Abstract

Current methods of evaluating the performance of a runner using Energy Storing and Returning (ESR) prosthesis rely heavily on metabolic and biological factors. That makes it difficult to differentiate between the contributions made by the athlete and the prosthesis to the act of walking or running. Static tests show these feet to have non-linear stiffness, making the prediction of dynamic response, based on static data, unreliable. A method approach has been developed that allows complete determination of the dynamic characteristics of a running prosthesis system (Natural frequency, Mode shapes, Damping and Energy Efficiency). This data is needed to inform the design of such systems in order to improve the overall athlete performance. Previous study show that there are suitable self selected frequency and mode shapes that if synchronized with the running step frequency can result in better interaction between the amputee and his prosthetic. However, these composite feet are expensive and their designs are complex. Making feet and testing them is costly and time consuming. Finite Element Analysis (FEA) is a powerful design tool capable of performing complex dynamic analysis of structures. FEA has successfully been used to predict the natural modes of vibration of structures. This paper examines thesuitability of FEA as design and analysis tool for studying highly nonlinear and anisotropic thick composite system with dynamic boundary conditions.