Zhao Miao, Liu Fei, Fu Guang, Zhang David Z, Zhang Tao, Zhou Hailun
State Key Laboratory of Mechanical Transmission, Chongqing University, Chongqing 400044, China.
College of Engineering, Mathematics and Physical Sciences, University of Exeter, North Park Road, Exeter EX4 4QF, UK.
Materials (Basel). 2018 Nov 29;11(12):2411. doi: 10.3390/ma11122411.
The triply periodic minimal surface (TPMS) method is a novel approach for lattice design in a range of fields, such as impact protection and structural lightweighting. In this paper, we used the TPMS formula to rapidly and accurately generate the most common lattice structure, named the body centered cubic (BCC) structure, with certain volume fractions. TPMS-based and computer aided design (CAD) based BCC lattice structures with volume fractions in the range of 10⁻30% were fabricated by selective laser melting (SLM) technology with Ti⁻6Al⁻4V and subjected to compressive tests. The results demonstrated that local geometric features changed the volume and stress distributions, revealing that the TPMS-based samples were superior to the CAD-based ones, with elastic modulus, yield strength and compression strength increasing in the ranges of 18.9⁻42.2%, 19.2⁻29.5%, and 2⁻36.6%, respectively. The failure mechanism of the TPMS-based samples with a high volume fraction changed to brittle failure observed by scanning electron microscope (SEM), as their struts were more affected by the axial force and fractured on struts. It was also found that the TPMS-based samples have a favorable capacity to absorb energy, particularly with a 30% volume fraction, the energy absorbed up to 50% strain was approximately three times higher than that of the CAD-based sample with an equal volume fraction. Furthermore, the theoretic Gibson⁻Ashby mode was established in order to predict and design the mechanical properties of the lattice structures. In summary, these results can be used to rapidly create BCC lattice structures with superior compressive properties for engineering applications.
三重周期极小曲面（TPMS）方法是一种在诸如冲击防护和结构轻量化等一系列领域中进行晶格设计的新方法。在本文中，我们使用TPMS公式快速准确地生成了具有一定体积分数的最常见晶格结构，即体心立方（BCC）结构。通过选择性激光熔化（SLM）技术，使用Ti-6Al-4V制造了体积分数在10%-30%范围内的基于TPMS和基于计算机辅助设计（CAD）的BCC晶格结构，并对其进行了压缩试验。结果表明，局部几何特征改变了体积和应力分布，这表明基于TPMS的样品优于基于CAD的样品，其弹性模量、屈服强度和抗压强度分别在18.9%-42.2%、19.2%-29.5%和2%-36.6%的范围内增加。通过扫描电子显微镜（SEM）观察发现，高体积分数的基于TPMS的样品的失效机制转变为脆性失效，因为它们的支柱更容易受到轴向力的影响并在支柱处断裂。还发现基于TPMS的样品具有良好的能量吸收能力，特别是在体积分数为30%时，在50%应变下吸收的能量比具有相同体积分数的基于CAD的样品高出约三倍。此外，还建立了理论吉布森-阿什比模型，以预测和设计晶格结构的力学性能。总之，这些结果可用于快速创建具有优异压缩性能的BCC晶格结构，以用于工程应用。
