超高速撞击波阻抗梯度材料形成的碎片云相变特性

Phase Transition Characteristics of Debris Cloud of Ti/Al/Mg Wave Impedance Gradient Material Subjected to Hypervelocity Impact

在超高速碰撞下,波阻抗梯度材料能使弹丸的动能更多地转变为靶板材料内能,使其发生熔化、气化等相变,分散和消耗弹丸的动能,进而实现航天器对空间碎片的防护。以钛、铝、镁3种材料组成的波阻抗梯度材料为研究对象,借助于光滑粒子流体动力学数值模拟方法,采用Tilloston状态方程和Steinberg-Guinan本构模型,给出各材料的冲击相变判据,结合速度为7.9 km/s的超高速碰撞实验结果,验证数值模拟结果的有效性。计算结果表明:钛、铝、镁波阻抗梯度材料在受到大于4 km/s速度撞击时,形成的碎片云会发生不同程度的熔化和气化;钛、铝、镁3种组分分别在受到6 km/s、5 km/s、4 km/s速度撞击时碎片云会发生熔化,在受到8 km/s、9 km/s、6 km/s速度撞击时碎片云会发生气化。

In hypervelocity impact,the wave impedance gradient material helps to transfer the kinetic energy into more internal energy,which causes the melting and vapor phase transition of debris cloud,and disperses and dissipates the kinetic energy of projectile,thus protecting the spacecraft from debris cloud.The wave impedance gradient material studied in this paper is made of titanium,aluminium and magnesium alloy(TAM).The smoothed particle hydrodynamics(SPH)method is used to simulate hypervelocity impact.Impact-induced phase transition criteria of various materials are given by using Tilloston equation of state and Steinberg-Guinan constitutive model.The simulated results were compared with the experimental results with impact velocity of 7.9 km/s.The results show that the impact-generated debris cloud is melted and vaporized to some extent when TAM wave impedance gradient material is impacted by the velocity more than 4 km/s.For Ti,Al and Mg,the debris cloud is melted at the impact velocities of 6 km/s,5 km/s and 4 km/s,respectively,and it is vaporized at the impact velocities of 8 km/s,9 km/s and 6 km/s.