矩形微缺损关节软骨在压缩载荷下损伤演化的数值分析

Numerical analysis on damage evolution of rectangular articular cartilage with micro-defect under compressive loads

目的研究软骨在压缩载荷作用下的损伤扩展行为和演变机制。方法采用有限元方法建立微缺损的纤维增强多孔弹性的软骨模型,对压缩载荷作用下损伤演化过程进行模拟和参数研究,获得不同损伤扩展阶段软骨基体和纤维的应力、应变分布规律。结果软骨损伤表层和损伤前沿的应变随压缩量的增大而显著增大,两者呈明显的正相关性;在软骨演化过程中同时存在向深层和左右两侧扩展的趋势;软骨中的裂纹和损伤优先沿着纤维切线方向延伸,随着损伤的加剧,软骨横向扩展度明显快于纵向扩展速度。结论软骨损伤演化过程与纤维的分布有着密切的关系,基质和纤维的损伤相互促进,骨演化速度和程度在不同层区和不同阶段存在变化。研究结果可为软骨创伤性退变的预测及修复提供定性的参考,为临床解释损伤退变病理现象和治疗提供理论依据。

Objective To study the damage propagation and evolution mechanism of cartilage under compressive loads. Methods The fiber-reinforced porous elastic model of cartilage with micro-defect was established by using finite element method, and the process of damage evolution under compressive loads was simulated and ana- lyzed with parameters. The patterns of stress and strain distributions on cartilage matrix and collagen fiber at dif- ferent damage extension stages were obtained. Results The strain in the surface and forefront of cartilage dam- age increased significantly with the increase of compression displacement, and they were obviously in positive correlation; in the process of damage evolution, there was a trend that cartilage extended to the deep and both sides simultaneously; cracks and damage in cartilage extended preferentially along the fiber tangent direction, With the aggravation of cartilage damage, the lateral extension speed was significantly faster than the longitudinal extension speed. Conclusions The process of cartilage damage extension has a close relationship with the distri- bution of fibers. The damages in matrix and fiber promote each other. The evolution speed and degree of carti- lage vary constantly in different layers and at different stages. These results can provide the qualitative reference for prediction and repair of cartilage damage, as well as the theoretical basis for explaining pathological phenome- na of damage degeneration and its clinic treatment.