TY - GEN
T1 - Finite Element Analysis of Articular Cartilage Model Considering the Configuration and Biphasic Property of the Tissue
AU - Hosoda, N.
AU - Sakai, N.
AU - Sawae, Y.
AU - Murakami, T.
PY - 2009
Y1 - 2009
N2 - Articular cartilage tissue has high water content from 70 to 80% and shows biphasic behavior in which both solid and fluid properties should be considered. Furthermore, the mechanical behavior of cartilage shows depth-dependence. Therefore it is necessary to consider not only the average tissue property but also the local one to explain mechanical and functional behavior. Previously, we created cartilage tissue model considering the depth-dependence of Young's modulus distribution and applied two-dimensional finite element method (FEM) based on biphasic theory[1]. As a result, the deformed profile of depth-dependent Young's modulus model immediately after unconfined compression corresponded to actual profile. Consequently, we confirmed that Young's modulus has a distribution in the depth direction. In contrast, the total load capacity in FEM analysis was about one order lower than the experimental one. Immediately after compression at high rate, it has not enough time for intrinsic fluid to flow in cartilage, and thus whole tissue including intrinsic fluid shows the behavior like elastic body. Furthermore, the polymeric materials increase their stiffness at higher strain rate. Therefore, apparent elastic modulus is assumed to be larger than the equilibrium Young's modulus. During total deflection is maintained after compression, the intrinsic fluid flow gradually occurs, and the stress relaxes with decrease of apparent elastic modulus. After enough stress relaxation, an apparent elastic modulus becomes an equilibrium Young's modulus. We think this is connected to configuration of the cartilage tissue. The aim of this study is to consider configuration of the tissue in addition to the character of biphasic property on the mechanical behavior of cartilage tissue. In this study, we created cartilage tissue model considering spring elements that express function arisen from collagen fiber and Young's modulus distribution depending on the depth. Then, we analyzed the unconfined compression and compared experimental results to FEM analysis.
AB - Articular cartilage tissue has high water content from 70 to 80% and shows biphasic behavior in which both solid and fluid properties should be considered. Furthermore, the mechanical behavior of cartilage shows depth-dependence. Therefore it is necessary to consider not only the average tissue property but also the local one to explain mechanical and functional behavior. Previously, we created cartilage tissue model considering the depth-dependence of Young's modulus distribution and applied two-dimensional finite element method (FEM) based on biphasic theory[1]. As a result, the deformed profile of depth-dependent Young's modulus model immediately after unconfined compression corresponded to actual profile. Consequently, we confirmed that Young's modulus has a distribution in the depth direction. In contrast, the total load capacity in FEM analysis was about one order lower than the experimental one. Immediately after compression at high rate, it has not enough time for intrinsic fluid to flow in cartilage, and thus whole tissue including intrinsic fluid shows the behavior like elastic body. Furthermore, the polymeric materials increase their stiffness at higher strain rate. Therefore, apparent elastic modulus is assumed to be larger than the equilibrium Young's modulus. During total deflection is maintained after compression, the intrinsic fluid flow gradually occurs, and the stress relaxes with decrease of apparent elastic modulus. After enough stress relaxation, an apparent elastic modulus becomes an equilibrium Young's modulus. We think this is connected to configuration of the cartilage tissue. The aim of this study is to consider configuration of the tissue in addition to the character of biphasic property on the mechanical behavior of cartilage tissue. In this study, we created cartilage tissue model considering spring elements that express function arisen from collagen fiber and Young's modulus distribution depending on the depth. Then, we analyzed the unconfined compression and compared experimental results to FEM analysis.
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U2 - 10.1007/978-3-540-92841-6_467
DO - 10.1007/978-3-540-92841-6_467
M3 - Conference contribution
AN - SCOPUS:84891907355
SN - 9783540928409
T3 - IFMBE Proceedings
SP - 1883
EP - 1887
BT - 13th International Conference on Biomedical Engineering - ICBME 2008
T2 - 13th International Conference on Biomedical Engineering, ICBME 2008
Y2 - 3 December 2008 through 6 December 2008
ER -