三角形波致LY12铝层裂的平板冲击实验研究

采用基于冲击波衰减动力学的实验技术,使平板碰撞层裂实验的LY12铝样品中,产生三角形冲击脉冲.采用VISAR技术记录样品自由表面历史,获得样品中发生层裂的信号.在经过高应力三角形波实验的软回收样品上,发现了两个层裂面.就样品中呈现三角形脉冲的平板冲击实验而言,样品中可以存在一些高拉伸应力区域并发生多次层裂.将该文提出的基于空穴聚集的层裂模型用于数值模拟这些特定条件的平板冲击试验,并将计算的样品自由面速度历史及样品中的损伤分布与实测的VISAR数据及软回收的样品层裂面等作了比较.研究表明,人为粘性、状态方程、本构方程以及层裂模型对于数值模拟三角形冲击脉冲引起的层裂有严重影响.

STUDY ON SPALLATION IN LY12 AL CAUSED BY TRIANGULAR WAVES USING PLATE-IMPACT TESTS

Experimental techniques based on the dynamics of shock wave attenuation were used to produce decaying triangular shock pulse in LY12 Al samples of plate-impact spall tests.Spall signals were measured by monitoring the time-resolved free surface velocity histories of the targets with VISAR technique.Two spall planes were observed in the soft recovered sample for the high stress triangular wave experiment.For triangular shock pulse,there can be several regions of relatively high tension and variable spall planes.The void coalescence-based spall model presented by the authors was used to simulate the spall tests,and compare the free surface velocity histories of targets and damage distributions through the thickness of the targets predicted by our model with the VISAR data and the damages observed in the soft recovered targets,respectively.It was noted that the modeling of spall process caused by triangular waves can be seriously influenced by the artificial viscosity,the equation of state,the constitutive equations of the sample and the spall fracture model.