Measurement of dynamic response of liquid metal subjected to uniaxial strain wave
Measurement of dynamic response of liquid metal subjected to uniaxial strain wave
复制标题
单轴应变波作用下液态金属动态响应的测量
DOI：
10.1051/jp4:2000940
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发表时间：
2000
期刊：
影响因子：
--
通讯作者：
R. Hino
中科院分区：
文献类型：
--
作者：
M. Futakawa;H. Kogawa;R. Hino
日本原子力研究所正在为建造高强度中子源设施进行研发，这可能会给我们带来创新的科学领域。将一束高功率质子束注入液态汞靶进行中子溅射。汞容器将经受由快速热膨胀产生的压力波，因为在汞中发生加热现象。为了研究压力波在水银中的传播，我们利用改进的分离式霍普金森压杆装置对水银进行了撞击实验。由输入杆和输出杆组成的腔室以及设置在两个杆之间的套环。汞被小心地插入腔室中，没有任何气泡。这样的刚性轴环可以将约束条件实现为水银中的单轴应变条件。通过显式有限元程序LS-DYNA计算了每个杆和液态汞上的应力传播。结果发现，除了应力波注入汞后的早期，实验结果与分析结果存在显著差异。而在撞击初期，分析结果与实验结果吻合较好。在假设单轴应变条件和Kolsky公式的情况下，得到了水银中的平均轴向压力和体积应变历史。在实验范围内，高压下水银的刚度几乎与撞击速度无关。在与汞接触的输入棒端面上发现了许多凹坑，这可能与汞中的空穴有关。
JAERI is carrying out R&D for constructing the facility of high intensity neutron spallation source which may bring us innovative science fields. A high power proton beam will be injected into the liquid mercury target for the neutron spallation. The mercury container will be subjected to the pressure waves generated by rapid thermal expansions because heating phenomena occurs in the mercury. In order to evaluate the pressure wave propagation in the mercury, we have carried out impact experiments on the mercury by a modified conventional split Hopkinson pressure bar apparatus. The chamber consisting of the input and out put bars and a collar was set between the two bars. The mercury was carefully inserted into the chamber without any air bubbles. Such a stiff collar may realize the constraint condition as a uniaxial strain condition in the mercury. The stress propagation on each bar and the liquid mercury was calculated by using an explicit FEM-code LS-DYNA. It is found that except very early time period just after stress wave injection into the mercury, a distinguished discrepancy is present between experimental and analytical results. While, in the early stage of impact, the analyses are appropriately representable to the experimental results. The average axial pressure and volume strain histories in the mercury were obtained as assuming the uniaxial strain condition and Kolsky formulas. It was recognized that the stiffness of mercury under high pressure is almost independent of the impact velocity in the experimental range. Many pits were found on the end surface of input bar being in contact with mercury, which may be associated with the cavitation in mercury.