The cavity characteristics in liquid-filled containers caused by high-velocity impacts represent an important area of research in hydrodynamic ram phenomena.The dynamic expansion of the cavity induces liquid pressure ...The cavity characteristics in liquid-filled containers caused by high-velocity impacts represent an important area of research in hydrodynamic ram phenomena.The dynamic expansion of the cavity induces liquid pressure variations,potentially causing catastrophic damage to the container.Current studies mainly focus on non-deforming projectiles,such as fragments,with limited exploration of shaped charge jets.In this paper,a uniquely experimental system was designed to record cavity profiles in behind-armor liquid-filled containers subjected to shaped charge jet impacts.The impact process was then numerically reproduced using the explicit simulation program ANSYS LS-DYNA with the Structured Arbitrary Lagrangian-Eulerian(S-ALE)solver.The formation mechanism,along with the dimensional and shape evolution of the cavity was investigated.Additionally,the influence of the impact kinetic energy of the jet on the cavity characteristics was analyzed.The findings reveal that the cavity profile exhibits a conical shape,primarily driven by direct jet impact and inertial effects.The expansion rates of both cavity length and maximum radius increase with jet impact kinetic energy.When the impact kinetic energy is reduced to 28.2 kJ or below,the length-to-diameter ratio of the cavity ultimately stabilizes at approximately 7.展开更多
The impact of high-velocity penetrators into liquid-filled containers can generate hydrodynamic ram effects,potentially causing catastrophic structural damage to the container.Previous studies have primarily focused o...The impact of high-velocity penetrators into liquid-filled containers can generate hydrodynamic ram effects,potentially causing catastrophic structural damage to the container.Previous studies have primarily focused on undeformed penetrators,such as fragments or bullets,with limited attention directed toward shaped charge jets.This study investigates the penetration characteristics of shaped charge jets impacting behind-armor liquid-filled containers,with particular emphasis on jet-liquid interactions.A theoretical penetration model incorporating material compressibility and jet stretching was developed based on the virtual origin theory.A high-speed imaging experimental system was designed to capture the jet motion within the container.The impact process was numerically reproduced using ANSYS/LSDYNA,and the effects of standoff and overmatch on jet penetration were analyzed.The results reveal that jet stretching induced by increased standoff enhances the penetration velocity of the jet.A proportional relationship between the stretching factor(λ)and the overmatch parameter(I)was identified,withλranging from approximately 1.22 to 1.38 times I across the studied standoff range(80-220 mm).The findings offer a basis for future studies on the pressure distribution in the liquid and the structural response of containers.展开更多
Analyzing the mass of behind-armor debris (BAD) generated by Rolled Homogeneous Armor (RHA) subjected to normal penetration of variable cross-section Explosively Formed Projectile (EFP) is the purpose of this paper. S...Analyzing the mass of behind-armor debris (BAD) generated by Rolled Homogeneous Armor (RHA) subjected to normal penetration of variable cross-section Explosively Formed Projectile (EFP) is the purpose of this paper. So theoretical analysis, numerical simulation and experimental data are combined to analyze the influence of variable cross-section characteristic on the time history of crater radius. Moreover the relationships between time history of crater radius (as well as mass of BAD) and the thickness of RHA (from 30mm to 70 mm) and the impact velocity of EFP (1650 m/s to 1860 m/s) are also investigated. The results indicate that: 1) being compared to the variable cross-section characteristic is ignored, the theoretical time history of crater radius is in better agreement with the simulation results when the variable cross-section characteristic is considered;2) being compared to the other three conditions of plug, the theoretical mass of BAD is in the best agreement with the simulation results when the shape of plug is frustum of a cone and the angle between generatrix and bottom is 45- and the axial length of mushroom is considered.展开更多
The behind-armor debris(BAD) formed by the perforation of an EFP is the main damage factor for the secondary destruction to the behind-armor components.Aiming at investigating the BAD caused by EFP,flash X-ray radiogr...The behind-armor debris(BAD) formed by the perforation of an EFP is the main damage factor for the secondary destruction to the behind-armor components.Aiming at investigating the BAD caused by EFP,flash X-ray radiography combined with an experimental witness plate test method was used,and the FEM-SPH adaptive conversion algorithm in LS-DYNA software was erployed to model the perforation process.The simulation results of the debris cloud shape and number of debris were in good agreement with the flash X-ray radiographs and perforated holes on the witness plate,respectlvely.Threedimensional numerical simulations of EFP's penetration under various impact conditions were conducted.The results show that,an ellipsoidal debris cloud,with the major-to-minor axis radio(a/b)smaller than that caused by shaped charge jets,was formed behind the target.With the increase of target thickness(h) and decrease of impact velocity(v_0) and obliquity(θ),the value of a/b decreases.The number of debris ejected from target is significantly higher than that from EFP.Based on the statistical analysis of the spatial distribution of the BAD,An engineering calculation model was established considering the influence of h,v_0 and θ.The model can with reasonable accuracy predict the quantity and velocity distribution characteristics of BAD formed by EFP.展开更多
为认识爆炸成型弹丸(Explosively Formed Projectile,EFP)靶后破片在空气中自由飞散及侵彻验证板的时空分布演化规律,基于分形理论建立了考虑破片表面状况的侵彻接触面积计算公式,通过破片云离散化对靶后破片在验证板材料阻力下时空分...为认识爆炸成型弹丸(Explosively Formed Projectile,EFP)靶后破片在空气中自由飞散及侵彻验证板的时空分布演化规律,基于分形理论建立了考虑破片表面状况的侵彻接触面积计算公式,通过破片云离散化对靶后破片在验证板材料阻力下时空分布特性进行了研究,并结合多层验证木板回收试验,获得了不同飞散角区间内破片侵彻的平均停留位置空间分布。研究结果表明:靶板破片的径向飞散距离整体上大于EFP破片;当验证板等效阻应力小于临界阻应力,破片侵彻停留位置空间分布呈现出一定的椭球形状,靶后破片在空气中飞散空间分布与在验证板内侵彻停留位置空间分布可以通过不同验证板等效阻应力下时空分布相互转化;各飞散区间破片侵彻后平均停留位置的计算结果与试验结果变化趋势基本一致,解决了以往后效验证板试验只能获得破片数量而无法获得破片侵彻停留位置空间分布的问题,为靶后破片对装甲车辆的毁伤效能评估提供技术支持。展开更多
Impact experiments of large-caliber PELE with various inner-outer diameter ratio perforating RHA plate at low velocity were performed.Experimental results showed the size of perforated holes on plate,average diameter ...Impact experiments of large-caliber PELE with various inner-outer diameter ratio perforating RHA plate at low velocity were performed.Experimental results showed the size of perforated holes on plate,average diameter of damage area on witness plate,and number of behind-armor fragments will increase as d/D increasing from 0.72 to 0.84.Expansion and fragmentation of large-caliber PELE in this condition were also numerically studied with ANSYS Autodyn.Then,an analytical model accounting for an additional radial shock wave was presented to predict radial expansion velocity and fragmentation of jacket,as well as an empirical approach to estimate diameter of damage area.Calculation results by these approaches were in good agreement with experiments and numerical simulations.Further discussion revealed that Shock/rarefaction wave interactions behavior varying with inner-outer diameter ratio is an important mechanism resulting in different lateral effect by PELE projectiles with various configurations.展开更多
为了准确描述爆炸成型弹丸(Explosively Formed Projectile,EFP)垂直侵彻有限厚靶板后效破片云的形状,基于量纲分析及正交设计理论,利用AUTODYN软件中SPH算法研究了EFP成型参数、弹靶材料参数对靶后破片云形状的影响,建立了EFP垂直侵彻...为了准确描述爆炸成型弹丸(Explosively Formed Projectile,EFP)垂直侵彻有限厚靶板后效破片云的形状,基于量纲分析及正交设计理论,利用AUTODYN软件中SPH算法研究了EFP成型参数、弹靶材料参数对靶后破片云形状的影响,建立了EFP垂直侵彻靶后破片云形状的数学描述模型。利用该模型计算了EFP垂直侵彻靶后破片云形状参量长半轴,并和仿真结果及相关试验结果进行对比,结果表明,该模型计算的后效破片云长半轴结果与相关试验结果误差控制在3%以内,能够准确描述EFP垂直侵彻有限厚靶板后效破片云的形状。展开更多
基金financial support from the National Natural Science Foundation of China(Grant No.11572159).
文摘The cavity characteristics in liquid-filled containers caused by high-velocity impacts represent an important area of research in hydrodynamic ram phenomena.The dynamic expansion of the cavity induces liquid pressure variations,potentially causing catastrophic damage to the container.Current studies mainly focus on non-deforming projectiles,such as fragments,with limited exploration of shaped charge jets.In this paper,a uniquely experimental system was designed to record cavity profiles in behind-armor liquid-filled containers subjected to shaped charge jet impacts.The impact process was then numerically reproduced using the explicit simulation program ANSYS LS-DYNA with the Structured Arbitrary Lagrangian-Eulerian(S-ALE)solver.The formation mechanism,along with the dimensional and shape evolution of the cavity was investigated.Additionally,the influence of the impact kinetic energy of the jet on the cavity characteristics was analyzed.The findings reveal that the cavity profile exhibits a conical shape,primarily driven by direct jet impact and inertial effects.The expansion rates of both cavity length and maximum radius increase with jet impact kinetic energy.When the impact kinetic energy is reduced to 28.2 kJ or below,the length-to-diameter ratio of the cavity ultimately stabilizes at approximately 7.
基金the financial support from the National Natural Science Foundation of China(Grant No.11572159)。
文摘The impact of high-velocity penetrators into liquid-filled containers can generate hydrodynamic ram effects,potentially causing catastrophic structural damage to the container.Previous studies have primarily focused on undeformed penetrators,such as fragments or bullets,with limited attention directed toward shaped charge jets.This study investigates the penetration characteristics of shaped charge jets impacting behind-armor liquid-filled containers,with particular emphasis on jet-liquid interactions.A theoretical penetration model incorporating material compressibility and jet stretching was developed based on the virtual origin theory.A high-speed imaging experimental system was designed to capture the jet motion within the container.The impact process was numerically reproduced using ANSYS/LSDYNA,and the effects of standoff and overmatch on jet penetration were analyzed.The results reveal that jet stretching induced by increased standoff enhances the penetration velocity of the jet.A proportional relationship between the stretching factor(λ)and the overmatch parameter(I)was identified,withλranging from approximately 1.22 to 1.38 times I across the studied standoff range(80-220 mm).The findings offer a basis for future studies on the pressure distribution in the liquid and the structural response of containers.
基金financially supported by the National Natural Science Foundation of China(Grant No.11372136)
文摘Analyzing the mass of behind-armor debris (BAD) generated by Rolled Homogeneous Armor (RHA) subjected to normal penetration of variable cross-section Explosively Formed Projectile (EFP) is the purpose of this paper. So theoretical analysis, numerical simulation and experimental data are combined to analyze the influence of variable cross-section characteristic on the time history of crater radius. Moreover the relationships between time history of crater radius (as well as mass of BAD) and the thickness of RHA (from 30mm to 70 mm) and the impact velocity of EFP (1650 m/s to 1860 m/s) are also investigated. The results indicate that: 1) being compared to the variable cross-section characteristic is ignored, the theoretical time history of crater radius is in better agreement with the simulation results when the variable cross-section characteristic is considered;2) being compared to the other three conditions of plug, the theoretical mass of BAD is in the best agreement with the simulation results when the shape of plug is frustum of a cone and the angle between generatrix and bottom is 45- and the axial length of mushroom is considered.
基金supported by National Natural Science Foundation of China(Grant no.11872123)。
文摘The behind-armor debris(BAD) formed by the perforation of an EFP is the main damage factor for the secondary destruction to the behind-armor components.Aiming at investigating the BAD caused by EFP,flash X-ray radiography combined with an experimental witness plate test method was used,and the FEM-SPH adaptive conversion algorithm in LS-DYNA software was erployed to model the perforation process.The simulation results of the debris cloud shape and number of debris were in good agreement with the flash X-ray radiographs and perforated holes on the witness plate,respectlvely.Threedimensional numerical simulations of EFP's penetration under various impact conditions were conducted.The results show that,an ellipsoidal debris cloud,with the major-to-minor axis radio(a/b)smaller than that caused by shaped charge jets,was formed behind the target.With the increase of target thickness(h) and decrease of impact velocity(v_0) and obliquity(θ),the value of a/b decreases.The number of debris ejected from target is significantly higher than that from EFP.Based on the statistical analysis of the spatial distribution of the BAD,An engineering calculation model was established considering the influence of h,v_0 and θ.The model can with reasonable accuracy predict the quantity and velocity distribution characteristics of BAD formed by EFP.
文摘为认识爆炸成型弹丸(Explosively Formed Projectile,EFP)靶后破片在空气中自由飞散及侵彻验证板的时空分布演化规律,基于分形理论建立了考虑破片表面状况的侵彻接触面积计算公式,通过破片云离散化对靶后破片在验证板材料阻力下时空分布特性进行了研究,并结合多层验证木板回收试验,获得了不同飞散角区间内破片侵彻的平均停留位置空间分布。研究结果表明:靶板破片的径向飞散距离整体上大于EFP破片;当验证板等效阻应力小于临界阻应力,破片侵彻停留位置空间分布呈现出一定的椭球形状,靶后破片在空气中飞散空间分布与在验证板内侵彻停留位置空间分布可以通过不同验证板等效阻应力下时空分布相互转化;各飞散区间破片侵彻后平均停留位置的计算结果与试验结果变化趋势基本一致,解决了以往后效验证板试验只能获得破片数量而无法获得破片侵彻停留位置空间分布的问题,为靶后破片对装甲车辆的毁伤效能评估提供技术支持。
文摘Impact experiments of large-caliber PELE with various inner-outer diameter ratio perforating RHA plate at low velocity were performed.Experimental results showed the size of perforated holes on plate,average diameter of damage area on witness plate,and number of behind-armor fragments will increase as d/D increasing from 0.72 to 0.84.Expansion and fragmentation of large-caliber PELE in this condition were also numerically studied with ANSYS Autodyn.Then,an analytical model accounting for an additional radial shock wave was presented to predict radial expansion velocity and fragmentation of jacket,as well as an empirical approach to estimate diameter of damage area.Calculation results by these approaches were in good agreement with experiments and numerical simulations.Further discussion revealed that Shock/rarefaction wave interactions behavior varying with inner-outer diameter ratio is an important mechanism resulting in different lateral effect by PELE projectiles with various configurations.
文摘为了准确描述爆炸成型弹丸(Explosively Formed Projectile,EFP)垂直侵彻有限厚靶板后效破片云的形状,基于量纲分析及正交设计理论,利用AUTODYN软件中SPH算法研究了EFP成型参数、弹靶材料参数对靶后破片云形状的影响,建立了EFP垂直侵彻靶后破片云形状的数学描述模型。利用该模型计算了EFP垂直侵彻靶后破片云形状参量长半轴,并和仿真结果及相关试验结果进行对比,结果表明,该模型计算的后效破片云长半轴结果与相关试验结果误差控制在3%以内,能够准确描述EFP垂直侵彻有限厚靶板后效破片云的形状。
