performed. Against polished counterfaces, the crosslinked UHMWPE showed negligible wear. Its wear against severely roughened counterfaces was close to that of conventional UHMWPE against polished counterfaces. The reduction in wear with crosslinked versus conventional UHMWPE was 80–86% in the hip and 87–96% in the knee wear simulation. The wear particles were of clinically relevant size and shape which indicated realistic wear mechanisms.

The Influence of Temperature on Failure Development in Steels Under Transition to Seizure

1996 ◽  
Vol 118 (3) ◽  
pp. 527-531 ◽  
Author(s):  
L. Rapoport
Keyword(s):  
Wear Mechanisms ◽  
Skin Effect ◽  
Oxide Films ◽  
Disk Surface ◽  
Wear Particles ◽  
Temperature Model ◽  
Mechanical Instability ◽  
Infinite Body ◽  
Temperature Instability ◽  
Adhesion Interaction

Seizure phenomena in pin-on-disk tests have been studied for “soft” and “hard” steel specimens. Differences in competing and dominant wear mechanisms under steady state friction have been preserved for “soft” and “hard” specimens in the region of transition to seizure or galling. Severe wear was observed for “soft” specimens under all loads tested, while adhesion and splitting off of wear particle conglomerates (microseizure) were identified for “hard” specimens. The contact temperature, calculated in accordance with the temperature model of plastically deformed contact spots (Kuhlmann-Wilsdorf), has appeared to be low for “soft” specimens and not sufficient for adhesion interaction. The effect of oxide films on the friction of “hard” specimens has been estimated in accordance with the temperature model for a coated semi-infinite body (Tian and Kennedy). The insulated oxide films on the surface of “hard” specimens create the “skin effect” and lead, therefore, to raising the temperature up to the temperature of adhesion interaction. Temperature instability of hard surfaces has been demonstrated to result from the “skin effect” and from a disturbance in equilibrium of formation and failure of oxide films. It has been shown that for “soft” specimens the prime cause of transition to seizure was the mechanical interlocking between the wear particles and the soft disk surface combined with mechanical instability, while for “hard” specimens the cause was temperature instability. A more realistic temperature model of the contact has been considered, which takes into account some competing wear mechanisms (oxidational wear, ploughing, delamination) and the effect of wear particles.

scholarly journals Macrophage Biocompatibility of CoCr Wear Particles Produced under Polarization in Physiological Hyaluronic Acid Solution

2018 ◽  
Author(s):  
Blanca Teresa Perez-Maceda ◽  
María Encarnación López-Fernández ◽  
Iván Díaz ◽  
Aaron kavanaugh ◽  
Fabrizio Billi ◽  
...  
Keyword(s):  
Hyaluronic Acid ◽  
Biological Effects ◽  
Phosphate Buffer Solution ◽  
Primary Response ◽  
Wear Particles ◽  
Buffer Solution ◽  
Fluid Concentration ◽  
Wear Products ◽  
Living Tissues ◽  
Pin On Disk

Macrophages are cells involved in the primary response to debris derived from wear of implanted CoCr alloys. The biocompatibility of wear particles from a high carbon CoCr alloy produced under polarization in physiological hyaluronic acid (HA) solution was evaluated in J774A.1 mouse macrophages cultures. Polarization was applied to mimic the electrical interactions observed in living tissues. Wear tests were performed in a pin-on-disk tribometer integrating an electrochemical cell in phosphate buffer solution (PBS) and in PBS supplemented with 0.3% HA, physiological synovial fluid concentration, used as lubricant solution. Wear particles produced in 0.3% HA solution showed a higher biocompatibility in J774A.1 macrophages in comparison to those elicited by PBS. A considerable improvement in macrophages biocompatibility in the presence of 0.3 % of HA was further observed by the application of polarization at potentials having current densities typical of injured tissues suggesting that polarization produces an effect on the surface of the metallic material that leads to the production of wear particles that are macrophages biocompatible and less cytotoxic. The results showed the convenience to consider electric interactions together with other particles parameters, as are size and composition, to get a better understanding of the biological effects of the wear products.

A Study of Airborne Wear Particles Generated From a Sliding Contact

2009 ◽  
Vol 131 (4) ◽  
Author(s):  
Ulf Olofsson ◽  
Lars Olander ◽  
Anders Jansson
Keyword(s):  
Ultrafine Particles ◽  
Fine Particles ◽  
Urban Environments ◽  
Airborne Particles ◽  
Wear Particles ◽  
Coarse Particles ◽  
Sliding Velocity ◽  
Airborne Particle ◽  
Particle Generation ◽  
Pin On Disk

Recently, much attention has been paid to the influence of airborne particles in the atmosphere on human health. Sliding contacts are a significant source of airborne particles in urban environments. In this study airborne particles generated from a sliding steel-on-steel combination are studied using a pin-on-disk tribometer equipped with airborne-particle counting instrumentation. The instrumentation measured particles in size intervals from 0.01μm to 32μm. The result shows three particle size regimes with distinct number peaks: ultrafine particles with a size distribution peak around 0.08μm, fine particles with a peak around 0.35μm, and coarse particles with a peak around 2 or 4μm. Both the particle generation rate and the wear rate increase with increasing sliding velocity and contact pressure.

scholarly journals Computer-Controlled Test System for the Excitation of Very High-Order Modes in Highly Oversized Waveguides

2019 ◽  
Vol 40 (3) ◽  
pp. 257-268 ◽  
Author(s):  
T. Ruess ◽  
K. A. Avramidis ◽  
G. Gantenbein ◽  
Z. Ioannidis ◽  
S. Illy ◽  
...  
Keyword(s):  
Test System ◽  
High Order ◽  
Oversized Waveguides ◽  
Computer Controlled ◽  
Very High

Ultrahigh Molecular Weight Polyethylene in Total Joint Components

1985 ◽  
Vol 55 ◽  
Author(s):  
Timothy M. Wright ◽  
Clare M. Rimnac ◽  
Donald L. Bartel
Keyword(s):  
Molecular Weight ◽  
Ultrahigh Molecular Weight Polyethylene ◽  
Knee Prostheses ◽  
Surface Degradation ◽  
Severe Problem ◽  
Total Hip ◽  
Analytical Studies ◽  
Ultrahigh Molecular Weight ◽  
Total Knee

ABSTRACTThis article reviews the problem of ultrahigh molecular weight polyethylene component surface degradation in total hip and total knee prostheses, including its clinical implications. Several factors affecting surface damage have been identified from a combination of the observations of in-vivo degradation made on retrieved components, experimental measurement of contact stresses on polyethylene components as a result of contact with their metallic counterpart, and analytical studies of both contact stress and the stresses beneath the polyethylene surface. Both the observations of in-vivo surface degradation and the analytical studies demonstrate that surface degradation is a more severe problem in total knee replacements than in total hip replacements. The performance of polyethylene components, as affected by design factors such as material thickness and material modification, is also considered.

scholarly journals Wear Properties of Sc-Bearing Zr-Based Composite BMG with Nano-CuZr2 under Lubrication

2020 ◽  
Vol 10 (14) ◽  
pp. 4909
Author(s):  
Shing-Hoa Wang ◽  
Chau-Chang Chou ◽  
Hsien-Hung Chung ◽  
Rong-Tan Huang ◽  
Horng-Yi Chang ◽  
...  
Keyword(s):  
Wear Rate ◽  
Wear Test ◽  
Surface Friction ◽  
Sample Surface ◽  
Optical Microscope ◽  
Wear Properties ◽  
Friction Coefficients ◽  
Adhesion Wear ◽  
Pin On Disk ◽  
New Phase

Lubricated sliding wear of amorphous (Zr55Cu30Ni10Al5)99.98Sc0.02/CuZr2 nanocrystal composite bulk metallic glasses (BMG) under various sliding velocities with a load of 20 N was investigated using the pin-on-disk test. After the wear test involving oil lubrication was performed, there was no wear induced new-phase transformation in the sample surface. Friction coefficients were within the range from 0.22 to approximately 0.29 under a 20-N load at different sliding velocities. Therefore, the calculated friction coefficients clearly indicated that the adhesion wear dominated from the experimental results. This deformation behavior resulted in a higher wear rate and wear coefficient. In addition, worn surfaces were characterized and examined under a scanning electron microscope (SEM) and optical microscope. The mechanism of high wear rate was clarified.

Sign in / Sign up

Export Citation Format

Share Document