预应力对LY12铝弹性前驱波的影响

通过过盈配合的热装配方法对LY12铝合金平面样品施加了径向预应力，采用平面飞片撞击方法获得了预应力对弹性前驱波的影响。结果表明:当飞片均以500 m/s的速度撞击样品时，压缩预应变为0(无预应变)、964.5×10-6和1 886.0×10-6时，弹性前驱波幅值分别为87.56、95.24、121.03 m/s，压缩预应力(变)提高了LY12铝弹性前驱波幅值。结合实验的特点，探讨了对样品施加静态径向预应力的数值模拟方法，结果表明，上升沿(100 μs)较为缓慢的加载可以达到与准静态加载应力分布一样的结果。采用该数值模拟方法给出和验证了弹性前驱波随压缩预应力增加而上升的计算结果，与实验结果较为吻合。

Influence of pre-stress on elastic precursor of LY12 aluminum

The effect of pre-stress on elastic precursor of disk-shaped LY12 aluminum samples was studied, and the radial pre-stress (or pre-strain) state was achieved by using an excessively-conjugated heat assembly device. In the experiment, the LY12 samples were impacted by flyer plates driven by a one-stage light-gas gun, and elastic precursor signals of the samples in several pre-strain states were measured by VISAR. The experimental results show that the elastic precursors are 87.56, 95.24 and 121.03 m/s respectively corresponding to the pre-strains of 0, 964.5×10-6 and 1 886.0×10-6 when the samples are impacted by the flyer plates with almost the same velocity. This clearly indicates that the pre-stress (pre-strain) increases the elastic precursor of LY12 aluminum. According to these experiments, we discussed how to apply static loading on the sample in the radial direction. The result shows that the loading with rising edge time 100 μs can produce the same stress distribution as that of static loading. Using this technology, the simulation results show that by increasing pre-stress we can enhance the elastic precursor velocity on the free surface of the samples. The simulated results are in good agreement with those from the experiments.