后墙拆分结构防护性能的实验和计算对比研究

为验证利用后墙拆分方式提升防护结构性能的可行性，通过开展数值模拟（铝弹丸直径6.0 mm，撞击速度5.0～8.3 km/s）和超高速撞击实验（铝弹丸直径6.0 mm，撞击速度约8.3 km/s），研究了3种防护结构的性能差异以及不同撞击速度对结构防护性能的影响。防护结构主要包括Whipple结构和两种后墙拆分结构。针对直径6.0 mm铝弹丸分别以5.0、6.0、7.0、8.3 km/s的速度撞击防护结构的工况，借助Autodyn软件开展了数值模拟，并将模拟结果与在弹道靶设备上获得的超高速撞击实验结果进行了对比。模拟结果与实验结果均表明，在相同撞击状态下两种后墙拆分结构的防护性能有所差异，但均优于相同面密度的Whipple结构，且随着撞击速度的提高，这种优势具有增大的趋势。

Comparative study of simulation and experiment on shielding performance of shield with separated rear wall

In order to study the feasibility and effectiveness of the shield with separated rear wall (SRW), both the hypervelocity experiments and simulations were performed to investigate the performances of shields with different separated rear walls. The effect of impact velocity on the shielding performance was also studied. Three kinds of shields were designed, including a Whipple shield and two kinds of SRW shields. The AUTODYN software was based on to numerically simulate the penetration of 6.0-mm-diameter aluminum projectiles with the initial impact velocities of 5.0, 6.0, 7.0 and 8.3 km/s, respectively, into the shields. By comparing the damages in the backs of the rear walls among the three kinds of shields, the preliminary conclusion was drawn that the performances of the SRW shields were better than that of the Whipple shield. And the higher the impact velocity, the more obvious the advantage of the SRW shields. The tests were carried out in the hypervelocity ballistic range of China Aerodynamics Research and Development Center. The diameter of an aluminum projectile is 6.0 mm, and the impact velocity is about 8.3 km/s. The perforation and spall characteristics of the rear walls in the tests are consistent with the simulated results. The experiments not only prove the effectiveness of the simulation method, but also prove that the SRW shields have better protecting performances. Compared with the complete aluminum plate, a new free interface is added inside the structures of the SRW shields, which will reflect the shock wave generated in the impact process. Thus the strength of the shock wave that spreads to the second plate is reduced, and the damage in the SRW shields is alleviated. As the impact velocity increases, the main damage mode on the rear wall will change from the penetration damage mode to the impact damage mode, and the propagation of shock wave will be the main reason for the damage of the rear wall, which leads to better protecting performance of the SRW shields at higher impact velocities.