基于轴向功能梯度模型的人体胫骨运动力学特性分析

Analysis of Motion Mechanical Characteristics of Human Tibia Based on Axial Functional Gradient Model

为了研究人体胫骨运动状态时力学特性,采集健康志愿者下肢精细计算机断层扫描图(computed tomography,CT)数据,利用MIMICS构建人体胫骨轴向功能梯度精确三维模型,在ANSYS Workbench中仿真分析人体胫骨运动状态下的应力分布与位移变形情况,模拟正常位姿屈曲状态与动态膝外翻屈曲状态人体胫骨的应力与变形,研究结果表明:①正常位姿组应力集中现象主要发生在胫骨中下段的正面,而动态膝外翻组的应力集中现象主要发生在胫骨中段内侧;②在4种屈曲角度下动态膝外翻组最大等效应力比正常位姿组分别增加了38.8%、39.65%、34.95%、27.52%;③对于胫骨平台而言,两组仿真研究的最大等效应力相差不大,但是正常位姿组等效应力为胫骨内侧大于胫骨外侧,而动态膝外翻组为胫骨外侧大于胫骨内侧。因此相较于正常位姿,动态膝外翻屈曲时,胫骨的应力分布情况发生改变,最大等效应力显著增加,胫骨骨干中段以及胫骨平台外侧为易损区域,日常生活及体育运动时应避免出现动态膝外翻位姿。

In order to study the mechanical characteristics of human tibia in motion state,accurate computed tomography(CT)data of lower limbs of healthy volunteers were collected,and then precise human tibia finite element model with axial functional gradient was constructed by MIMICS.The stress distribution and displacement deformation of human tibial movement were simulated and analyzed in ANSYS Workbench.The stress distribution and displacement study of dynamic knee valgus flexion compared with normal posture of tibia show these as follows.Stress concentration in the normal posture group occurre mainly on the frontal aspect of the middle and lower tibia,whereas in the dynamic knee valgus group it occurre mainly on the medial surface of the middle tibia.The maximum von-Mises stress in the dynamic knee valgus group increase by 38.8%,39.65%,34.95%and 27.52%compared to the normal posture group in the four flexion angles respectively.For the tibial plateau,the maximum von-Mises stress of the medial tibia is greater than the lateral tibia in the normal posture group and the lateral tibia greater than the medial tibia in the dynamic knee valgus group.The stress distribution in tibia was altered and the maximum von-Mises stress is significantly increased from normal posture to dynamic knee valgus flexion.The middle tibial and the lateral tibial plateau are vulnerable areas,dynamic knee valgus posture should be avoided in daily life and sports.