Additive manufacturing (AM) routes have brought abundant geometric defects into as-fabricated lattice materials. Researchers take it for granted that any defects in lattice struts would decrease the mechanical properties of lattice structures, which has also been a rule followed by all engineering designers. In this paper, novel design strategies of actively utilizing defects to improve the mechanical properties of BCC lattice structures are proposed. Firstly, effects of non-periodic microstructure, waving struts and missing struts on the mechanical properties (i.e. compressive modulus and initial yield strength) of BCC lattice structures are investigated through finite element analysis. Simulation results indicate that mechanical properties of the BCC lattice structures exhibited certain sensitivity to the defects. Then, strategies to enhance the performance of BCC lattice patterns by utilizing the imperfections actively are also proposed. Finally, some typical lattice specimens are fabricated and experimental tests are also conducted to validate the accuracy of design strategies. We believe that the proposed new strategy could markedly expand the design space for the development of future materials by actively utilizing the geometric defects.

中文翻译：

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BCC桁架格子结构性能缺陷敏感性的数值和实验评估

增材制造（AM）路线给制造出来的晶格材料带来了丰富的几何缺陷。研究人员理所当然地认为，晶格支柱中的任何缺陷都会降低晶格结构的力学性能，这也是所有工程设计师遵循的规则。本文提出了积极利用缺陷来提高 BCC 晶格结构力学性能的新颖设计策略。首先，通过有限元分析研究了非周期微观结构、波动支柱和缺失支柱对BCC点阵结构力学性能（即压缩模量和初始屈服强度）的影响。模拟结果表明BCC晶格结构的力学性能对缺陷表现出一定的敏感性。然后，还提出了积极利用缺陷来增强 BCC 晶格图案性能的策略。最后，制作了一些典型的晶格试件并进行了实验测试以验证设计策略的准确性。我们相信，所提出的新策略可以通过积极利用几何缺陷来显着扩大未来材料开发的设计空间。