基于CT股骨有限元模型精确重建及模态分析

Finite Element Model Accurately Reconstruct and Modal Analysis Based on CT Images

研究股骨模型优化设计问题,快速而精确的模型重建方法,不仅可以为模型的前处理提高效率,而且为后续的分析提供可靠的保障。首先对CT扫描图片进行预处理,选择灰度值阀值,经过边分割,补洞处理及去除冗余数据等操作,利用3D插补法进行三维重建得到精确几何模型。并依据模型灰度值赋予模型不同的材料属性得到非均质模型。后期在ansys12.1中进行了生理状态下的自由振动分析。最后提取前7阶股骨振型和固有频率。实例表明,建模方法提高了精度和效率,达到了几何和材料精确重建,并且分析结果可以为股骨的修复和置入假体设计提供依据。

Femur model is the basis of the finite element analysis. The fast and accurate model reconstruction method can not only improve the efficiency of the preprocess of FEA, but also provide reliable protection for subse- quent analysis. Firstly, the CT scan images were preprocessed, and the gray value thresholds were selected. After edges segmentation, we filled up holes, remove redundant data, and used 3D interpolation method to establish 3D model. After that, it was divided into different material properties to get heterogeneous model according to gray val- ues. In the end, we used Ansysl2. 1 to carried out free vibration analysis in physiological conditions. After analysis of simulated vibration characteristics, the form 7 step modes and natural frequence were extracted. The example shows that this method has higher modeling accuracy and efficiency, and can achieve the exact reconstruction of geo- metric and material. Which can provide a basis for the design of the femur repair prosthesis.