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Abstract:The characteristic parameters of double layer liners explosively formed penetrators(EFP) warhead with different charge structures were obtained by using LS-DYNA software. Liner material density, radius of liner curvature, liner thickness ratio and aspect ratio of L/D (the length/diameter) and density of charge were also investigated by the grey system theory. Based on the results, double layer liners EFP warhead with different structures were designed and penetration experiments were also carried out. Results show that double layer liners EFP warhead can effectively break down about 0.67 times of the charge diameter with the liner thickness ratio of 1.33, which is about twice penetration depth compared with EFP in the same shape charge structure. Penetration depth of Cu-Cu double layer liners warhead and Cu-Fe double layer liners warhead is at roughly the same level but perforation shape made by Cu-Cu double layer liners warhead is approximate in circle shape.

Abstract:In shaped charge, the detonation control structure parameters of the charge has important influences on the propagation of detonation wave and the formation of dual mode damage element, the influences and regulars of partition′s structure parameters(partition′s diameter, partition′s thickness, partition′s cone angle) and charge′s structure parameters(charge′s height and small explosive column′s height) on the formation of explosive formed projectile (EFP) and jetting projectile charge (JPC) dual mode damage element under the condition of 110 mm charge caliber and JH-2 explosive were researched using LS-DYNA simulation software.The optimal range of the parameters was determined, among them, partition′s diameter and thickness are taken for 0.8-0.87 and 0.05-0.09 times of charge caliber, respectively, partition′s cone angle is taken for 52°-60°, the charge′s height and small explosive column′s height are taken for 1.1-1.2 and 0.06-0.12 times of charge caliber, respectively.Combining with the orthogonal optimizing design method, the best parameter′s group of the charge detonation structure was determined : the diameter, thickness and cone angle of partition were taken for 0.91, 0.07 times of charge caliber and 52°, respectivel.Charge′s height and small explosive column′s height were taken for 1.14 and 0.1 times of charge caliber, respectively, the thickness of shell was taken for 0.09 times of charge caliber.X light photographic test was carried out, revealing that the simulation results are in good agreement with the experimental ones.

Abstract:To study the effect of structure parameters (the peripheral number N, radial depth H and axial length L of breakage) of the jacket breakage on the penetrated hole size for penetrating reinforced concrete target of penetrator with enhanced lateral effect (PELE), the orthogonal optimization analysis of PELE which has different structure parameters of the jacket breakage penetrating reinforced concrete targets was performed by means of numerical simulation method and the study of translating the axial kinetic energy of projectile as the lost energy which jacket expanding brokes reinforced concrete targets was carried out by defining lateral effect contribution value. Results show that the largest size of the reinforced concrete penetrated hole is 409 mm, the lateral effect contribution value is the largest, and the lateral effect of PELE is the best, when the structure parameters of the jacket breakage of N=8, H=5.5 mm, L=150 mm are taken. At the same time, the influencing degreel of structure parameters of the jacket breakage on the lateral effect of PELE is that L is maximum, N is second, H is minimum.

Abstract:Numerical simulations for the jet formation behavior and its terminal effect of damaged shaped charge warhead were carried out using the AUTODYN-3D to investigate the influence of hole location, hole depth and hole diameter on jet lateral velocity and its penetration ability. Results show that any hole in the shaped charge can increase the radial velocity obviously and cause deviation of jet from the axis, which even results in jet break up into small fragments and reduced the penetration ability of jet severely. Compared to the intact shaped charge, the penetration power for damaged shaped charge with hole diameter d=0.278 times charge diameter is reduced 24% on equal conditions. It is a fact that hole location and hole diameter are the main influence factors of radial velocity for jet. With distance between the hole and the top of liner decreasing, the radial velocity of jet increases significantly and the penetration depth of the target plate decreases. The radial velocity of jet is 19.0 m·s^-1 for the hole location x=0 times of charge diameter. The radial velocity of the jet increases with the hole-diameter increasing and it can reach up to 41.1 m·s^-1 for the hole diameter d=0.278 times of charge diameter.

Abstract:To study the effects of ingredients in formulation on the performance of deflagration to detonation transition(DDT) for dinitrofurazanfuroxan(DNTF) based explosives, three kinds of formulations that the molar ratio of AP and Al powders is 0.306, 0.414 and 0.574, were designed. The performance test of DDT for three kinds of DNTF-based composite explosive formulations was carried out by the coaxial ionization probe test technology. The influence of molar ratio of AP and Al powders on the deflagration to detonation transition of explosive was analyzed by change of wave front velocity and inducement detonation distance. Results show that with increasing the molar ratio of AP and Al from 0.306 to 0.574, the initial burn duration time increases from 1065 μs to 1395 μs, and the burning rate decreases from 141 m·s^-1 to 108 m·s^-1, but the duration time of convection combustion section and deflagration section decreases rapidly, and the convection burning rate increases from 500 m·s^-1 to 1668 m·s^-1, and deflagration velocity increases from 3000 m·s^-1 to 4800 m·s^-1, the inducing detonation distance occurring DDT decreases from about 675 mm to 425 mm.

Abstract:A novel energetic complex [Ag₂(DAT)₄](NO₃)₂ (DAT=1, 5-diaminotetrazole) was synthesized by using 1, 5-diaminotetrazole (DAT) and AgNO₃ as raw materials, and the yield was 86%.Its structure was characterized by elemental analysis and Fourier transform infrared (FT-IR) spectroscopy. The single crystal of the target complex was cultured and its structure was determined by X-ray single-crystal diffraction instrument. Its thermal decomposition behavior was investigated by differential scanning calorimetry (DSC).Its kinetic parameters (activation energies E_K and E_O) of non-isothermal reaction were calculated by Kissinger method and Ozawa method. Its critical temperature of thermal explosion T_b was calculated. Its constant-volume energy of combustion (Q_v) was measured by using an oxygen bomb calorimeter. Its standard heat of formation was calculated. The impact, friction and flame sensitivities of the target complex were measured. Results show that the crystal of the target complex is monoclinic, space group P21/n with the cell parameters of a=6.8109(9) Å, b=19.654(3) Å, c=8.4510(11) Å, β=102.590(3)°, V=1104.1(3) ų, Z=2, D_c =2.228 g·cm^-3, F(000)=729. For the target complex, E_K=204.9 kJ·mol^-1, E_O=202.8 kJ·mol^-1, T_b=224.4 ℃, Q_V=-4177.59 kJ·mol^-1, Δ_fH₂₉₈^Θ=258.14 kJ·mol^-1. The target complex is insensitive to impact and flame, but sensitive to friction.

Abstract:3, 7, 10-Trioxo-2, 4, 6, 8, 9, 11-hexabenzyl-2, 4, 6, 8, 9, 11-hexaaza[3, 3, 3]propellane (HBPTO) is a key intermediate of synthesizing high energetic density material 2, 4, 6, 8, 9, 11-hexanitro-2, 4, 6, 8, 9, 11-hexaaza[3, 3, 3]propellane.Target compound HBPTO was synthesized via oxidation, addition, condensation and substitution using uric acid (UC) and potassium ferricyanide as initial materials with an overall yield of 8.58%.Its structure was characterized by ¹H NMR, ¹³C NMR, FT-IR, MS and elemental analysis.The reaction mechanism of synthesizing intermediate glycoluril diamine (DAGU) was discussed and its microscopic reaction process was revealed.The process conditions of synthesizing DAGU was optimized.The synthetic process of 3, 7, 10-trioxo-2, 4, 6, 8, 9, 11-hexaaza[3, 3, 3]propellane(PTO) was improved.A new method of synthesizing PTO via an one-step condensation reaction of DAGU and N, N′-carbonyldiimidazole(CDI) was self-designed.Results show that the optimized process conditions of synthesizing DAGU are: n(UC):n(K₃Fe(CN)₃)=1:4.2; reaction temperature of 25 ℃ and reaction time of 0.5 h.

Abstract:A series of arylpentazoles were synthesized from p-aminophenol and its derivatives at -45 ℃. Their structures were characterized by MS and ¹H NMR. The effects of the number and position of the substituents on the stability of arylpentazoles were investigated. The decomposition pathway of arylpentazoles at different collision energy (10 eV, 60 eV)was infered by electrospray tandem mass spectrometry. The relationship between the arylpentazole stability and the relative intensity of the generation of N₅^- was also discussed. Results show that the stability of 3, 5-dimethyl-4-hydroxyphenylpentazole is the best and the ability to generate N₅^- from cleavage of C—N is most strong in these arylpentazoles at high collision energy (60 eV).

Abstract:The boron-based propellant samples were prepared through coating boron particles with a recrystallization method selecting ammonium perchlorate(AP), ammonium nitrate(AN), nitroguanidine(NQ) and octogen(HMX) as four kinds of oxidants. The effect of different oxidant coating on the ignition and combustion characteristics of boron-based propellant was studied by using TG-DSC and laser ignition test system. The mechanical mixing sample was set as control group. Results show that AP coating can induce low-temperature deflagration of the sample, so as to promote the low-temperature oxidation of boron particles. It helps to effectively shorten the ignition delay time of the sample to 330 ms. By comparing with the mechanical mixing sample, the recrystallization method was found to be the main cause of low-temperature deflagration of the sample. The sample coated by AN has a lower initial reaction temperature of 327.6 ℃. However, its whole exothermic properties are poor, the average combustion temperature is only 642.8 ℃. The coating of NQ and HMX can effectively improve the combustion strength of B-based propellants, shorten the combustion time. Among them, NQ can help to improve the maximum combustion intensity. HMX is more conducive to the upgrade of the whole combustion intensity. The coating of HMX makes the combustion time of B-based propellant shorten to 2750 ms, the average combustion temperature reaches 845.5 ℃ and the heat release is raised to 9968 J·g^-1.

Abstract:The reactive Al/Fe₂O₃/PTFE material was prepared by molding and sintering method. The quasi-static compression feature and impact sensitivity of Al/Fe₂O₃/PTFE material molded in different proportioning and at different sintering temperature were comparatively tested by universal testing machine, drop hammer machine and high-speed photography instrument. Its ignition performance was analyzed. Results show that: specimens with 60% and 70% polytetrafluoroethylene(refer to as PTFE) sintering at 330 ℃ have the highest strength and the maximum real stress is 46 MPa. Specimens with 40% PTFE sintering at 350 ℃ have the highest impact sensitivity, and its characteristic drop height H₅₀ is 95 cm. The Al/Fe₂O₃/PTFE material under the impact ignition conditions will appear the high temperature metal slag jet phenomenon. The research results have raised the understanding of the deformation behavior and impact reaction of Al/Fe₂O₃/PTFE material, which has laid a good foundation for the following research.

Abstract:To improve the combustion performances of single-base propellant, GAP-base polyurethane was used as the coating material, the 4/7 single-base propellant was coated by using premixed-sprayed-cured technology. The effect of coating was observed by a three-dimensional video microscope. The compatibility of GAP-base polyurethane and single-base propellant was investigated by differential scanning calorimetry(DSC). The energies and combustion performances of coated single-base propellant were studied through theoretical calculation and closed-bomb test. The results show that the thickness of GAP-base polyurethane layer is relatively uniform, which has good adhesion and good compatibility with the single-base propellant. The introduction of GAP-base polyurethane makes the powder force and detonation temperature of gun propellant decrease, but the powder force is significantly lower than that of the inert polymer. GAP-base polyurethane coated single-base propellant has significant combustion progressivity, with increasing the coated amount, the progressivity gradually increases. Compared with the single-base propellant, the relative pressures at split point(B_s) of the GAP-base polyurethane coated single-base propellant with the coated amount of 7.05%, 9.67% and 11.88%, increases from 0.151 to 0.453, 0.480 and 0.489 respectively, and the values of the progression factor(P_r) increases from 0.090 to 0.293, 0.340 and 0.358, respectively.

Abstract:A high performance liquid chromatography to analyze 3, 3′-diamino-4, 4′-azoxyfurazan(DAOAF) was established and characterization of impurities trapped in the DAOAF product was carried out by MS. Results show that the chromatographic conditions after optimization are: chromatographic column, ZorbaxSB-C18(250 mm×4.6 mm, 5.0 μm) column; mobile phase, acetonitrile/water (V:V=40:60); flow rate, 0.8 mL·min^-1; column temperature, 25 ℃; wavelength, 230nm; injection volume, 10 μL. Under the optimized chromatographic conditions, DAOAF and impurities in DAOAF are effectively separated. The calibration curves of DAOAF within the mass concentration of 10.02-100.20 mg·L^-1 have good linearity with the linear correlation coefficient of 0.9990. The main impurities in DAOAF are diaminoglyoxime, 3, 4-diaminofurazan and 3, 3′-diamino-4, 4′-azofurazan. The method has high sensitivity and good reproducibility, can be used for the determination of the related substances in the product of DAOAF.

Abstract:To reduce the charge amount of welding explosive, TA2 titanium and Q345 steel plates were used as flyer and base plates of dovetail groove, respectively. The upper side length, the lower side length and the height of dovetail grooves were 2 mm, 3 mm and 1mm, respectively. All the intervals between dovetail grooves were 3 mm. The Ti-steel clad plate with dimension of 7.0 mm×300 mm×750 mm was obtained via Q345 steel and TA2 titanium plates with dovetail groove were loosely fitted and bonded by explosive pressure welding and hot rolling technology. Bonding quality at the interfaces of Ti-steel clad plate was analyzed by mechanical property test and microscopic morphology observation. Results show that the metallurgical bonding at the interfaces of TA2 titanium and Q345 steel plates is achieved by explosive pressure welding and hot rolling. Bonding quality at the interfaces of the clad plate is good, and the interfaces exhibit a linear shape, and intermetallic compounds do not occur. The clad plate has excellent bending performance. Compared with explosive welding, the charge amount of Ti-steel clad plate produced by explosive pressure welding and hot rolling may save by 62.7%.

Abstract:To evaluate the limit transmitting detonation distance (i.e. maximum transmitting detonation distance at a confidence level of 0.95 and reliability of 0.999) in the air of bi-directional booster used in oil and gas wells, a transmitting detonation test of bi-directional booster was performed by the mathematical statistic method-up-and-down method commonly adopted in sensitivity test of pyrotechnics. The numerical simulation of transmitting detonation mechanism and explosion process for bi-directional booster was carried out by LS-DYNA software. Results show that the maximum transmitting detonation distance with reliability of 0.999 under a confidence level of 0.95 in the air of bi-directional booster is 82.8 mm. The numerical simulation results support the experimental one of about 82.8 mm in a certain extent.

Abstract:Aza-polyaromatic ring energetic compounds are a kind of important nitrogen-rich energetic compounds, which are one of the hotspots in the research field of energetic materials at home and abroad. A wide variety of various aza-polyaromatic ring energetic compounds were obtained via different bonding methods of C—C or C—N single bond etc of aza-aromatic rings. These compounds mainly contain two kinds of symmetrical and nonsymmetrical structures. Their classification is also performed according to ring system characteristics of bicyclic, tricyclic and polycyclic structures. The synthesis of aza-polyaromatic ring compounds is simple. Currently, a large number of new high energy density compounds with excellent properties were obtained. In this paper, the research progresses on aza-polyaromatic ring energetic compounds consisted of furazans or azoles etc nitrogen-rich ring system, which are connected by C—C or C—N single bond, were summarized. The construction methodologies of aza-polyaromatic ring and the synthesis technology route of aza-polyaromatic ring energetic compounds are emphatically reviewed, at same time, the physicochemical and detonation performances of typical aza-polyaromatic ring energetic compounds were briefly introduced. Developing the synthesis method of new ring system with simple, efficient and mild reaction conditions, introducing new energetic groups and designing new aza-polyaromatic ring energetic compounds should be the emphasis of research in this field in the next stage.

Abstract:A new energetic compound 3, 5-diamino-2, 6-dinitropyrazine-1-oxide (DDPZO-i) was synthesized with a yield of 40% from 2, 6-dichloropyrazine as the starting material. Its structure was characterized by IR, NMR and MS techniques. Its single crystal structure was determined by X-ray diffraction (XRD) technique. Its thermal stability was studied by DSC and thermal decomposition peak temperature determined is 215 ℃ The measured density of DDPZO-i is 1.935 g·cm^-3, which is slightly higher than LLM-105. The standard enthalpy of formation calculated by Gaussain03 software is 169.4 kJ·mol^-1. A possibile mechanism of oxidation reaction of pyrazine skeleton was given. The detonation properties of DDPZO-i were estimated by Explore 5 v6.02 software, and the detonation velocity and detonation pressure are 9070 m·s^-1 and 36.9 GPa, respectively, which are better than those of LLM-105. The impact sensitivity measured by BAM impact sensitivity instrument is 5 J, which is higher than LLM-105.

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