关键词: 压力袜, 脚踝, 压力分布, 有限元模型, 压力测试

Abstract:

Varicose veins of the lower extremities are a common and frequentlyoccurring disease in clinical practice. Lower extremity venous diseases affect 25%－40% of women and 10%－20% of men worldwide. With the improvement of medical theory and application technology, the treatment methods and techniques of lower extremity venous diseases have been continuously improved. Compression therapy has a long history in the treatment of varicose veins. Pressure socks are widely used in the treatment of varicose veins. The pressure socks are designed in a progressive segmented manner, and the pressure applied to the leg is gradually reduced from the ankle to the thigh. Due to the different shapes and sizes of human legs, the pressure distribution of different individuals is different. Therefore, it is particularly important to detect the pressure distribution of the actual human body wearing medical socks. At present, the finite element analysis method is widely used in pressure analysis. However, the existing pressure simulation models are mostly fixed single models, which cannot accurately change the thickness according to the circumference of the tester's test site, and cannot easily simulate multiple sets of pressure values under different circumferences according to the leg size.

In orderto simulate the exact pressure distribution exerted by compression stockings on ankles with different girths, an anklecompression stocking simulation model based on finite element software was proposed to simulate the pressure exerted by compression stockings on human ankles with different girths. Firstly, the initial shape and size of ankle were obtained by threedimensional human body scanning, and the geometric model of anklepressure sock was established. Then, the material density, elastic modulus and Poisson's ratio of fabrics at ankle were tested and calculated, and the material models of grade I, grade II and grade III compression stockings and ankle were established. On this basis, the finite element software was used to mesh and establish the contact force simulation model of medical socks and legs. From the simulation results, the simulated pressure values of the anterior and posterior two points of the ankle were obtained, and the contact pressure of the human body after wearing the pressure socks was tested. The results show that the pressure value of the anterior part of the ankle is always greater than that of the posterior part. When people wear different grades of compression stockings, the pressure increases with the increase of the grade of compression stockings. When people wear the same grade of compression stockings, the pressure value of the ankle increases with the increase of the circumference of the ankle, which is linearly distributed. The finite element model is reasonable and effective.

While establishing an effective finite element pressure simulation model, this study provides a new idea for the research of compression stockings from the perspective of the physical and mechanical properties of knitted fabrics.Giving play to the potential of finite element analysis technology in the gradient compression stockings research and application can greatly save product development time and reduce development costs. In practical applications, this study can be used for personal customization of pressure socks, so that the pressure value of each test product conforms to the comfort range of human body, and provides reference for the development and testing of pressure socks products and sportswear protection products, which is conducive to better measurement of clothing pressure.

Key words: compression stockings, ankles, pressure distribution, finite element model, pressure test