Nonuniform Deformation of Cell Structures Owing to Plastic Stress Wave Propagation
Nonuniform Deformation of Cell Structures Owing to Plastic Stress Wave Propagation
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DOI：
10.3390/applmech2040053
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发表时间：
2021-11
影响因子：
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通讯作者：
K. Tateyama;Hiroyuki Yamada
中科院分区：
文献类型：
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作者：
K. Tateyama;Hiroyuki Yamada
在细胞结构中，不像在致密体中，不均匀的变形发生在冲击端，即使在每秒几十到几百米的速度。在这项研究中，我们实验研究细胞结构的非均匀变形机制。他们制备了两种试样：泡沫镍（Ni foam）和硅橡胶填充泡沫镍（Ni/Silicone foam）。作为动态和冲击试验方法（压缩速度为20 m/s或更高），我们使用了带有相对测力传感器的动态和冲击载荷测量装置，以在一次试验中评估试样两端的载荷。在20 m/s或更小的压缩速度下，在Ni泡沫和Ni/硅酮泡沫中没有观察到不均匀变形，并且冲击端和固定端上的载荷实现了力平衡。随着应变速率的增加，泡沫镍的流变应力没有明显变化，而泡沫镍/硅树脂的流变应力表现出很强的应变速率依赖性。在约26 m/s的压缩速度下，在Ni/硅酮泡沫的两端处的载荷不同，并且我们观察到从冲击端开始的不均匀变形。从试样两端获得的载荷和变形行为的可视化结果表明，塑性应力波的速度和试样的长度是重要的不均匀变形。
In cell structures, unlike in dense bodies, nonuniform deformation occurs from the impact end, even at velocities in the order of tens to hundreds of meters per second. In this study, we experimentally examine the nonuniform deformation mechanism of cell structures. They prepared two kinds of specimens: nickel foam (Ni foam) and silicone-rubber-filled nickel foam (Ni/silicone foam). As a dynamic and impact test method (compression velocity of 20 m/s or more), we used a dynamic and impact load-measuring apparatus with opposite load cells to evaluate the loads on both ends of the specimen in one test. At compression velocities of 20 m/s or less, no nonuniform deformations were observed in the Ni foam and the Ni/silicone foam, and the loads on the impact and the fixed ends achieved force equilibrium. The Ni foam showed no change with an increasing strain rate, and the Ni/silicone foam showed a strong strain rate dependence of the flow stress. At a compression velocity of approximately 26 m/s, the loads differed at the two ends of the Ni/silicone foam, and we observed nonuniform deformation from the impact end. The results of the visualization of the load and deformation behavior obtained from both ends of the specimen revealed that the velocity of the plastic stress wave and the length of the specimens are important for nonuniform deformation.