Biomedical Engineering Reference
In-Depth Information
3D reconstruction by CAD
Experimental basis:
∗
Exposure time
6-DOF motion of knee
Calculation:
∗
Exposure rate
∗
Sliding velocity
∗
Slip ratio
∗
Change of slip direction
Calculation:
∗
Contact pressure
Analysis of wear index
Figure 5.11
Flow chart of experimentally based numerical
analysis for total knee-joint prostheses.
The tribological phenomena discussed in this chapter have not been entirely
elucidated, since this would require a mathematical representation of the entire
tribological system, which is not feasible. A more reasonable solution to these
problems is through experiment-based numerical analysis (Figure 5.11) [34].
Numerical analyses using simplified configuration wear tests have identified
individual factors that affect tribological phenomena and have established individual
numeric models and correlated functions. The results from the integration of these
individual numeric models or correlated functions, however, should be compared
to the results from simulated body environments such as
in vitro
joint simulators.
The new numerical models derived from these simulations could then be used
to develop a more precise representation of the actual tribological phenomena.
Considering the range of factors that influence the wear rate of a bearing material,
further theoretical and experimental modeling is required in order to predict the
in
vivo
behavior of bearing materials used in human joint replacements.
References
1.
Nakanishi, Y. and Higaki, H. (2007)
Jpn. J. Tribol.
,
52
(4), 401-409.
Machines and Corresponding Environmen-
tal Conditions for Test
.
2.
ISO 14242-1 (2002)
Implants for
Surgery - Wear of Total Hip-Joint
Prostheses - Part1: Loading and Dis-
placement Parameters for Wear-Testing
3.
ISO 14242-2 (2000)
Implants for
Surgery - Wear of Total Hip-Joint
Prostheses - Part 2: Methods of
Measurement
.
