PBX装药弹体侵彻混凝土薄板的数值模拟

Numerical Simulation on the Dynamic Damage of PBX Charges Filled in Projectiles During Penetrating Thin Concrete Targets

为探究浇注型高聚物粘结炸药(PBX)装药在弹体侵彻过程中的力学响应和损伤分布情况,将孔隙压塌损伤、炸药晶体破碎损伤和粘结剂脱粘三种损伤形式的演化规律引入粘弹性本构模型,拟合了浇注型PBX在不同温度下的低应变率至中高应变率的力学响应,利用动力有限元数值软件模拟了含装药弹体侵彻混凝土靶板中炸药的力学损伤响应,分析了炸药应力波的传播、压力分布和三种损伤分布及演化。结果表明,加载初期炸药装药的头部承受较大的压缩应力,当应力波传播至尾部反射回拉伸波时,由于弹体的惯性作用,装药尾部和壳体内表面发生撞击,迅速形成高压区,压力高至0.25 GPa,因此装药头部和尾部损伤较为严重,应作为重点防护区域。

This paper is devoted to the building of a viscoelastic model based on actual damage mechanisms for explosive charges filled in projectiles during penetrating concrete targets. The characteristic damage modes present in polymer bonded explosive（PBX）s include intragranular voids, crystal fractures, and interfacial debonding. Quasi-static uniaxial compression tests and split-Hopkinson pressure bar tests were modelled to study mechanical responses and damage evolutions of PBXs at different loading conditions, and the dynamic finite element algorithm was applied to estimate the mechanical responses of PBXs under low intensity stimulus. Analyzing the damage and pressure distributions and the variations of different damages, the position of PBXs that is ready to be ignited, we find that the initial loading of the explosive charge head is suffered from the greater compressive stress. When the stress wave is propagated to the tail, reflected tensile waves are produced. Furthermore, the pressure increases rapidly to 0.25 GPa, leading to the more serious damages on the head and the tail, attributed to the inertia of the projectile body and the collision between the charge tail and the inner surface of the shell. It suggests that the head and the tail could be two key protection areas.