Zhang M, Turner-Smith A R, Roberts V C, Tanner A
Department of Medical Engineering & Physics, King's College School of Medicine & Dentistry, London, UK.
Med Eng Phys. 1996 Apr;18(3):207-14. doi: 10.1016/1350-4533(95)00038-0.
The frictional action at stump/socket interface is discussed by a simplified model and finite element model analyses and clinical pressure measurements. The friction applied to the stump skin produces stresses within tissue and these stresses may damage the tissues and affect their normal functions. The combination of normal and shear stresses is considered to be a critical factor leading to amputee's discomfort and tissue damage. However, friction at the stump/socket interface has a beneficial action. A simplified residual limb model and a finite element model using real geometry have been developed to analyse the support action of friction. Both results show that the friction plays a critical role both in supporting the load of the amputee's body during the support phase of the gait cycle and in preventing the prosthesis from slipping off the limb during swing phase. Pressure at the below-knee socket during walking were measured with conditions of different friction. The results reveal that a larger pressures was produced at the lubricated interface than at the normal interface. A proper choice of coefficient of friction will balance the requirements of relief of load stress and reduction of slip with the general ability to support loads.
通过简化模型、有限元模型分析以及临床压力测量，对残肢/接受腔界面的摩擦作用进行了探讨。施加于残肢皮肤的摩擦力会在组织内产生应力，而这些应力可能会损伤组织并影响其正常功能。法向应力和剪应力的组合被认为是导致截肢者不适和组织损伤的关键因素。然而，残肢/接受腔界面的摩擦也有有益作用。已开发出一个简化的残肢模型和一个使用实际几何形状的有限元模型，以分析摩擦的支撑作用。两者结果均表明，摩擦在步态周期支撑阶段支撑截肢者身体负荷以及在摆动阶段防止假肢从肢体上滑落方面均起着关键作用。在不同摩擦条件下测量了行走过程中膝下接受腔处的压力。结果显示，润滑界面处产生的压力比正常界面处更大。合理选择摩擦系数将在减轻负荷应力、减少滑动的需求与支撑负荷的总体能力之间取得平衡。
