三种骨支架单胞结构构造及SLM打印成形

Monocell Structure and SLM Printing of Three Bone Scaffolds

多孔骨支架具有一系列的优点,选区激光熔化技术(selective laser melting,SLM)为创新多孔骨支架的制造及应用提供了技术支持,尤其是由规则单胞基元构成的多孔骨支架具有可设计性与优异的力学性能。本文构造了VC(圆柱连杆立方)、SHC(球形孔立方)、FCC(面心立方)3种单胞结构,通过有限元分析对应特征尺寸和孔隙率及弹性模量之间的关系,建立了3种单胞模型特征尺寸与孔隙率以及弹性模量之间的数学模型,明确了3种单胞结构在所优化的特征尺寸范围内皆适用于股骨支架的结构设计。使用SLM技术打印对应特征尺寸的单胞为基元的316L 5×5×5点阵结构,通过准静态压缩实验,对仿真结果进行验证。实验表明:对应特征尺寸的点阵结构实际弹性模量与仿真的弹性模量平均误差为14.8%,且误差随着结构实体尺寸的增大而减小,其中VC、SHC、FCC单胞结构尺寸分别为r∈[0.28 mm,0.32 mm]、d∈[2.24 mm,2.36 mm]、R∈[0.20 mm,0.24 mm]条件下打印出的点阵结构,满足股骨支架的使用要求。

This paper explores the application of selective laser melting(SLM)technology in the fabrication of innovative porous bone scaffolds,highlighting the advantages of such scaffolds in terms of designability and mechanical properties.Three types of regular cellular structures,VC(cylindrical connecting rod cube),SHC(spherical pore cube)and FCC(face centered cube),are constructed.Through finite element analysis of the relationship between the corresponding characteristic size,porosity and elastic modulus,the mathematical model between the characteristic size,porosity and elastic modulus of the three single cell models is established.It is clear that the three cell structures are suitable for the structural design of femur scaffolds within the optimized characteristic size range.In addition,SLM technology is used to print the 316L 5×5×5 lattice structure with the corresponding feature size cell as the primitive.The simulation results are verified by quasi-static compression test.Experimental results show that the average error between the actual and simulated elastic modulus of lattice structures with corresponding feature sizes is 14.8%,and the error decreases with the increase of the physical size of the structure,in which the single cell structure sizes are VC:r∈[0.28 mm,0.32 mm],SHC:d∈[2.24 mm,2.36 mm,FCC:The lattice structure printed under the condition of R∈[0.20 mm,0.24 mm]meets the use requirements of femur scaffolds.