碎片云动量特性数值仿真研究

Models for Momentum of Debris Cloud and Ejecta Produced by Hypervelocity Impacts of Aluminum Spheres with Thin Aluminum Sheets

铝合金球形弹丸高速撞击薄铝板时，会造成薄铝板穿孔并自身发生破碎，在铝板前后两侧产生碎片云，分别为反溅碎片云和穿透碎片云。反溅碎片云及穿透碎片云具有各自的动量特性，对其动量特性的研究有助于为碎片云理论建模提供依据。采用AUTODYNV6．0软件对直径为6．35mm的Al1100-O球形弹丸高速正撞击6种厚度的Al6061-T6薄板进行了数值仿真计算，撞击速度为1．0～5．0km／s。得到上述两种碎片云的动量，确定了动量值随撞击速度口及薄板厚度艿的变化规律。同时，利用仿真得到的动量数据，采用多元回归方法，分别建立了两种碎片云动量模型。最后，对美国国家航空航天局（NASA）报告给出的7种工况下的撞击实验进行了数值仿真计算，并将动量值与实验结果进行了比较，得到的比较结果可用以分析数值仿真的有效性。

Debris clouds produced by the normal impact of an aluminum alloy sphere with an aluminum alloy sheet can scatter flying downrange,as well as an ejecta veil is produced at the same time. The momentum of debris clouds and ejecta are necessary to create the debris clouds and ejecta theoretical models. 54 numerical simulations were performed using the SPH（smoothed particle hydrodynamics） tech- nique in AUTODYN-2D,in which 6.35 mm diameter of 1100-O aluminum spheres impacted six thicknesses of 6061-T6 aluminum sheets at velocities ranging from 1.0 km/s to 5.0 km/s. Using the data from the numerical simulations,two respective regression models are developed for characterizing the momentum of debris clouds and ejecta produced by impacts with 1.0km/s≤v ≤5.0 kin/s,0. 5 mm≤δ 43.0 mm. In the two models, the independent variables are the impact velocity, v, and the thickness of the sphere,t, while the dependent variables are the momentum ratios （ratios of debris clouds momentum and ejecta momentum to sphere momentum）. The effects of v and δ on the momentum of debris clouds and ejecta are investigated. Seven additional numerical simulations in the same way as above were carried out and values obtained are compared with the experimental data of NASA to evaluate the performance of the simulation.