面向3D打印可变模量金属假体的微结构设计

发布时间：2018-12-27 19:12

【摘要】：为了解决假体与骨的弹性模量存在较大差异而造成应力遮挡的问题,基于3D打印在制造多孔微结构的优势,将假体设计为多孔结构能有效降低模量,缓解应力遮挡。但是,如何优化微结构几何参数以实现假体模量的最佳匹配仍然没有得到解决。因此,提出了一种面向3D打印的可变模量金属假体的微结构设计方法,旨在获得与宿主骨模量相匹配又具有可加工性的生物型假体。针对体心立方单元(BCC)和增强体心立方单元(RBCC),采用有限元法计算了两种多孔单元沿轴向、面对角线和体对角线方向的弹性模量,建立了单元弹性模量与支柱直径的函数关系,分析了单元各向异性随支柱直径变化的规律,研究了棱边直径和单元尺寸对单元弹性模量的影响。结果表明:在加工精度范围内,通过减小支柱直径能实现单元等效弹性模量与骨模量一致性要求;在各向同性上BCC单元要优于RBCC单元,而且增大棱边直径有助于提高单元各向同性;由于BCC单元能实现相邻不同模量的单元界面连续拼接,故选用BCC单元构建模量可调的假体,可变模量范围为15.9~100 GPa。该设计方法可用于构建具有模量梯度结构的生物假体,以实现关节应力最优分布。
[Abstract]:In order to solve the problem of stress occlusion caused by the large difference of elastic modulus between prosthesis and bone, based on the advantage of 3D printing in the fabrication of porous microstructures, the design of prosthesis as porous structure can effectively reduce the modulus and relieve the stress occlusion. However, how to optimize the geometric parameters of microstructures to achieve the optimal matching of prosthetic modulus has not been solved. Therefore, a 3D print-oriented microstructural design method for metal prosthesis with variable modulus is proposed, which aims to obtain a bioprosthesis with machinability that matches the modulus of the host bone. The elastic moduli of two kinds of porous elements along axial, plane and diagonal directions are calculated by finite element method for (BCC) and (RBCC),. The functional relationship between the elastic modulus of the element and the diameter of the pillar is established. The variation of the anisotropy of the element with the diameter of the pillar is analyzed, and the influence of the edge diameter and the size of the element on the elastic modulus of the element is studied. The results show that the equivalent elastic modulus and bone modulus of the unit can be achieved by reducing the diameter of the pillar in the range of machining accuracy. The BCC element is better than the RBCC element in isotropy, and increasing the edge diameter can improve the isotropy of the element. Because the BCC element can realize the continuous splicing of the interface of the adjacent units with different moduli, the BCC element is used to construct the prosthesis with adjustable moduli, and the variable modulus range is 15.9 ~ 100 GPa.. This design method can be used to construct biological prosthesis with modulus gradient structure to achieve optimal distribution of joint stress.
【作者单位】：西安交通大学机械制造系统工程国家重点实验室;陕西恒通智能机器有限公司;利兹大学机械工程学院;
【基金】：陕西省科技统筹工程计划(2014KTZB01-02-02) 中央高校基本科研业务费专项资金资助项目
【分类号】：R318.08

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