基于DICOM数据构建股骨三维有限元模型的精确力学分析

Precise mechanical analysis on the femoral three-dimensional finite element model constructed based on DICOM data

背景:有限元模型已经由二维发展到三维,由线性模型发展到非线性,由于该方法在分析不太规则物体的力学特点方面具有优越性,因此在骨科生物力学研究特别是髋关节方面得到广泛应用。目的:利用有限元方法分析人体股骨在载荷下的受力状态,探索一种快速建立股骨有限元模型并能进行精确力学分析的方法。方法:选择标准成年男性志愿者行股骨CT扫描成像,得到股骨每层横截面图像,应用DICOM数据和MIMICS软件行三维重建,结合有限元分析软件ABQUS 6.8构建股骨三维有限元模型,并分析股骨模型载荷状态下的应力分布。结果与结论:结果显示,基于DICOM数据建立的股骨三维有限元模型,划分网格后形成38636个节点,201422个单元,其中包括股骨松质骨体网格模型与皮质骨体网格模型。有限元分析结果与以往的实验数据一致性较好,能够客观实际地反映股骨真实解剖形态和生物力学行为,分析精度较高。提示运用Mimics软件提供了简单有效的建模方法,极大程度上提高了建模效率,基于DICOM数据的三维有限元模型几何形状较准确,可以为股骨正常力学行为研究提供精确模型。利用ABQUS6.8分析得到的应力分布情况与临床观察一致。

BACKGROUND：The finite element model has been developed from two-dimensional model to three-dimensional model, from linear model to nonlinear model. As the advantage of this method in the analysis of mechanical characteristics of the irregular objects, the finite element model has been widely used in the research of orthopedic biomechanics, especial y in the research of hip joint. OBJECTIVE：To analyze the stress state of human femur with finite element analysis method and to investigate a method that can rapidly construct femoral finite element model and precisely analyze the biomechanics. METHODS：Normal male femur was used as specimen for CT scan to obtain cross-sectional images of femur in each slice. Three-dimensional reconstruction was performed with DICOM data and MIMICS software, then the femoral three-dimensional finite element model was established with the finite element analysis ABQUS 6.8 software, and the stress distribution of the model was analyzed under loading condition. RESULTS AND CONCLUSION：Based on DICOM data, three-dimensional finite element model of femur was constructed more quickly and precisely. The models were divided into 38 636 nodes and 201 422 units. The model included the parts of cortical and cancel ous bone. The biomechanical test results were accorded with the previous results, so the model could objectively reflect the real femur shape and biomechanical behavior with high precision. The Mimics software provided a simpler and effective method for the construction of femur model and improved the efficiency of modeling, and the three-dimensional finite element model based on DICOM data was accurate in shape and can be used for the normal research on biomechanical behavior of femur. The stress distribution analyzed with ABQUS 6.8 software is consistent with the clinical observation.