Document Type
Thesis
Date of Award
2025
Degree Name
Master of Science (MS)
Department
Biomedical Engineering
First Advisor
Lisa N MacFadden
Abstract
By 2050, an estimated 3.6 million individuals will be living with lower limb loss, with transtibial (below the knee) amputations being the most common type of lower limb surgery. Prosthetic devices are the standard of care for rehabilitating these amputees; each device is explicitly designed to enhance stability, energy storage and release, flexibility, and active propulsion. Prosthetic selection is based on user specifications, including activity level, comfort, and anthropometry. Despite the consensus that prosthetics help to restore impaired gait, traditional, commercial prosthetics fabricated with carbon fiber via injection molding are expensive and often require multiple modifications by a prosthetist before they are suitable for use. Additive manufacturing (AM) presents an alternative prosthetic manufacturing approach. By leveraging computer-aided engineering (CAE), AM enables the rapid and cost-effective fabrication of customized and complex 3D-printed geometries. While AM has become increasingly popular, design efforts have focused on the upper extremities, leaving the development of physically accurate 3D-printed models of the human foot relatively unexplored. This thesis aimed to develop and validate a unilateral, 3D-printed, multi-axis prosthetic ankle-foot complex capable of coordinating multi-planar dynamic movements effectively mimicking the intrinsic behavior of an intact foot. By analyzing the anthropometry of a theoretical individual with a mass of 91 kg (200 lbs.) and standing 1.745 m (5'7”), a CAD model was devised to emulate the natural biomechanics of the left foot. The prosthetic was fabricated with a rubber-like, hyper-elastic material, thermoplastic polyurethane (TPU), in conjunction with a rigid elastomer, polyethylene terephthalate glycol (PETG), to provide the essential balance of flexibility and stiffness. Numerical and experimental testing adhering to AOPA's Prosthetic Foot Project and ISO 10328:2016 was used to validate the design, specifically finite element analysis (FEA) in silico simulations accurately assessed the prosthetic's mechanical response, while physical testing evaluated its dynamic movement across three anatomical planes of motion. Results demonstrated the prosthetic's resistance to permanent deformation under applied loading simulations, indicating its potential as a viable, low-cost option for transtibial amputees. Preliminary findings confirmed the 3D-printed prosthetic foot's capacity to support functional gait, suggesting that future design iterations and extensive clinical testing could establish this model as a practical, assistive device.
Subject Categories
Biomedical Engineering and Bioengineering
Keywords
CAD model, Prosthetic devices, 3D-printed, multi-axis prosthetic ankle-foot complex capabl
Number of Pages
155
Publisher
University of South Dakota
Recommended Citation
Landeen, Brogan Rene, "Design and Validation of a Multiple Axis, Passive 3D-printed Ankle-Foot Prosthetic for Functional Gait" (2025). Dissertations and Theses. 337.
https://red.library.usd.edu/diss-thesis/337