中文摘要：

目的在COMSOL关节软骨计算中引入胶原纤维增强特性，并分析引入前后模型结果的差异。方法以软骨中胶原纤维的走向为基础，对胶原纤维的应力单独建模，将胶原纤维的应力写入到原来软骨多孔弹性模型中。为避免应变2次项的出现采用了函数调用方式，同时提高求解器的迭代次数以更好收敛。结果胶原纤维增强模型表面的y方向初始位移仅为15μm，是非增强模型的17．6％。增强模型的X方向正应变仅为非增强模型的10％，而近表面的X方向正应力超过非增强模型的10倍。结论在COMSOL关节软骨计算中实现了胶原纤维增强特性的引入，为软骨胶原纤维损伤提供了计算模型和理论分析。胶原纤维通过横向增强约束了竖直方向的应变，提高了软骨承载能力，改善了软骨的力学性能。

英文摘要：

Objective To evaluate and compare the differences in COSMOL articular cartilage （AC） simulation due to the application of collagen fibril reinforcement property. Methods Collagen fiber stress was modeled inde- pendently according to its orientation in AC and written into the original poro-elastic AC model. Function call was used to avoid quadric strain term. The iteration of solver was increased for better convergence. Results The ini- tial superficial Y displacement of the reinforced model was 15 μm, which was 17.6% of the non-reinforced model. X normal strain of the reinforced model was 10% of that in the non-reinforced model, but the superficial X normal stress of the reinforced model was 10 times higher than that of the non-reinforced model. Conclusions The appli- cation of collagen fibril reinforcement property in COMSOL AC simulation is achieved, which provided the compu- tational model and theoretical analysis for collagen fibril lesion. Lateral reinforcement of collagen fiber can con- strain the vertical strain, by which enlarge AC load capacity and improve AC mechanical properties.