弹簧矫形器分析-复合材料的有限元建模和优化

本文介绍了一种由预浸渍碳纤维环氧复合材料构建的弹簧矫形器的有限元分析和优化。弹簧矫形器是骨科行业中使用的最先进的辅助工具之一。这项工作是与哥德堡FS Dynamics的bor医院Ortopedteknik合作进行的。分析的目的是找到矫形器的弱点，并提出如何改变其性质和行为的建议。矫形器有两个主要有趣的部位，弹簧和脚趾。对这两个区域的层料旋转角度和层料堆积顺序进行了分析。在分析过程中，矫形器的几何形状、材料类型和脚趾和弹簧的复合层数保持不变。采用平面应力假设，将材料建模为平衡正交各向异性层。为了验证材料模型的有效性，在Abaqus/CAE软件中对复合材料板进行了四点弯曲试验，并与实验数据进行了比较。采用交互Tsai-Wu破坏准则作为相对应力测量。 The FE model of the orthosis was created from a scan of the real orthosis. From this the front surface was extracted and used as a thin shell model. The composite layup of the orthosis was created in the way to best imitate the manufacturing procedure used by the engineers at Ortopedteknik. To be able to analyze the orthosis a walking cycle was recorded from a person wearing the orthosis. This walking cycle was then applied to the model in Abaqus by prescribing reference points and using boundary conditions and multi point constraints. The maximum Tsai-Wu values in the toe and spring part during this walking cycle indicate that the orthosis is not close to failure. The Design Of Experiment (DOE) methodology was used to analyze how the stacking sequences of both the spring (18 plies) and the toe (5 plies) affect the bending stiffness. This was done using the four point bending test in Abaqus where the vertical reaction force was used as stiffness measure. It was found that the angle variation of the outermost plies of the spring has the most effect on the bending stiffness. For the toe the rotation of the two outermost plies are almost alone deciding the bending stiffness of the toe. From the DOE data approximations were created and then used to optimize stacking sequences based on requested bending stiffnesses.