Chu T M, Reddy N P, Padovan J
Department of Mechanical and Industrial Engineering, New Jersey Institute of Technology, Newark 07102, USA.
Med Eng Phys. 1995 Jul;17(5):372-9. doi: 10.1016/1350-4533(95)97317-i.
An asymmetric 3-dimensional finite element model (FEM) of the ankle-foot orthosis (AFO) together with the ankle-foot complex was developed using the computer aided design (CAD) program PATRAN. Static analysis of normal and pathological motions of the ankle-foot complex such as the "drop-foot" problem were conducted using the FEM program ADINA. A total of 313 three dimensional solid elements and 10 truss elements were used. Heel strike and toe-off condition were simulated. Results revealed that the peak compressive stress (1.6 MPa) in the AFO model occurred in the heel regions of the AFO and the maximum tensile stress (0.8 MPa) occurred in the neck region of the AFO during toe-off. Parametric analyses revealed that the model was sensitive to the elastic moduli of the AFO and of the soft tissue, but was relatively insensitive to the ligament stiffness. The results confirmed the hypothesis that peak stresses in the orthosis occur in the heal and neck regions of the orthosis.
利用计算机辅助设计（CAD）程序PATRAN建立了踝足矫形器（AFO）与踝足复合体的非对称三维有限元模型（FEM）。使用有限元程序ADINA对踝足复合体的正常和病理运动（如“垂足”问题）进行了静态分析。总共使用了313个三维实体单元和10个桁架单元。模拟了脚跟触地和脚尖离地的情况。结果显示，AFO模型中的峰值压应力（1.6兆帕）出现在AFO的脚跟区域，而最大拉应力（0.8兆帕）出现在脚尖离地时AFO的颈部区域。参数分析表明，该模型对AFO和软组织的弹性模量敏感，但对韧带刚度相对不敏感。结果证实了矫形器中的峰值应力出现在矫形器的脚跟和颈部区域这一假设。
