Numerical tests were conducted on a novel design of a Dynamic Energy Return (DER) prosthetic foot. The technology of the proposed prosthetic foot includes a flexible keel capable of storing and liberating energy. In contrast to traditional models, the proposed model does not consider soft components. All absorption and energy return is done by means of the foot geometry and of the material properties. The principal methods used in the DER foot measurement assume the existence of a prototype. However, during the early stages of the design process a physical prototype is typically not available; therefore it is necessary to use numerical models to perform the necessary tests. Recent work conducted by researchers of Queen's University Ontario developed experimental methodologies based on the IS022675 curve. This method allows the study of the mechanical properties of the heel and the toe regions of prosthetic feet using 15 critical points selected to approximate the loading conditions. The authors also presented results for three commercial feet like Niagara, Axtion and SACH. We applied this methodology, but by means of the numerical analysis using the FEM. As a result it was possible to prove that the new design is capable of storing and returning energy. In the heel contact phase, the displacement diminishes and stiffness increases after the maximum load (1173 N). The DER foot has typically stiffer heels and softer toes.
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