bluuebunny/crossref_metadata_2025 huggingface dataset:
Research on the Cooperative Attack of Multiple Guided Bombs
Authors: Wang Mingxiang , Wang Xiaoguang , Zheng Yuanxun
Published: June 2023

In order to enhance the coordinated strike capability of multiple guided bombs attacking ground targets, this paper studies the time-consistent strike problem of multiple guided bombs on the ground targets. First, for the nonlinear motion model of the bomb and the target, under the assumption that the speed of the bomb is constant and the target is stationary, the problem of simultaneous strikes of multiple guided bombs on the ground target is transformed into the remaining flight time and the velocity deflection angle of the bomb under the second-order integrator model, and a cooperative guidance law is designed in the longitudinal plane to solve the time-consistent strike problem of multi-guided bombs without a leader. Furthermore, in order to ensure the accurate determination of the cooperation, the time-consistent strike problem of the dynamic change of the bomb speed is considered in the leader mode, and the velocity deflection angle is used to design the cooperative guidance law in the horizontal plane, combined with the proportional guidance law of the longitudinal plane, to ensure the consistency of followers and leaders. Finally, the backstepping method is used to generalize the design of the velocity deflection angle for consistency to the design of the vertical overload, and the low-pass filter is used to further reduce the computational complexity. The simulation results show that the cooperative guidance law can ensure that multiple guided bombs can strike the target almost simultaneously, which proves the effectiveness of the cooperative guidance law.
Distributed Cooperative Formation Control for Multi-agent System based on Virtual Centre Strategy
Authors: He Weizhen , Cheng Yuzhen , Peng Pei , Yuan Yuwen , Li Shixuan
Published: June 2023

In this study, a distributed cooperative formation consistency control strategy is investigated for multi-agent system (MAS) to achieve formation consensus. Firstly, the virtual-centre-based reference formation is presented. Then a distributed cooperative formation control law based on virtual-centre is developed for MAS to achieve formation consensus. Finally, the new control scheme is applied to MAS consisting of 5 UAVs and the resulting closed-loop MAS is stable. The effectiveness of the new cooperative control behavior strategy is verified by simulations.
Research on the Working Performance of UAV Hybrid Power System Based on Mission Profile
Authors: Chai Xiyuan , Fu Xin , Zhai Shijie
Published: June 2023

Currently, UAVs can be divided into two main types based on the type of power unit, fuel-powered UAVs and electrically powered UAVs. Most drones that are generally smaller and lighter in weight are electrically powered; while larger drones are usually fuel-powered. Both have their advantages and disadvantages, with fuel-powered drones being highly polluting and noisy, while electric drones usually have a shorter range. Fuel-powered UAVs are noisy and polluting, while electrically powered UAVs are usually shorter. The hybrid system combines the advantages of both and reduces pollution while ensuring a longer range. In this paper, an oil-electric hybrid power system for a tilt-rotor UAV is studied, a mathematical model of the hybrid power system is built, and the performance of the hybrid power system is studied and analyzed based on the mission profile. The mission profile of the UAV is determined, and the UAV demand power curve under this mission profile is given. The overall performance of the oil-electric hybrid power system is simulated and calculated. The results show that the oil-electric hybrid power system meets the power demand of the tilt-rotor UAV under the mission profile given in this paper, and can work normally within the full envelope.
Adaptive random sample consensus method for ground filtering of airborne LiDAR
Authors: Zheng Zhen , Wang Chengjun , Liu Haodong , Tan Yuran
Published: June 2023

Ground filtering is an essential step in the comprehensive processing of airborne LiDAR point clouds. However, the performances of existing ground filtering algorithms are usually affected by manual thresholds, and many algorithms have high complexity and are not suitable for applications with high timeliness requirements. In this paper, a fast ground filtering algorithm for airborne point clouds based on Random Sample Consensus (RANSAC) and adaptive threshold acquisition is proposed. Statistical filtering algorithm is used to filter out outliers and abnormal points based on the Z-scale sequence of the point clouds, the threshold is adaptively obtained according to the filtered Z-scale sequence, and then the adaptive threshold and RANSAC are combined to achieve rapid ground filtering. The proposed algorithm is used to perform threshold calculation and ground filtering on point clouds dataset and real-world point clouds, the results show that the adaptively obtained threshold is located in the optimal threshold interval, and the algorithm in this paper can extract ground points quickly and with small errors. The proposed method provides a reference algorithm for the airborne point clouds processing field that requires high timeliness, such as reconnaissance and Strike Integrated UAV, ground target identification and tracking, etc.
The investigation of lateral/heading characteristics and the influence of jet control at high attack angle
Authors: Zhao Xin-yang , Chen Kun
Published: June 2023

When the aircraft does high maneuvers at a high attack angle, the rapid transition of flight state induces a series of complex flow phenomena such as flow separation and vortex breakdown, leading to a series of uncommanded motions such as self-excited roll oscillation, which brings great danger to the flight of the aircraft. Therefore, it is important to investigate the mechanism of this phenomenon and suppress it. In this paper, the numerical method is based on Lattice Boltzmann Method (LBM) and Large Eddy Simulation (LES) for the SACCON standard flying-wing layout aircraft model. The accuracy of the numerical method is validated by comparing the simulation results of aerodynamic loads at different attack angles with the experimental results. Then the phenomena of the vortex breakdown and shedding at different roll angles and sideslip angles at high attack angles are analyzed, and the relationship between the jet flow coefficient and the control moment is obtained by adding the jet flow to the fuselage. Finally, the rolling motion of the aircraft is simulated in the dynamic simulation. The simulation results show that the model generates self-excited roll oscillations around a nonzero mean angle at high attack angles. The dynamic numerical simulation based on the LBM method can be an effective complementary tool for the study of the dynamic characteristics of the aircraft with a high attack angle.
Research on Timing Compensation of Shadow Photograph System with Three-sequence Laser Sparking
Authors: He Zhen , Luo Honge , Kong Xiaofang
Published: June 2023

The accuracy of the laser sparking time interval measurement plays a key role in the measurement results when the projectile velocity is measured by shadow photograph system with three-sequence laser sparking. By comparing with the original single-chip measurement results, it was found that there was a certain deviation in the measurement results of the laser sparking time. Then the principle of the laser sparking time measurement circuit is introduced in detail, and the reasons for this error phenomenon are summarized. And analyze the original laser sparking time measurement data column and the data column accurately measured with an oscilloscope, use the Pearson correlation coefficient to describe the correlation between the two data columns, and obtain the sample correlation coefficient, the first laser sparking interval coefficient r1=0.50, the second laser sparking interval coefficient r2=0.52. According to the three-level division rule, when 0.4≤|r|<0.7, the two variables are significantly correlated. In order to compensate the original data, it is necessary to find a suitable Δ value to minimize the residual sum of squares of the measured column data after compensation. The mathematical model is developed and solved for the nonlinear system of equations, and the optimal value of Δ for the original data is obtained using a global search for the optimal value: Δ1= 0.238μs, Δ2= 0.201μs. Comparing the compensated data with the original data, The standard deviation of the measured columns of the first flash interval decreased from 0.117μs to 0.022μs after compensation, and the second decreased from 0.102μs to 0.014μs. This shows that the two columns error of compensated data are significantly reduced, which is important for the improvement of the velocity measurement accuracy of the target channel.
Solid Rocket Motor Propellant Grain Burnback Simulation Based on Level Set Method
Authors: chao-fan Han , jin-sheng Xu , Shuang-hong Wang
Published: June 2023

Burning surface calculation is an important item in solid rocket engine design. In order to accurately calculate the parameters such as burning surface change law in the combustion chamber, the level set based method is used for burning surface calculation, firstly, the complex burning surface is divided into a uniform grid by voxelization; then the distance transformation method is used to calculate the signed distance function, and finally the information of the contour surface in the grid is obtained to generate the burning surface change curve. The comparison with the CAD method shows that the relative root-mean-square error of the method used in this paper is within 2% with the numerical calculation results.
Effects of Cylindrical Structure on Bullet In-Bore Action Process
Authors: Li Jinming , Lu Dabin , Wang Shu , Li Fengxia , Pan Yu
Published: June 2023

To explore the effects of bullet cylindrical difference on in-bore dynamic engraving resistance and muzzle swing, a finite element model of bullet-barrel interaction is built. With the proposed model, real bore bottom pressure curves are obtained through experiments. In the numerical simulation, the in-bore motion processes of two all-copper bullets with different cylindrical structures are reproduced according to the real bore bottom pressure curves, so as to qualitatively analyze the relationship between bore pressure curves and bullet in-bore motion. The association between curve inflection points and bullet motion is identified, and the engraving forces of the two bullets are found to exhibit roughly the same trend. In addition, there is an abnormal phenomenon that the bullet with a shorter engraving length should have a larger engraving force. This is due to the interaction between the shape of bore pressure curves and the engraving process, as well as the larger muzzle swing caused by straight slotted structures that have a shorter engraving length. The findings of this study can provide a basis for the design of internal ballistics and the further analysis of the effects of in-bore motion on external ballistics.
Research on adaptive normalization method for attitude measurement of rotating projectile based on four-axis infrared
Authors: Chao Hongxiao , Cao Zhiyuan , Cao Yihan , Pu Xiongzhu , Song Yang
Published: June 2023

In view of the problems that the current attitude measurement method of rotating projectile based on three-axis infrared needs to normalize the sensor according to the surrounding environment in advance, resulting in the troublesome application of infrared attitude measurement method and insufficient environmental adaptability, an adaptive normalization method for attitude measurement of rotating projectile based on four-axis infrared is proposed. Based on the mathematical relationship between four-axis infrared sensors, an adaptive algorithm for the output amplitude and offset of infrared sensors is designed, which can realize the adaptive normalization of the environment of infrared sensors at any time. By building the semi-physical experiment and changing the surrounding environment, it is proved that the adaptive normalization method of rotating projectile attitude measurement based on four-axis infrared is effective, which provides convenience for the use of infrared attitude measurement method and further improves the infrared attitude measurement theory.
Study on the influence of barrel venting on the overload waveform of projectile in bore
Authors: Zhao Na , Chao Hong-xiao , Cao Yong-jie , Dou Song-song
Published: June 2023

In order to evaluate the anti shock overload ability of electronic components and parts in explosive device launcher, half sine wave generator with certain amplitude and pulse width is often used to verify it. In this paper, gun launcher is used as the shock wave generator. Different charge structures are studied for the interior ballistics process of barrel with or without venting according to certain requirements of mechanical overload. The influence of different charge structure, chamber volume and vent hole size on the overload waveform of projectile in the process of interior ballistic is studied by numerical simulation. The simulation results show that the larger the vent diameter is, the closer it is to the standard waveform. The research results can provide references for the matching design of projectile and artillery, the research and development of intelligent ammunition and the assessment. The research results can provide for the matching design of new artillery projectile and artillery and the research and development of intelligent ammunition.
Modal Research on Photoelectric Turntable of a Medium Caliber Tracked Anti-aircraft Gun
Authors: Chen Chen , Wang Hua-ting , Cheng Guang-wei , Zeng Yu-yun , Chen Xiao-ming
Published: June 2023

Aiming at the problem of violent vibration of the photoelectric turntable caused by the high frequency firing work load during the firing of a medium caliber tracked anti-aircraft gun, the tracking accuracy of the photoelectric tracker is unstable, and the law of the vibration of the gun on the platform is obtained by combining mechanical simulating and experiment. According to the finite element theory, a model of certain type of the gun is built, modal analysis is carried out through the ANSYS Workbench, the natural frequency and mode shape of the turntable are gained, and the hammering method modal test is carried out to verify the simulation outcomes. Through the strength check of the gun mount assembly under three typical working conditions, the weak link in the structural design is found. The results show that the research results can provide a reference for the structural design optimization of the photoelectric turntable on a vehicle-mounted antiaircraft gun.
Research on Electromagnetic Protection Characteristics of Vehicle-mounted Electromagnetic Railgun Launcher Lifetime Counting Device
Authors: Jin Yinxiang , Wang Dawei , Guo Zhangxia , Zou Libo , Chen Jiahao , Xie Jingyun
Published: June 2023

When the vehicle-mounted electromagnetic gun is launched, the vehicle body is subjected to strong arc reaction, magnetic field interference and shock wave phenomenon. By establishing the external magnetic field model of the multi-tube launch chamber, the electromagnetic protection characteristics of the vehicle-mounted electromagnetic gun launcher’s full-life counting device are studied, and the magnetic field characteristics during launch are analyzed by COMSOL software, and the distribution position of the counting device is selected. Then, based on the electromagnetic shielding technology, conduct anti-interference technology research on the counting device, adopt the method of combined shielding, compare and analyze the shielding effectiveness of each shielding body, and propose the best shielding scheme. The life counting device works safely and normally. Therefore, the research method in this paper can provide an electromagnetic shielding scheme for the anti-jamming technology of the remaining electronic equipment of the vehicle-mounted electromagnetic gun, and can provide guidance for the design of the vehicle-mounted multi-barrel electromagnetic gun launching system.
Research on the deployment of communication networks in circular areas under field conditions
Authors: Wang Yi , Chen Zhihua
Published: June 2023

This paper provides a solution for the deployment of communication nodes for network coverage in a circular area in a field environment. First, considering the overlapping of communication node coverage areas, two deployment methods are proposed, namely the regular hexagonal and the ring deployment methods, based on deployment from the center of the circle outwards and from the circumference of the circle inwards. Then, the number of nodes required for the regular hexagonal deployment method is derived and proved, and the calculation of the minimum number of communication nodes required for the ring deployment method is given. Finally, the optimal selection interval for the communication radius of the nodes is obtained through simulation, and the selection criteria for the two deployment methods are given based on the ratio of the point communication radius to the radius of the operational area.
Simulation and Experimental Study on Coupling Effect of Fuze under Ultra-wide Spectrum Strong Electromagnetic Pulse
Authors: Lv Sining , Xiao Chuan , Lou Wenzhong , Su Wenting , Zheng Fuquan
Published: June 2023

The lack of anti-strong electromagnetic interference ability of fuze has become an important aspect restricting the effectiveness of weapon system. Taking a certain type of fuze as an example, this paper analyzes the coupling mechanism of ultra-wide spectrum transient strong electromagnetic pulse to the fuze, analyzes the action mode of aperture coupling and field line coupling, establishes the mathematical model of space electromagnetic field, and then simulates the effect of aperture coupling and field line coupling of the fuze by using CST Microwave Studio software. It is concluded that the strongest coupling state is when the polarization direction of the electromagnetic field is parallel to the axis of the fuze. Combined with the theory and simulation, the ultra-wide spectrum transient strong electromagnetic pulse simulation system is used to conduct the strong electromagnetic pulse irradiation test, and the electromagnetic pulse effect threshold is obtained. It is concluded that the effect threshold leading to communication failure is about 27~40kV/m, which provides a certain theoretical and experimental basis for fuse strong electromagnetic protection.
Analysis on reliability evaluation standards of Initiating devices about “duds” checkout efficiency
Authors: Li Fang , Ma Hong , Li Li Ming , Han Xu Dong , Zhang Rui , Liang Ma Hong
Published: June 2023

The detecting efficiency about “duds” is studied by the simulation according to the standards GJB376-1987 and GJB 8185-2015 in this paper. The note and advice are given when the standards are used. The results show that detecting efficiency according to the GJB376-1987 is better than the GJB 8185-2015.
Study on the influence of constraint conditions on the slow cook-off response characteristics of melting and casting explosives
Authors: Zheng-feng Liang , hai Deng
Published: June 2023

In order to study the slow cook-off test response characteristics of melt cast explosive and cast explosives under different constraint conditions, the heating characteristics, ignition characteristics and response law of melt cast B explosive and cast nitrate PBX explosive were studied by using self-designed slow cook-off test device when the ratio of discharge hole area to charge cross-section area Sh/Sc
was 10%, 5% and 0%, respectively. The results show that in the slow cook-off process of two kinds of charge, the shell drain hole can effectively discharge gas or part of explosive before ignition. After ignition, the pressure can be released reliably, the increase of internal pressure in the shell can be restrained, and the intensity of response can be reduced; With the decrease of the size of the drain hole, the reaction intensity increases and the damage degree of the shell increases; When Sh
/Sc
=10, the combustion reaction takes place in both casting charge and casting charge; When Sh
/Sc
=5, the deflagration reaction occurs in the melt casting charge, which first burns and then deflagration reaction occurs in the casting charge; When Sh
/Sc
=0, the fusion charge and the casting charge have explosive reaction; Under the same constraint conditions, the safety of cast explosive is slightly higher than that of cast explosive.
Research on the Control Method of Micro-gas Turbine Power Supply Modulation System for Primary Energy in Electromagnetic Launch Technology
Authors: Shi Yaoling , Li Yalu , Li Zhenxiao , Wan Gang
Published: June 2023

Combining the advantages of micro-gas turbine generation system (MTGS) and power converters, moreover, comparing the various design ideas for the primary energy of electromagnetic launch technology, we design a primary energy to meet the reliability, stability, safety and portable of electromagnetic launch technology. We discuss the control ideas and methods to be adopted in this system, the first step is to output a stable DC bus voltage through rectification, and then to step up the voltage through a series resonant converter to achieve the desired output voltage. Through theoretical analysis and simulation, it reveals the effect of this load on the performance of MTGS, and the parameter optimization design is combined with the voltage outer loop control strategy to achieve the purpose of outputting stable voltage. We used a ARM controller to implement the control of this system to measure the response curve of the system under different input commands. According to the theoretical analysis, numerical simulation and experimental results, the control strategy designed in this paper can better meet the performance index requirements of micro-gas turbine engine (MTE) and power converter as well as the control method is simple and easy to implement in engineering. The results of this paper confirm the feasibility of this primary energy application for electromagnetic launch technology.
Numerical simulation of Non-Lethal Kinetic Energy Projectile Impact on Human Torso Model
Authors: Lu Haitao , Qin Bin , Li Weibing
Published: June 2023

In order to analyse the dynamic response and damage characteristics of human tissues and organs under the non-lethal kinetic energy projectiles, a numerical simulation model of human torso is established based on the Chinese visual human (CVH) data sets. By the dummy established with CVH data sets, the calculation accuracy of movement of human torso impact by non-Lethal kinetic energy projectile of finite element model were validated, and the skin perforation performance were validated by animal test. The non-lethal kinetic energy projectile, which is rubber ball in diameter 8mm and 50 shores hardness, impact on human torso with different velocity were calculated, the dynamic responses of sternum, rib and lung were captured and analysed. The results shows that, if the projectile speed is near the probability perforation velocity, due to the hardness of projectile and structure of organs and ribs, the projectile will rebound no matter the skin is perforation or not, and the vulnerable organ lung may not be damaged. At the same time, the pressure of lungs without skin penetration were significantly higher than skin without penetration, the human damage risk under soft projectiles is greater than hard projectiles when skin with damage but without perforation.
Study on influence of missile-target intersection parameters on damaged steel plate of blast-fragmentation warhead
Authors: Chen Haojie , Yin Jianping , Li Xudong
Published: June 2023

In order to study the damage effect of blast-killing warhead on steel target at different falling velocities and falling angles, AUTODYN-3D software was used to numerically simulate the damage of blast-killing warhead on steel target at different falling velocitis and falling angles using SPH algorithm. The results show that the hole shape of the target plate is quadrilateral when the falling angle is 0°, the hole shape of the target plate is round when the falling angle is 90°, the hole shape of the target plate is circular and fan-shaped when the falling angle is 30° and 60°. At the same falling angle, the hole area of the target plate increases with the increase of falling velocities. At the same falling velocities, the hole area of the target plate increases first and then decreases with the increase of falling angle.
Application and Research of Automatic Ammunition Resupply and Replenishment System for Artillery: A Review
Authors: Meng Fanzhe , Guo Anxue , Qu Wubin , Huang Qiang , Zhang Yao , Zhang Zhenyi
Published: June 2023

Rapid ammunition resupply is important for artillery to enhance combat capability and guarantee combat effectiveness, and the application of automatic ammunition resupply system to artillery ammunition resupply equipment is a hot spot in the current research of logistics ammunition resupply. This paper summarizes the current situation of automatic ammunition resupply vehicle and ammunition self-loading technology of artillery combat vehicles, which has reference significance for understanding the development status of automatic ammunition resupply system of artillery weapons. The research trend of automatic ammunition resupply for artillery is reviewed. It is found that the application of robotic arm is a hot spot for the research of ammunition self-loading technology of artillery combat vehicles, which can be used for reference for the technical direction of automatic ammunition supply and replenishment system for artillery in the future.
Rapid Pressure Hemostatic Drug Delivery and Microsystem Design Based on Battlefield Trauma
Authors: Su Wenting , Sun Yi , Lv Sining , He Bo , Lou Wenzhong
Published: June 2023

The battlefield rapid pressure hemostatic microsystem maximizes hemostasis efficiency. Battlefield wound has the characteristics of rapid blood loss and irregular surface, which needs to be treated in a very short time. The existing rapid hemostasis method has poor efficiency and no sterilization and disinfection effect. Therefore, we reported a wound pressure hemostatic microsystem based on gas generated by rapid chemical reaction. Before the device is used, the two chemicals in the device are isolated. During hemostasis, the flexible device is applied to the wound surface, and the two chemicals in the device are mixed and chemically reacted. And the large amount of gas generated by the reaction causes the balloon in the device to expand and exert lateral and longitudinal pressure on the surface of the wound, so that the wound quickly closed. At the same time, the drug storage unit in the device is under pressure to release the drug to the wound surface. In addition, the chemical reaction of the device has an endothermic effect, which can rapidly cool the wound surface. The lateral and longitudinal pressures of the flexible microsystem in the process of hemostasis were analyzed by numerical simulation. In the experiment, the maximum longitudinal pressure reached 270mmHg, meeting the requirements of surface wound hemostasis.
Study on the three-stage method to calculation scattering parameters of prefabricated fragments along the axis based on energy conservation
Authors: Wang H , ji L , Feng X L , Zhou M X , Teng D
Published: June 2023

To study the axial distribution rules of the initial velocity and direction angle of prefabricated fragments, first, the acceleration process of prefabricated fragments is divided into three stages:"detonation wave acceleration stage”,"metal medium interaction stage” and “detonation product acceleration stage”, to establish the three-stage detonation drive model based on energy conservation, the correction coefficients in the model were subsequently fitted using numerical simulations, finally, the test results are compared with the theoretical calculations of the model. The comparison results indicate: the axial distribution results of the prefabricated fragments initial velocity calculated by the three-stage detonation drive model fit well with the experimental results, and the error is within 100 m/s, and the axial distribution rules of the initial velocity showed a trend of the first increasing and then decreasing, the maximum value of the velocity all appeared at the ratio of the prefabricated fragment distance from the burst core to loading length was 0.7; the three-stage detonation drive model fit the results of axial distribution of the direction angle of prefabricated fragments accurately.
A Multi-machine Jamming Method for Side-lobe Cancellation
Authors: Huang Yi , Yu Jianyu , Su Ruolong , Li Chenzi
Published: June 2023

Adaptive side-lobe cancellation technology is an anti-jamming method commonly used in modern radars. In order to improve the jamming effect, it is necessary to study feasible jamming methods according to its characteristics. By analyzing the principle of adaptive side-lobe cancellation technology, this paper proposes a method that combines multi-directional jamming and correlated jamming. In order to verify the feasibility and advantages of this method, the simulation and analysis of the multi-machine interrupted-sampling cycle repeated jamming pattern signal against side-lobe cancellation system are carried out.
The improved thermal and mechanical properties of polyurea nanocomposites with SiC
Authors: Liu Q , Zhai H B , Xiao Y , Zhao J Q , Qiu X J , Mao B Y
Published: June 2023

Polyurea as one kind of polymer is widely used in the field of protective under blast and impact loading. Polyurea matrix with nanofillers has superior mechanical properties than the pure polyurea. In this work, in order to develop polyurea with thermal stability and high mechanical properties, using Silicon carbide (SiC) as the nanofillers, polyurea nanocomposites with different content of SiC nanoparticles were prepared via in-situ polymerization method. The morphology and structure of SiC/polyurea nanocomposites were characterized by using SEM, XRD and FTIR. From the structure studies, the nanofillers of SiC had not altered the basic structure of polyurea. Thermal stability and mechanical properties were also studied by TGA and tensile testing machine, respectively. The results indicated that the incorporation of SiC nanoparticles (1.5 wt%) into polyurea could obviously improve thermal properties and mechanical properties in comparation with the pure polyurea. The enhancement of performance is relative to SiC nanoparticles reinforced polyurea matrix and high temperature properties of SiC. At higher content of SiC, the mechanical properties of SiC/polyurea nanocomposites tend to decrease. It can be inferred from the results that SiC/polyurea nanocomposites have the potential for using in protective structures.
Study on the relationship between the design parameters of bridge wire electric initiating devices and the electrothermal response curve
Authors: Zhang Jing Xin , Li Li Ming , Ci Fu Xin , Bai Bing
Published: June 2023

The parameter settings of the transient thermal response test conditions of bridge wire electric initiating devices are studied. The effects of bridge wire resistance parameters and charge pressure on the electrothermal response curve were explored. The results show that when the state of the bridge wire and the surrounding agents are basically the same, the electrothermal response curve can clearly reflect the difference in the resistance of the bridge wire. The larger the bridge wire resistance, the more sensitive the bridge wire to the electrical pulse, and the charging pressure parameters also have a significant impact on the electrothermal response curve. The smaller the charging pressure, the more sensitive the product electrothermal response. When the density of the agent is basically the same, the approximate response curve and parameter calculation results can be obtained.
Numerical Simulation of Shock Wave Damage to Medium-Range and Long-Range Targets
Authors: Wang J T , Hang G Y , Shen H M , Liu Z Y , Xue H J , Wang T , Yu W
Published: June 2023

In order to accurately analyze the effect of a shock wave on a missile launch vehicle as a whole and on its components when the launch vehicle is at a medium or long distance from the detonation center, a simulation method based on the empirical algorithm and numerical analysis was carried out in this study. The method significantly reduced the computational cost while ensuring computational accuracy. Based on the simulation method, a finite element model for a typical missile launch vehicle was established that consisted of 2.5 million elements. Based on the structured arbitrary Lagrangian-Eulerian method and the fluid-structure coupling algorithm, it took the model only a few hours to simulate the second-level physical process. Next, a shock wave load model was built with a 2000 kg TNT equivalent detonation condition, and the degree of damage to the launch vehicle within 25–45 m from the detonation center was analyzed. The results showed that the joint action of the shock wave overpressure and the dynamic pressure was the main source of damage. Specifically, the missile launcher, the cab, and the fuel tank were the key vulnerable parts. The effective damage radius of the 2000 kg TNT equivalent detonation to the missile launch vehicle was 35 m.
A Study on Numerical Analysis of High-Temperature And Oxidation Damage of C/C Composites
Authors: jiaxing Li , hongying Xu , fanfan Zhang , hua Gao
Published: June 2023

Due to coupling of oxidation damage and mechanical damage,failure mechanism of C/C composites is complex under high-temperature and oxidation environment.In this paper,establishment of cumulative damage analysis method is based on coupling of oxidation damage and mechanical damage.Based on this method,high-temperature and oxidation damage model of C/C composites is established: Initial damage criterion and degradation mode of stiffness in mechanical damage model are modified by oxidation state parameter;Diffusion coefficient of oxygen in oxidation damage model is modified by mechanical damage parameter.Through joint simulation of multiple physical fields of MATLAB and ABAQUS,oxidation damage and mechanical properties of C/C composites under high-temperature and oxidation environment are studied,which has a certain reference significance for structural failure prediction of C/C composites.
Numerical analysis of initial cloud of powder dynamic dispersion
Authors: Zongshu Mei , Peng Chen , Jianghai Liu
Published: June 2023

Numerical simulations were performed to investigate the explosion dispersion characteristics of powder materials with respect to the implicated velocity, and a fluid–solid coupling simulation model of the explosion dispersion process of the initial cloud was established. Explicit dynamics models of Finite-element method and smooth particle hydrodynamics for the detonation driving stage of central charge and the cloud isentropic expansion stages were developed, the pressure loads of the explosive-driven were generated using the user-defined function program, and computational fluid dynamics models for the isentropic expansion and free expansion stages of the initial cloud were developed. Additionally, the maximum expansion radius of the cloud in explosion dispersion tests and theoretical calculations were compared with the radius in the numerical simulation results to verify the accuracy of the simulation model. Analyses of the morphology, concentration, and turbulence field in the numerical simulation revealed that vortex stratification occurred in the “two wings” of the initial cloud in its development process and that a particle-free “hollow” area is subsequently formed. Analyses also revealed that the vortex stratification occurs earlier as the implicated velocity of powder material increases. Additionally, an increase in the implicated velocity can effectively weaken the concentration of cloud and make the distribution of cloud particles more uniform.
Influence of Micro Initiation Train parameters on critical detonation thickness of medium
Authors: Liu Lan , Liu Wei , Ken-xin Yu
Published: June 2023

In this paper, copper azide of 2mm in diameter was exerted as the burster, and the study object was the micro initiation train of Cl20-based explosive that generated by flyer plate impacting the medium in the accelerating chamber. Results shows that: the thickness of critical burst increased with the thickness of flyer plate.Simulation calculation and experimental verification were conducted to study the parameter influence of flyer plate and accelerating chamber on the critical burst thickness of medium. which could serve as a reference for the design of MEMS products. The larger diamete of accelerating chamber was conducive to forming the stable detonation inside the explosive, and the critical burst thickness of the medium increased accordingly.The thickness of critical burst increased with the length of acceletating chamber.
Study on the cylinder test of aluminized explosives with different content of Al powder
Authors: Yuan Xiaoxia , Ma Hongliang , Zhang Lei , Li Fang
Published: June 2023

To investigate the effect of the content of Al powder on the acceleration ability of the aluminized explosives, a series of 25mm cylinder experiments was conducted, and the content of Al/LiF powder is 0%, 15%, 30%. The radial expansion velocities of the cylinder wall were measured through the Photonic Doppler Velocimetry (PDV) system. The cylinder experiments verify that Al powder could react with detonation products to release energy, which enhance the accelerating ability of explosives. By comparing the different content of Al powder of aluminized explosives, it is found that the accelerating ability of aluminized explosives is related to the content of Al powder, and the optimal content of Al powder is 15% in this experiment. By comparing the same content of Al/LiF powder, it is indicated that the reaction delay time of Al powder in RDX80/Al15 explosive does not exceed 2.8µs, and as RDX65/Al30, the reaction delay time is less than 3µs. Finally, through normalization method, the specific reaction delay time of Al powder are 0.147 and 0.203, with the content of Al powder 15% and 30%.
Regioselective introduction of 1,2,4-triazole into 1,2,3-triazole on N2-position with low sensitivity
Authors: Wang Xudong , Zeng Zhiwei , Huang Wei , Tang Yongxing , Liu Yuji
Published: June 2023

Resolving the regioselectivity of N-position on nitrogen-rich heterocycles is an important task in the synthesis of high energy density materials (HEDMs). In this work we developed a simple two-step route to introduce 1,2,4-triazole into 4-nitro-1,2,3-triazole on N2-position, which shows excellent regioselectivity. The target compound 4-nitro-2-(1H-1,2,4-triazol-3-yl)-1,2,3-triazole (3) was characterized by IR, multinuclear NMR, single crystal X-ray diffraction and DSC. Compound 3 exhibits a high thermal stability (T
m = 210 °C, T
d = 230 °C). It also shows good detonation performances (D
v = 7094 m s−1, P = 19.0 GPa) with low mechanical sensitivities (FS > 360 N, IS > 20 N). As a result, compound 3 has a potential as a novel insensitive explosive.
Effects of aluminum on combustion characteristic of HTPE propellants
Authors: Liang Bei , Zhang Ning , Liu Changyi , Xia Min , Zhang Weihai , Gao Xifei
Published: June 2023

The surface morphology of four kinds of aluminum powders with different particle sizes was observed by scanning electron microscope (SEM), and the effects of four different particle sizes of aluminum powder on the combustion performance of HTPE propellant were studied by means of underwater acoustic emission method, differential sanning calorimetry and high-speed photography. The results show that the smaller the particle diameters of aluminum powder, the higher the burning rate pressure index of HTPE propellant, and its pressure index will increase from 0.26 to 0.48 in the pressure range of 5-11MPa. And as the particle size of aluminum powder decreases, the combustion activation energy shows a decreasing trend. When the pressure increases from 2MPa to 4MPa, as the particle size of the aluminum powder decreases, its specific surface area increases, the reaction activity becomes higher, and the aluminum powder combustion performance becomes more intense and sufficient, the maximum combustion flame temperature of the propellant increased from 2375°C~2403°C to 2425 °C ~2482 °C, respectively, and the overall flame temperature fluctuation range was relatively small.
A PBX Modeling Powder Compressibility Evaluation Method Based on Energy Description
Authors: Yuan H W , Yan X L , Zhu X Y , Zhan C H , Tang W , Zhao L , Dong T B
Published: June 2023

In view of the lack of comprehensive consideration of the pressing process in the existing Polymer Bonded Explosive (PBX) powder compressibility evaluation method, the re-analysis of the pressing process is firstly carried out, and the loading and unloading section in the pressing process should be simultaneously considered during the PBX modeling powder compressibility evaluation. Based on this idea, a specific energy method for rapidly evaluating the compressibility of PBX modeling powder is proposed through energy description. This method comprehensively considers the pressing and unloading process, and the compressibility factor can be obtained only by simple integration. Using the experimental data of four typical PBX modeling powders under the same process conditions, the correlation coefficient between the compressibility coefficient and the compaction density reached 0.993, which verified the correctness of the prediction of the density of compaction by the specific energy method.
Research on aluminum agglomeration characteristics of Al/NEPE propellant
Authors: Chengyin Tu , Xiong Chen , Yuqian Zhuang , Fan Chen
Published: June 2023

Adding aluminum particles to solid propellants is used to improve the energy density of the propellant and the specific impulse of the engine. However, the aluminum particles will agglomerate to form large-sized condensed combustion products, which can cause nozzle erosion and two-phase flow loss. Therefore, it is necessary to study the aluminum agglomeration characteristics of solid propellants. In this paper, the combustion process of the Al/NEPE propellant was recorded by a high speed camera and a fiber optic spectrometer, and the condensed combustion products of the propellant were collected. The microstructure of the condensed combustion products was analyzed by a scanning electron microscope coupled with energy dispersive (SEM-EDS). These results show that the agglomeration process of aluminum particles may go through three stages: accumulation, aggregation and agglomeration. The condensed combustion products are mainly divided into aluminum agglomerates and smoke oxide particles. Generally, the size of agglomerates exceeds 50 μm, while the size of smoke oxide particles is less than 1 μm.
Effect of current intensity on properties of the carbon fiber fabric and composites
Authors: Wang Z Y , Chen G , Wang Q F , Yu Q Q , Qi F J , Kong G Q
Published: June 2023

The carbon fiber fabric was electrified at the current intensities of 4 A for 1 h, 8 A for1 h, 16 A for 1 h and 16 A for 2 h, and then the carbon fiber reinforced epoxy composite laminates (CF/EP) were prepared. The effects of different current intensities on the surface temperature of the carbon fiber fabric, the micro morphology of the carbon fiber, the mechanical properties of CF/EP composites and the fracture morphology of the tensile specimens were studied. The significance of the effect of current intensities on the mechanical properties of CF/EP was investigated by means of quantitative statistical analysis. The results show that the maximum surface temperature of the carbon fiber fabric during heating is 115 °C ~125 °C; At significance level α= 0.01, the mechanical properties of CF/EP composites were not significantly affected by different current intensities; The surface micro morphology of the carbon fiber fabric treated with current intensity of 4 A for 1 h, 8 A for 1 h and 16 A for 1 h was not significantly different from that of untreated. After current intensity of 16 A for 2 h, the surface grooves were deepened and the surface granular protrusions were increased; No obvious difference was observed in the fracture morphology of samples with different current intensity. The results show that in the self heating process of carbon fiber composites, when the current intensity of single-layer carbon fiber fabric is less than 16 A and 2 h, it will have no significant impact on the properties of the composites.
Effect of heat treatment process on microstructure and properties of depleted uranium No.2 alloy
Authors: Zhifei Yan , Ping Gao , Xinmin He , Xiaodong Bai
Published: June 2023

By controlling the heat treatment temperature, the influence of aging process on the microstructure and mechanical properties of depleted uranium No.2 alloy was studied, and the dynamic properties of No.2 alloy were analyzed by Hobkinson device, and the stress-strain relationship was tested. The results show that, after solution treatment at 850 °C × 2h and aging treatment at 350 °C × 4h, the microstructure of No.2 alloy is mainly U(γ) phase and U (α /), and the dynamic yield strength of the alloy reaches the peak, which can reach 1580MPa, which is more than 40% higher than the quasi-static yield strength and has a strong strain rate hardening effect.
Fabrication and Mechanical Properties of FeAl Metal-Intermetallic Laminated (MIL) Composite
Authors: Lu Xiaonan , Wang Yu , Peng Xiangfei , Zhao Wenjuan , Xu Hong
Published: June 2023

With the rapid development of science and technology, the requirements for material performance in fields such as defense and military industry are getting higher and higher, and it is becoming more and more difficult to meet multiple performance requirements with a single material at the same time. Inspired by the special structure of shells, Metal-Intermetallic-Laminated composites (MIL) with composite, low-cost, and multifunctional properties have been prepared to combine the performance advantages of each component to achieve properties that cannot be achieved by a single material. In this paper, Fe/FeAl laminated composites were prepared by stacking pure Fe foil and pure Al foil alternately and using a vacuum hot-pressure sintering process to first consume all the Al layers by reacting at 655°C for a period of time, and then ramping up to 950°C for high-temperature annealing with different holding times. The microstructure and phase composition were analyzed by SEM and EDS, and the static and dynamic compressive strength and failure strain of the laminated material were measured by a universal testing machine and Hopkinson rod.
Effect of Pb on microstructure and mechanical properties of Tin Babbitt alloy
Authors: Ren Xiaoyan , Chen Ningning , Zhang Guowei , Xu Hong , Zhang Yougui , Shi Zhenhua , Zhaojie Wang , yijun Liu
Published: June 2023

This paper mainly studies the microstructure and properties of babbitt alloys, and analyzed the influence of lead on the microstructure and properties of the alloys by adding alloying element Pb, The results show as follows:with the increase of Pb content, the hardness of ZSnSb11Cu6 alloy first increases and then decreases. The maximum at 0.75% is 26.96HB. The tensile strength and elongation showed a trend of rising, then falling and then rising, and the mechanical properties were relatively high at 0.35%.The addition of Pb changes the morphology of Cu6Sn5 phase. With the increase of lead content, the β phase decreases and then grows, and the needle-like η phase dendrite grows.