Finite element biphasic indentation of cartilage: a comparison of experimental indenter and physiological contact geometries
Finite element biphasic indentation of cartilage: a comparison of experimental indenter and physiological contact geometries
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DOI：
10.1243/0954411011536082
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发表时间：
2001-01-01
期刊：
影响因子：
1.8
通讯作者：
Clift, SE
中科院分区：
文献类型：
--
作者：
Warner, MD;Taylor, WR;Clift, SE
在实验软骨压痕研究中，压头通常是平面端或半球形端的圆柱体，并且可以是多孔的或无孔的。然而，髋关节和膝关节等关节的曲率半径比实验压痕测试中使用的曲率半径高得多。为了在生理学背景下解释这种测试的结果，因此探索接触几何形状对软骨层中产生的孔隙压力和应变分布的影响是有用的。关节软骨可以被描述为饱和多孔介质。并且可以认为是由多孔的、可渗透的固体基质和间隙流体相组成的双相材料。在本研究中，使用ABAQUS土壤固结程序预测了这种行为。四个接触几何模型：两个典型的实验配置（5毫米半径圆柱形压头和半球形压头）和两个有效半径代表髋关节和膝关节（20和100毫米）。变形10%。或者在2s的斜坡时间内施加0.9kN的载荷，然后再保持100s。多孔压头产生较小的孔隙压力相比，相当于无孔压头和固体基质中产生较高的压缩应变值。使用圆柱压头进行预测。多孔和无孔。主要由压头边缘处的浓度决定，与髋关节模型相比，分别高估了组织中的峰值压缩应变21倍和14倍。半球形压头预测的峰值应变在类似的位置，使用生理半径预测。然而，与膝关节相比，该幅度被高估了2.3倍，与髋关节相比，高估了5.7倍。随着压头半径的增加，整个软骨层的孔隙压力显著降低。
In experimental cartilage indentation studies, the indenter is typically a plane-ended or hemispherically ended cylinder and can be either porous or non-porous. Joints such as the hip and knee, however, have much higher radii of curvature than those used in experimental indentation testing. In order to interpret the results from such testing in a physiological context it is therefore useful to explore the effect of contact geometry on the pore pressure and strain distribution generated in the cartilage layer. Articular cartilage can be described as a saturated porous medium. and can be considered a biphasic material consisting of a porous, permeable solid matrix, and an interstitial fluid phase. This behaviour has been predicted in this Study using the ABAQUS soils consolidation procedure. Four contact geometries were modelled: two typical experimental configurations (5 mm radii cylindrical indenter and hemispherical indenters) and two effective radii representative of the hip and knee (20 and 100 mm). A 10 per cent deformation. or a load of 0.9 kN was applied over a ramp time of 2 s, which was then maintained for a further 100 s. The porous indenter generated less pore pressure compared with the equivalent non-porous indenter and produced higher values of compressive strain in the solid matrix. The predictions made using the cylindrical indenters. porous and nonporous. were dominated by the concentrations at the edge of the indenter and overestimated the peak compressive strain in the tissue by a factor of 21 and a factor of 14 respectively when compared with the hip model. The hemispherical indenter predicted peak strains in similar positions to those predicted using physiological radii. however, the magnitude was overestimated by a factor of 2.3 when compared with the knee and by 5.7 when compared with the hip. The pore pressure throughout the cartilage layer reduced significantly as the radius of the indenter was increased.