人工韧带疲劳测试装置设计及其耐疲劳性能评价

针对人工韧带在膝关节腔内复杂力学环境作用下出现移植失效的问题,研制了一种人工韧带疲劳测试装置,由拉伸运动模块、扭转运动模块、屈曲运动模块和恒温液体回流系统组成。通过筛选人体正常行走过程中拉伸位移、扭转角度及屈曲角度等参数对人工韧带试样进行疲劳测试以及耐疲劳性能评价。结果表明:纤维和纱线之间的相互摩擦损伤是人工韧带试样的主要疲劳损伤模式,其拉伸断裂性能在疲劳测试后有一定的损失,归一化的拉伸模量随时间以指数函数形式下降;试样中各条大分子链在疲劳测试过程中会受到拉、压、扭、弯等一系列多个方向载荷的共同破坏作用,最终导致结晶度下降。

Design of fatigue testing device and fatigue resistance evaluation of artificial ligaments

Aiming at the graft failure of artificial ligaments under complex mechanical environment in the knee joint cavity, an artificial ligament fatigue testing device was built, composing of a tensile motion module, a torsion motion module, a flexion motion module and an insulation temperature liquid return system. Clinical physiological parameters such as tensile displacement, torsion angle and flexion angle of the human body during normal walking were selected for fatigue tests and evaluation of fatigue resistance of artificial ligament specimens. The results showed that the friction damage between fibers and yarns was the main fatigue damage mode of the specimens and the tensile property of the specimens suffered some loss after fatigue and the normalized tensile modulus decreased exponentially with time. The macromolecular chains of the specimens were subjected to a series of multi-directional loads such as tension, compression, torsion and flexion during the fatigue test, which ultimately led to a decrease in crystallinity.