Publication detail
Enhanced lubricant film formation through micro-dimpled hard-on-hard artificial hip joint: An in-situ observation of dimple shape effects
CHOUDHURY, D. REBENDA, D. SASAKI, S. HEKRLE, P. VRBKA, M. ZOU, M.
English title
Enhanced lubricant film formation through micro-dimpled hard-on-hard artificial hip joint: An in-situ observation of dimple shape effects
Type
journal article in Web of Science
Language
en
Original abstract
This study evaluates the impact of dimple shapes on lubricant film formation in artificial hip joints. Micro-dimples with 20–50 µm lateral size and 1 ± 0.2 µm 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 (≥ 500 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 (204 nm). Remarkably, the prosthesis with square-shaped dimple arrays showed a very fast lubricant film formation reaching their peak values within 0.5 s of pendulum movement, followed by prosthesis with triangular-shaped dimple arrays with a transition period of 42.4 s. The fully developed lubricant film thicknesses (≥ 700 nm) are significantly higher than the surface roughness (≈ 25 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.
English abstract
This study evaluates the impact of dimple shapes on lubricant film formation in artificial hip joints. Micro-dimples with 20–50 µm lateral size and 1 ± 0.2 µm 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 (≥ 500 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 (204 nm). Remarkably, the prosthesis with square-shaped dimple arrays showed a very fast lubricant film formation reaching their peak values within 0.5 s of pendulum movement, followed by prosthesis with triangular-shaped dimple arrays with a transition period of 42.4 s. The fully developed lubricant film thicknesses (≥ 700 nm) are significantly higher than the surface roughness (≈ 25 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.
Keywords in English
Lubricant film formation; Micro-dimple; Artificial hip joints; in-situ; Lubrication
Released
01.05.2018
Publisher
Elsevier B.V.
Location
Radarweg 29, 1043 NX Amsterdam, The Netherlands
ISSN
1751-6161
Volume
81
Number
5
Pages from–to
120–129
Pages count
10
BIBTEX
@article{BUT146334,
author="David {Rebenda} and Pavel {Hekrle} and Martin {Vrbka},
title="Enhanced lubricant film formation through micro-dimpled hard-on-hard artificial hip joint: An in-situ observation of dimple shape effects",
year="2018",
volume="81",
number="5",
month="May",
pages="120--129",
publisher="Elsevier B.V.",
address="Radarweg 29, 1043 NX Amsterdam, The Netherlands",
issn="1751-6161"
}