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Abstract:Molecular dynamics (MD) simulation was employed to investigate safety performance (sensitivity), thermal expansion and mechanical properties of solid propellant. The models of high energy multi-component systems with different sets of proportion were studied at different temperatures. It is found that the maximum bond lengths (L_max) of both O—N and N—N trigger bonds in the five-component system with the mass ratio of (PEG/NG/BTTN):AP:HMX＝2.5:3.5:2.3 are the longest among the four sets of the systems. Results show that the safety of the system having this proportion is relatively low. The L_max of each deflagrating component in the six-component system (PEG/NG/BTTN)/AP/HMX/Al increases monotonously with the increasing temperature, which agrees with the experimental fact that energy materials become more sensitive as the temperature increases. It is suggested that structure parameter L_max can also be used as a theoretical criterion of thermal or impact sensitivity to predict the relative safety of multi-component complicated systems. Based on the simulation results for the six-component system, thermal expansion coefficients at different temperatures are calculated and mechanical properties are obtained with the static method.

Abstract:The compatibilities of hydroxyl-terminated polytrher(HTPE) with dibutyl phthalate(DBP), dioctyl sebacate(DOS), diethyl phthalate(DEP) and the glass transition temperatures of the HTPE-plasticizer mixed systems were studied by molecular dynamics simulation method. Results show that by analyzing the binding energy, radial distribution function and glass transition temperature, the compatibility of the mixed system with the plasticizer which contains intermolecular hydrogen bonds could be evaluated. The compatibility of HTPE with the plasticizer is in the order: HTPE/DBP > HTPE/DOS > HTPE/DEP. The glass transition temperatures of HTPE, HTPE/DBP, HTPE/DOS and HTPE/DEP obtained from the relationship of temperature and specific volume are 190.26, 176.30, 168.82K and 178.33 K, respectively.

Abstract:Multi-point initiation explosively formed projectile(EFP) charges with different N (the number of initiation points), D_I (the diameter of annular initiation), L_C/D_C (the length/diameter of charge) were studied by LS-DYNA program. program The influences of multi-point initiation charge configuration parameters, such as N, D_I, L_C/D_C, on the formation parameters of EFP with fins were studied. The results of numerical simulation indicate that there are remarkable effects of N, D_I and L_C/D_C on the formation parameters, including v, L_E/D_E (the length/diameter), W_S/D_E (the wingspan/diameter) of EFP with fins. The number of fins is equal to the number of initiation points. When the N is 4, the W_S/D_E of EFP with fins approaches the maximum. Increasing D_I and L_C/D_C effectively enhances the v and L_E/D_E of EFP with fins. The formation parameters of EFPs formed by hemispherical liner with uniform or variational wall-thickness were compared. Results indicate that hemispherical liner with variational wall-thickness is a more feasible option. When N=4, D_I=40 mm, and L_C/D_C=0.8 respectively, EFP with more appropriate configuration can be approached.

Abstract:To study the characteristics and laws of penetrating steel ingot of linear shaped charge(LSC) with oval cover, three-dimensional numerical model was established by ANSYS/LS-DYNA program. A numerical simulation study was performed, and the actual cutting test was implemented on the base of numerical simulation. By using the method of actual cutting experiment and three-dimensional numerical simulation, the characteristics and laws of penetrating steel ingot of LSC with oval cover were studyed. Results show that the cutting depth first increases and then decreases with the standoff increasing. The cutting depth showed insensitivity in a standoff range. The best standoff was 60 mm. The cutting cross shape of the steel ingot of different time was obtained under the different condition of standoff. With the standoff increasing, the cross-section bottom width of penetrating steel ingot was from 55 mm to 75 mm, and the medial depth was from 70 mm to 88 mm, and the both sides depth was from 40 mm to 70 mm. The penetration results of numerical simulation were consistent with the cutting test results. The characteristics and laws of penetrating steel ingot from the simulation model can from the simulation model reflect the actual cutting process.

Abstract:To get the explosion rule of field ammunition detonated by jet, the explosive with various spaced targets was used as field ammunition simplified model. The jet initiation models of shield explosive were established and calculated by impedance match technology, theory of penetration by quasi-steady fluid dynamics and Held criterion. Results show that the biggest detonating abilities of shock wave and remainder jet are about 2.75×10⁴ m³·s^-2 and 1.55×10⁵ m³·s^-2, respectively, which prove that the primary influence factor of detonating ability is the bomb case comparing with protective coating. During the field ammunition detonated by jet, the changing of jet diameter would be to 22.2% and its influence could not be ignored. Furthermore, preventing the penetration of jet is the first focus of field ammunition, for the detonating ability of remainder jet is more than the shock wave.

Abstract:In order to study the influence of the reinforced concrete target(RC) thickness on penetrator with enhanced lateral effect(PELE)penetrating, the different thickness RC impacted with the velocity of 800 m·s^-1 was simulated by LS-DYNA 3D software. Results show that PELE can penetrate the 80 cm thickness target at large. In this range, PELE body shell residual length is shorter with the target getting thicker when PELE could penetrate the targets, and the residual axial velocity of PELE decreases at the same time. With increase of target thickness, the undermining effect of penetration first increases, then decreases. The kinetic energy consumes totally in the penetration process when the targets thickness is over 80 cm. The experiment was carried to verify the simulation results. The experimental and simulated results both show that the 35 cm thickness target is damaged most severely, implying that the simulation are correct and reliable.

Abstract:To achieve a balance among safety, efficiency and environment-friendliness of waterjet cleaning process of solid rocket motor, on the basis of waterjet cleaning experiments and wastewater collection experiments, a multi-objective optimization method for waterjet cleaning process of solid rocket motor was established with propellant massloss rate and wastewater generation rate as the optimization objectives, and waterjet pressure, target distance, nozzle diameter and single cleaning time as the variables with constrained conditions.The calculation models of propellant massloss rate and wastewater generation rate were established with agent modeling technology, and Pareto optimal solution set was obtained by the non-dominated sorting genetic algorithm (NSGA-Ⅱ). Results show that the optimal solution set can offer a variety of programs for the matching between propellant massloss rate and wastewater generation rate in waterjet cleaning process design under different conditions. With the best matching between them, the wastewater production caused by HTPB propellant′s unit massloss is only 14.25 mL·g^-1.

Abstract:The growth kinetic process of efficient bacteria flora (FYD) for degrading unsymmetrical dimethyl hydrazine (UDMH) was simulated by Haldane kinetic model of growth inhibition. The degradation kinetic process of UDMH was simulated by Andrews noncompetitive kinetic model of substrate inhibition. The kinetic equations were fitted out, and the ratio growth rate and ratio degradation rate were calculated by the fitted equations. Results show that when the initial concentration of UDMH is 43.6980 mg·L^-1, the flora has maximum ratio growth rate. When the initial concentration of UDMH is 50.2261 mg·L^-1, the UDMH has maximum ratio degradation rate. The theoretical value is very close to the experimental one as UDMH concentration is 50 mg·L^-1. The yield coefficient that FYD degrades UDMH is 0.229, which reflects the tolerance and utilization ability of FYD to UDMH. The linear relationship between the maximum ratio growth rate and the maximum ratio degradation rate shows a material balance exists in the process of degrading UDMH by flora FYD. The change in cell growth with UDMH concentration exists bacteria rationality.

Abstract:To understand the thermal response behavior of the structure with explosive under fire circumstance, in view of some related main heat transfer problems, the numerical models of pool fire′s temperature rise heat transfer, carbon/bakelite ablatant′s high temperature endothermic decomposition, inner air layer′s complex heat transfer and explosive′s exothermic decomposition were established. The thermal response and thermal ignition delay time for the structure with explosive under the conditions of different temperature (constant value 1073 K, 1273 K, and measured temperature rise curve proposed in this work), different fire′s emissivity (0.1-0.9) and different surface emissivity for the shell with different air gap (0.1-0.9) were calculated and obtained using the established numerical models. Results show that the thermal ignition phenomenon of the inner explosive occurrs at 28.92 min when the fire′s temperature is 1273 K in 30 min fire case. The highest temperature of inner explosive is 448 K and 535 K, respectively when the fire′s temperature is 1073 K and real temperature rise curve. The highest temperature of the explosive decreases from 535.5 K to 344.6 K and the thermal ignition delay time increases from 1917 s to 3520 s when the fire′s emissivity reduces from 0.9 to 0.1. The highest temperature of the explosive decreases from 535.5 K to 329.0 K and the thermal ignition delay time increases from 1917s to 3739s when the surface emissivity for the shell with air gap reduces from 0.9 to 0.1.

Abstract:Zirconium 3,5-dinitrosalicylate (DNS-Zr) was synthesized firstly by using 3,5-dinitrosalicylic acid, zirconyl nitrate and sodium hydroxide as raw materials. Its structure was characterized by elementary analysis, X-ray fluorescence diffraction and FTIR spectra. The thermal behavior and decomposition mechanism of DNS-Zr in a temperature-programmed mode were investigated by means of TG-DTG, DSC and condensed phase thermolysis/FTIR techniques. The decomposition products of DNS-Zr are ZrO₂ and C. The sample of propellants containing DNS-Zr were prepared by extrusion technology, and the effects of DNS-Zr on combustion properties of DB/CMDB propellants were investigated. Results show that the catalytic efficiency of DNS-Zr is 10%-20%.

Abstract:The effect of CuO, Fe₂O₃, carbon black (CB), PbCO₃, Bi₂O₃ and (NH₄)₂Cr₂O₇ on the thermal decomposition properties of P(BAMO/AMMO) energetic binder was investigated by TG and DSC. Results show that the six burning rate catalysts make the initial decomposition temperature of P(BAMO/AMMO) binder shift downwards and the exothermic decomposition reaction of azide groups advance, and the exothermic decomposition reaction of binder is promoted, in which, CB and PbCO₃ make the initial decomposition temperature of the binder shift 8.3 ℃ and 24.2 ℃ downwards at a heating rate of 10 ℃·min^-1 , respectively. CuO, Fe₂O₃, PbCO₃ and (NH₄)₂Cr₂O₇ make the apparent decomposition heat of azide groups in P(BAMO/AMMO) binder increase by 0.05, 0.09, 0.10 kJ·g^-1 and 0.06 kJ·g^-1, respectively, whereas CB and Bi₂O₃ make the apparent decomposition heat of azide groups decrease.

Abstract:2, 2, 4, 4, 6, 6-Hexanitroadamantane (HNA) was synthesized via cyclization, decarboxylation, ketalization, ozonation, oximation, and oxidative nitration etc. steps, using diethyl malonate and paraformaldehyde as raw materials. The reaction conditions of the preparation of Meerwein′s ester, ozonation and nitration were optimized, and the overall yield of HNA was promoted to 3%. The effects of substrates ratio, reaction temperature, reaction time and solvent on the gem-nitration reaction were investigated using nitrogen pentoxide as nitrating agent of gem-nitration reaction of ketoxime.The optimum reaction conditions were determined as with the yield of gem-dinitro compound being 65%: n(compound 7):n(N₂O₅)=1:3, reaction temperature 50 ℃, reaction time 30 min and methylene chloride as solvent. The structures of intermediates and target compound were characterized by ¹H NMR, ¹³C NMR, IR and elemental analyses. The single crystal of HNA was cultivated and its single crystal structure was determined by a four-circle X-ray diffractometer. The thermal decomposition properties of HNA were studied by thermogravimetry(TG) and differential scanning calorimetry(DSC). Results show that the crystal belongs to monoclinic system, space group P2(1)/n with crystal parameters of a=1.2011(2) nm, b=2.1129(4) nm, c=1.1967(2) nm, α=90°, β=90.59(3)°, γ=90°, V=3.0368(11) nm³, Z=8, D_c=1.777 g·cm^-3, μ=0.166 mm^-1, F(000)=1664. The thermal decomposition process of HNA can be divided into three stages and the total mass loss from start to the end of decomposition reaction is 94%. There is an obvious exothermic peak at 256.21 ℃ on DSC curve of HNA, revealing that an intense exothermic decomposition reaction of HNA would occur on heating.

Abstract:1-Amino-3, 5-dinitropyrazole (ADNP) was synthesized using 3, 5-dinitropyrazole as raw material and 2, 4, 6-trimethylbenzenesulfonic hydroxylamine (MSH) as aminating agent with a yield of 60.7%. Its structure was characterized by IR, NMR, MS and element analyses. The single crystal was cultivated in ethanol. Its single crystal structure was determined by a four-circle X-ray diffractometer. Its thermal properties were studied by TG-DSC. Results show that the crystal is orthorhombic, space group P2 (1)/n with crystal parameters of a=5.543(2)Å, b=9.866(4)Å, c=11.745(5)Å, Z=4, D_c=1.79 g·cm^-3, V=642.3(4)ų. Thermal analyses demonstrate that there is a sharp mass loss process from 170 ℃ to 266 ℃ with 99.1% mass loss. The two endothermic peaks temperatures appear at 110 ℃ and 264 ℃.

Abstract:By using split Hopkinson pressure bar (SHPB) device, the dynamic compression experiments of polymer bonded explosive (PBX) simulants were performed under high strain rates (1763~2650 s^-1) loading. Sine pulse of the incident bar was obtained with a lead pulse shaper. The stress states on both ends of the specimen were monitored by polyvinylidene fluoride(PVDF) pressure sensor, respectively. The deformation and failure process of the specimen were shot by high speed camera, and the axial strain of the specimens was monitored by the laser displacement meter. Mesoscopic structure morphology and damage model of the specimen were observed by electron microscope. Results show that the PBX simulant is sensitivity to strain rates. Combining with interface debonding and crystal fracture theory, the grain fracture and the separation between grain and binder are mainly mesoscopic damage model for the PBX simulant.

Abstract:To analyze the effects of component and proportion of composite binder on the interfacial interaction of polymer bonded explosive (PBX), based on different theoretical models, the interfacial interaction between fluoropolymer F2314/acrylonitrile-styrene copolymer (AS) composite and 1, 3, 5-triamino-2, 4, 6-trinitrobenzene (TATB) was evaluated using multiple parameters (parameters A、β and effective volume fraction φ_e). Results show that the interfacial interaction between F2314/AS composite binder and TATB is related to phase transition of F2314 and AS, with a fluctuation as temperature increases. The values of interfacial interaction parameter β of TATB/F2314 composite and TATB/AS composite are 0.969 and 0.840, respectively. With the F2314 content increasing at 20 ℃, the effective volume fraction φ_e of explosive particles and the relative value of the effective volume per single particle B increase, and the interfacial interaction between explosive particles and composite binders in PBX can be enhanced.

Abstract:To research the ignition and combustion characteristics of base bleed propellant in the base bleed unit and improve the accuracy of numerical simulation, the specific heat capacity and conductivity coefficient for unaged and naturally aged (stored in a sealed plastic bag under room temperature) AP/HTPB base bleed propellant used in a 155mm base bleed projectile were determined by differential scanning calorimeter (DSC) and conductometer, respectively. Results show that the maximum endothermic peak temperature and the maximum exothermlic peak temperature on DSC curve of the aged base bleed propellant at a heating rate of 20 ℃·min^-1 are 253.52 ℃ and 437.54 ℃, respectively. The function of specific heat capacity as temperature with in 40-180 ℃ is obtained based on DSC curves by polynomial fitting method. The average specific heat capacity and conductivity coefficient are 0.9868 kJ·kg^-1·℃^-1 and 0.2292 W·m^-1·K^-1 for the aged base bleed propellant and 0.8887 kJ·kg^-1·℃^-1and 0.4020 W·m^-1·K^-1 for unaged base bleed propellant, respectively. In comparison with unaged base bleed propellant, the average specific heat capacity of aged base bleed propellant increases about 11%, whereas conductivity coefficient of aged bleed propellant decreases about 43%.

Abstract:The influence of compressive stress and Shore hardness on the annular gap defect of a casting polymer bonded explosive(P-1 explosive)charge after curing was studied using a compression technology. The relationship between stress and strain was analyzed. The equation of stress-strain for P-1 explosive compression curing process was obtained. The detection of the explosive was carried out by CT. Results show that the compressive stress is lower than 0.071 MPa and the compression modulus is 2.27 MPa when the strain is less than 3.232%. The values of stress and modulus rise rapidly when the strain is greater than 3.232%. The Shore hardness of the explosive increases from 3 HA to 59 HA after 5~25 h curing. When the initial value of Shore hardness is within 8~24 HA and the compressive stress of 14.2 kPa is imposed on the explosive, the compressive strain is 1.3%. The auxiliary compression technology can effectively eliminate the annular gap defect of the charge.

Abstract:Aluminum film explosive was obtained by replacing aluminum powder in traditional aluminized explosives with aluminum film. The pressure-time curves at different position for composite explosives with aluminum film content of 10%-40%, and RDX were obtained by underwater explosion contrast experiments. The peak pressure, impulse, specific shock wave energy and specific bubble energy were obtained via analysis and calculation of the curves. When aluminum film content is 10%, the impulse of aluminum film explosive relative to RDX increases by 9%-9.5% and the specific shock wave energy relative to RDX increases by 9%-12%. The effect of aluminum film content on underwater explosion performances of aluminum film explosive is different from that of traditional aluminized explosive, which is caused by the grain structure of aluminum film explosive and the reaction extent of aluminum film.

Abstract:To guide the formulation design of thermobaric explosive(TBE) and study the relationship between TBE energy output, TBE component and experimental atmosphere, the energy output characteristics of TBE were analyzed via the shock wave energy, bubble energy and total energy, using an underwater explosion test method. Results show that under the experimental conditions, the shock wave energy and total energy of TBE with the aluminum powder content of 40% are maximum, their values are 338.27, 2549.84 kJ, respectively. The bubble energy of TBE with the aluminum powder content of 50% is maximum, its value is 16.08 kJ·g^-1. The oxygen content is an important factor affecting the energy output of TBE.

Abstract:In order to meet the piston micro-actuator used in the small-caliber Ammunition Fuze Safety System structural and functional requirements, ANSYS/LS-DYNA finite element software was applied to analyze the structure design of the piston micro-actuator, and the structure and size parameters which affect its performance were determined. The anti-thrust force and setback force of different structural size parameters piston micro-actuators was obtained through the piston micro-actuator performance experimental test. With step height of 0.03 mm, anti-thrust force is 142 N, and the setback force was 38.5 N. The fitting curve and expression of the piston micro-actuator and thrust distance were got under different charges. With thrust distance of 2.0 mm, the minimum thrust is greater than 20 N. Results show that the deviation of the numerical simulation results with experiment values with 15%, indicating that the numerical simulation method can be applied to research micro-actuator function process.

Abstract:In order to resolve the problem about the backward method of charge and low energy efficiency of explosives, the explosives with structure of honeycomb were prepared to ensure the quality of charge, and applied to double side explosion cladding to clad two combination plates. Results show that this technology significantly reduce the critical thickness of stable detonation of explosives, increases the energy efficiency of explosives, and saves the amount of explosives. Emulsion explosives with the thickness of 5 mm can stably detonate. The feasibility experiment of double side explosion cladding for steel of 45^# with thickness of 2 mm and steel of Q235 with thickness of 16 mm was carried out. Compared with the existing explosive cladding method, the consumption of explosives reduces by 83% in the case of cladding the same number of combination plates. The explosive cladding windows and collision speed of flyer plate are calculated before experiment. Upper and lower limits for collision velocity of flyer plate is 192 m·s^-1 < υ_p < 983 m·s^-1, and collision velocity of flyer plate for two groups which are 1089 m·s^-1 and 863 m·s^-1, respectively. It has shown that the calculation prefigures exactly the explosion cladding for steel of 45^#/steel of Q235.

Abstract:To analyze and compare the thermal stability of commercial ammonium nitrate (AN) and homemade non-explosive and irrestorable fertilizer-grade ammonium nitrate (NEIFAN), the crystal transformation changes, thermal decomposition characteristics and adiabatic decomposition processes of AN and NEIFAN were studied by thermogravimetry (TG)-differential thermal analysic (DTA)-derivative thermogravimetry (DTG), differential scanning calorimetry (DSC) and accelerating rate calorimetry (ARC). The curves of thermal decomposition temperature and pressure vs time, self-heating rate and pressure vs temperature for AN and NEIFAN under the adiabatic decompositions condition were obtained. The kinetic parameters (apparent activation energy and pre-exponential factor) of pseudo zero order adiabatic decomposition reaction for AN and NEIFAN were calculated. The results show that in comparison with AN, the crystal transformation peak at about 88 ℃ of NEIFAN disappears, revealing that NEIFAN has better thermal physical stability. The decomposition peak temperature of NEIFAN obtained by TA-DTA-DTG and DSC curves and the apparent activation energy of the pseudo zero order adiabatic decomposition reaction of NEIFAN obtained by ARC data are much higher than those of AN, indicating that NEIFAN has a higher heat-resistance ability than AN. Considering that the increase of physicochemical stability of NEIFAN is attributed to the joint action of inorganic and organic additives in NEIFAN.

Abstract:To study the treatment effect of wastewater containing nitrobenzene explosives with advanced oxidation technologies of ozone, the comparative experimental study on the degradation of nitrobenzene compounds in simulated waste water was carried out by four different combined processes [RPB(rotating packed bed)-O₃/H₂O₂, RPB-O₃, BR(bubbling reactor)-O₃/H₂O₂ and BR-O₃].Results show that the RPB-O₃/H₂O₂ process shows a strong oxidation capacity to nitrobenzene compounds, the removal rate of nitrobenzene compounds can reach 99%, and wate indicators can meet the discharge standard of nitrobenzene compounds in integrated waste water discharge standard GB8978-1996.Under the same reaction time, the BR-O₃/H₂O₂ and BR-O₃ processes show low oxidation capacity to nitrobenzene compounds.In the RPB-O₃/H₂O₂ and RPB-O₃ processes, the removal rates of the nitrobenzene compounds enhance with increasing of the high gravity factor and initial pH value.With increasing the H₂O₂ concentration and liquid flow rate, the removal rate of nitrobenzene compounds first increases and then reduces.Under the experimental conditions of a nitrobenzene liquid flow rate of 120 L·h^-1, a H₂O₂ concentration of 4.9 mmol·L^-1, a high gravity factor of 80 and an initial liquid pH value of 10.5, the removal effect of nitrobenzene compounds is good.And the degradation processes of nitrobenzene is in conformity with the pseudo-first-order reaction kinetics.

Abstract:Tetrazole-based energetic materials have the advantages of high nitrogen content, high density, good thermal stability and large gas production.It summarized and reviewed the progresses of study about the synthesis, performance and application of N, N-bis(1(2)H-tetrazol-5-yl)amine(H₂BTA) and its nonmetallic salt compounds and metallic complexes.It suggested:(1) the compounds aiming at more nitrogen, oxygen atoms and coordinated oxygen within molecule are designed to improve the oxygen balance and improve the density.(2) choosing the compounds with easy preparation, simple structure and excellent performance as research target, or the application research of in the field of insensitive high energy explosives, solid propellants, initiating explosive device and novel gas generating agent.

Abstract:The compatibilities of dihydroxylammonium 5, 5′-bistetrazole-1, 1′-diolate(HATO) with composite modified double base(CMDB) propellant components, including nitrocellulose(NC), NC/nitroglycerine(NG) absorbent, N-nitrodihydroxyethylaminedinitrate(DINA), cyclotrimethylene-trinitramine(RDX), cyclotetramethylenete-tranitramine(HMX), lead 3-nitro-1, 2, 4-triazole-5-onate(NTO-Pb) and aluminum powder(Al powder) were studied by differential scanning calorimetry(DSC) and vacuum stability test(VST) method.DSC results show that the binary systems of HATO with NC, NC/NG, DINA, and RDX are incompatible, with HMX, NTO-Pb and Al powder are compatible.VST results show that the binary systems of HATO with NC/NG absorbent and DINA are incompatible, with RDX is slightly sensitive, and with NC is compatible.

Abstract:Boron triazide(B(N₃)₃)was synthesized via low-temperature reaction in acetonitrile with trimethylsilylazide and boron tribromide as starting materials.The structure of target compound was characterized by means of IR and ¹⁴N NMR.

Abstract:An improved one-pot method for the preparation of 2, 4, 5-trinitroimidazole from 4-nitroimidazole was reported.Its structure was identified by ¹H NMR, IR, MS and elemental analysis.The reaction time, reaction temperature and the molar ratio of the reagents of the synthetic route were optimized.Results show that the yield of 2, 4, 5-trinitroimidazole can reach up to 80.6% under the conditions of reaction time 4 h, reaction temperature 120 ℃ and the molar ratio of n (4-nitroimidazole):n(65% HNO₃):n(AcOH)=1:30:30.

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