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Abstract:Low⁃temperature co⁃fired ceramic (LTCC) technology was employed to realize the integrated fabrication of exploding foil initiation chip. 5 μm thick Au bridge foil (300 μm×300 μm) was prepared by screen printing,using raw porcelain sheets of 25 μm and 50 μm thickness as the flyers for the chip. Two kinds of chips with the barrel shape of circular (Φ=400 μm) and square (L×W=300 μm×300 μm) were obtained. The electrical explosion characteristics of Au bridge foil were studied under the discharge of 0.22 μF capacitor. The velocity characteristics of the ceramic flyer and its morphology in motion process were analyzed by photon Doppler velocimetry. Results show that the maximum energy utilization rate of Au bridge foil at 1.8 kV, and the final speed of flyer increases with the increase of the firing voltage. Besides, the outlet velocity of flyer in square barrel is 106-313 m·s^-1,which is higher than that in circular barrel at the same firing condition. In addition, the thicker of the ceramic flyer, the more complete it will be during the course of flying. The exploding foil initiation chip prepared by the LTCC technology can successfully detonate the HNS explosive and ignite the BPN ignition powder. The minimum detonation voltage and minimum ignition voltage of LTCC exploding foil initiation chip (50 μm thick ceramic flyer, circular barrel) are 2.5 kV and 1.4 kV, respectively.

Abstract:To explore the exploding mechanism of composite multilayers, the properties of Ni/Cu multilayer exploding foil were studied. Ni/Cu composite multilayers (modulation period 200 nm/300 nm and 300 nm/400 nm, respectively), pure Cu and Ni films with the same thickness were prepared by electrochemical deposition. The plasma emission spectroscopy was measured. Under different discharge current conditions, the electron temperature of electrically exploded plasma of Ni/Cu composite multilayers with different structures, pure Cu and Ni films was calculated, respectively. After matching barrels and flyers with exploding foils, the velocity of flyer driven by different exploding foils was measured by PDV method. The performance of the exploding foils driving flyer under different discharge current conditions were obtained. The results show the plasma emission spectroscopy intensity and electron temperature of (Ni₂₀₀Cu₃₀₀)₈ and (Ni₃₀₀Cu₄₀₀)₅Ni₃₀₀ is higher than pure Cu and Ni at discharge current of 2.5 kA, indicating the Ni/Cu composites have higher electrically exploding energy density at the same condition. The Ni in Ni/Cu composites promotes the plasma to push flyer forward, resulting in the accelerating time and final velocity of flyer driven by (Ni₂₀₀Cu₃₀₀)₈ and (Ni₃₀₀Cu₄₀₀)₅Ni₃₀₀ are both higher than those of flyer driven by pure Cu.

Abstract:Using microelectromechanical system (MEMS) technologies including magnetron sputtering, ultraviolet lithography and chemical vapor deposition, two kinds of high-voltage switches based on Schottky diode and p-n diode were designed and fabricated. Electrical characterizations were performed to investigate their performances under no-load condition, which showed that the current peaks of the two switches reached up to about 2000 A at 0.22 μF/1500 V and 0.22 μF/1200 V, respectively. The influence of trigger capacitor, trigger voltage, main voltage, dielectric film thickness and bi-diode structure on the conduction performance of single shot switch was studied. It is revealed that the minimum trigger voltage decreased gradually with the increase of capacitance. Reducing the thickness of dielectric film, increasing the trigger voltage and main voltage are all beneficial to improve the current peak. Besides, bi-diode structure can also improve the current peak. Finally, according to the electrical curves of single shot switch, its action process can be divided into three stages, namely the electro-explosion of diode, the breakdown of dielectric film and the rise of pulse current. The conduction mechanism and resistance model of single shot switch were also established. The results indicate that the resistance of single shot switch is very low, almost negligible.

Abstract:Electrical explosion of the thin golden wire is fundamental for the EBW detonator. In this paper, the expansion process of plasma generated in 0.04 mm wire explosion was captured using interferometry diagnostic. Moreover, the transient current during the electrical explosion was also measured in order to establish the connection between current and plasma expansion in time domain using a photoelectric transducer. 3D dynamic simulation of plasma expansion was conducted, in which JWL equation of state containing energy term was selected to describe the dynamic behavior of plasma. The results shows the simulation result was in good agreement with experimental results. And under the condition of 0.22 μF capacitor and 3900 V charging voltage, the expansion velocity of plasma reaches 8913 m·s^-1,and then 3000-4000 m·s^-1 after travelling for 1.63 mm. The pressure of plasma is higher than 2.4 GPa. The satisfactory agreement between simulation and experiment indicates that the JWL equation of state is suitable for plasma generated in electrical explosion. The simulation results show that the change of the pressure and density of plasma with travelling distance could be described using polynomial function. The result in this paper was able to give more insight of the mechanism of EBW detonator and thus provide suggestions for the design of the EBW detonator.

Abstract:Since it is important to judge the metal bridge wire completely detonated whether or not in the metal bridge wire explosion experiment, a method was proposed to judge the detonation state of the bridge wire by the electromagnetic pulse radiation effect. The electromagnetic pulse signal of the metal bridge wire during the detonation process was measured by the antenna, while the measured electromagnetic pulse signal was analyzed to judge the bridge wire detonation status. The electromagnetic pulse signal shows that the electromagnetic pulse generated by the complete detonation and the incomplete detonation state, has a significant difference in duration and radiation spectrum. When the bridge wire is completely detonated, the electromagnetic signal duration in the intrinsic explosion phase is short, and the electromagnetic signal generated in the plasma phase lasts long. The electromagnetic pulse signal includes high frequency electromagnetic radiation of 90 MHz to 100 MHz. When the bridge wire is not completely detonated, the electromagnetic signal generated during the intrinsic explosion phase lasts for a long time, while the electromagnetic signal generated during the plasma phase has a short duration. The frequency of the electromagnetic pulse signal is mainly concentrated in the low frequency region below 40 MHz.

Abstract:To study the interior ballistic performance of charge for partially cut multi-perforated stick propellant, a interior ballistic simulation model of charge for partially cut multi-perforated stick propellant was established based on the classical interior ballistic theory. The calculation of interior ballistic performance of charge was performed using the partially cut multi-perforated stick propellant with high energy nitramine propellant formulations. The experimental validation were carried out on 30 mm artillery. The effect of incision intervals, incision web and incision depth on the interior ballistic performance of partially cut multi-perforated stick propellant was analyzed. The results show that the maximum bore pressure calculated by the established interior ballistic model of partially cut multi-perforated stick propellant is 430.2 MPa. The calculated error of the maximum bore pressure is 5.0% compared with average value of testing maximum bore pressure of 409.7 MPa. The calculated muzzle velocity is 1378.2 m·s^-1, and the calculated error is 2.2% compared with average value of testing muzzle velocity of 1409.6 m·s^-1. The maximum bore pressure and muzzle velocity decrease with the increase of incision intervals. When the incision intervals increase from 5 mm to 50 mm, the maximum bore pressure reduces by 12.0%. And the muzzle velocity reduces by 3.1%. The effect upon the interior ballistic performance is gradually reduced when the numerical value of incision intervals is greater than 20 mm. The value of maximum bore pressure and muzzle velocity increases with the increase of incision depth and incision web. The effect of incision depth upon the maximum bore pressure is more significant than that upon the muzzle velocity. The interior ballistic performance of the propellant is insensitive to the change of incision web′s value.

Abstract:To prevent accidents and assess the risk of static disasters in propellant mixing process, we designed devices to test electrostatic parameters such as resistivity, dielectric constant and charge accumulation. 11/7 single-base propellant was chosen to be tested as a typical product. It shows that the volume resistivity, surface resistivity and dielectric constant of 11/7 single-base propellant are 1.87×10¹⁰ Ω·m，1.06×10¹² Ω, and 1.88, respectively, and the saturated charge-to-mass ratio at friction state of chute is -1.85 μC·kg^-1. ANSOFT MAXWELL software was used to simulate the electrostatic field in mixing silo of 11/7 propellant, obtaining the change curve of the maximum field strength with powder′s height in 1000 mm diameter mixing silo. Results show that the electric field strength increases with the increase of powder′s height. When the powder′s height is 40 mm, the air breakdown field strength is reached and there is a risk of electrostatic discharge. In addition, the critical discharge powder′s heights at different diameters of mixing silos were simulated, and the corresponding change curve was also obtained. It shows that the critical discharge powder′s heights are 81, 46, 42, 41 mm and 40 mm when the diameters of material silo are 100, 200, 300, 400 mm and 500 mm, respectively. However, when the diameter is greater than 500 mm, the critical discharge powder′s height reasonably maintains at 40 mm.

Abstract:Synthesized organic gelling agent (Gn) and gaseous silica (SiO₂) were used to prepare corresponding gelled hydrocarbon fuels with four kinds of high density liquid fuels HD-01, HD-03, HD-03-I and QC respectively. The minimum addition amount of gelling agents required was studied.The basic physical propertiessuch as density, viscosity, heat value for Gn and SiO₂ gelled fuels were determined. Their thermal stability, centrifugal stability, long-term storage perforemance and other stability properties, as well as rheological properties were also investigated. Results show that at least 6% SiO₂ was added to make the liquid fuel form the gelled fuel, while addition amount of Gn required for gelling the fuels is not greater than 1% with little influence on the density and heat value of the fuel itself. No liquid exudation phenomenon happens after Gn galled hydrocarbon fuels are stored at -40 ℃, room temperature or high-speed centrifugation. The viscosity of Gn gelled hydrocarbon fuels decreases significantly with the increasing shear rate, approaching the viscosity of liquid fuel at high shear rate. By scanning electron microscopy,it is found that Gn can be self-assembled to form a three-dimensional fiber network structure in fuel, which can be damaged by stirring or high temperature (150 ℃) and recovered by static or cooling, making the rheological and thixotropic properties of Gn gelled hydrocarbon fuels significantly better than those of SiO₂ gelled hydrocarbon fuels and more conducive to pipeline transportation and atomization.

Abstract:To determine the influence of various factors in the production process of solid propellant on the friction sensitivity, the response surface methodology (RSM) combined with central composite design (CCD) was used to design the experiments based on the pendulum angle, the strut pressure and the sample temperature were taken as influencing factors, and the friction sensitivity value of solid propellant was considered as the response value. The friction sensitivity tester was used to test and analyze, the testing results were fitted to the response surface model. Results show that in three response surface evaluation accuracy indexes, the relative root mean square error RMSE is 0.14, the determination coefficient R² is 0.9309, and the correction fitting degree is 0.8686, showing that the fitting precision of the equation is high and the error is small. The variance ratio F obtained by variance analysis of the model is 14.96, indicating that the model has a higher influence on the response surface. The probability value p is 0.0001, indicating that the probability of 0.01% of the model has no effect on the response surface. The response surface map shows the interaction between the various factors. The three-factor operating range corresponding to the minimum friction sensitivity value obtained by the model optimization is less than 45° in angle, less than 2 MPa in pressure, and less than 45 ℃ in temperature.

Abstract:To determine anionic impurities in energetic plasticizer triethylene glycol dinitrate (TEGDN) , the anions in TEGDN were qualitatively and quantitatively analyzed by a preparative liquid chromatography-ion chromatography method. The effect of different mobile phase ratio, injection volume and collection time on the effect of separation and collection of anionic impurities in TEGDN in preparative liquid chromatographic experiments, and the effect of eluent system and eluent flow rate on the separation effect of anions in ion chromatographic experiments were investigated. Results show that the preparative liquid chromatographic conditions after optimization are: Eclipse XDB-C18 chromatographic column (250 mm×9.4 mm, 5.0 μm); mobile phase, V_methanol∶V_water=50∶50; flow rate, 1.5 mL·min^-1; detection wavelength, 210 nm; column temperature, 30 ℃ ; injection volume, 0.25 mL. The ion chromatographic conditions after optimization are: Metrosep A Supp 5 anion analysis column (250 mm× 4.0 mm, 5.0 μm); 3.2 mmol·L^-1 Na₂CO₃ / 1.0 mmol·L^-1 NaHCO₃ solution as eluent ; flow rate, 0.7 mL·min^-1 ; suppression conductivity detector ; column temperature, 40 ℃ ; injection volume, 20 μL. Under the optimized preparative liquid chromatographic conditions, anionic impurities in TEGDN are effectively separated and collected. Under the optimized ion chromatographic conditions, the linearity of the anions is good, the linear correlation coefficients are greater than 0.999 ; the detection limits of anions are 0.0025-0.0100 μg·mL^-1. The relative standard deviations of the precision test (n=6) and the repeatability test (n=6) are less than 2.0%, the average recoveries of anions are 95.5%-103.5%. The method has high sensitivity and good reproducibility, can be used for the determination of the anionic impurities in TEGDN.

Abstract:Aiming at the failure problem of cased explosive charge under impact of kinetic energy penetrators, the velocity of case driven by explosive charge under different reaction rate was analyzed. The grade of characterizing explosive charge failure was proposed using equivalent gurney velocity or equivalent gurney energy. The method of solving equivalent gurney velocity and equivalent gurney energy was given accordingly. Based on equivalent gurney velocity, the failure grades of cased explosive charge were divided and the criterion was given ，the idea of deflagration failure is proposed which is considered to be more effective to realize. The deflagration failure problem of cased composition B under impact of kinetic energy penetrators was studied based on experimental tests, numerical simulation and analytical calculation. The relations between deflagration failure and normal detonation failure were analyzed and the lower limit value of deflagration failure criterion was given. The results shows that it can be regarded as the lower limit of deflagration failure of explosive when equivalent gurney velocity reaches 1% of gurney velocity.

Abstract:To achieve efficient damage of the ammunition, a directional and focusing multiple explosively formed penetrator (EFP) warhead was designed. The structure and operational principle of the warhead, and the relation between deployment angle and number density of EFP on the target were described. In addition, to obtain the optimal structural parameters of the warhead, the multi-objective optimization model of warhead parameters was established with the velocity and total number of EFP as the objective function, and the Pareto optimal solution was obtained by NSGA-Ⅱ genetic algorithm. Based on the optimized parameters of the warhead, the EFP formation process of the single charge structure under the optimized structure was numerically simulated, and the change of the focusing ability of warhead with the deployment angle of directional segment at different target distance (10, 15 m and 20 m) was analyzed. Results show that the initial velocity of EFP under the optimized structure reaches to 2283.4 m·s^-1. When the EFP is stable, the calculation from formula shows that it can penetrate 35.94 mm thick 45 steel target. At the target distance of 15 m, the optimal deployment angle of the directional segment is 91.15°, and the EFP number density is 169 per square meter.

Abstract:To improve the damage power.of anti-armor and anti-personnel composite warhead, the effect of charge-shell weight ratio on the armor-penetrating and killing power of warhead was researched. The formation and killing radius of fragments were calculated by theoritical analysis mehtod when the charge-shell mass ratio of warhead increased from 0.71 to 2.00. A non-linear finite element software, LS-DYNA, was used to compare and analyze the depth of armor penetration by molding jet when the charge-shell mass ratio of warhead was 0.80, 1.00, 1.20, 1.40 and 1.60, and the relationship of the charge-shell mass ratio vs. the killing radius of fragments and the depth of armor penetration by molding jet was obtained. Results show that the killing radius increases from 9.1 m to 10.2 m with the increase of charge-shell mass ratio from 0.71 to 1.86. The killing radius doesn′t increase anymore when the charge-shell mass ratio increases to 2.00. The average weight of fragments decreases with the increase of charge-shell mass ratio.The depth of armor penetration decreases first and then increases with the increase of charge-shell mass ratio from 0.80 to 1.60, and the maximum perforation deep is 143.30 mm.

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