行走中股骨生物力学特性的有限元分析

Finite element analysis of biomechanics of human femur during gait

目的利用有限元的方法,模拟人体最佳边界条件,探寻行走过程中股骨的生物力学情况。方法根据股骨CT数据进行三维重建,并且网格化。利用计算机仿真软件Any Body模拟正常人平地行走时的动作,导出股骨在整个运动过程中受到的肌肉力。利用Geomagic studio和Hypermesh软件完成目标模型与Any Body模型的坐标匹配,将肌肉力加载在股骨上。在有限元分析软件Abaqus上计算步态过程中股骨受到的von Mises应力、应变的大小及其集中部位。结果在站立相中期,股骨受到的应力最大,为27.70 MPa,应力集中在小转子稍下方偏后侧。股骨在对侧承重期的受到的应力最小;在摆动相,应力集中在股骨中下段的内侧,为3.52 MPa。最大应变出现在站立相中期,大小为0.39 mm,位于股骨头;在摆动相,应变最大位于股骨中段,大小为0.12 mm;对侧承重期股骨的局部应变最小。结论人体行走过程中,在站立相中期,股骨的小转子稍下方偏后侧局部受到的应力最大,而最大应变集中出现在股骨头。

Objective To simulate the optimal boundary conditions with the utilization of finite element,and to explore biomechanics of human femur during gait. Methods Volunteer＇s femoral CT data was extracted before three- dimensional reconstruction and meshing. A computer simulation software,Anybody,was used to simulate the normal movements during gait and export the muscle force exerted on femur during the activity. Geomagic studio and Hypermesh were used to match the coordinates between the target model and the model provided by Any Body and load the muscle force to femur. After that,finite element analysis in Abaqus was performed to analyze the magnitude and concentration region of von Mises stress and strain on femur in gait process. Results The magnitude of von Mises reached the maximum of 27. 70 MPa during the midstance phase of the gait cycle,which was located inferoposteriorly to the lesser trochanter. The stress magnitude reached the minimum of 0. 62 MPa during the contralateral loading phase. The stress on femur during the swing phase concentrated on the medial mid- diaphysis,with a magnitude of 3. 52 MPa. It was also during the mid- stance phase when the maximum of strain of 0. 39 mm was observed at the femoral head. The maximum strain of 0. 12 mm during the swing phase concentrated on femoral mid- diaphysis. The minimum strain of femur occurred in the contralateral loading phase. Conclusion During the mid- stance phase of gait cycle,the magnitude of stress reaches the maximum,which is located inferoposteriorly to the lesser trochanter of femur. The maximum strain of femur is located on the femoral head.