Design and manufacture of enhanced running-specific prosthetic blades based on randomly oriented carbon fiber/epoxy composites

Abstract

Every year, more than 850,000 people worldwide undergo major limb amputations due to causes such as vascular diseases and traumatic incidents. Despite the growing number of amputees, access to specific prosthetic devices remains limited, particularly in regions like Mexico. This highlights a significant gap in prosthetic accessibility and technology application. This study addresses this gap by creating a new prosthetic blade design, leveraging innovative material technologies and manufacturing processes. The primary goal is to develop a biomimetic design for a running-specific prosthetic blade using static simulations, assess the mechanical performance of randomly oriented fiber-reinforced composites, and evaluate the feasibility of using forged composites as a more sustainable manufacturing process. This alternative could significantly reduce material waste and production time for expanding production beyond elite athletes to everyday users. The methods involved in the study include developing in-house prepregs and randomly oriented strands to investigate their impact on mechanical properties, designing an improved prosthetic and utilizing Finite Element Analysis (FEA) for geometry selection and design comparisons, characterizing randomly oriented composite material evaluating the impact of reinforcement configuration, and producing components using the suggested curing process. The study demonstrated a reduction in waste since the process averaged a waste of 16%, showcasing a 4% reduction compared to the minimal waste reported for hand layup (20%). The proposed biomimetic blade showed superior strain energy with less deformation than the reference commercial design in static simulations. Also, highlighted the impact of thickness on component performance. Randomly oriented composites fabricated with the alternative curing process demonstrated superior handling and achieved tensile strengths up to 88 MPa and Young’s modulus of 11.03 GPa at 125°C. While comparable to the measured [± 45°] composite properties, there is room for improvement to meet the necessary strength requirements for running blades (≥ 700 MPa). Enhancing fiber distribution, refining heat treatment processes, exploring hybrid composites, and potential automation can further elevate the process's mechanical properties, sustainability, and cost-effectiveness. This study provides valuable insights into advanced composite materials and innovative manufacturing techniques, setting the stage for future advancements in high-performance prosthetic devices.