Compressive deformation behaviour of additively manufactured lattice structures based on re-entrant tetrakaidecahedral unit-cell geometry were experimentally investigated under quasi-static and dynamic loading conditions. Specimens of four different structures formed by three-dimensional periodical assembly of selected unit-cells were produced by a laser powder bed fusion technique from a powdered austenitic stainless steel SS316L. Quasi-static compression as well as dynamic tests using split Hopkinson pressure bar (SHPB) apparatus at two strain-rates were conducted to evaluate the expected strain-rate sensitivity of the fundamental mechanical response of the structures. To evaluate the experiments, particularly the displacement fields of the deforming lattices, optical observation of the specimens using a high-resolution camera (quasi-static loading) and two synchronised high-speed cameras (SHPB experiments) was employed. An in-house digital image correlation algorithm was used in order to evaluate the anticipated auxetic nature of the investigated lattices. It was found that neither of the investigated structures exhibited auxetic behaviour although strain-rate sensitivity of the stress–strain characteristics was clearly identified for the majority of structures.

中文翻译：

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增材制造周期性再入四面体晶格在低和高应变率下的压缩行为

在准静态和动态加载条件下实验研究了基于重入四面体晶胞几何结构的增材制造晶格结构的压缩变形行为。通过激光粉末床融合技术从粉末状奥氏体不锈钢 SS316L 中，通过三维周期性组装选定的晶胞形成四种不同结构的样品。使用分体式霍普金森压力棒 (SHPB) 装置在两个应变率下进行准静态压缩和动态测试，以评估结构基本机械响应的预期应变率敏感性。为了评估实验，特别是变形晶格的位移场，使用高分辨率相机（准静态加载）和两个同步高速相机（SHPB 实验）对样品进行光学观察。使用内部数字图像相关算法来评估所研究晶格的预期拉胀性质。结果表明，尽管大多数结构的应力-应变特性的应变率敏感性已被清楚地识别出来，但所研究的结构都没有表现出拉胀行为。