EFFECTS OF NON-LINEAR STRAIN-DEPENDENT PERMEABILITY AND RATE OF COMPRESSION ON THE STRESS BEHAVIOR OF ARTICULAR-CARTILAGE
EFFECTS OF NON-LINEAR STRAIN-DEPENDENT PERMEABILITY AND RATE OF COMPRESSION ON THE STRESS BEHAVIOR OF ARTICULAR-CARTILAGE
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DOI：
10.1115/1.3138261
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发表时间：
1981-01-01
影响因子：
1.7
通讯作者：
ROTH, V
中科院分区：
文献类型：
--
作者：
LAI, WM;MOW, VC;ROTH, V
关节软骨是一种纤维增强的、多孔的、可渗透的充满水的固体基质，其压缩粘弹性行为主要由组织内间质水的流动及其渗出穿过关节表面决定。液体流动又由组织的渗透性和施加在其表面的载荷控制。但对于关节软骨，渗透性与应变呈非线性关系：K=Koexp(Me)。这里，M是非线性限流参数，e是扩张量。在这项研究中，我们研究了M和Ro=Koha/U·h(其中HAa是固体基质的弹性平衡模数，h是组织的厚度，U·是通过刚性、多孔、自由排水过滤器施加在表面的压缩速率)对附着在骨上的圆形软骨试件的应力历史的影响。结果表明，这两个参数对预测的压应力历史有很大影响。对于非常大的Ro，流体流动的影响变得可以忽略不计。对于小的围岩和大的M，预测的瞬时压应力比在平衡时观测到的大几倍。这种压应力的放大是由于相对流体流动效应(Ro→0)和非线性限流效应(M>；0)的重要性增加。此外，理论曲线还预测，应力增加率最初减小(凸起)，最后变为常量。5%偏移量压缩实验的结果与理论预测吻合较好。
The compressive viscoelastic behavior of articular cartilage, a fiber-reinforced, porous, permeable solid matrix filled with water, is predominately governed by the flow of the interstitial water within the tissue and its exudation across the articular surface. The fluid flow is in turn governed by the permeability of the tissue and the loading imposed upon its surface. But for articular cartilage, the permeability depends nonlinearly on the strain: k = koexp(Me). Here, M is the nonlinear flow-limiting parameter and e is the dilatation. In this investigation, we studied the influence of M and Ro= koHA/ U˙h (where HAis the elastic equilibrium modulus of the solid matrix, h is the tissue’s thickness and U˙ is the rate of compression applied onto the surface via a rigid, porous, free-draining filter) on the stress history of circular plugs of cartilage specimens attached to the bone. It was found that these two parameters have profound effects on the predicted compressive stress history. For very large Ro, the fluid flow effects become negligible. For small Roand large M, large instantaneous compressive stresses several times larger than those observed at equilibrium are predicted. This amplification of compressive stress is due to the increase of importance of the relative fluid flow effect, i.e., Ro→ 0, and nonlinear flow-limit effect, i.e., M > 0. Also, the theoretical curves predict that the rate of increase of stress initially decreases (convex) and finally becomes a constant. The results of our 5 percent offset compression experiments are in good agreement with the theoretical predictions.