滑动载荷作用下关节软骨不同层区的法向位移

Normal displacement of different layers for articular cartilage under sliding loads

目的获得滑动载荷作用下关节软骨不同层区的法向位移分布,探讨压缩应变、滑动速率和滑动次数对不同软骨深度法向位移的影响。方法以新鲜猪关节软骨为研究对象,采用非接触式数字图像相关技术,对滑动载荷作用下软骨不同层区的法向位移分布进行研究。结果滑动载荷作用下,关节软骨表层的法向位移最大,深层的法向位移最小,中间层的位移介于二者之间;随着压缩应变的增大,沿软骨厚度方向的法向位移都增大,并且表层的法向位移增加幅度最大。滑动速率越大,软骨沿厚度方向的法向位移越小。在不同的滑动次数下,法向位移随滑动时间的进行都呈上升趋势;随着滑动次数的增加,不同滑动时间时的法向位移都增大,并且发现从第1次到第2次滑动时法向位移增大最明显。结论滑动载荷作用下,软骨不同层区的法向变形有差异,不同层区的法向位移随着压缩应变、滑动速率和滑动次数的变化而变化。本研究可以为临床软骨疾病治疗和软骨缺损修复等方面提供依据,同时对人工软骨结构组成、人工构建、力学功能评价有重要意义。

Objective To obtain distributions of normal displacement on different layers of articular cartilage under sliding loads and investigate effects of compressive strain, sliding rate and sliding numbers on depth-dependent normal displacement of articular cartilage. Methods The non-contact digital image correlation （DIC） technique was applied to investigate the normal displacement of different layers for fresh pig articular cartilage under sliding loads, respectively. ResultsThe largest normal displacement was found on the superficial layer, while that on the deep layer was the smallest, with the middle layer was in between under sliding loads. The normal displacement for cartilage at different normalized depth increased with compressive strain increasing and the largest increasing amplitude was in the superficial layer. The depth-dependent normal displacement for cartilage decreased with sliding rates increasing. The normal displacement for cartilage kept increasing with different sliding numbers within its sliding time. The most significant increasing amplitude of normal displacement was found between the first and second slide. Conclusions Under sliding loads, the normal displacement of cartilage usually changes along with its depth from surface to deep layer, and compressive strain, sliding rate and sliding numbers all play important roles in such normal displacement distributions on different layers. These results can provide the basis for clinical cartilage disease treatment and cartilage defect repair, and are also important for structure and construction of artificial cartilage as well as in mechanical function evaluation.