轴向压缩载荷作用下大鼠胫骨表面应变分布的三维有限元分析

Objective: To construct a three-dimensional finite element model of rat tibia based on Micro CT and obtain the spatial distribution of tibial surface strain under axial compressive load through finite element analysis. Methods: The tomographic images obtained by Micro CT scanning were used to establish a three-dimensional solid model of rat tibia through Mimics, Geomagic Studio and Solidworks software, and then imported into ABAQUS 6.14. The tibia was simplified into an isotropic material, and the mesh was divided by tetrahedral elements. The boundary conditions were defined as the distal end of the tibia being fixed and an axial load being applied at the proximal end. The spatial distribution of tibial surface strain and the "strain - load" relationship curve were obtained through finite element analysis, and based on this, the anatomical locations of the maximum tensile strain and compressive strain on the tibial surface were determined. Results: The finite element analysis of rat tibia found that there was a significant linear positive correlation between the applied load and the strain; the analysis of the spatial distribution of tibial surface strain under different loads showed that the maximum tensile strain occurred at the proximal-middle-lower 1/3 of the tibia, and the maximum compressive strain occurred in the middle of the tibia. Conclusion: The three-dimensional finite element analysis method based on Micro CT can successfully establish a stress load loading model of the rat tibia in the axial direction, and can accurately quantify the spatial distribution of tensile and compressive strains on the tibial surface under different compressive loads through this method, providing theoretical support for predicting the spatial location distribution of bone microdamage. The sites with the highest risk of bone microdamage in the tibia are the middle of the tibia and the proximal-middle-lower 1/3. This model can lay an important foundation for the animal and clinical experimental research on bone microdamage in the research group.

目的:构建基于Micro CT的大鼠胫骨三维有限元模型,通过有限元分析计算得到在轴向压缩载荷作用下的胫骨表面应变的空间分布。方法:将Micro CT扫描得到的断层图像通过Mimics、Geomagic Studio和Solidworks软件建立大鼠胫骨的三维实体模型,导入ABAQUS 6.14中,将胫骨简化成各向同性材料,采用四面体单元划分网格,边界条件定义为胫骨远端固定、近端施加轴向载荷,经有限元分析计算得到胫骨表面应变的空间分布及"应变-载荷"关系曲线,并基于此确定胫骨表面最大张应变和压应变的解剖位置。结果:对大鼠胫骨的有限元分析计算发现,施加载荷与应变之间存在着显著的线性正相关关系;通过对不同载荷下大鼠胫骨表面应变空间分布的分析显示,最大张应变发生在胫骨近中下1/3处,最大压应变发生在胫骨中段。结论:基于Micro CT的三维有限元分析方法可以成功建立大鼠胫骨轴向的应力载荷加载模型,并可通过该方法精确定量不同压缩载荷作用下的胫骨表面张应变和压应变的空间分布,为预测骨微损伤发生的空间位置分布提供理论支撑。胫骨骨微损伤发生风险最高部位为胫骨中段及近中下1/3处。该模型可为课题组骨微损伤的动物和临床实验研究奠定重要基础。