Ghassemi A, Mossayebi A R, Jamshidi N, Naemi R, Karimi M T
Department of Mechanical Engineering, Najafabad Branch, Islamic Azad University, Isfahān, Iran,
Australas Phys Eng Sci Med. 2015 Mar;38(1):63-70. doi: 10.1007/s13246-014-0319-0. Epub 2014 Dec 24.
Diabetes is one of the metabolic diseases. Uncontrolled diabetes can lead to diabetic foot ulcers and if it was not treated would lead to amputation. Foot ulcers can be prevented by using suitable insoles which are made of appropriate material and geometrically designed by constituent layers. In this study, single-layer and three-layer insoles have been compared during static and dynamic loading. The selected materials were silicone gel (SG), plastazote foam (PLZ), polyfoam (PF) and ethyl vinyl acetate foam (EVA). Four single-layer and 18 combinations of three-layer insoles were selected. Materials behaviors were determined by using a uniaxial pressure test. The description of stress and strain is obtained by using the model of three dimensional nonlinear Finite Element Method (FEM). Then samples were tested by using commercially available plantar pressure measurement system. The FEM results showed that the SG and PLZ insoles are more appropriate compared to single-layer insoles. The combinations of PLZ, SG and EVA (from top to bottom) are recognized as the best between three-layer insoles. Also the best three-layer insole is more effective in promoting a favourable stress and strain distribution than single-layer insoles, especially in dynamic mode. According to simulation results, three-layer insole decreases stress concentration by 9%. Also experimental tests showed that using three-layer insole decreases plantar pressure by 63% compared to barefoot condition bare foot.
糖尿病是一种代谢性疾病。未得到控制的糖尿病会导致糖尿病足溃疡，若不加以治疗会导致截肢。使用由合适材料制成且经各组成层进行几何设计的合适鞋垫，可预防足部溃疡。在本研究中，对单层和三层鞋垫在静态和动态加载过程中进行了比较。所选材料为硅胶（SG）、普拉扎托泡沫（PLZ）、聚酯泡沫（PF）和乙烯 - 醋酸乙烯酯泡沫（EVA）。选择了四种单层鞋垫和18种三层鞋垫组合。通过单轴压力试验确定材料性能。使用三维非线性有限元法（FEM）模型获得应力和应变的描述。然后使用市售的足底压力测量系统对样品进行测试。有限元法结果表明，与单层鞋垫相比，硅胶和普拉扎托泡沫鞋垫更合适。在三层鞋垫中，普拉扎托泡沫、硅胶和乙烯 - 醋酸乙烯酯泡沫（从上到下）的组合被认为是最佳的。而且，最佳的三层鞋垫在促进有利的应力和应变分布方面比单层鞋垫更有效，尤其是在动态模式下。根据模拟结果，三层鞋垫可使应力集中降低9%。实验测试还表明，与赤脚状态相比，使用三层鞋垫可使足底压力降低63%。
