摘要
在炸药爆轰驱动含间隙双层钢飞片情况下,两层钢飞片间的间隙会影响外层飞片的首次、二次入射波波形及强度,进而影响外层飞片自由面速度等。为了更好地认识爆轰加载条件下金属飞片的运动特征,需要深入研究间隙对该动力学过程的影响规律。首先,开展了爆轰驱动含初始间隙双层钢飞片的简化建模及数值模拟,通过模拟与实验结果的对比,验证了简化建模的合理性;然后,对该模型的加载动力学过程进行了深入分析,给出了首次、二次加载的来源;最后,开展了不同间隙厚度对该动力学过程影响的模拟分析研究。自由面速度结果表明,随着间隙厚度由0.1 mm增加至1 mm以上,外层飞片自由面的首次起跳速度峰值先逐渐降低后基本保持恒定、二次起跳速度峰值由逐渐增加至基本不变。动力学分析结果表明,可将不同间隙大小的影响分为两个阶段,其分界判据是在爆轰加载后内层金属飞片是否能够在间隙部位发展为脱体层裂片:在间隙较小的情况下,内层飞片在间隙一侧无法发展为层裂片,在此阶段内,随着间隙厚度的增加,外层飞片的首次加载峰值压力降低、二次加载峰值压力增加;在间隙较大的情况下,内层飞片在间隙一侧可以形成厚度不变、速度稳定的层裂片,在此阶段内,随着间隙厚度的增加,外层飞片的首次加载与二次加载的峰值压力均基本不变,但首次与二次加载之间的时间间隔缩短。研究结果对爆轰驱动含间隙飞片的自由面速度曲线的解读具有指导意义,从而能够更好地认识工程实验中由间隙造成的一些非预期物理现象。
Clearance of certain thickness often exists between two stacked metal flyers.When a double-layer metal flyer with clearance is loaded by detonation,the closing of the clearance may affect the form and shock intensity of the first and second loading waves inside of the outer flyer,and then affects the free surface velocity of the outer flyer.In order to better grasp the motion characteristics under detonation loading,the effect of clearance on the dynamic process needs to be studied.Firstly,a detonation driven two-layer steel flyers model is presented,in which a clearance of certain thickness is assumed to exist between two steel flyers.In this model,the free surface of the outer flyer is loaded twice.By comparing the simulation results and experimental results of free surface velocity at different positions,it is confirmed that the simulation can correctly catch the dynamic process.Then,the sources of the first and second loading in the outer flyer are given by the analysis of the simulated dynamic process.The first loading wave in the outer flyer comes from the clearance closing collision,and the second loading wave mainly comes from the sustained high pressure loading of detonation products.Finally,the simulation with various clearance thicknesses is carried out,and the effect of clearance thickness change is summarized.The simulated results of free surface velocity show that with the increase of clearance thickness from 0.1 mm to more than 1 mm,the peak value of the first take-off free surface velocity first decreases and then remains unchanged,and the peak value of the second take-off free surface velocity first increases and then remains unchanged.The dynamic analysis shows that the size of the clearance thickness directly affects whether the inner steel flyer has enough time to develop into spallation on the clearance side after detonation loading.If the size of clearance is small,the inner flyer cannot develop into a spallation on clearance side,and the first loading wave formed in the outer flyer has a triangular like pulse.In this stage,with the increase of the clearance thickness,the first loading peak pressure decreases and the second loading peak pressure increases.If the size of clearance is large,the inner flyer can form a spallation with constant thickness and stable velocity on clearance side,and the first loading wave formed in the outer flyer is an approximate square wave.In this stage,with the increase of clearance thickness,the peak pressures of the first and second loading remain basically unchanged,but the time interval between the first and second loading decreases.The understanding has guiding significance for the interpretation of the free surface velocity measurement results in experiments,and some unexpected physical phenomena caused by clearance in practical problems could be better understood,too.
作者
刘军
孙致远
张凤国
殷建伟
LIU Jun;SUN Zhiyuan;ZHANG Fengguo;YIN Jianwei(Institute of Applied Physics and Computational Mathematics,Beijing 100094,China)
出处
《爆炸与冲击》
EI
CAS
CSCD
北大核心
2023年第4期1-9,共9页
Explosion and Shock Waves
基金
国家自然科学基金(12101062)
于敏基金(TCYM1820-02)。
关键词
爆轰驱动
金属飞片
间隙
二次冲击
detonation driving
metal flyer
clearance
second loading
作者简介
第一作者:刘军(1981-),男,硕士,副研究员,caepcfd@126.com。
