Analysis of biphasic lubrication of articular cartilage loaded by cylindrical indenter
Analysis of biphasic lubrication of articular cartilage loaded by cylindrical indenter
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DOI：
10.1016/j.triboint.2011.03.016
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发表时间：
2012-02
影响因子：
6.2
通讯作者：
N. Sakai;Y. Hagihara;T. Furusawa;Natsuko Hosoda;Y. Sawae;T. Murakami
中科院分区：
文献类型：
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作者：
N. Sakai;Y. Hagihara;T. Furusawa;Natsuko Hosoda;Y. Sawae;T. Murakami
结合关节软骨的理论双相分析和相应的实验测量，成功地揭示了含大量水的关节软骨的基本材料特性和随时间变化的力学行为。固体和流体之间的载荷分配的洞察力推进了关节软骨的摩擦行为的预测。最近对双相有限元（FE）分析的关注之一似乎是在材料测试之外的机械功能方面作为关节系统承重的动态和生理条件，主要集中在相对较小和低速压缩下的时间依赖性反作用力和变形。最近，采用往复滑动运动的双相有限元模型来验证摩擦对迁移接触面积的影响。结果表明，圆柱压头在软骨表面滑动的模型比没有迁移接触面积的模型显著地维持了更高比例的流体载荷支撑，但本构材料性能的有效性尚未得到充分的评估。在我们目前的研究中，在第一阶段，用高精度试验机检测关节软骨的压缩响应。在圆柱压痕试验中，通过实验时间依赖行为与有限元模型模拟之间的曲线拟合，估计了双相有限元模型的材料性能，包括固相沿深度的非均匀表观杨氏模量、应变依赖渗透率和拉伸应变下胶原蛋白的增强。然后，模拟关节软骨的双相润滑机制，包括迁移接触面积，以阐明作为承重材料的功能。结果表明，在无迁移接触区条件下，压实作用对固相渗透性的影响较为明显，而在滑动条件下，压实作用对流体载荷支护比例的影响并不明显。固相的增强，代表了组织中的胶原网络，提高了流体负载支撑的比例，特别是在滑动条件下。因此，本研究通过有限元模型模拟来评估本构力学性能作为承重的功能集成。
Combination of theoretical biphasic analyses and corresponding experimental measurements for articular cartilage has successfully revealed the fundamental material properties and time-depending mechanical behaviors of articular cartilage containing plenty of water. The insight of load partitioning between solid and fluid phases advanced the prediction of the frictional behavior of articular cartilage. One of the recent concerns about biphasic finite element (FE) analysis seems to be a dynamic and physiological condition in terms of mechanical functionality as a load-bearing for articular joint system beyond material testing, which has mainly focused on time-dependent reaction force and deformation in relatively small and low speed compression. Recently, the biphasic FE model for reciprocating sliding motion was applied to confirm the frictional effect on the migrating contact area. The results indicated that the model of a cylindrical indenter sliding over the cartilage surface remarkably sustained the higher proportion of fluid load support than a condition without migrating contact area, but the effectiveness of constitutive material properties has not been sufficiently evaluated for sliding motion. In our present study, at the first stage, the compressive response of the articular cartilage was examined by high precision testing machine. Material properties for the biphasic FE model, which included inhomogeneous apparent Young's modulus of solid phase along depth, strain-dependent permeability and collagen reinforcement in tensile strain, were estimated in cylindrical indentation tests by the curve fitting between the experimental time-dependent behavior and FE model simulation. Then, the biphasic lubrication mechanism of the articular cartilage including migrating contact area was simulated to elucidate functionality as a load-bearing material. The results showed that the compaction effect on permeability of solid phase was functional particularly in the condition without the migrating contact area, whereas in sliding condition the compaction effect did not clearly show its role in terms of the proportion of fluid load support. The reinforcement of solid phase, which represented the collagen network in the tissue, improved the proportion of fluid load support especially in the sliding condition. Thus, a functional integration of constitutive mechanical properties as a load-bearing was evaluated by FE model simulation in this study.