3D finite element dynamic analysis of interface stress at residual limb of a trans-tibial amputee

目的:研究接受腔/残肢界面应力分布特征,为假肢优化设计提供基础.||方法:基于核磁共振图像,获得小腿截肢患者残端和假肢几何特征,建立三维非线性有限元模型,通过比较站立状态和行走过程中的界面应力,研究动态载荷对界面压力的影响.||结果:界面压力主要分布在髌韧带、胫骨内外侧和腘窝区,一个平地正常速度行走的步态周期内,残肢界面的最大平均正压力是单腿站立状态下的1.15倍,最大平均切应力是单腿站立状态的1.4倍.||结论:动态载荷使残肢和接受腔之间的界面应力增大,行走过程的动态影响不宜忽略.||Objective:A quantitative understanding of the interface stress distribution between prosthetic socket and residual limb is fundamental for an optimal design of artificical limb.||Method: The geometry of residual limb and prosthesis was obtained based on MR images, a 3D nonlinear finite element(FE)model was developed.The interface stresses were compared between walking and standing state, and the effect of dynamic loads of interface stress was investigated.||Result:Interface stress was mainly distributed at patella tendon,lateral tibia,media tibia and popliteal pit regions,and the average peak interface pressure during walking was 1.15 times as the one with single-leg standing,and the shear stress was 1.4 times.||Conclusion:Interface stress between the residual limb and prosthetic socket increases due to the dynamic loads.The dynamic effects during walking can′t be ignored.