Design and Manufacturing of a Low-Cost Prosthetic Foot

Abstract

Below-knee prosthetics are used to restore the functional activity and appearance of persons with lower limb amputation. This work attempted to design and manufacture a low-cost, novel, comfortable, lightweight, durable, and flexible smart below-knee foot prosthesis prototype. This prosthesis foot was designed according to the natural leg measurement of an adult male patient. The foot is composed of rigid PVC layers interspersed with elastic strips of PTFE, and the axis of the ankle joint is flexible and consists of metal layers and a composite of polymeric damping strips with different mechanical properties, making it flexible and allowing it to absorb shocks and store and release energy. The design, modeling, and simulation of the manufactured prosthetic foot were performed via the ANSYS 18.0 software and the finite element method (FEM), where a large number of parallel and oblique planes and sketches were created. This work included four adult patients weighing 50, 75, 90, and 120 kg with different walking cycles. The results show that the highest equivalent von Mises stress and total deformations for the prosthetic limb occur at the beginning of the walking step, while the highest equivalent elastic strains and strain energy release rates are observed at the end of the walking step, regardless of the weight. This prototype can satisfactorily perform the biomechanical functions of a natural human foot, and it can be produced in attractive sizes, models, and shapes to suit different levels of below-knee amputations for different ages and weights, especially for patients with limited income.