复合负泊松比人工骨材料胞元结构参数与力学性能的匹配

Matching of Cell Structural Parameters and Mechanical Properties of Composite Negative Poisson´s Ratio Artificial Bone Materials

基于手性结构和内凹结构设计了一种新型复合负泊松比多孔结构;采用Ti6Al4V钛合金球状粉末,通过选区激光熔化成形技术制备了复合结构试样,基于响应曲面法研究了胞元长度与环径比(0.7~0.9)、杆径(0.4~0.6 mm)和内凹角度(60°~80°)及其交互作用对复合结构试样弹性模量和屈服强度的影响,获得优化的胞元结构参数。结果表明:当孔隙率为75%时,复合结构试样的弹性模量和屈服强度介于手性和内凹结构试样之间;采用小胞元长度与环径比、小杆径和大内凹角度时,复合结构试样的弹性模量较低,采用大胞元长度与环径比、大杆径和小内凹角度时,屈服强度较高;复合结构的优化参数为胞元长度与环径比0.9、内凹角度60.1°、杆径0.546 mm,预测得到该优化复合结构试样的弹性模量为3.71 GPa,与试验值(3.65 GPa)的相对误差为1.64%,说明采用响应曲面法建立的负泊松比结构参数与力学性能关系模型可靠,实测该复合结构试样的屈服强度高达210.36 MPa。

A new composite porous structure with negative Poisson's ratio was designed based on the chiral structure and concave structure.The composite structure samples were prepared with Ti6Al4V spherical powder by selective laser melting forming technique.The effects of ratio of cell length to ring diameter(0.7—0.9),rod diameter(0.4—0.6 mm),concave angle(60°—80°)and their interactions on the elastic modulus and yield strength of the samples were analyzed by response surface methodology,and the cell structure parameters were optimized.The results show that when the porosity was 75%,the elastic modulus and yield strength of the composite structure sample were between those of the chiral and the concave structure samples.The elastic modulus of the composite structure sample was low when the ratio of cell length to ring diameter and rod diameter were small,and the concave angle was larg.The yield strength was high when the ratio of cell length to ring diameter and rod diameter were larg and concave angle was small.The optimization parameters of the composite structure were listed as follows:ratio of cell length to ring diameter of 0.9,concave angle of 60.1°and rod diameter of 0.546 mm.The predicted elastic modulus of the optimized composite structure sample was 3.71 GPa,and the relative error to the test value(3.65 GPa)was 1.64%,indicating that the model of relationship between negative Poisson's ratio structure parameters and mechanical properties established by the response surface methodology was reliable.The measured yield strength of the optimal composite structure sample reached 210.36 MPa.