Estimating Elastic Energy Storage in a Footplate for Orthosis Design
Open Access
- Author:
- Sweeney, Carolyn A
- Area of Honors:
- Mechanical Engineering
- Degree:
- Bachelor of Science
- Document Type:
- Thesis
- Thesis Supervisors:
- Anne Elizabeth Martin, Thesis Supervisor
Dr. Jacqueline Antonia O'Connor, Thesis Honors Advisor - Keywords:
- biomechanics
ankle-foot orthosis
finite element analysis
AFO
energy storage - Abstract:
- The purpose of this thesis was to investigate the elastic energy storage in a footplate, the flat sole-shaped base of an orthotic brace. To quantify the strain energy stored in the footplate throughout a step, a method utilizing both a physical footplate lined with reflective markers and a 3D model in a finite element analysis (FEA) software was developed. The method was developed through stages of experiments that investigated model boundary conditions, the impact of missing data, as well as the accuracy of data placement within the model for the purposes of FEA testing. The physical footplate was worn by four subjects while footplate deflection data was collected by a motion capture system during gait. The collected deflection data was then used in FEA to quantify the strain energy. The maximum deflection of the footplate measured using the root mean square error (RMSE) to a plane occurred slightly before the maximum strain energy. This was due to the non-uniform shape of the footplate; the maximum deflection deformed the narrowest part of the footplate, which did not store the most elastic energy. In addition, the equivalent rate of increase and decrease in the RMSE results suggest that elastic energy storage and return in the footplate do not impact gait. However, work from this thesis can provide insights into the design optimization of footplates as well as methods to investigate energy storage in an orthotic brace.