Mechanical Engineering Graduate Seminar

PRESENTATION: Ankle-foot orthoses (AFOs) are assistive devices used by people with neuromuscular conditions that affect gait. AFO stiffness is the resistance to sagittal-plane, rotational motion around the ankle joint. Individually optimizing AFO stiffness improves gait performance, but it is not typically quantified in clinical practice. A major barrier to the evaluation and development of AFOs is the absence of AFO testing standards, resulting in significantly different measurements between methods. There is limited understanding of the effect of different testing parameters on measured properties and a lack of validation methods, severely hindering the ability to standardize AFO testing and implement methods into clinical settings. To address these gaps, a scoping review was conducted to analyze existing approaches to AFO mechanical testing. Common design and operational trends were synthesized to establish a taxonomy for organizing and describing testing methods, facilitating cross-device comparisons. Additionally, the effect of rotation axis location on AFO stiffness was evaluated to begin a systematic investigation of the effect of different testing parameters on measured properties. This work revealed small but significant effects of rotation axis translation on measured AFO stiffness, suggesting a fixed rotation axis is sufficient, but its location should match the AFO's bending axis. Proposed research includes characterizing dynamic AFO properties under biomimetic nonlinear testing speeds, evaluating the impact of biological limb tissue mechanics on measured AFO properties, and creating a standardized AFO with known mechanical properties will be developed to validate AFO testing methods. Overall, these contributions will provide evidence for AFO testing standardization and enable implementing these methods into clinical settings.

PRESENTER: Katherine Vaiciulis is a Ph.D. student studying mechanical engineering at the University of Iowa. She graduated with her M.S. in Mechanical Engineering in 2024 and her B.S.E in Biomedical Engineering in 2023, both from the University of Iowa. Katie is a research assistant in the Robotics and Assistive Devices Laboratory (RAD Lab). Her research is focused on evaluating the stiffness of ankle-foot orthoses (AFOs) using a benchtop testing device and working toward biomimetic, standardized measurement of AFO properties. Katie is interested in healthcare innovation and medical device design.