Abstract The quasi-static and high strain rate response of chiral auxetic cellular structures were evaluated in this work. Samples of the chiral auxetic structures were fabricated with the Selective Electron Beam Melting (SEBM) technique from copper powder. Uniaxial quasi-static and low-speed dynamic compression tests were performed on a universal testing machine, while high strain rate tests up to 5000 s−1 were performed using the one-stage powder gun. The experimental measurements together with infrared thermography and high-speed camera images were used to study the deformation mechanism of chiral auxetic structures. A significant effect of the shock enhancement observed in experiments at higher loading velocities was characterised by evaluating the specific energy absorption and specific strength. This phenomenon was further analysed in more detail by using parametric computational simulations, which offered more detailed analysis of mechanical behaviour at different strain rates. The computational results indicate that the plateau stress of chiral auxetic structure increases exponentially with increasing loading velocity. An empirical polynomial approximation was extracted from the computational results, which enables estimation of the plateau stress of auxetic cellular structures at arbitrary loading velocity in between the analyses velocity limits.

中文翻译：

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不同应变率下手性拉胀细胞结构的压缩行为

摘要 在这项工作中评估了手性拉胀细胞结构的准静态和高应变率响应。手性拉胀结构的样品是用选择性电子束熔化 (SEBM) 技术从铜粉制造的。在万能试验机上进行了单轴准静态和低速动态压缩试验，而使用一级粉末枪进行了高达 5000 s-1 的高应变率试验。实验测量结合红外热成像和高速相机图像用于研究手性拉胀结构的变形机制。在更高加载速度的实验中观察到的冲击增强的显着效果通过评估比能量吸收和比强度来表征。通过使用参数化计算模拟，对不同应变率下的机械行为进行了更详细的分析，进一步更详细地分析了这种现象。计算结果表明，手性拉胀结构的平台应力随着加载速度的增加呈指数增加。从计算结果中提取了一个经验多项式近似，这使得能够在分析速度限制之间的任意加载速度下估计拉胀细胞结构的平台应力。