股骨有限元模型材料属性分配梯度的优化分析

The Optimized Analysis on the Distribution Gradient of Material Attributes of Femur Finite Element Model

优化分析股骨有限元模型材料属性分配梯度,从而得到相对准确且经济的划分层数,为CT灰度值赋值法在医学有限元研究领域的应用奠定理论基础。首先选取1名成人志愿者的股骨进行CT密扫,将获取的DICOM格式CT序列医学图像数据输入Mimics中,并建构出3D渲染模型。在此基础上通过Solid Works对模型实体化,导入Hyper Mesh进行体网格划分,再返回Mimics中,选择2、4、5、10、50、100、200、400层等8种梯度进行赋材质,最后将有限元模型在ABAQUS软件中设定工况,并实施仿真分析;同时构建股骨近端有限元模型,通过与文献数据对比分析来验证其有效性。结果表明,研究所构建的股骨有限元模型的应力、应变水平与有关文献的实验结果一致,其有效性得到充分验证。在材料属性分配梯度的优化分析中,2、4、5、400层材料属性时的应力与其他层材料属性相比具有显著性差异(P<0.05),同时这4组材料属性之间的应力也具有显著性差异(P<0.05),而10、50、100、200层的材料属性间应力则没有明显的结果偏差。10层材料属性既能提高运算速度,节省运算量,又能保证运算结果的精准性;CT灰度值赋值法适用于临床个体化快速有限元仿真分析。

The aim of this work is to investigate the optimized analysis on the femur finite element model in the distribution gradient of material attributes,getting the precise and economic divided layers,which can be used as the theoretical support for the application of CT gray value assignment in the research area of medical finite element.The femur of an adult volunteer was firstly selected for CT scanning,the obtained DICOM format CT serial medicinal image data were input into Mimics,and the 3 D rendering model was constructed.On this basis,using SolidWorks to substantiate the model,importing it into HyperMesh for volume mesh division,and then returning to Mimics,choosing layer 2,4,5,10,50,100,200 and 400 eight kinds of the gradient for material assignment.Finally,the working condition of the finite element model was set in ABAQUS software for simulation analysis.At the same time,the femur proxima finite element was established,and its validity was verified through the comparative analysis with literature data.Results showed that the level of stress and strain of the established femur finite element model had similar results with the experimental results in the literature;thus the effectiveness of the femoral finite element model was fully verified.The optimized analysis on the distribution gradient of material attributes:compared with the material properties of other layers,the stress of layer 2,4,5 and 400 was significantly different(P<0.05),and the stress between the four groups of material properties was significantly different(P<0.05),while the stress results of layer 10,50,100 and 200 were not significantly different.The material properties of the finite element model should be divided in an appropriate way.We found out that the material properties in 10 layers could not only improve the calculation speed and save the calculation amount,but also ensure the accuracy of the calculation results;the CT gray value assignment could be used to the analysis on the clinical individualized rapid finite element simulation.