A workflow for evaluating J-shaped prosthetic blades using shape memory alloys: Finite element analysis and material comparison

The limitations faced by individuals with transtibial leg amputations highlight the need for rehabilitation devices with enhanced performance. Energy Storing and Returning (ESAR) prosthetic devices have emerged as a promising solution, utilizing innovative designs and materials to enhance the range of motion for these individuals. This study presents a workflow for evaluating J-shaped ESAR prosthetic blades under gait-specific conditions, investigating their behavior during various states of movement corresponding to the natural human gait cycle. A model based on the general structure of J-shaped below-knee prosthetic blades have been designed and simulated using different materials. The performance of the prosthesis has been evaluated during standing, walking, running, and hurdling. Finite Element analyses have been conducted using Abaqus CAE. OpenSim has been employed to simulate the natural gait cycle during walking and running, and the results have been utilized as loading input and boundary conditions for Abaqus simulations. Abaqus built-in Auricchio-Taylor Constitutive model has been utilized to simulate the super-elastic behavior of NiTinol. In the results section, various parameters such as von Mises stress, elastic strain, total deformation, strain energy, and mass have been compared. NiTinol composite and carbon fiber composite exhibited the best performance, with the carbon fiber composite being significantly lighter, weighing 68% less than NiTinol composite. The comprehensive method and procedure proposed in this study can be employed for further research in the field of prosthetic feet, as well as generalized for a wide range of rehabilitation devices.