基于CT图像的股骨上段有限元建模及单元尺寸分析
|
摘要
目的基于CT图像构建5个不同的股骨上段有限元模型,并分析模型单元尺寸对股骨模型材料属性分布以及生物力学性能的影响。方法利用螺旋CT扫描股骨上段并以DICOM格式输出图像文件,利用Mimics软件提取三维几何文件,分别使用Mimics、3-Matica、ICEM软件生成体素网格模型、四面体网格模型和3个六面体网格模型(单元尺寸分别为2、1和0.5 mm),在Mimics中对网格文件进行材料赋值,将最终的有限元模型导入ABAQUS中进行力学行为分析。结果单元尺寸对5个模型总质量影响较小,5个模型沿相同路径上节点处Von Mises应力和节点位移整体变化趋势一致,但是各个节点处Von Mises应力误差较大,单元尺寸为0.5 mm的六面体网格模型与体素网格模型各节点处Von Mises应力值接近。结论基于CT灰度值进行材料赋值时,单元尺寸对模型的总质量和节点位移影响较小,但是单元尺寸的减小将导致模型中各材料含量和分布的改变,引起应力分布的变化。当模型单元尺寸与体素尺寸接近时,能较好反映股骨的质量分布和力学行为。
Objective To establish 5 different finite element models of proximal femur based on CT images,and analyze the influences of the element size on material property distribution and biomechanical behavior of the proximal femur model. Methods The proximal femur was scanned by spiral CT. The images,stored as DICOM format,were extracted by Mimics to obtain 3D geometric data,and then meshed separately by Mimics,3-Matic and ICEM software to createa voxel element model,a tetrahedral element model and 3 hexahedral element models( with element size of 2,1,0. 5 mm,respectively). These meshed models were assigned materials by Mimics,and their mechanical behavior was analyzed by ABAQUS eventually. Results For the proximal femur model with material assignment based on CT images,the influence of element size on the total mass of all the 5 models was not significant. The nodal Von Mises stress and nodal displacement along the same path in 5 models showed a similar tendency,while the Von Mises stress at each node displayed an obvious deviation. The nodal Von Mises stress in the hexahedral element model with the element size of 0. 5 mm showed accordance with the voxel element model. Conclusions The element size has a small influence on the total mass and nodal displacement when the material assignment is attributed to the model based on CT gray values,while decrease in the element size will change the materials distributions and affect stress distributions of the model. When the element size of the proximal femur model is close to its voxel size,the mass distributions and mechanical behavior of the femur can be preferably reflected.
Objective To establish 5 different finite element models of proximal femur based on CT images,and analyze the influences of the element size on material property distribution and biomechanical behavior of the proximal femur model. Methods The proximal femur was scanned by spiral CT. The images,stored as DICOM format,were extracted by Mimics to obtain 3D geometric data,and then meshed separately by Mimics,3-Matic and ICEM software to createa voxel element model,a tetrahedral element model and 3 hexahedral element models( with element size of 2,1,0. 5 mm,respectively). These meshed models were assigned materials by Mimics,and their mechanical behavior was analyzed by ABAQUS eventually. Results For the proximal femur model with material assignment based on CT images,the influence of element size on the total mass of all the 5 models was not significant. The nodal Von Mises stress and nodal displacement along the same path in 5 models showed a similar tendency,while the Von Mises stress at each node displayed an obvious deviation. The nodal Von Mises stress in the hexahedral element model with the element size of 0. 5 mm showed accordance with the voxel element model. Conclusions The element size has a small influence on the total mass and nodal displacement when the material assignment is attributed to the model based on CT gray values,while decrease in the element size will change the materials distributions and affect stress distributions of the model. When the element size of the proximal femur model is close to its voxel size,the mass distributions and mechanical behavior of the femur can be preferably reflected.
引文
[1]邹冬华,李正东,黄平,等.股骨有限元模型的建立及损伤生物力学验证[J].法医学杂志,2011,27(4):241-245.
[2]Neugebauer R,Werner M,Voigt C,et al.Experimental modal analysis on fresh-frozen human hemipelvic bones employing a 3D laser vibrometer for the purpose of modal parameter identification[J].J Biomech,2011,44(8):1610-1613.
[3]雷建银,刘海波,王志华,等.站立位下骨盆与骨折内固定稳定性分析[J].医用生物力学,2014,29(6):517-523.Lei JY,Liu HB,Wang ZH,et al.2014.Stability analysis of the pelvis and fracture fixation in standing position[J].J Med Biomech,2014,29(6):517-523.
[4]姜海波,葛世荣.基于CT扫描人体股骨的有限元分析[J].工程力学,2007,24(10):156-159.
[5]El’Sheikh HF,Macdonald BJ,Hashmi MJ.Finite element simulation of the hip joint during stumbling:A comparison between static and dynamic loading[J].J Mater Process Tech,2003,143-144(1):249-255.
[6]王倞,李元超,汪方,等.人体松质骨矿质密度与弹性模量关系[J].医用生物力学,2014,29(5):465-470.WANG J,LI YC,WANG F,et al.Relationship between mineral density and elastic modulus of human cancellous bone[J].J Med Biomech,2014,29(5):465-470.
[7]Taddei F,Pancanti A,Viceconti M.An improved method for the automatic mapping of computed tomography numbers onto finite element models[J].Med Eng Phys,2004,26(1):61-69.
[8]覃勇,樊继波,李莎,等.股骨上段有限元几何模型的建立与分析[J].中国骨质疏松杂志,2012,18(4):305-308.
[9]张国栋,廖维靖,陶圣祥,等.股骨有限元分析赋材料属性的方法[J].中国组织工程研究与临床康复,2009,13(43):8436-8441.
[10]张国栋,廖维靖,陶圣祥,等.股骨颈有限元分析的赋材料属性方法探讨及有效性验证[J].中国组织工程研究与临床康复,2009,13(52):10263-11026.
[11]张思能,黄潮桐,陈隆福,等.股骨生物力学有限元分析研究进展[J].中国骨科临床与基础研究杂志,2013,5(6):368-373.
[12]Marco V,Luisella B,Luca C,et al.A comparative study on different methods of automatic mesh generation of human femur[J].Med Eng Phys,1998,20(1):1-10.
[13]Peng L,Bai J,Zeng XL,et al.Comparison of isotropic and orthotropic material property assignments on femoral finite element models under two loading conditions(2)[J].Med Eng Phys,2006,28(3):227-233.
[14]Zohar Y,Nir T,Milgrom C.Reliable simulations of the human proximal femur by high-order finite element analysis validated by experimental observations[J].J Biomech,2007,40(16):3688-3699.
[15]Lengsfeld MP.Comparison of geometry based and CT voxel based finite element modelling and experimental validation[J].Med Eng Phys,1998,20(7):515-522.
[16]彭亮,曾小丽,白净.基于CT数据的股骨三维有限元建模方法[J].清华大学学报(自然科学版),2007,47(3):416-419.
[17]尚禹,彭亮,刘加成,等.均匀材料和基于CT灰度值材料的股骨-胫骨有限元分析[J].中国生物医学工程学报,2008,27(5):722-727.
[2]Neugebauer R,Werner M,Voigt C,et al.Experimental modal analysis on fresh-frozen human hemipelvic bones employing a 3D laser vibrometer for the purpose of modal parameter identification[J].J Biomech,2011,44(8):1610-1613.
[3]雷建银,刘海波,王志华,等.站立位下骨盆与骨折内固定稳定性分析[J].医用生物力学,2014,29(6):517-523.Lei JY,Liu HB,Wang ZH,et al.2014.Stability analysis of the pelvis and fracture fixation in standing position[J].J Med Biomech,2014,29(6):517-523.
[4]姜海波,葛世荣.基于CT扫描人体股骨的有限元分析[J].工程力学,2007,24(10):156-159.
[5]El’Sheikh HF,Macdonald BJ,Hashmi MJ.Finite element simulation of the hip joint during stumbling:A comparison between static and dynamic loading[J].J Mater Process Tech,2003,143-144(1):249-255.
[6]王倞,李元超,汪方,等.人体松质骨矿质密度与弹性模量关系[J].医用生物力学,2014,29(5):465-470.WANG J,LI YC,WANG F,et al.Relationship between mineral density and elastic modulus of human cancellous bone[J].J Med Biomech,2014,29(5):465-470.
[7]Taddei F,Pancanti A,Viceconti M.An improved method for the automatic mapping of computed tomography numbers onto finite element models[J].Med Eng Phys,2004,26(1):61-69.
[8]覃勇,樊继波,李莎,等.股骨上段有限元几何模型的建立与分析[J].中国骨质疏松杂志,2012,18(4):305-308.
[9]张国栋,廖维靖,陶圣祥,等.股骨有限元分析赋材料属性的方法[J].中国组织工程研究与临床康复,2009,13(43):8436-8441.
[10]张国栋,廖维靖,陶圣祥,等.股骨颈有限元分析的赋材料属性方法探讨及有效性验证[J].中国组织工程研究与临床康复,2009,13(52):10263-11026.
[11]张思能,黄潮桐,陈隆福,等.股骨生物力学有限元分析研究进展[J].中国骨科临床与基础研究杂志,2013,5(6):368-373.
[12]Marco V,Luisella B,Luca C,et al.A comparative study on different methods of automatic mesh generation of human femur[J].Med Eng Phys,1998,20(1):1-10.
[13]Peng L,Bai J,Zeng XL,et al.Comparison of isotropic and orthotropic material property assignments on femoral finite element models under two loading conditions(2)[J].Med Eng Phys,2006,28(3):227-233.
[14]Zohar Y,Nir T,Milgrom C.Reliable simulations of the human proximal femur by high-order finite element analysis validated by experimental observations[J].J Biomech,2007,40(16):3688-3699.
[15]Lengsfeld MP.Comparison of geometry based and CT voxel based finite element modelling and experimental validation[J].Med Eng Phys,1998,20(7):515-522.
[16]彭亮,曾小丽,白净.基于CT数据的股骨三维有限元建模方法[J].清华大学学报(自然科学版),2007,47(3):416-419.
[17]尚禹,彭亮,刘加成,等.均匀材料和基于CT灰度值材料的股骨-胫骨有限元分析[J].中国生物医学工程学报,2008,27(5):722-727.