TC4负泊松比复合结构的人工骨力学性能调控研究

目的 基于不同变形机制的负泊松比结构优化设计新型复合多孔结构样件，增加力学性能的调控维度，以满足人体骨低弹性模量的匹配要求。方法 用内凹多边形替代手性结构的圆环，以获得新型的复合胞元结构。利用选区激光熔化成形技术制备负泊松比多孔人工骨样件，通过压缩实验揭示胞元结构类型、结构参数、孔隙率对屈服强度、弹性模量的影响规律，评测不同结构样件与人体骨间的力学性能匹配程度。结果 当孔隙率为65%～85%时，复合结构样件的成形质量、力学性能基本介于手性结构的和内凹结构的之间，且与孔隙率密切相关。手性结构、内凹结构和复合结构的弹性模量分别为2.39～4.64、1.12～3.77、1.01～3.47 GPa，屈服强度分别为65.19～223.06、45.25～195.81、26.54～143.58MPa。复合结构的弹性模量随环径和内凹角度的增大而减小。当孔隙率为75%时，环径由2.4 mm变至2.0 mm，弹性模量由2.651 GPa降低至2.082 GPa。当内凹角度由85°变至65°时，弹性模量则由3.566GPa降低至1.982GPa。结论 复合胞元结构可以融合材料特性，增加调控维度，进而匹配人工...

Regulation of Mechanical Properties of TC4 Artificial Bone with Composite Negative Poisson's Ratio Structure

The work aims to design a new composite porous structure sample based on the optimization of negative Poisson''s ratio structure with different deformation mechanisms to increase the regulatory dimension of mechanical properties, so as to meet the matching requirements of low elastic modulus of human bone. Inner concave polygons were substituted for the chiral structure of rings to obtain the new composite cytoskeletal structure. The porous artificial bone samples with negative Poisson''s ratio structure were formed by selected laser melting. Through compression test, the effects of cytoskeletal structure type, structural parameters and porosity on yield strength and elastic modulus were revealed and the matching degree of mechanical properties between samples and human bone was evaluated. In the porosity range of 65%-85%, the forming quality and mechanical properties of the composite structure samples were mostly between those of the chiral structure and the inner concave structure, and were directly related to the porosity. The elastic modulus of the chiral; structure, inner concave structure and composite structure was 2.39-4.64, 1.12-3.77 and 1.01-3.47 GPa, and the yield strength was 65.19-223.06, 45.25-195.81 and 26.54-143.58 MPa, respectively. The elastic modulus of the composite structure decreased with the increase of ring diameter and inner concave angle. At the porosity of 75%, the elastic modulus decreased from 2.651 GPa to 2.082 GPa when the ring diameter was changed from 2.4 mm to 2.0 mm, and from 3.566 GPa to 1.982 GPa when the internal concave angle was changed from 85° to 65°. The composite cytoskeletal structure can fuse the material characteristics and increase the dimension of regulation to match the low elastic modulus requirement of artificial bone structure.