基于点阵结构的混合结构的各向同性研究

HYBRID STRUCTURAL ISOTROPY RESEARCH BASED ON LATTTICE STRUCTURES

  • 摘要: 点阵多孔结构在力学性能上通常表现为各向异性,在多孔骨植入物工程应用中,可能因弹性模量各向异性在部分方向发生应力屏蔽效应。针对上述问题,本文借助均匀化理论和有限元方法分析了典型点阵结构的力学性能及各向同性。研究表明,结构孔隙度对各向同性有较大影响,孔隙度越大,齐纳因子越大。其中,Gyroid、边心立方单元各向同性最优,I-WP、体心立方单元均匀性较差。对Primitive、体心立方单元进行单元混合,优化结构各向同性,P60BCC65,P65BCC70,P70BCC70和P75BCC80结构齐纳因子均接近于1,其中P75BCC80点阵结构的齐纳因子为1.02,孔隙度为62.4%,在适用的骨科植入体孔隙度范围之内。

     

    Abstract: The mechanical properties of lattice porous structures are usually anisotropic. In the engineering applications of porous bone implants, stress shielding effect may occur in some directions due to the anisotropy of elastic modulus. To solve these problems, the mechanical properties and isotropy of typical lattice structures are analyzed by means of homogenization theory and finite element analysis. The results show that the structure porosity has a great influence on isotropy, i.e., the greater the porosity, the greater the Zener factor. The lattices of Gyroid and Edge-centered cube are the best isotropy, while the lattices uniformity of I-WP and Body-centered cubic are poor. In order to achieve the effect of isotropy, the hybrid elements of Primitive and Body-centered cubic can optimize the structural isotropy. The Zener factor of P60BCC65, P65BCC70, P70BCC70 and P75BCC80 structures is close to 1, and the Zener factor of P75BCC80 lattice structure is 1.02 and the porosity is 62.4%, which is within the applicable orthopedic implant porosity range.

     

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