bluuebunny/crossref_metadata_2025 huggingface dataset:
Attitude Measuring for Spinning Air Vehicle Based on Kinematics
Authors: Xiaojuan Huang , Yaojun Li , Weigang Zhang , Kang Li
Published: June 2023

The attitude measurement method of satellite navigation for spinning air vehicles is innovatively proposed. As an attitude measurement backup solution for inertial navigation system or magnetometer, based on kinematics principle, the velocity vector from GNSS receiver could be used to measure attitude for spinning air vehicles without any other sensors. The three-dimensional pseudo-attitude kinematics modelling is realized under the condition that the flight angle of attack and sideslip angle are small; the pseudo-attitude is transformed into inertial coordinates through Euler attitude matrix, and its accuracy index meets the actual working requirements.
Design of Guidance Law for Smart Missile Based on Direct Mode Configuration with Implicit Dynamic-Inverse
Authors: Yefei Yin , Xu Li , Qiaoqi Li
Published: June 2023

The design of guidance law for smart missile based on implicit dynamic-inverse direct mode configuration is described in this paper. The dynamic-inverse theory and direct mode algorithm are applied to the design of guidance law. The pitching acceleration and yaw acceleration are designed for the pitch channel by using the augmented proportional guidance and for the yaw channel by using the dynamic-inverse theory respectively. The attacking time parameter and the attack time error equation are introduced as the constraint criteria for the design of the dynamic-inverse. According to the singular perturbation theory, the fast and slow subsystems are designed by dynamic-inverse control, and then the required control quantities are obtained by solving the relative motion equations of the missile and the target. The simulation results showed that the guidance law can fully meet the guidance trajectory performance requirements of the smart missile.
The study on the preparation of ultra-low thermal expansion ceramic with high elastic modulus
Authors: Zhang C , Liu F F , Guo J B , Guo Z Z , Guo M , Yang S Y , Xu C Y , Sun M Y , Xu H , Fang S J
Published: June 2023

The paper studied the synthesis of cordierite powders and the preparation of ultra-low thermal expansion ceramic with high elastic modulus. The powder was synthesized by solid state reaction using MgO, Al2O3 and SiO2 as raw materials. The effect of temperature on powder purity, phase and properties of ceramic was mainly studied. The results show that the cordierite powder with higher purity and reactivity was synthesized at 1390°C, containing two kinds of phase (α-cordierite and β-cordierite). The compact cordierite ceramic could be obtained at 1420°C with homogeneous and compact organizations, besides, this sample had a wide operating temperature area with low thermal expansion, and the higher elastic modulus.
Error Comparison of CNFFFT and Hankel Method in RCS Near-Field to Far-Field Transformation
Authors: Zhao Peng , Hu Weidong , Liu Yang , Yao Zhiyu , Sun Jianhang
Published: June 2023

At present, there are mainly two kinds of image-based near-field to far-field transformation (NFFFT) algorithms: Hankel method and circular near-field-to-far-field transformation (CNFFFT). Due to the approximation in the measurement distance, the accuracy of Hankel method is lower than that of CNFFFT. However, the implementation of CNFFFT is complex and time-consuming. It is necessary to determine the detailed relationship between the transformation error and the near-field test distance for both algorithms to provide a basis for the choice of which algorithm to use. In this paper, the effect of the near-field test distance approximation of the two algorithms is obtained by simulating 4, 5, and 9 scattering point models. Meanwhile, an accurate comparison method for two NFFFT algorithms under different test distances is proposed.
Research on Architecture Modeling of Aviation-guided Munitions System Based on MBSE
Authors: Wang Jiuhe , Ma Xiaodong , He Xiaofu , Hu Lifeng
Published: June 2023

In order to explore the forward R & D mode of aviation-guided munitions, an architecture modeling method of aviation-guided munitions weapon system based on MBSE(Model Based System Engineering) is proposed. Based on MBSE typical methodology and SysML language, taking a certain type of aviation-guided munition as an example, the system architecture model is constructed, and the design process including the requirements analysis, functional logic analysis, architecture balance and analysis, and scheme detailed design of aviation-guided munitions is described. The simulation analysis and verification are carried out, and the complete description of the continuous dynamic behavior of the aviation-guided munitions system architecture is realized. The research results can provide support for the scheme design and agile research and development of aviation-guided munitions equipment.
Numerical Study of Shock Wave Boundary Layer Interaction Based on an Anisotropic Turbulence Model
Authors: Hao Chunhui , Yan Wenhui , Zhou Junwei
Published: June 2023

This paper presents numerical simulations of incident oblique shock wave impinging on a flat plate with a turbulent boundary layer using a nonlinear anisotropic turbulence model. Three cases with different incident shock angles under the same free-stream Mach number are studied, including attachment flow, incipient separation flow and outstanding separation flows. Convection terms and diffusion terms are calculated using the third-order Roe’s flux difference splitting scheme and the second-order central difference scheme in the code, respectively. The Runge-Kutta time marching method is employed to solve the governing equations for steady state solutions. Comparisons between the simulated results and experimental data are carried out, which include density contours, pressure distribution, skin friction coefficients distribution and streamline vectors. To capture the essential behavior of this complex anisotropic turbulence separation flow caused by the shock-wave-boundary-layer-interaction (SWBLI), an anisotropic eddy viscosity tensor and a nonlinear Reynolds stress-strain constitutive relationship are used in this model. The anisotropic eddy viscosity tensor is composed of turbulent fluctuation velocity vector and characteristic length vector which are obtained by statistical partial average scheme. With proper modeling of anisotropic eddy viscosity tensor, the numerical results are in good agreement with the experimental data. It is worthy to point it out that the computation accuracy decreases with increasing interaction intensity.
Effects of Stage Spacing on Contra-Rotating Propeller Aerodynamic Interactions
Authors: Wenhui Yan , Kun Zhang
Published: June 2023

To identify the law of aerodynamic interactions of contra-rotating propellers (CRPs) and improve their aerodynamics, this study investigates the aerodynamic interactions of 4 CRPs (six blades in front and six in back) with different stage spacings using the Reynolds-averaged Navier-Stokes (RANS) equations-based method. The results showed that the CRP whose stage spacing was 0.25 times the propeller diameter delivered the highest average efficiency and that the aerodynamic interactions between the front and rear propellers decreased as the spacing widened, and compared with the rear propeller, the front one was more sensitive to stage spacing due to the aerodynamic interaction-generated thrust fluctuations. It can be seen that stage spacing exerts a significant effect on CRP aerodynamic interactions. Therefore, choosing an appropriate stage spacing in CRP design is of great significance to enhance its aerodynamics.
Simulation analysis of dynamical performance and economic performance for the electric vehicle
Authors: Pan Jiang-li , Yang Xu , Zou Bo , Lv Bu , Liu Zun-fei , Zhang Wen-juan , Ye Shuang-ping , Feng-Min
Published: June 2023

Aimming at the problem that it is difficult to evaluate whether the dynamical performance and economic performance meet the expected indicators after selecting powertrain for the special vehicle, a vehicle simulation model was built based on the vehicle dynamics theory for the simulation analysis of dynamical performanc and economic performance. The maximum speed, acceleration time, maximum climbing slope and the biggest continue voyage course were obtained by simulating. The simulation results show that its dynamical performance and economic performance meet the expected targets, and the vehicle simulation model has high accuracy and short modeling cycle, which can provide reference for the development of the electric vehicle.
Interface failure analysis of coating in gun barrel under thermal-pressure coupling effect
Authors: Geng Xuehao , Liu Feifei , Gan Jinjie , Si Zhihui , Zhang Rui
Published: June 2023

This paper is devoted to research the interface failure mechanism of coating in gun barrel, three interface failure models (interface shear failure, interface bending failure and interface crack growth failure) of coating in gun barrel are built with consideration of thermal-pressure coupling effect, and the failure criterion is given. The critical failure length/thickness ratio of coating segments for different failure models during firing process are calculated based on temperature field simulation result, then by comparison of the calculation results, the main interface failure way of coating in gun barrel is confirmed.
Overall Structural Design of a Radar with 2-D Arrayed Independent Conjugate Sealed Air Ducts Under Strong Electromagnetic Radiation
Authors: Wang Yuhan , Li Zhi , Fang Yiqi , Bai Yajie
Published: June 2023

An overall radar structure with 2-D arrayed independent conjugate sealed air ducts is discussed. It can operate well in a strong electromagnetic radiation environment. Completely sealed, the case consists of two installation cavities. The front cavity achieves wave transmission and reception and lessens electromagnetic radiation from large power microwave weapons, making it possible for the radar’s transmitting and receiving waves to pass with low attenuation. The horizontal air duct in the front cavity dissipates heat of the antennae, ensuring the conformity of the direction figure formed by the transmitting chips. The two-sided surface-mount technology applied in the vertical air duct in the back cavity lowers the utilization space and thickness of the radar while raising the dissipation efficiency.
Research on Theoretical Model of Ceramic/PE Composite Protection for Projectile
Authors: Zhang Tianlong , Dong Fangdong , Ma Xuejiao , Liu Zide , Yu Pan
Published: June 2023

In order to predict the ballistic limit of ceramic/ UHMWPE composite protection, a theoretical model of ceramic/UHMWPE composite protection for projectile was established based on A-T model and fiber energy dissipation model. In the ballistic impact process, the fragments will experience ceramic dwell, ceramic fragmentation and fiber layer energy dissipation. The theoretical model obtained is compared with the experimental and simulation results. The results show that the residual velocity obtained by the theoretical model is in good agreement with the experimental and simulation results, and it can be applied to ceramic/UHMWPE composite protection of projectile penetration to a certain extent.
Experimental study on energy release effect of reactive bullet impacting soil simulated target
Authors: Cui H L , Jia Z J , Hu X B , Ren X H , Liu Y
Published: June 2023

To study the energy release of PTFE-Al reactive material bullets penetrating soil target, by firing the bullet with a 12.7mm ballistic gun, and using a high-speed camera to record the energy release process when impacting a simulated target, a nylon 6 plate with 5mm thickness, which has an approximate wave impedance to soil target. The result shows that when the velocity of the bullet is at 553m/s, a flame extinguishes immediately after the PTFE-Al is evoked but could not continue. With the increase of impact velocity, the secondary energy release reaction with greater strength can be realized after the first energy release of the reactive material is excited and maintained for a certain period. It is concluded that the critical velocity of the PTFE-Al reactive material impacting the soil is about 553m/s, and the energy release effect becomes more severe with the increase of impact velocity.
Influence of liner structure on EFP formation and penetration performance of a Ta-Zr liner
Authors: Hu XB , Wang TY , Wang JH , Wen XM , Liu ZY , Yuan GQ
Published: June 2023

In order to study the formation and penetration performance of reactive liner, in this paper, a Ta-Zr alloy is used as the liner material, and large cone angle liner, spherical liner and arc-cone liner are simulated and analyzed by using AUTODYN software. The following conclusions are obtained: (1) The EFP formed by large cone angle liner has good flight stability, followed by arc cone liner; (2) The length diameter ratio of spherical shaped charge liner is larger than that of arc cone shaped charge liner; (3) The EFP penetration depth of the arc cone shaped liner is larger, and the EFP incident aperture of the large cone angle shaped liner is larger.
Research on the Effect of Inner Lining on Fragment Scattering Characteristics of Fragmentation Warhead
Authors: Liu Wei , Cao Lei , Li Xin , Liang Zheng-feng
Published: June 2023

In order to improve the axial fragments killing power of fragmentation warhead, based on the Shapiro formula, a design method of the lining curve of the fragmentation warhead was proposed, and the fragmentation warhead was designed with a fragment scattering angle of 5° and 9° by using this method. Using LS-DYNA software and ALE algorithm, the numerical simulation calculation of fragment scattering process was carried out, and the static explosion test of the warhead prototype was carried out to verify the rationality of the lining curve design method. The influence of the shape and thickness of the inner lining curve on the scattering characteristics of the fragments is analyzed. The results show that the error value between the experimental value and the simulated value of the scattering angle and the theoretical design value is within 8%; the smaller the design value of the fragment scattering angle, the greater the curvature of the lining curve, and the smaller the initial scattering speed of the fragment; When the thickness of the inner lining is appropriately increased, the initial scattering speed of the fragments increases, and the scattering angle of the fragments decreases.
The application of EET in high-entropy alloy
Authors: Guo J B , Guo Z Z , Zhang W , Han H , Xu C Y
Published: June 2023

High-entropy alloy with multi-principal elements is a novel design concept for the field of alloy, which breaks through the traditional alloy development frame based on “one or two major alloy elements”. High entropy alloy composed of different metallic elements (generally ≥ 5) can present different novel properties by changing mole ratios or elements. In this work, the valence electron structure of high entropy alloys with compositions near Nb25Mo25Ta25W25 and V20Nb20Mo20Ta20W20 was studied using the Empirical Electron Theory of Solid and Molecules (EET). The predicted results agree well with the experimental data. Results shows that EET can be used to forecast the HEAs’ properties and design the constituent of HEAs.
The study on booster output characteristic for conducted electrical weapon applying on biological target and surrogates
Authors: Gao Tong , Qin Bin
Published: June 2023

The effectiveness and safety of conducted electrical weapons (CEWs) are closely related with their booster output characteristics. In this paper, the no-load of a police CEW, and the comparison of booster output characteristics between biological target and equivalent resistance under the same condition are measured, where the results verify the biological target cannot be simply replaced by an equivalent resistance, and a coupling model of resistance and capacity is necessary for next research. Considering the component similarity, a surrogate for biological target consisted of gelatin, water and different percentage of salt is prepared. On this basis, the equivalent load profiles for both biological target and salt gelatin surrogate targets, which obtains from the booster output voltage and current data, shows the transient pass for high-frequency signal and the cut-off for low-frequency signal simultaneously. Moreover, the little difference in high-pass equivalent resistance between biological target and gelatin surrogate target identify the gelatin surrogate is a suitable CEWs target.
Finite Element Simulation and Experimental Investigation on Progressive Forming
Authors: Gu By Peng , Wang Baichao , Sun Lizhong , Ou Xibin , Liu Jinsong , Zhang Hongguang , Yang Hao , Zhang Lei , Li Jing , Mu Jiaqing , Zhang Yiqun , Liu Xia
Published: June 2023

A non-linear finite element technique is used to study the progressive forming process of the sheet, and the elastic-plastic distribution is analyzed based on Abaqus/Explict. Finite element simulations of progressive forming with different process parameters were carried out to analyse the effects of the tool head diameter, layer feed and sheet properties on forming quality. The results show that increasing the tool head diameter or decreasing the layer feed will result in better sheet forming quality, and the influence of the tool head diameter on the sheet forming quality is greater than that of the layer feed, and the selection of materials and the selection of suitable process parameters are more conducive to the improvement of forming quality and forming efficiency.
Analysis and simulation of the influence of initial liquid level on lubricating flow state and oil-churning resistance moment of planetary reducer
Authors: Wang Lei , Zhang Yunqing , Li Yi
Published: June 2023

In order to study the influences of the initial liquid level on lube characteristics and oil-churning resistance moment of gear reducer, the heat generating power of one special kind of planet gear reducer under the special working condition is calculated. The fluid temperature at different initial liquid levels is calculated by FEA method. According to the relation between the physical parameters of the lube and the fluid temperature, the corresponding relation between the physical parameters of the lube and the initial liquid level is deduced. Based on the FEA results, the physical parameters of the lube are set to conduct the co-simulation of the oil-churning process of the planetary reducer under different initial liquid levels by MPS method. Depend on the simulation results, the influence of initial liquid level on lubricating flow state and oil-churning resistance moment of planetary reducer is analysed, and the initial liquid level is sifted. These studies provide methods and reference for lubrication medium set in transmission boxes, such as planet gear reducer and so on.
Research onthedelamination damage algorithm offiber reinforced composites
Authors: Ronghui Wang , Shuhu Li , Yan Liu , Yingying Gao , Haiyun Zhang , Huamin Jia , Jianfen Guo
Published: June 2023

Aiming at the typical delamination damage mode of fiber-reinforced composites, the constitutive model and failure criterion of composites that commonly used in dynamic simulation are studied, and the principles and characteristics of cohesive element and tiebreak contact algorithm are analyzed.Then the simulation calculation of two fiber-reinforced composite targets anti penetration is take as an example,The accuracy of the cohesive element and the tiebreak contact algorithm are verified respectively, and the protection mechanism of fiber-reinforced composites in the process of anti penetration is revealed, which provides an important reference for the development and design of new composite protection structures and equipment.
Discussions on Influencing Factors of Mechanical Sensitivities of Energetic Materials Taking Dihydroxylammonium 5,5’-bistetrazole -1,1’-diolate as an Example
Authors: Zhang Wei-peng , Liu Yan-ping , Huang Ya-feng , Zhao Dong-kui
Published: June 2023

Mechanical sensitivities of energetic materials are influenced by some factors, such as crystal type, particle size, additives, and so on. In literature, conclusions from different authors are often different, even opposite. In this paper, depending on experimental data by ourselves and amounts of data from literature, we discussed some factors influencing mechanical sensitivities of energetic materials. Results show that impact sensitivities of flaky energetic materials is usually higher than corresponding particle one, and friction sensitivity of energetic materials particles easier to roll is often lower. Although processing additives often lessen the mechanical sensitivities of energetic materials, in some case, mechanical sensitivities of energetic materials with binder increase obviously. The mechanism inducing erratic results of mechanical sensitivities of energetic materials in testing is discussed in this paper, too.
Combustion performance of surface-deterred gun propellants with varied deterrent contents
Authors: Gou Yong-liang , Wei Lun , Yue-juan Yao , Liu Bo , Wang Jia-peng
Published: June 2023

This paper explores how the combustion performance of surface-deterred granular gun propellants relates to the deterrent content to further improve combustion progressivity and low temperature sensitivity. Five types of propellants with different deterrent contents are prepared with the surface deterring technology. Through the analysis of explosion heat and experimental data from closed bomb tests, we investigate the energetic and static combustion properties of the propellants. Results show that the deterred propellants have a higher combustion progressivity than the blank propellant, and as the deterrent content increases, the progressive index increases gradually. In addition, the maximum pressure measured by closed bomb tests is linearly related to the deterrent content. At high temperatures, the average absolute values of the temperature coefficients of relative activity for surface-deterred propellants are lower than that for the blank propellant, indicating better low temperature sensitivity of surface-deterred gun propellants at high and normal temperatures.
Research on preparation and high temperature resistance of primary explosive chromium azide
Authors: Lei Zhang , Yanlan Wang , Jianhua Chen , Rui Zhang , Fang Zhang
Published: June 2023

The research on novel high-temperature resistant primary explosives is an inevitable trend to adapt to the development of weapons. In this paper, high temperature resistant primary explosive cadmium azide was prepared from sodium azide and cadmium nitrate tetrahydrate by hydrothermal reaction. Then, the high-temperature storage performance was tested by cook-off test, and the influence of high temperature was analyzed in combination with microscopic morphology, crystal structure, and thermal decomposition temperature. The reliable ignition voltage was tested by electric ignition sensitivity, and the initiation performance of cadmium azide was verified by using CL-20 as secondary explosive. The results show that cadmium azide is an excellent high temperature resistant initiating agent primary explosive with the thermal decomposition temperature of 384.21°C and a 50% electric ignition voltage of 4.82 V, which can reliably initiate the CL-20 into complete detonation.
Mechanical Sensitivity Reduction of Energetic Materials by Using Carbon Nanomaterials
Authors: Xiao L Q , Zhao Y , Fu X L , Xie W X , Fan X Z
Published: June 2023

Mechanical sensitivities (such as friction and impact sensitivity) are the most important evaluation index to characterize the risk of energetic materials (EMs), as they are the most common stimulus during preparation, transportation and usage of EMs. Recently, carbon nanomaterials (CNMs) have been found to be effective in reducing mechanical sensitivities of EMs with small amount of addition. This review covers updated researches of the desensitization of EMs by using fullerenes, expanded graphite (EG), carbon nanotubes (CNTs), graphene and graphene oxide (GO), their desensitization results and relative mechanisms are summarized. It has been shown that graphene and its derivatives are more effective due to their superior thermal conductivity and layered structure.
Study on master curve of tensile strength of thermal aging composite modified double base propellant
Authors: Liu Jia-ming , Fan Xing-gui , Wang Ting-yu
Published: June 2023

In order to study the mechanical properties of thermal aging composite modified double-base propellant (CMDB), the tensile properties of CMDB propellant were investigated at four temperatures (323, 293, 273, 253 K) and different strain rates (3.3 × 10-5- 3.3 × 10-2 s−1). Uniaxial tensile tests were carried out on CMDB propellant samples with different aging time (0,10,20,35,50,65,80,100 d). The mechanical properties of CMDB propellant after aging were studied. The results show that the maximum tensile strength decreases with the aging time, and the strength value fluctuates within a certain range (Δσ<30 %). The master curve of the maximum tensile strength of CMDB propellant was obtained by using the time-temperature equivalence principle (TTSP), and the master curve equation of the aging strength was established. The equation can be used to predict the maximum tensile strength of CMDB propellant with different aging time in the range of quasi-static strain rate.
Simulation of Solid Propellant Regression with Cracks Based on Level-Set Method
Authors: Wang Junjie , Xiong Yongliang , He Xiaoqiu
Published: June 2023

Traditional methods are difficult to deal with solid propellant regression in complex geometry, especially for a finocyl grain with cracks. In this work, the Level-Set method is adapted to solid propellant regression. The advantage of this method is the implicit representation of interface and no restriction on geometrical configuration. Therefore, tiny cracks can be easily captured by the Level-Set method without any complex grids. A three-dimensional solid propellant regression evolution process of a finocyl grain is presented. A one-dimensional unsteady internal ballistics numerical method is applied to obtain pressure and thrust time histories, coupled with the three-dimensional grain burnback model. The mass and energy injection in the governing equations can be computed from the Level-Set formulation. And the propellant burning rate can be computed from the local pressure. The results show that a crack increases the head-end pressure and thrust at early stage, because of the increment of the burning surface area. It can be seen from the evolution of propellant regression that the crack gradually expands.
Mechanical response of HTPB propellant grain under ultra-high overload
Authors: Zhang Yiming , Wang Ningfei , Wang Ran , Chen Xiaoxu , Wu Yi , Dang Jinfeng , Tian Xiaotao
Published: June 2023

In this study, the mechanical response of HTPB propellant grain under ultra-high loads is investigated. The low, intermediate and high strain rate of uniaxial compression tastings (1.7×10−4~3×103s−1) of the hydroxyl terminated polybutadiene (HTPB) propellant at room temperature were carried out by using the universal testing machine and the split Hopkinson pressure bar (SHPB) system, respectively. The uniaxial compression tests of the cellular rubber, the EPDM rubber and felted wool were carried out. A linear viscoelastic constitutive model of the HTPB propellant was developed by using the test data. The mechanical property of the cellular rubber, the EPDM rubber and the felted wool were studied by the test data. The dynamic mechanical response of the propellant grain under high overloads was simulated with the developed constitutive model by using the finite element method. The deformation of the grain under high overload was studied. The result shows when the overload value is maximum, the stress value of the grain is maximum. The location where the stress value of the grain is maximum is the center of the inner hole of the cushion. The maximum stress value is 20.17MPa.
Review of the Application Progress of 2,6-diamino-3,5-dinitropyrazine-1-oxide
Authors: Li Guofeng , Zhang Yongming , Yuan Ye , Dai Qiuhong , Xie Yangjun , Bao Liyuan , Zhang Jun
Published: June 2023

Since the first synthesis of 2,6-diamino-3,5-dinitropyrazine-1-oxide (LLM-105) in Lawrence Livermore National Laboratory (LLNL) of America in 1993, efforts of investigation into LLM-105 have never ended due to its premium performance. Therefore, with the goal to further emphasize the importance of this material and to provide reference to the application of LLM-105 in propellants and explosives, the properties and performance of LLM-105 are briefly introduced at first and then the application of LLM-105 is reviewed in various areas, including polymer bonded explosives, double-base rocket propellants with low signature and low sensitivity, propellants for perforating cartridges in oil and gas fields and gun propellants.
Thermal History Effects on Decomposition Behavior and Pyrolysis Mechanism of Cellulose Nitrate
Authors: Gao Xu , Jiang Lin , Xu Qiang , Das Oisik
Published: June 2023

Nitrocellulose is an important kind of energetic material produced by replacing hydroxyl of cellulose molecule to nitro, which has a wide application range in social life. During transportation and storage, inevitably the quality of the nitrocellulose will be affected due to external ambient heating. In this study, two kinds of NC samples, original and heated ones, were used as research objects and taken into DSC experiments under several constant heating rates to explore thermal history effects on its decomposition and combustion behavior. A series of calculation methods based on model fitting were main ways for research, so were model free methods. Numerical results by model fitting method showed that decomposition reaction of NC followsn-th reaction model. The comparison between experimental results of two kinds of samples claimed that thermal history had positive influence on heat flow, and increased the reaction order of decomposition process, and decreased the characteristic temperatures. So the thermal history made the decomposition reaction more difficult to take place and more stable. This study is obviously meaningful for the research of thermal pyrolysis process of NC after thermal history.
Creep properties and prediction model of composite solid propellant
Authors: Wu Xuan , Wang Chen-yu , Zheng Jian
Published: June 2023

In order to describe the creep properties of HTPB propellant, uniaxial tensile creep tests of propellant under different stresses were conducted. Based on the principle of viscoelastic theory, the Burgers model was used to describe the creep properties of the propellant. Combined with the experimental data, the parameters of Burgers model under different stresses were determined, and the model parameters were expressed as a function related to creep stress, and finally the model was verified by using the test data under creep stress 0.2 MPa. The results show that the Burgers model can describe the creep properties of the composite propellant well.
Effect of hexafluorophosphate and conjugated fluoride on the combustion of aluminum powder
Authors: Zhang Lichen , Wang Shuo , Zhu Lixiang , Li Xiaodong , Zou Meishuai , Su Xing
Published: June 2023

In this study, the alumina layer on the surface of aluminum powder was removed with hydrofluoric acid. 2-Azido-1,3-dimethylimidazolinium Hexafluorophosphate (ADMHFP) and 4-azido-2,3,5,6-tetrafluorobenzoic acid (ATFBA) were coated on the surface of aluminum to form Al@ADMHFP and Al@ATFBA. Scanning electron microscope and FTIR test results proved that the ADMHFP and ATFBA were coated on aluminum powder. The Al@ADMHFP and Al@ATFBA showed better thermal reaction and combustion performance. The exothermic enthalpy of Al@ADMHFP and Al@ATFBA were increased by about 1.6 times and 1.0 time, with lower ignition temperature and longer burning duration, compared with raw aluminum powder.
Preparation of perfluorobutane glycidyl azide polymer and its coating on aluminum powder
Authors: Zhang Lichen , Zhu Lixiang , Su Xing , Wang Shuo , Jiang Hao , Li Xiaodong , Zou Meishuai
Published: June 2023

In this study, perfluorobutyl iodide (PI) and glycidyl azide polymer (GAP) were used to synthesize perfluorobutane glycidyl azide polymer (PGAP) and coated on aluminum powder to form Al@PGAP. PGAP, an energetic fluoride, was used to explore the combustion promotion of aluminum powder. The Al@PGAP showed better thermal reaction and combustion performance. The exothermic enthalpy of Al@PGAP were increased by about 1.5 times, with higher combustion heat, lower ignition temperature and longer burning duration, compared with raw Al.
Study on explosion reaction mechanism and energy release characteristics of HMX-based explosives containing B-Al
Authors: Gao D Y , Zhao F , Cao W , Song Q G , Wen S G , Zheng B H , Li X L , Zhang Y P
Published: June 2023

To explore the application of the micro-sized B-Al (boron-aluminum) compound powder in enhanced blast explosive(EBX) and thermobaric explosive(TBX), three HMX-based explosives containing B-Al (PF-1, PF-2 and PF-3)were designed and prepared. The ignition and combustion characteristics of various samples (micro- and nano-sized B, B-Al compound powders without and with HMX) under different pressures and atmospheres were studied by a laser ignition and combustion experimental system, and the flame evolution images and emission spectral characteristic parameters of the ignition and combustion process were obtained. The structures of detonation reaction zone of ideal and non-ideal explosives were studied by PDV (photonic doppler velocimeter), and the characteristic parameters and explosion reaction mechanism of wave profile were obtained. The energy output characteristics of explosives containing B-Al were evaluated by air blast and underwater explosion test. The results show that nano-sized B has better ignition and combustion characteristics than micro-sized B; the ignition and combustion property of B-Al compound powder with HMX is obviously superior to that of B-Al compound powder. PBX-1 is an ideal explosive, and the reaction zone width is 44ns, whilePF-1 and PF-3 are typical non-ideal explosives, the reaction zone widths are 112ns and 102ns, respectively. In the air blast and underwater explosion test, under the detonation of HMX, the combustion of micro-Al can promote the afterburning effect of micro-B, which releases a great amount of combustion heat, then generates expansible products with higher temperature and pressure, and finally increases the duration of fireball and total energy in underwater explosion.
Effect of CF on mechanical properties and ignition characteristics of Al/PTFE reactive materials under quasi-static compressive
Authors: Ren Xin-xin , Liu Jin-chun , Fu Xian-wen , Cheng Xi
Published: June 2023

The chopped carbon fiber (CF) was introduced into Al (aluminum) /PTFE (polytetrafluoroethylene) reactive materials, and Al/CF/PTFE reactive materials with different mass fractions of CF were prepared. In order to study the effect of CF on the mechanical properties and ignition characteristics of Al/PTFE reactive materials, quasi-static compression tests were carried out on different types of specimens. The fracture characteristics of the specimens were observed by SEM, and the ignition mechanism was analyzed by crack-induced hot spots. The results show that yield strength and elastic modulus increase while compressive strength and yield strain decrease with increasing CF mass fraction. The decrease in interfacial adhesion between CF and PTFE matrix, uneven load transfer of CF during compression and stress concentration lead to the decrease of mechanical properties of the material. The decrease of compressive strength of Al/CF/PTFE material and the failure of crack tip without ductile brittle transition are the main factors for the non ignition reaction in quasi-static compression. CF did not improve the quasi-static pressure properties of Al/PTFE, but decreased the quasi-static pressure sensitivity.
Reactivity of high active aluminum powder with RDX and HMX mixtures
Authors: Xu Si-yu , Yao Er-gang , Jiang Han-yu , Pei Qing
Published: June 2023

In order to reveal the interaction law of high active aluminum powder with RDX and HMX mixture, the thermal decomposition behavior of highly active Al powder and its interaction with typical nitramine explosive RDX and HMX were studied by differential scanning calorimetry (DSC), thermogravimetry (TG), thermo-mass spectrometry (TG-DTG-DSC-MS) and CO2 laser ignition technology. Results show that when the nanometer aluminum powder and RDX and HMX respectively, two typical nitramine explosive mixing action is of little influence on the mixing action to respond to the thermal decomposition of HMX, depress RDX points liberation degree of temperature, both the thermal decomposition process of mixed system for random nucleation and subsequent growth process, the ignition delay time decreases with the increase of laser ignition power density. The ignition delay time and ignition energy of the mixture of high active aluminum powder and RDX are greater than that of the mixture of high active aluminum powder and HMX and the high active aluminum powder.
Preparation, Characterization and Properties of NC-coated Zirconium Composite Particles
Authors: Jiang Han-Yu , Yu Jin , Wang Xuan-jun , Jiao Xu-ying , Mu Xiao-gang
Published: June 2023

Zirconium has certain application advantages compared with other metals due to its high density, high volume calorific value and combustion performance. Unfortunately, the applications of current Zirconium powders are limited due to its high electrostatic discharge sensitivity, making Zirconium powders more pyrophoric and less amenable to functionalization. To improve the security, Zr/NC composite particles with reduced electrostatic discharge sensitivity are prepared by solvent-antisolvent method and characterized by FT-IR, XRD, TG, SEM and ESD test. The measurement confirmed that the 50% firing energy (E50) of Zr/NC is increased from 5.13 mJ to 25.2 mJ, which is 5 times higher than that of raw Zr powder. The results show that surface coating modification is a feasible method for decreasing the ESD of Zr powder. This study provides technology support for its application in high density propellant.
Combustion characteristics of Al-Li alloy powder and its application in solid propellant
Authors: Zhou Xing , Huang Lei , Liu Xufeng , Yu Haiyang
Published: June 2023

This article is focused on the analysis of Al-Li alloy powder’s thermal oxidation reactivity. The Scanning electron microscope (SEM) analysis results show that the Al-Li particles are uniform and spherical. The phase transformation of the Al-Li alloy powder during the oxidation process was characterized by X-ray Diffraction (XRD), the phase composition of the oxide alloy particles is mainly oxides such as LiAlO2 and LiAl5O8, indicating that the particles are fully burned. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TG) are performed coupled with thermodynamic calculations. The analysis results show that Li can reduce the activation energy required for the powder reaction, promote the combustion of Al powder, reduce the ignition temperature, and make the particles begin to oxidize at low temperature. At the same time, Li can shorter the ignition time of Al-Li alloy particles and improve the particles or propellant combustion characteristics. The results of this work demonstrate that fuel particle engineering for more complete combustion and energy conversion can be achieved by adding other elements and changing the powder formulation.
Research on the Needle Deformation of Extrusion Mold for 19-hole Propellant
Authors: Ji Dandan , Mao Changyong , Xiao Yong , Ma Tao , Huifang Shi
Published: June 2023

Pore diameter and arc thickness of propellant are decided by the extrusion mold parameters. Mold needles deform during propellant’s forming process because of the propellant material’s high viscosity and needle’s flexibility, which affects the quality of propellant products. Based on fluid-structure interaction, we simulated the extrusion process of 19-hole nitroguanidine propellant and studied the influence law of mold structural parameters on the deformation of needles. The results show that forming section length has the greatest impact on the needles’ deformation, and the effect of compression section height is the second, while contraction angle is the least. The deformation of mold needles increase with forming section length, compression section height, and contraction growing.
Thermal Risk Assessment of Sandmeyer Reaction from 5-Aminotetrazole (5-AT) to Hydronium Copper(II)-tris(5-nitrotetrazolate) trihydrate
Authors: Ni Debin , Hou Jian , Liu Jiang , Jia Yuxin , Chen Li , Yu Guoqiang
Published: June 2023

5-NaNT was the raw key material of copper(I) 5-nitrotetrazolate (DBX-1) and tetraaminecis-bis(5-nitrotetrazolato) cobalt(III) perchlorate (BNCP), which was prepared from 5-AT by Sandmeyer reaction. This reaction was usually happened slightly blast due to release heat and nitrogen gas during whole procession. In order to enhance the safety of reaction, differential scanning calorimetry (DSC) was used to measure exothermal of reaction solution and intermediate, reaction calorimeter (RCle) was used to assess the thermal risk, adiabatic calorimeter (RAC) was used to estimate the stability of technological process and hydronium copper(II)-tris(5-nitrotetrazolate) trihydrate (Cu(H-NT)(NT)2(H2O)4) which was intermediate for 5-NaNT. The Td24 was 168h, the maximum temperature of the synthesis reaction (MTSR) was 17°C, adiabatic temperature rise was 43 K, the maximum heat accumulation was 9%, the specific heat release was 3654 kJ/kg. The result shown that dangerous chemical processes risk rank was 1, which mean that the risk of this reaction was relatively low. Matrix evaluation of thermal runaway reaction was level 1, it was that immediately cut off the feed raw material was useful if the cooling system out of service.
Comparison of Three CL-20 Based Explosive Parameters
Authors: Yi-dong Jing , Yuan Cao , Bo Chang , Da-yu Shu , Ming Jia , Qiong Xiao
Published: June 2023

Due to differences in charging technology, test methods, etc. the same explosive can obtain different explosive parameters in different tests. The difference in performance of explosives with different parameters is the focus of engineer’s design. This paper uses the TNT equivalence (TNTe) to compare the parameters of three CL-20 based explosives reported in the previous literature. In this paper, TNTe is attained from Peak overpressure (OP) and impulse (IM), calculated by AUTODYN software and is compared with the TNTe calculated by Cooper Method, Hydrodynamic Work, heat of detonation method. The results show that the difference of TNTe among different parameters can reach 30%. The TNTe calculated by heat of detonation method is too low to be recommended. The average value of TNTe calculated by other methods is 1.69±0.09. More accurate TNTe needs to be used with caution, including data sources and limitations.
Research on NEPE Propellant at High Strain Rates
Authors: Zhengwei Sun , Xinggui Fan , Jiaming Liu
Published: June 2023

In order to study the mechanical properties of Nitrate Ester Plasticized Polyether (NEPE) propellant at high strain rates, the impact tests of NEPE propellant were carried out by the split Hopkinson bar, and the stress-strain curves of NEPE propellant under different strain rates ( 1500s−1-4500s−1 ) were obtained. The test results show that NEPE propellant has obvious nonlinear elasticity and strain rate sensitivity. The microstructure of NEPE propellant was observed by scanning electron microscope, and the fracture mechanism of NEPE propellant under high strain rate was obtained by analyzing the microstructure of propellant. In this paper, a nonlinear visco-hyperelastic constitutive model is adopted, in which Rivlin model and the viscoelastic model are used to describe the mechanical properties of materials. The constitutive parameters of the material were obtained by fitting the test data, and it was proved that the model could well describe the mechanical properties of NEPE propellant at high strain rates by comparing the test curve under different strain rates.
Study on the safety of modified aluminum powder in 3D printing process
Authors: Bai D Y , Yao Y D , Liu J P , Xu S , Kang L M , Liu D B , Luo Y M , Li Y
Published: June 2023

The application of 3D printing technology in the field of explosives has been a research hotspot in recent years. As the most common explosive additive, how to improve the reactivity of aluminum powder has been widely concerned by many scholars. In order to explore the influence of coating modification process on the safety of aluminum powder in 3D printing process, Hartmann tube and Ignition temperature test system were used to study the sensitivity of dust samples to energy and temperature. The results show that the sensitivity of coated aluminum powder to electrostatic energy is significantly reduced, and the sensitivity to temperature is slightly increased. Better modification technology improves the safety of aluminum powder in 3D printing process. And the flame front propagation law is studied, the results show that the modified aluminum powder has more excellent reactivity. It provides basic theoretical data support for the safe application of the modification technology of aluminum powder in the 3D printing process, which has important reference value for the future application research of 3D printing technology in the field of explosives, and is also one of the key development directions in the future. in constructing both.
Research on catalytic performance of transition-metal-based MOFs towards thermal decomposition of RDX
Authors: Ren Jia-Tong , Wei Ding , Tan Bo-Jun , Cui Peng-Teng
Published: June 2023

It is beneficial for the efficient energy utilization of propellants to develop high - efficiency catalysts for thermal decomposition of energetic materials. Herein, catalytic characteristics of different transition-metal-based MOFs on thermal decomposition of cyclotrimethylenetriamine (RDX) were studied, such as [Zn2(atz)3(N3)]n, MIL-88B and ZIF-67. ZIF-67 was found to exhibit superior properties therein. On this basis, size effect of ZIF-67 when catalyzing the thermal decomposition of RDX was further investigated. It has been found that the catalytic performance can be boosted as the size of ZIF-67 is reduced. However, the performance will decline when the size is ulteriorly reduced into nanoscale. Besides, the doping of Ni, Cu or Zn into ZIF-67 has little effect on the promotion of the catalytic performance. Among all the catalysts, ZIF-67-S shows the best catalytic performance for the thermal decomposition of RDX, which is superior to most existing catalysts. Specifically, it can reduce the thermal decomposition peak temperature of RDX by 22.4 °C and enhance the apparent decomposition heat by 59.9%. As a consequence, it is expected to be used as a combustion catalyst in propellants such as 3D printing gun propellants with high RDX contents.