The Comfort Evaluation And Design Of Shoes Based On Biomechanics

Footwear is necessary in people’s daily life, and the footwear design is the main factors influencing foot comfort. The objective comfort evaluation method of footwear, which is the basis of footwear design improvement, is studied by using foot biomechanics and Finite Element Analysis (FEA) technologies in this paper, and the comfort evaluation method is applied to insole design research.Based on foot CT image data, an accurate geometrical foot model including bones, cartilages, soft tissue is developed by Reverse Engineering method. The finite element mesh model is established by the finite element pre-treatment software ANSA. At last, the plantar aponeurosis and short plantar ligaments is added in the finite element software ABAQUS, and the load, constraints, boundary conditions is added also, then a complete foot finite element model for static simulation is established. The force of foot in standing and gait neutral phase is simulated, and the simulation results are compared with the results of other researchers. The comparison result indicate that the plantar pressure are consistent with other researcher’s results, namely, the foot contact peak stress is in the heel, and metatarsals’peak stress appears in the 2nd metatarsal.Two insole material rigidity and two insole geometric surface are simulated. It is found that when wearing the insole with curved surface, the plantar pressure distribution is improved and the metatarsal stress value decrease; when wearing soft insole, the plantar pressure distribution is improved but the metatarsal stress value increases. The plantar pressure distribution can’t reflect the metatarsal stress. Excessive metatarsal stress may cause diseases such as plantar joint pain, fractures and hallux valgus foot. Therefore, a new comfort evaluation method which takes both the plantar pressure distribution and the metatarsal’s peak stress value into consideration is put forward.To find the most comfortable of different arch-height insole,5 different arch-height insole models were developed and the objective evaluation method proposed is to evaluate the comfort influences of insole arch-height. It is found that comfort is improved with increased insole arch-height, while the 1st and 2nd metatarsals are squeezed when wearing the full arch-height insole. The evaluation results are very close to other researchers’.To overcome shortcomings of the full arch support insole, air cushion in the fore-foot and rear-foot are added to the full arch support insole. The insole with air cushion is simulated and the comfort is evaluated by using the objective evaluation method proposed. The evaluation results indicate that air cushion structure with proper internal pressure can relieve the 1st and 2nd metatarsal oppression, and the overall comfort including planta and metatarsal are improved.Plantar pressure distribution and metatarsal stress are two quantitative indexes of objective evaluation method of footwear comfort. The evaluation method proposed not only can be used to guide shoes comfort design, but also provide some useful references for the diagnosis and treatment of foot diseases such as plantar joint pain and hallux valgus.