球形弹丸超高速撞击靶板时背表面材料破碎的数值模拟分析

Numerical Simulation Analysis of Back Fragmentation of Sphere by Hypervelocity Impact

选取合适的材料状态方程和强度模型,通过数值模拟分析超高速撞击下弹丸材料的破碎行为。弹丸的破碎主要有两种:稀疏波引起的层裂和材料在高压作用下的碎裂。由于层裂影响和高压影响下弹丸的破碎方式不同,导致两种情况下材料产生的碎片形状和大小不同。分析球形弹丸在撞击靶板过程中压力脉冲的传播及衰减形式发现:在弹丸和靶板尺寸相同的情况下,弹丸中压力脉冲的脉宽基本保持不变,而峰值压力随着撞击速度的增加而增加;在撞击速度相同的情况下,弹丸中压力脉冲的峰值压力基本不变,而压力脉冲的脉宽随着靶板厚度的增加而增加。弹丸中传播的压力脉冲与后期弹丸背表面的层裂相关,其峰值及变化速率直接影响背表面层裂厚度,其脉宽直接影响背表面沿弹丸径向的层裂深度。得到层裂厚度以及层裂破碎方式的影响区域,对研究后期碎片云分布有重要参考价值。

The appropriate material state equations and strength models were chosen. Through the numerical simulation results, the fragmentation behavior of the projectile material is analyzed. The fragmentation of the projectile mainly consists of spallation caused by release waves and fragmentation of the material under high pressure. Due to the influence of the spallation and the fragmentation method of the projectile under the influence of high pressure, It also causes the shape and size of the fragments produced by the material in two cases. This paper analyzes the propagation and attenuation of pressure pulses in a projectile during the impact of a spherical projectile on a target plate. It was found that the pulse width of the pressure pulse in the projectile remained substantially unchanged when the size of the projectile and the target were the same, and the peak pressure increased as the impact velocity increased. At the same impact velocity, the peak pressure of the pressure pulse propagating in the projectile is substantially constant, and the pulse width of the pressure pulse increases as the thickness of the target increases. The pressure pulse propagated in the projectile is related to the spallation of the back surface of the projectile. The peak value and rate of change of the pressure pulse directly affect the thickness of the back surface layer. The width of the pressure pulse directly affects the depth of the lamination of the back surface along the radial direction of the projectile. The affected area of the fracture-cracking method and the thickness of the spar are obtained, which have important reference value for the distribution of fragments in the debris cloud in the later stage.