Elastohydrodynamic lubrication analysis of metal-on-metal hip-resurfacing prostheses

Udofia, I.; Zhang, Jin

doi:10.1016/s0021-9290(02)00422-0

Cited by 73 publications

(37 citation statements)

References 15 publications

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“…To keep the tribological test in the boundary lubrication regime, testing parameters were chosen to ensure that the thickness of the lubricant film was smaller than the surface roughness (18). According to the Hamrock-Dowson equation (19), this condition can be met by applying a 10-N load to the pin while the linear sliding speed of the disk relative to the pin is 10 mm/s. The maximum Hertzian contact pressure was about 1 GPa (20,21).…”

Section: Dispersion and Aggregation-resistant Properties Of Crumpled mentioning

confidence: 99%

Self-dispersed crumpled graphene balls in oil for friction and wear reduction

Dou

Koltonow

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

183

113

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Ultrafine particles are often used as lubricant additives because they are capable of entering tribological contacts to reduce friction and protect surfaces from wear. They tend to be more stable than molecular additives under high thermal and mechanical stresses during rubbing. It is highly desirable for these particles to remain well dispersed in oil without relying on molecular ligands. Borrowing from the analogy that pieces of paper that are crumpled do not readily stick to each other (unlike flat sheets), we expect that ultrafine particles resembling miniaturized crumpled paper balls should selfdisperse in oil and could act like nanoscale ball bearings to reduce friction and wear. Here we report the use of crumpled graphene balls as a high-performance additive that can significantly improve the lubrication properties of polyalphaolefin base oil. The tribological performance of crumpled graphene balls is only weakly dependent on their concentration in oil and readily exceeds that of other carbon additives such as graphite, reduced graphene oxide, and carbon black. Notably, polyalphaolefin base oil with only 0.01-0.1 wt % of crumpled graphene balls outperforms a fully formulated commercial lubricant in terms of friction and wear reduction.

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Section: Dispersion and Aggregation-resistant Properties Of Crumpled mentioning

confidence: 99%

Self-dispersed crumpled graphene balls in oil for friction and wear reduction

Dou

Koltonow

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

183

113

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“…The role of diametral clearance in THA lies in the establishment of elastohydrodynamic lubrication between the femoral head and acetabular bearing surface in metalon-metal (MOM) device designs [3,13,18]. In a tribologic study of MOM performance in a hip simulator, Dowson et al [3] recommended femoral heads be as large as possible with minimal diametral clearance to establish a scenario of mixed-film lubrication.…”

Section: Introductionmentioning

confidence: 99%

Acetabular Cup Design Influences Deformational Response in Total Hip Arthroplasty

Meding

Small

Jones³

et al. 2013

Clinical Orthopaedics &Amp; Related Research

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Background Press-fit acetabular components are susceptible to deformation in an underreamed socket, with excessive deformation of metal-on-metal (MOM) components potentially leading to increased torsional friction and micromotion. Specifically, however, it remains unclear how cup diameter, design, and time from implantation affect shell deformation. Questions/purposes We asked whether (1) changes in component geometry and material altered maximum shell deformation and (2) time-dependent deformational relaxation processes occurred. Methods Diametral deformation was quantified after press-fit implantation of metal shells into a previously validated polyurethane model. Experimental groups (n = 6-8) consisted of 48-, 54-, 60-, and 66-mm MOM cups of 6-mm wall thickness, 58-mm cups of 10-mm wall thickness, and CoCrMo and Ti6Al4V 58-mm modular cups. Results Greater cup diameter, thinner wall construction, and Ti6Al4V modular designs generated conditions for maximum shell deformation ranging from 0.047 to 0.267 mm. Relaxation (18%-32%) was observed 120 hours postimplantation in thin-walled and modular designs. ConclusionsOur findings demonstrate a reduction of shell deformation over time and suggest, under physiologic loading, early component deformation varies with design. Clinical Relevance Component deformation should be a design consideration regardless of bearing surface. Designs neglecting to adequately address deformational changes in vivo could be susceptible to diminished cup survival, increased wear, and premature revision.

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“…However, analyses based on these techniques are complex and typically limited to only two points of a given gait cycle. Finite element modeling (Kurtz et al, 1997;Udofia and Jin, 2003) is one of the options to calculate contact pressure, however, when dealing with contact in a three-dimensional model this approach can involve extensive non-linear terms that degrade the reliability of results. The level of computation time and complexities of these simulations are not suitable for acquiring information for treatment in individual cases in a timely manner.…”

Section: Introductionmentioning

confidence: 99%