Advancing Lower Limb Prosthetics: Custom Design, Simulation, and Experimental Evaluation

Abstract

Addressing the rehabilitation needs of individuals with lower limb amputations, prostheses play a crucial role in providing comfort and functionality, facilitating walking and daily activities. Prostheses for transtibial amputon specifically cater to the area below the knee joint, encompassing the tibia, fibula, and foot. Conventionally, prosthetic feet are mass-produced through molding techniques using the autoclave process, resulting in standardized designs lacking personalization. In pursuit of a tailored and cost-effective solution, this study endeavors to conceptualize, fabricate, and assess the feasibility of a novel prosthetic foot design. The methodology involves 3D scanning of a real human foot to obtain an editable design model, subsequently utilized in crafting the structural component of the foot from carbon fiber/epoxy composite. Finite element analysis is employed to evaluate structural integrity, encompassing stress analysis, deformations, and the Tsai-Wu failure criterion. Full-scale models are then 3D printed using thermoplastic polyurethane (TPU) filament, augmented with an internally fabricated reinforcement structure comprising a polymer matrix composite reinforced with carbon fiber. Mechanical testing, in accordance with ISO 10328:2016 standards, is conducted to validate the proposed structures. Correlation between numerical simulations and experimental results demonstrates satisfactory agreement. Notably, mechanical tests reveal a 358% over performance in the heel region, surpassing standard requirements. Conversely, the forefoot segment exhibits failure under a 20% load due to defects inherent in the composite manufacturing process. The findings underscore the potential of the proposed concept as a promising alternative in lower limb prosthetics, offering both customization and affordability.