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摘要: 设计了一种基于分离式Hopkinson压杆(SHPB)的冲击膨胀环实验装置，实验装置包括一个液压腔，一侧为驱动活塞，另一侧为圆环试件封闭。对活塞施加轴向冲击，利用液体体积近似不可压缩的特性，通过液压腔截面积的大比例缩小，将较低速度的对活塞冲击转化为圆环试件沿径向的高速膨胀，驱动试件发生拉伸变形直至断(碎)裂。使用这种冲击膨胀装置，获得了LY12铝环在不同撞击速度下碎裂过程的初步结果。实验结果显示，随着撞击速度增大，圆环试件碎裂产生的碎片的尺度减小，试件的表观断裂应变增加。这为研究材料的动态拉伸碎裂问题提供了一种加载方式。Abstract: Based on the split Hopkinson pressure bar (SHPB), a new loading experimental technology was developed for conducting expanding ring test which is used to study the dynamic tensile deformation and the fracture (fragmentation) properties of materials. The loading fixture includes a hydraulic cylinder filled with incompressible fluid, which is pushed by a piston connected to the input bar. As the liquid is driven, it expands the metallic ring specimen in the radial direction. The approximately incompressible property of the liquid makes it possible to drive the specimen in very high radial velocity by low velocity movement of piston, according to the large sectional area ratio of the cylinder to specimen. The ring specimens of LY12 aluminum alloy were tested by this experimental technology. The results show apparent increase of the fragment number and the fracture strain of the specimen with the increase of the impact velocity.
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Key words:
- solid mechanics /
- expanding ring /
- SHPB /
- dynamic tension /
- fragmentation /
- apparent fracture strain
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图 3 安装在SHPB系统上的冲击膨胀环实验装置示意图
Figure 3. Schematic diagram of the impact loading fixture installed between SHPB
图 7 平均断裂应变随撞击速度的变化规律
Figure 7. Average fracture strain under different impact velocity
表 1 铝合金环动态拉伸实验数据
Table 1. Data obtained from the dynamic tensile experiment of auminium alloy
实验 v0/(m·s-1) n l/mm 1 10.8 2 57.0 2 11.0 2 56.8 3 10.9 4 60.8 4 14.1 4 62.6 5 16.1 4 59.0 6 16.8 3 62.9 7 21.5 6 68.0 8 22.1 5 64.9 9 21.7 6 66.8 10 25.2 7 71.7 11 25.7 8 71.1 12 25.5 8 62.4 13 31.6 7 72.4 14 35.1 8 78.9 
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