PDF(Pubmed)
Abstract：
The present study investigated the influence of pore size of strut-based Diamond and surface-based Gyroid structures for their suitability as medical implants. Samples were made additively from laser powder bed fusion process with a relative density of 0.3 and pore sizes ranging from 300 to 1300 μm. They were subsequently examined for their manufacturability and mechanical properties. In addition, non-Newtonian computational fluid dynamics and discrete phase models were conducted to assess pressure drop and cell seeding efficiency. The results showed that both Diamond and Gyroid had higher as-built densities with smaller pore sizes. However, Gyroid demonstrated better manufacturability as its relative density was closer to the as-designed one. In addition, based on mechanical testing, the elastic modulus was largely unaffected by pore size, but post-yielding behaviors differed, especially in Diamond. High mechanical sensitivity in Diamond could be explained partly by Finite Element simulations, which revealed stress localization in Diamond and more uniform stress distribution in Gyroid. Furthermore, we defined the product of the normalized specific surface, normalized pressure drop, and cell seeding efficiency as the indicator of an optimal pore size, in which this factor identified an optimal pore size of approximately 500 μm for both Diamond and Gyroid. Besides, based on such criterion, Gyroid exhibited greater applicability as bone scaffolds. In summary, this study provides comprehensive assessment of the effect of pore size and demonstrates the efficient estimation of an in-silico framework for evaluating lattice structures as medical implants, which could be applied to other lattice architectures.
摘要：
本研究调查了基于支柱的金刚石和基于表面的甲状腺结构的孔径对其作为医疗植入物的适用性的影响。样品是由激光粉末床熔融工艺相加制成的，相对密度为0.3，孔径为300至1300μm。随后检查它们的可制造性和机械性能。此外,进行了非牛顿计算流体动力学和离散相模型来评估压降和细胞接种效率。结果表明，钻石和甲状腺都具有较高的建成密度和较小的孔径。然而,甲状腺显示出更好的可制造性，因为其相对密度更接近设计密度。此外,基于机械测试，弹性模量在很大程度上不受孔径的影响，但是产生后的行为不同，尤其是钻石。金刚石的高机械灵敏度可以部分通过有限元模拟来解释，这揭示了金刚石中的应力定位和甲状腺中更均匀的应力分布。此外，我们定义了归一化比表面的乘积，归一化压降，和细胞接种效率作为最佳孔径的指标，其中该因素确定了金刚石和甲状腺的最佳孔径约为500μm。此外,基于这样的标准，甲状腺作为骨支架表现出更大的适用性。总之,这项研究提供了对孔径影响的全面评估，并证明了评估晶格结构作为医疗植入物的有效评估，这可以应用于其他晶格架构。
