Journal of Rehabilitation Research & Development (JRRD)

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Volume 51 Number 10, 2014
   Pages 1525 — 1536

Abstract — Experimental and computational analysis of composite ankle-foot orthosis

Dequan Zou, DSc;1* Tao He, MS;1–2 Michael Dailey, MBA, CO;3 Kirk E. Smith, BS;4 Matthew J. Silva, PhD;5 David R. Sinacore, PhD, PT;1 Michael J. Mueller, PhD, PT;1 Mary K. Hastings, DPT, MSCI1

1Program in Physical Therapy, Washington University School of Medicine, St. Louis, MO; 2College of Power and Energy Engineering, Harbin Engineering University, Harbin, China; 3Orthotic & Prosthetic Design, St. Louis, MO; 4Mallinckrodt Institute of Radiology and 5Department of Orthopaedic Surgery, Washington University School of Medicine, St. Louis, MO

Abstract — Carbon fiber (CF) ankle-foot orthoses (AFOs) can improve gait by increasing ankle plantar-flexor power and improving plantar-flexor ankle joint moment and energy efficiency compared with posterior leaf spring AFOs made of thermoplastic. However, fabricating a CF AFO to optimize the performance of the individual user may require multiple AFOs and expensive fabrication costs. Finite element analysis (FEA) models were developed to predict the mechanical behavior of AFOs in this study. Three AFOs, two made of CF composite material and one made of thermoplastic material, were fabricated and then mechanically tested to produce force-displacement data. The FEA models were validated by comparing model predictions with mechanical testing data performed under the same loading and boundary conditions. The actual mechanical testing demonstrated that CF performs better than thermoplastic. The simulation results showed that FEA models produced accurate predictions for both types of orthoses. The relative error of the energy return ratio predicted by the CF AFO FEA model developed in this study is less than 3%. We conclude that highly accurate FEA models will allow orthotists to improve CF AFO fabrication without wasting resources (time and money) on trial and error fabrications that are expensive and do not consistently improve AFO and user performance.

Key words: ankle-foot orthosis, boundary condition, carbon fiber, computed tomography, energy return, finite element analysis, fracture, mechanical property, posterior leaf spring, thermoplastic.

View HTML ¦ View PDF ¦ Contents Vol. 51, No.10

This article and any supplementary material should be cited as follows:
Zou D, He T, Dailey M, Smith KE, Silva MJ, Sinacore DR, Mueller MJ, Hastings MK. Experimental and computational analysis of composite ankle-foot orthosis. J Rehabil Res Dev. 2014;51(10):1525–36.

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