A functional effect of the superficial mechanical properties of articular cartilage as a load bearing system in a sliding condition
A functional effect of the superficial mechanical properties of articular cartilage as a load bearing system in a sliding condition
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DOI：
10.1016/j.bsbt.2016.02.004
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发表时间：
2016-03
影响因子：
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通讯作者：
N. Sakai;Chie Hashimoto;S. Yarimitsu;Y. Sawae;M. Komori;T. Murakami
中科院分区：
文献类型：
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作者：
N. Sakai;Chie Hashimoto;S. Yarimitsu;Y. Sawae;M. Komori;T. Murakami
关节软骨的结构和成分在深度方向上具有不均匀性和各向异性。特别是，致密的胶原蛋白网络覆盖并加强了组织的浅表切向区。人们认为，这种特殊的结构提供了关节软骨的优良摩擦学性能。本研究的目的是调查的功能浅切带（STZ）的关节软骨作为一个承载系统。采用二维有限元模型计算了具有足够滑移距离的滑移结构。作为对照的标准模型进行了从我们以前的研究，其中包括深度依赖性的杨氏模量的固相，纤维增强与应变依赖性和渗透性与压实效果。表面层的机械性能进行了修改，其功能的参数研究。根据以往的研究成果，提高了STZ模型中纤维增强体的切向刚度，并对随后的各向异性渗透率进行了修正。研究了静态接触条件和移动接触条件，比较了表面切向层的影响。结果表明，在STZ模型的迁移接触条件下，摩擦系数显著降低。在有限元分析的现场输出观察中，接触面形成了一个薄的低渗透层，这将使高流体压力和低流体流量同时发生。表面层纤维增强体的硬化促进了低渗透层的形成。除了双相基质的纤维增强对间隙流体增压的有效性之外，本研究的结果表明，在长期迁移接触滑动中，压实对渗透率的影响将涉及相当复杂的现象。
The structure and composition of articular cartilage show depth-wise inhomogeneity and anisotropy. In particular, the dense collagen network covers and reinforces the superficial tangential zone of the tissue. It is thought that this peculiar structure offers the excellent tribological property of articular cartilage. The purpose of this study was to investigate the functionality of the superficial tangential zone (STZ) of articular cartilage as a load bearing system. The 2-dimensional finite element (FE) model was accepted for sliding configuration with sufficient extent of sliding distance. The standard model as a control was carried from our previous study, which included depth-dependent Young׳s modulus of the solid phase, fiber reinforcement with strain-dependency and permeability with compaction effect. The mechanical property of the superficial layer was modified for a parametric study of its functionality. According to research results in the past, the tangential stiffness of the fiber reinforcement of the STZ model was enhanced, and the following anisotropic permeability was also modified. The stationary contact condition and the migrating contact condition were examined to compare the effect of the superficial tangential layer. The result showed that the significant reduction of friction coefficient was found in migrating contact condition of the STZ model. In the observation of field output of FE analysis, the contacting surface formed a thin low permeability layer, which would enable the high fluid pressure and the low fluid flow at the same time. It seemed that the stiffening of the fiber reinforcement of the superficial layer promoted the formation of the low permeability layer. Beyond the effectivity of the fiber reinforcement of biphasic matrix on the interstitial fluid pressurization, the findings of this study indicated that the compaction effect on the permeability would involve a quite complex phenomenon in long term migrating contact sliding.