School of Mechanical Engineering, Shanghai Jiao Tong University
目的 分析对比杆状与片状三周期极小曲面(Triply Periodic Minimal Surface , TPMS)模型孔隙特征与力学性能，构建高比表面积、低刚度和高强度的多孔结构。方法 构建相同孔隙率的D、G、P三种单元杆状TPMS（Solid-TPMS）与片状TPMS（Sheet-TPMS）模型，对比模型的孔径、杆径、比表面积等孔隙特征；利用有限元方法分析模型的力学性能，采用增材制造技术制作多孔钛样件，利用显微镜和扫描电镜观测多孔钛孔隙特征，通过压缩试验检测多孔钛力学性能。结果 CAD模型显示，同种单元片状结构的比表面积均显著高于杆状结构；有限元分析和多孔钛压缩实验结果均表明，同种单元片状结构的力学性能明显优于杆状结构，其中，D单元片状TPMS模型的优势最显著，比表面积为13.00 mm-1，多孔钛样件的弹性模量、屈服强度和抗压强度分别为5.65±0.08GPa、181.03±1.30MPa和239.83±0.45MPa，比杆状多孔钛分别提高了43.87%、55.08%和67.21%。结论 相同单元的片状TPMS模型有更大的比表面积，更有利于细胞的粘附生长,其低刚度、高强度的力学特性能有效降低应力遮挡，提供足够的力学支撑，是一种理想的骨缺损修复替代物孔隙结构模型。
Abstract：Objective The pore characteristics and mechanical properties of solid and sheet Triply Periodic Minimal Surface(TPMS) structures were compared and studied. Methods Construct solid TPMS and sheet TPMS models of D, G, and P units with the same porosity, and compare the pore characteristics of the model such as pore diameter, rod diameter, and specific surface area; The mechanical properties of the model were analyzed by finite element method, porous titanium samples were made by additive manufacturing technology, the pore characteristics of porous titanium were observed by microscope and scanning electron microscope, and the mechanical properties of porous titanium were detected by compression test. Results The CAD model shows that the specific surface area of the sheet structure of the same unit is significantly higher than that of the solid structure; The results of finite element analysis and porous titanium compression experiment show that the mechanical properties of the sheet structure of the same unit are significantly better than those of the solid structure. Among them, the D unit sheet TPMS model has the most significant advantages, the specific surface area of 13.00 mm-1. And the elastic modulus, yield strength and compressive strength of the titanium sample are 5.65±0.08GPa, 181.03±1.30MPa and 239.83±0.45MPa, respectively, which are 43.87%, 55.08% and 67.21% higher than the solid porous titanium sample. Conclusions The sheet TPMS model of the same unit has a larger specific surface area, which is more conducive to cell adhesion and growth, and its low stiffness and high strength mechanical properties effectively reduce stress shielding and provide sufficient mechanical support. It is an ideal pore structure model for bone defect repair substitutes.