Enhanced lubricant film formation through micro-dimpled hard-on-hard artificial hip joint: An in-situ observation of dimple shape effects.
J Mech Behav Biomed Mater
; 81: 120-129, 2018 05.
Article
em En
| MEDLINE
| ID: mdl-29501964
ABSTRACT
This study evaluates the impact of dimple shapes on lubricant film formation in artificial hip joints. Micro-dimples with 20-50⯵m lateral size and 1⯱â¯0.2⯵m depths were fabricated on CrCoMo hip joint femoral heads using a picosecond laser. Tribological studies were performed using a pendulum hip joint simulator to apply continuous swing flexion-extension motions. The results revealed a significantly enhanced lubricant film thickness (≥â¯500â¯nm) with micro-dimpled prosthesis heads at equilibrium position after the lubricant film has fully developed. The average lubricant film thickness of dimpled prostheses with square- and triangular-shaped dimple arrays over time is about 3.5 that of the non-dimpled prosthesis (204â¯nm). Remarkably, the prosthesis with square-shaped dimple arrays showed a very fast lubricant film formation reaching their peak values within 0.5â¯s of pendulum movement, followed by prosthesis with triangular-shaped dimple arrays with a transition period of 42.4â¯s. The fully developed lubricant film thicknesses (≥â¯700â¯nm) are significantly higher than the surface roughness (≈â¯25â¯nm) demonstrating a hydrodynamic lubrication. Hardly any scratches appeared on the post-experimental prosthesis with square-shaped dimple array and only a few scratches were found on the post-experimental prosthesis with triangular-shaped dimple arrays. Thus, prostheses with square-shaped dimple arrays could be a potential solution for durable artificial hip joints.
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Base de dados:
MEDLINE
Assunto principal:
Líquido Sinovial
/
Fenômenos Mecânicos
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Prótese de Quadril
Limite:
Animals
Idioma:
En
Ano de publicação:
2018
Tipo de documento:
Article