Design of cushioned footwear for children with obesity based on gait dynamics and motion simulation

Abstract

Obesity will cause changes in foot structure and plantar pressure distribution, increasing the risk of foot pain and injury [1]. Functional footwear (outsole) is an essential way to distribute the local plantar pressure for children with obesity. However, the traditional design and research of outsoles need to go through the whole process of design, molding, production, fitting experiments, and so on, which is a long time and high-cost consumption. How to obtain the optimal design scheme of cushioned footwear for children with obesity through finite element analysis? Based on the database of foot morphology of children with obesity, a 3D outsole model was established, and the arch height of the outsole was set as 30%, 60%, and 100% of the arch height of children with obesity. Based on the anthropometric data, biomechanical data, and CT imaging data of children with obesity, a biomechanical simulation model of the lower limb musculoskeletal system and a finite element model of the foot were established. To verify the validity of the finite element model, the simulation results of the maximum principal stress of children with obesity during walking were compared with the actual measured data.The structure of the outsole is preliminarily constructed in Solidworks. The arch height (30%, 60%, and 100%) of the outsole was set to simulate the support at the arch. The foot-outsole-ground structure was assembled, and the pressure on the foot-shoe interface was simulated in ANSYS Workbench, to explore the dispersion effect of different arch heights. After obtaining the best design scheme, the actual relief effect of the outsoles was tested through the try-on trials. The simulation results showed that the 60% arch height support could effectively achieve the dispersion of plantar pressure in the plantar toe area and heel area. The try-on results showed that, when wearing the cushioned footwear, the peak pressure in the central forefoot and heel were relieved by 36.8% and 43.8%, respectively, from176.5 kPa and 310.9 kPa to 111.6 kPa and 174.7 kPa. Fig. 1 (a) 3D model of coushioned outsole. (b) Finite element analysis and verfication results. (c) Construction and assembly of the outsole structure. (d) The finite element analysis results between foot and outsole with the 60% arch height. (e) The cushioned footwear. (f) The cushioned effects of the outsole in the try-on experiments.Download : Download high-res image (244KB)Download : Download full-size image Through finite element analysis and fitting verification test, we found that when the arch height of the outsole is 60% of the arch height of the children with obesity, the decompression function is the best, which can transfer the pressure of the front palm and heel to the arch and toe. Finite element analysis makes functional shoe development process more efficient.