Abstract Direct impact testing with a Hopkinson bar is, nowadays, a very popular experimental technique for investigating the behavior of cellular materials, e.g., lattice metamaterials, at high strain-rates as it overcomes several limitations of the conventional Split Hopkinson Pressure Bar (SHPB). However, standard direct impact Hopkinson bars (DIHB) have only single-sided instrumentation complicating the analysis. In this paper, a DIHB apparatus instrumented with conventional strain-gauges on both bars (a so called Open Hopkinson Pressure Bar - OHPB) was used for dynamic impact experiments of cellular materials. Digital image correlation (DIC) is used as a tool for investigating the displacements and velocities at the faces of the bars. A straight-forward wave separation technique combining the data from the strain-gauges with the DIC is adopted to increase the experiment time window multiple times. The experimental method was successfully tested at impact velocities in a range of 5 − 30 m · s − 1 with both linear elastic and visco-elastic bars of a medium diameter. It is shown that, under certain circumstances, a simple linear elastic model is sufficient for the evaluation of the measurements with the visco-elastic bars, while no additional attenuation and phase-shift corrections are necessary. The applicability of the experimental method is demonstrated on various experiments with conventional metal foams, hybrid foams, and additively manufactured auxetic lattices subjected to dynamic compression.

中文翻译：

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多孔固体和晶格结构的动态冲击试验：双面直接冲击霍普金森杆的应用

摘要 使用霍普金森杆直接冲击测试是当今非常流行的实验技术，用于研究蜂窝材料（例如晶格超材料）在高应变率下的行为，因为它克服了传统分裂式霍普金森压力杆 (SHPB) 的几个限制. 然而，标准的直接冲击霍普金森杆 (DIHB) 只有单面仪器，使分析复杂化。在本文中，DIHB 装置在两个杆上都装有常规应变计（所谓的开放式霍普金森压力杆 - OHPB），用于多孔材料的动态冲击实验。数字图像相关 (DIC) 被用作研究钢筋表面位移和速度的工具。采用将应变计数据与 DIC 相结合的直接波分离技术，以多次增加实验时间窗口。该实验方法在 5 - 30 m · s - 1 范围内的冲击速度下成功地测试了具有中等直径的线性弹性和粘弹性棒。结果表明，在某些情况下，简单的线弹性模型足以评估粘弹性棒的测量结果，而无需额外的衰减和相移校正。该实验方法的适用性在传统金属泡沫、混合泡沫和受动态压缩的增材制造拉胀晶格的各种实验中得到证明。该实验方法在 5 - 30 m · s - 1 范围内的冲击速度下成功地测试了具有中等直径的线性弹性和粘弹性棒。结果表明，在某些情况下，简单的线弹性模型足以评估粘弹性棒的测量结果，而无需额外的衰减和相移校正。该实验方法的适用性在传统金属泡沫、混合泡沫和受动态压缩的增材制造拉胀晶格的各种实验中得到证明。该实验方法在 5 - 30 m · s - 1 范围内的冲击速度下成功地测试了具有中等直径的线性弹性和粘弹性棒。结果表明，在某些情况下，简单的线弹性模型足以评估粘弹性棒的测量结果，而无需额外的衰减和相移校正。该实验方法的适用性在传统金属泡沫、混合泡沫和受动态压缩的增材制造拉胀晶格的各种实验中得到证明。一个简单的线性弹性模型足以评估粘弹性棒的测量结果，而无需额外的衰减和相移校正。该实验方法的适用性在传统金属泡沫、混合泡沫和受动态压缩的增材制造拉胀晶格的各种实验中得到证明。一个简单的线性弹性模型足以评估粘弹性棒的测量结果，而无需额外的衰减和相移校正。该实验方法的适用性在传统金属泡沫、混合泡沫和受动态压缩的增材制造拉胀晶格的各种实验中得到证明。