Development of Design Techniques of Plastic Ankle Foot Orthosis for the Hemiplegics(I)

편마비 환자용 플라스틱 단하지보조기의 설계기술개발 (I) - 응력 해석을 통한 접근 -

  • Published : 2002.01.01


In this study, a stress analysis is made fur an ankle foot orthosis (AFO) in the view point of structural stability. The investigated AFO is a solid and standard type. To analyze the stress distribution on the neck of AFO, the maximum AFO angular translation data is obtained by gait analysis. The material test of polypropylene is made to obtain the mechanical properties of AFO. The maximum dorsiflexion appears at the midstance in the gait analysis. The experimental angular translation at the top of AFO is about 10.3$^{\circ}$ at mid stance. Three models of AFO with different width of neck are made and analyzed with ABAQUS 6.1. The stress levels and distributions of 3 different width(W$_1$, W$_2$=0.85W$_1$, W$_3$=0.60W$_1$) AFO are investigated. As a result, the standard type(W$_1$) appears to the maximum stresses at the medial edge of cutout area surrounding ankle joint. The maximum stresses of the narrower type(W$_2$) are occured on medial edge and center of ankle. The narrowest type(W$_3$) appears to the maximum stresses at center of ankle. The maximum stresses become smaller as ankle width of AFO is narrower.


Plastic Ankle Foot Orthosis(AFO);FE Analysis;Gait Analysis;Material Nonlinearity


  1. 임현균, 최경주, 길기남, 조강희, 김봉옥, 이영신, 1999, '3차원 보행분석을 통한 플라스틱단하지 보조기의 응력해석,' 대한기계학회 추계 학술대회 논문집 A, pp. 551-516
  2. Brandup, J., Immergut, E.H., Grulke, E.A. and Abe, A., 1999, 'Polymer Handbook,' John Wiley & Sons
  3. Kroschwitz, J. I., Ed., 'Encyclopedia of Polymer Science and Engineering,' 2nd ed., John Wiley & Sons
  4. 윤승호, 김봉옥 공역, 1994, '임상보행분석,' 도서출판 세진기획
  5. McHugh, B, 1999, 'Analysis of Body-Device Interface Forces in the Sagittal Plane for Patients Wearing Ankle-Foot Orthoses,' Prosthetics and Orthotics International, Vol. 23, No. 1, pp. 75-81
  6. Chu, T. M., Reddy, N. P. and Padovan, J., 1995, 'Three-Dimensional Finite Element Stress Analysis of the Polypropylene, Ankle-Foot Orthosis: Static Analysis,' Journal of Medical Engineering and Physics, Vol. 17, No. 5, pp. 372-379
  7. Chu, T.M., 1998, 'Determination of Stress Distribution in Various Ankle-Foot Orthoses: Experimental Stress,' Journal of Prosthetics and Orthotics, Vol. 10, No. 1, pp. 11-16
  8. 이동희, 장태성, 이정주, 윤용산, 2000, '유한요소해석과 다구찌방법을 이용한 에너지 저장형 의족 용골의 설계에 대한 연구,' 대한기계학회논문집 A권, 제 24권, 제3호, pp. 613-624
  9. 통계청, Http://www.nso,go,kr/report/data/pope95.htm
  10. 권혜정외 역, 1997, '보장구의지학,' 고문사
  11. Miyazaki, S., Yamamoto, S. and Kubota, T., 1997, 'Effect of Ankle -Foot Orthosis on Active Ankle Moment in Patients with Hemiparesis,' Medical & Biological Engineering and Computation, Vol. 35, No. 4, pp. 381-385
  12. Balmaseda, M.T. Jr., Koozekanani, S.H., Fatehi, M.T., Gordon, C., Dreyfuss, P.H. and Tanbonliong, E.C., 1988, Ground Reaction Forces, Center of Pressure, and Duration of Stance with and without an Ankle-Foot Orthosis, Archive of Physical Medicine and Rehabilitation, Vol. 69, No. 12, pp. 1009-1012
  13. Leone, D. J., 1987, 'A Structure Model for Thermoplastic Ankle-Foot Orthoses,' Transactions of the ASME Journal of Biomechanical Engineering, Vol. 109, No. 4, pp. 305-310