bluuebunny/crossref_metadata_2025 huggingface dataset:
Early corrosion properties of titanium alloys, Ni-based alloys and stainless steel in supercritical water oxidation of sewage sludge
Authors: Yan Lijun , Xu Yaofeng , Fan Binning , Wang Daye , Xu Donghai
Published: June 2023

Supercritical water oxidation (SCWO) can efficiently and harmlessly dispose sewage sludge, while corrosion phenomena can lead to rapid shutdown and/or failure of expensive process equipments in a supercritical water system. The corrosion behavior of titanium alloys, Ni-based alloys and stainless steel exposed in supercritical water oxidation of sewage sludge at 450 °C, 26 MPa for 60 h was investigated by means of gravimetry, scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction. 316 SS (stainless steel) showed the highest corrosion rate, while TA10 had the lowest corrosion rate. The oxide scale on the surface of 316 SS contained magnetite and FeCr2O4, while Cr2O3 and NiCr2O4 were the main components of oxide layer on Inconel 600. Among them, magnetite and NiCr2O4 mainly existed in the inner oxide layers of SS 316 and Inconel 600, respectively. The lack of Cr2O3 on the 316 SS surface resulted in severe pitting corrosion and poor corrosion resistance.
Hybrid feature extraction method of MFCC+GFCC helicopter noise based on wavelet decomposition
Authors: Hu Wen-long , Feng Shun-shan , Zhang Bo , Gao Yue-guang , Xiao Xiang , Qi-Huang
Published: June 2023

Aiming at the issue that the recognition accuracy of traditional acoustic signal features is low for helicopter acoustic signals with wind noise in the near field, a method of extracting mixed noise features of MFCC+GFCC based on wavelet decomposition is proposed. Firstly, the three-layer wavelet decomposition and reconstruction are applied to the helicopter acoustic signals; then, the Mel-Frequency Cepstral Coefficients (MFCC) and Gammatone-Frequency Cepstrum Coefficient (GFCC) are respectively extracted for the approximation and detail components; next, the coefficients of detail components which are averaged are combined with those of approximation components to form the hybrid feature parameters; finally, the convolutional neural network is used to classify the signal, to realize the correct recognition of helicopter acoustic signals. Experimental results show that the recognition accuracy is improved by almost 40% in contrast with other traditional methods, such as MFCC and GFCC, when the SNR is equal to -5dB. Further, When the SNR is -10dB, the recognition accuracy is more than 49%, while the traditional methods cannot effectively recognize the helicopter acoustic targets. The proposed feature extraction method can significantly improve the recognition accuracy in the low SNR environment, and provide a reference for near-field detection and recognition of helicopter acoustic targets.
Research on strain testing technology of electromagnetic railgun’s abnormal barrel
Authors: Li Shili , Qin Peiyu , Yang Weixi , Fan Wei
Published: June 2023

Aiming at difficult strain test and unable to accurate strain test for electromagnetic railgun’s special-shaped barrel bore, the strain testing technology of special-shaped barrel was studied. According to electromagnetic railgun strain test characteristics analysis, the back of the rail and the back of insulation support plate are selected as the strain test points, FBG(Fiber Bragg Grating) stain sensor is embedded along the circumference of the barrel to obtain the special-shaped barrel true stain value. At the same time, in order to comparison, The papers studies the rail’s strain simulation technology for electromagnetic railgun, the simulation result is accordance with strain test result, show that stain measurement method is feasible, and measurement results is reliable. The research results can provide data support for location to position of projectile in the special-shaped barrel bore by strain feature.
Study on microstructure of rare earth Mg-9%Gd-2%Y-3%Nd -0.7%Zr alloy and properties of micro-arc oxidation films
Authors: Yang Xiaoyu , Qi Guo , Tang Shengming , Zhang Lijun , Chen Gang , Dong Jiajing , Kai Liu , Xu Hengqiu , Duan Xiuchao , Wang Yongxu
Published: June 2023

The micro-arc oxidation protective film has been prepared on the surface of Mg-9%Gd -2%Y-3%Nd-0.7%Zr alloy by using the microarc oxidation technique of “step by step depressurization”. The microstructure of magnesium alloy substrate and micro-arc oxidation film were measured by OM, SEM and XRD, and the properties of the film were evaluated by electrochemical test of film thickness and surface morphology. The results show that the discontinuous network multiple eutectic phases are distributed in the grain boundary and there are dispersed-granular precipitates in the alloy matrix. After the micro-arc oxidation treatment, the thickness and corrosion resistance of the micro-arc oxidation film increased with the increase of oxidation time, and the surface micropore size increased first and then decreased, and the surface morphology of the micro-arc oxidation film changed from no micro-crack to micro-crack, and finally the micro-crack disappeared.
Validity analysis of outdoor evacuation signs based on eye movement behavior
Authors: Liu Xinyan , Jiang Fan , Shi Jiguang , Ding Ning
Published: June 2023

In recent years, with the rapid economic development, people’s spiritual needs are also increasing, and more and more concerts and sports games appear in public life. However, these activities have great potential risks, and the frequent occurrence of security incidents poses a great threat to the safety of the city and the public. How to evacuate quickly and effectively has become an urgent problem to be solved. Studies have shown that during emergency, people show herd behavior during evacuation, and do not necessarily follow evacuation signs. In this paper, through simulated evacuation experiments, combined with eye movement technology, this paper studies the influence of the direction of evacuation signs and disturbing crowd on the validity of evacuation signs during the evacuation process. And the processing and analysis of the experimental data has certain reference significance for the related research on the validity of evacuation signs.
Key Technologies of Collaborative Target Detection between Self-propelled Anti-aircraft Weapons
Authors: Tianbao Ding , Chenxi Bao , Zhiwei Lin
Published: June 2023

In the case of a lack of target information, a self-propelled anti-aircraft weapon can complete its own combat functions by using the detection information of other vehicles through detection coordination technology. When using the detection coordination technology to process the detection information of other vehicles into information that can be used by the vehicle, the relative position and attitude of the vehicle and data transmission delay will affect the accuracy of the processed target information. With the system of detection collaborative technology expounded, emphasis is attached to the research on the detection coordination method based on pure angles without considering distance. A mathematical model of detection coordination technology is created, the approximate statistical law of the processed detection coordination information is obtained through the Monte Carlo method, and the influence of various factors on transmission error analyzed. In addition, the polynomial curve fitting method is used for time alignment, and the unscented Kalman filter method based on singular value decomposition adopted to reduce the information transfer error. The simulation results show the the method is effective for that end.
Thermal Analysis and Optimal Design of Artillery Integrated Electronic Case Based on FloEFD
Authors: Zhang Zhipeng , Li Zhong , Cui Haohao , Guo Jiachen , Liu Yanfeng
Published: June 2023

With the highly integrated artillery integrated electronic system, the power density in the integrated electronic chassis has risen sharply, and the temperature has also risen sharply. In order to solve the heat dissipation problem of the artillery integrated electronic case, this article firstly designs the artillery integrated electronic case according to the technical requirements, and uses heat density calculation and heat dissipation simulation technology to model and simulate the heat dissipation of the artillery integrated electronic case. According to the simulation results, conduct thermal analysis and optimization design of the chassis, and finally conduct a temperature test experiment with an infrared imager. The experimental results show that the heat dissipation simulation method can reflect the heat dissipation of the chassis more accurately and effectively, and lays a technical foundation for the application of temperature digital twin technology in the integrated electronic system of artillery.
Fatigue crack propagation in thick-walled pressure vessels under hydraulic testing condition
Authors: Wu B , Zheng J , Bai X L , Si D Y , Luo T F , Zou Z Q
Published: June 2023

Fatigue is one of the failure modes in gun barrel. It is still an important problem to understand crack propagation behavior due to fatigue loading of firing cycles. This paper presents a hydraulic fatigue test method to simulate crack propagation in a tube containing a pre-machined defect on its inner surface. A close inherent relation is found between crack propagating rate and hoop strain on the outside surface of the tube, which provides a feasible approach for investigation of fatigue behavior in gun barrel under actual firing condition.
Simulation Study on Jet Formation and Penetration Capability of Double-layer Cylinder-cone Shaped Charges with Different Outer Liner Materials
Authors: Wang Yifan , Wang Zhijun , Xu Yongjie
Published: June 2023

In order to discuss the effect of different outer liner material on the performance of the double cylinder-cone shaped charge, the nonlinear dynamics software Autodyn-2D was used to carry out numerical simulation, and the jet shape and penetration of steel target were analysed when copper, nickel, tungsten, tantalum and steel were used as outer liner materials and copper was used as inner cover material. The result shows that the jet head is formed by the cylindrical part of the inner liner, and all the outer liner forms a slug. The total length of the projectile is the longest when the outer liner material is copper. The jet head velocities are the biggest when the outer liner materials are nickel and steel 4340. The shaped charge with copper outer liner yields much longer depths.
Analysis of rain effects on millimeter wave fuze ground-echo characteristics
Authors: Yang Bing , Wu Kaiwei , Guo Zhe , Huang Zhonghua
Published: June 2023

Due to the wide antenna beam of the ground fuze and the similar size between the millimeter wave wavelength and raindrop particles, the ground millimeter wave fuze will suffer from serious rainfall interference in the rainfall environment, which greatly affects the accurate ranging performance of fuze. In this paper, we establish ground target echo signal model in the rain condition, and analyze the effects of target distance, rainfall and frequency on the ground millimeter wave fuze in rain. The results provide theoretical basis of anti-rain interference for millimeter wave fuze.
Research on Cooperative Strategy Guidance Based on Game Theory
Authors: Xin Wang , Xinghua Wang , Junjie Gong , Yao Lu
Published: June 2023

Multi-missile cooperative combat refers to the joint execution of the same combat task through the cooperation and cooperation between multiple same missiles or multiple different missiles. As the combat environment of the future battlefield becomes more and more complex, not only the precision guidance performance of the missile itself can be continuously improved, but also the cooperative operation of multiple missiles is needed to maximize the effectiveness of group combat. In this paper, the cooperative guidance strategy of multi-to-one interception problem will be studied again according to the game theory. According to the establishment of multi-to-one missile-target game model, the strategy set of missile and target is determined. Then according to the multi-to-one missile-target game model, the system equation is determined, and the cooperative guidance strategy is obtained by calculating the results. Finally, the simulation results are analyzed to further verify the effectiveness of the cooperative interception guidance law based on this method.
Simulation study on penetration depth of spherical fragments into concrete
Authors: Wang Zhening , Yin Jianping , Yi Jianya , Li Xudong
Published: June 2023

In order to study the influence of different spherical fragments on the penetration depth of concrete targets, AUTODYN-2D software is used to model and simulate the penetration of fragments with different diameters, materials and velocities. Through the analysis of penetration depth data, it is found that the penetration depth of tungsten alloy fragments will not continue to increase at higher speeds (when v > 1400 m / s, the penetration depth of tungsten alloy fragments begins to decrease). The process of spherical fragment penetrating concrete is analyzed, and the relationship between the penetration depth and the velocity, diameter, material parameters and concrete strength of spherical fragment is clarified. The simulation results show that the penetration depth curve parameters of different materials are quite different, due to the high utilization rate of tungsten alloy fragments, the calculation formula of penetration depth of tungsten alloy spherical fragments with respect to fragment parameters is obtained by fitting the penetration data. The penetration depth of tungsten alloy spherical fragments under different diameters and velocities can be predicted accurately by this formula.
Optimization design of cartridge adapter based on launch dynamics
Authors: Yunpeng Du , Zhaoyong Li , Ziqiang Wang , Zhiyong Zhao , Jing Zhang , Meijie Du , Yan Zhang , Liqiong Zhang
Published: June 2023

To study the influence of the cartridge adapter on the initial disturbance of the rocket shell launch, the dynamic simulation model of the interaction between the cartridge and the storage and distribution box during the rocket shell launch is established. With the aim of reducing the initial disturbance, the structure optimization and design parameters of the cartridge adapter are obtained fro m the dynamics simulation optimization analysis of rocket shell launch. The optimization results suggest that the number and layout of the cartridge adapter can greatly reduce the initial disturbance to launch and the optimization of cartridge adapter can greatly reduce the initial disturbance to rocket shell. The optimization method and results can provide reference for the design of rocket shell.
Review of Live-Virtual-Constructive Simulation Technology
Authors: Liang Yuxin , Wang Xiaoguang , Yue Tong , Xu Shuo , Yao Chuang , Liu Dongxing , Liu Qi
Published: June 2023

With the improvement of network communication technology, creative computer simulation architectures and today’s cutting-edge hardware, the live-virtual-constructive (LVC) simulation technology gradually matures adequately to synthesize joint heterogeneous systems. Firstly, the development of typical LVC architectures and their key technologies are analysed, such as Advanced Distributed Simulation (ADS), High-Level Architecture (HLA), Test and Train Enabling Architecture (TENA), Joint Simulation Supporting Platform (JoSim) and so force. Then, applications in the field of US and Chinese military are reviewed, as well as cases in air combat training and other scholarly research concept. Finally, a summary of LVC technology is given, and the development trend of military LVC simulation technology is predicted to explore the specific content that needs to be studied.
Study on Applicability of Phase Field Method in Quasi-Static Fracture Behavior Simulation of PBX Components
Authors: Yuan H W , Chen Y L , Tang W , Li Y X , Zhao L , Dong T B
Published: June 2023

Crack in polymer bonded explosive (PBX) components will influence the safety and reliability of weapon system. In order to accurately simulate the quasi-static fracture behavior of PBX components, the quasi-static arc Brazilian experiment of PBX explosive was carried out first. Then, the phase field method (PFM) and the traditional extended finite element method (XFEM) are used for the comparative simulation of the arc Brazil test process, in which both the maximum principal stress and the maximum principal strain initiation criterion are used in XFEM simulation. The calculation results show that the relative error of failure load calculated by PFM is small (less than 1%), while the error of XFEM calculation is large (the error of strain criterion and stress criterion are -61% and 42% respectively). Meanwhile, the fracture initiation locations calculated by PFM are located at 1/4 and 3/4 away from the end face of the Brazilian sample, which is in good agreement with the experimental results. In addition, PFM avoids the problems of crack mutation and discontinuity in XFEM. The results show that the PFM can accurately calculate the quasi-static fracture behavior of PBX components.
Simulation study of flushing ablation by gas-solid two phase flow of artillery barrel
Authors: Yan Lijun , Xu Yaofeng , Zhu Wenfang , Wang Daye , Xu Donghai
Published: June 2023

For the wear problem of artillery barrel bore during artillery launching, this work uses particle erosion and deposition modules in Fluent Software to simulate the erosion process of gunpowder gas particles on artillery barrel, analyses steady and transient states simulation results, and compares the effects of different influencing factors on barrel bore wear. The results showed that in a certain range, the erosion rate of barrel bore wall was positively correlated with particle velocity and mass flow. 0.25 mm was a critical particle size, and the erosion rate decreased with the increase of particle diameter. This information is valuable for prolonging the service life of artillery barrel.
Real-time signal processing method of ultra-wideband fuze using LSTM
Authors: Wu Ji , Liu Chunhua , Li Tie , Hao Shijun
Published: June 2023

The extraction of target features from the ultra-wideband (UWB) fuze echo signal and target recognition and distance determination are the key to controlling the precise detonation of the fuze. In this paper, a real-time signal processing method of UWB fuze based on Long Short-Term Memory (LSTM) network is proposed. The time domain and frequency domain features of echo signal are recognized through a small-scale LSTM network. Matlab is used to build the network model and simulation results show that the method can effectively avoid noise interference, correctly recognize the target signal, and avoid false alarm.
Study on microcharge design and output performance test
Authors: Yanlan Wang , Fang Zhang , Ruishan Han , Feipeng Lu , Shaoqun Li
Published: June 2023

Taking copper azide microcharge as research object, PVDF piezoelectric sensor was used to test the detonation pressure of copper azide microcharge and the detonation pressure of titanium flyer driven by copper azide microcharge explosion respectively. The effect of titanium flyers on the output performance of copper azide microcharge was investigated. The research results shown that: different microcharge structure parameters affected charge weight, and the charge weight directly affected the output pressure. The output pressure of copper azide microcharge to drive titanium flyer is much greater than the output pressure of copper azide microcharge. Titanium flyer driven by copper azide microcharge explosion, which could play the role of energy gathering and amplification.
Method and apparatus for automatic high-throughput synthesis of energetic salts
Authors: Wang Qiuxiao , Wang Tao , Zhou Yifei , Gao Haixiang
Published: June 2023

Energetic materials can instantly combust and release a large amount of energy in responding external impulses. Due to its energy characteristics, it has a wide range of practical applications: military and civilian. Designing high-energy-density materials with better performance, lower sensitivity, and more environmental friendliness has become a hotspot in the field of energetic materials in recent years. Energetic salts are formed by acid-base or metathesis reactions of different types of anions and cations. Energetic salts are a new class of energetic materials which were developed in recent years. Usually, they have high nitrogen content, high enthalpy of formation, high detonation performance, are relative stable to external stimuli, and have a wide range of application prospects in the fields of new explosives: low characteristic signal propellants, gas generators, low smoke or smokeless pyrotechnics. The synthesis method of energetic salts is simple, and the types of energetic materials are greatly enriched. This research takes energetic salts as the synthesis target and adopts multi-channel automation technology for high-throughput synthesis, which can improve the efficiency, reduce labor costs, and greatly increase the synthesis speed, which is of great significance for accelerating the synthesis of new energetic salts.
The Influence of Propellant Deterrent Concentration Profile on Combustion Performance
Authors: Gou Yong-liang , Li Zi-chao , Bian Xiao-yu , Tian De-qing , Lv Hao , Wang Jia-peng
Published: June 2023

This paper builds a theoretical model concerning the influence of deterrent concentration profiles on the combustion performance of spherical propellants and identifies the effects of deterrent diffusion depth (A) and combined strength of deterring (P) on propellant Γ~Ψ curves. In addition, a calculation method for quantitatively comparing the combustion progressivity of Γ~Ψ curves is presented. The results show that the percentage of the propellant burned corresponding to the maximum gas generation intensity Ψmax has a good linear relationship with both the parameters P and A, with a correlation coefficient of 0.986 and 0.982, respectively. The progressivity index is non-linearly associated with deterrent diffusion depth A, but linearly associated with the combined strength of deterring P.
Effect of CuO powder on the combustion and micro-explosion of Mg and Al12Mg17 particles
Authors: Xie Xiao , Zhang Yan , Hua Jian , Jian Chang
Published: June 2023

In this paper, the effects of CuO powder on the combustion and micro-explosion characteristics of Mg and Al12Mg17 were studied. A laser was used to ignite particles and a high-speed micro-camera was used to record the particle ignition, flame propagation, combustion and particle changes before and after micro-explosion. Moreover, emission spectra during combustion and combustion products were analysed. The results show that the addition of CuO contributes to the micro-explosion of Mg particles during combustion, but it is not conducive to the micro-explosion of Al12Mg17 particles. Meanwhile, whether Al12Mg17 particles or Al12Mg17/CuO particles, the radiation peaks during combustion mainly correspond to Mg or MgO, which means that the addition of CuO cannot promote the gas phase combustion of Al in Al12Mg17.
Study on anti-infrared performance of organohalogen polymer smoke agent
Authors: Zhang Mingxing , Zhu Chenguang , Wang Yikai , Li Jingwei , Liu Feifan , Tang Jingshuang
Published: June 2023

Presented herein is an experimental study on the organohalogen polymer smoke agent. In smoke box experiment, the transmittance of smoke agent at 3-5 μm and 8-14 μm was used as the index, the effects of each factor on the anti-infrared performance of smoke agent were analyzed by orthogonal test method. The results showed that the main factors affecting the extinction properties of the organohalogen polymer smoke agent in the infrared band were zinc magnesium mass ratios of Zn-Mg alloy powders, Particle size of Zn-Mg alloy powders, and types of organohalogen polymer, and the secondary factor was the organohalogen polymer mass ratio. The transmittance of the best organohalogen polymer smoke agent composed of 30% Zn-10%Mg alloy powder (>325mesh), 50% CP-70, and 20% KClO4 to the 3-5μm and 8-14μm bands is 27.67% and 58.07%, respectively, and the corresponding TOP is 93.82 m2·kg1 and 39.69 m2·kg1. The combustion of the smoke agent composed of Zn-10%Mg alloy powder and Zn powder was compared in combustion experiment. The smoke agent composed of Zn-10%Mg alloy powder instead of Zn powder has a faster burning speed, larger burning flame area, and higher temperature.
Tailorable Energetic Behavior of Al/Ti/CuO Composites
Authors: Chang Y K , Zhao W J , Ren W , Nie J X , Wei C Q , Zhang H L , Zen X
Published: June 2023

Aluminum (Al)/Copper oxide (CuO) are mostly common thermites in energetic materials. However, the ignition and combustion of Al/CuO are constrained by the oxide shell coating on the Al core. Titanium (Ti) nanoparticles have been incorporated into Al/CuO system to tune their energetic behavior. The reactivity and combustion heat of Al/Ti/CuO ternary composites have been measured via combustion cell and calorimetry, respectively. The pressurization rate of Al/30% Ti/CuO (the molar percent of Ti in the fuel is 30%) and Al/70% Ti/CuO is 1 and 1.5 times greater than Al/CuO. Consequently, Ti nanoparticles are promising candidate for enhancinging the reactivity of Al/CuO thermites. The results also suggest that Ti nanoparticles could be employed as useful additive in Al-based thermites to tune their combustion behavior.
Initiation of PETN and HNS-IV Explosives by Laser Driven Al Flyer Plate
Authors: Aifeng He , Enyi Chu , Bo Jing , Chunqiang Cao , Jianhua Chen , Jia Zhao , Minjie Diwu
Published: June 2023

Initiation experiment of Pentaerythritol Tetranitrate (PETN) and Hexanitrostilbene IV(HNS-IV) explosives by laser driven flyer plate is conducted. By using an optimum selection of 5μm Al flyer and φ0.5×0.3 metal barrel, the explosive samples of about 1μm mean grain size and 90% theoretical maximum density(TMD) in a metal case are detonated successfully. The PETN has a much lower critical firing laser energy than HNS-IV, which is in accordance with the electrical slapper exploding practices. The much lower critical firing laser energy of the explosives makes it possible for safe transmission of laser by a fiber optic line with the core diameter no more than 600μm, and in turn makes it possible for the use of optical detonation technique in multipoint synchronous initiation of warheads.
Numerical and experimental investigation of a Mg/N2O powdered fuel rocket engine
Authors: Huang L Y , Meng L , Li P F , Yang H
Published: June 2023

Powdered metal fuel rocket engines, utilizing high energy density metal powder as fuel, have great potential in the development of propulsion systems for upper-stage rockets, and thrusters for attitude or trajectory control. The main challenges of this rocket engine technology currently lie in the realization of stable powder fuel supply, quick engine start-up, and high combustion efficiency. In this paper, we present a computational analysis of the reactive flow in a Mg/N2O powdered metal fuel rocket engine. Consideration in this work includes effects of a flame holder, mass flow rate ratio and entry angle of N2O on combustion efficiency. Based on the numerical simulation results, an experimental Mg/N2O powdered metal fuel rocket engine was designed, and working processes of the engine were investigated through hot fire tests with Mg powder as fuel and N2O as oxidant. A ground test system, consisting of a high-precision test bench, a fuel feed unit, an oxidant feed unit, and a measurement and control unit, was established. The test results show that the combustion of Mg powder and N2O can be sustained.
The Influence of the Material and Thickness of the Barrel on the Speed of Flying Plates
Authors: Zhou Mi , Men Qingying , Tong Honghai , Wang Yin , Li Jiao
Published: June 2023

In order to reduce the ignition energy of the slapper plate detonator and optimize its performance, for the slapper plate detonator with the size of 0.4mm × 0.4mm × 5µm and the thickness of the flying plate 25µm, the material and diameter of the barrel were optimized by using photon Doppler velocity testing technology (PDV). Three kinds of materials including ceramic, sapphire and stainless steel and accelerating bore with thickness 0.3mm, 0.45mm and 0.6 mm are analyzed.. The experimental results show that: at the same discharge voltage, the ceramic barrel flyer The speed of the sapphire barrel is the highest. The speed of the flyer of the sapphire barrel is basically the same as that of the ceramic barrel. The barrel made of stainless steel has the lowest speed of the flyer. For the ceramic barrel of different thicknesses, the speed of the flyer is compared. The ceramic barrel with a thickness of 0.45mm is in displacement. The acceleration inflection point appears at 0.45mm, at this time, the parameter state of the shock sheet detonator and the initiation circuit have reached a best matching state.
Preparation and properties of spherical super thermite for 3D printing of energetic materials
Authors: Qi Z Y , Yao W S , Zhang M H , Xia M , Luo Y J
Published: June 2023

3D printing technology is a new rapid prototyping technology that has attracted much attention since its inception. It is promising to apply 3D printing technology to energetic materials. However, the 3D printing of energetic materials requires high raw materials, and there is no suitable thermite powder as the printing raw materials at present. In this paper, Al@CuO energetic composites with single core spherical core-shell structure were prepared by spray drying method. The prepared powder was confirmed to have a single core spherical core-shell structure by SEM/EDS/XRD, and it was proved to have good fluidity by the fluidity test. High-speed photographic ignition tests show that the Al@CuO Micron spheres have excellent energy release performance and can be used as burning rate catalysts. In addition, this method has the advantages of simple operation, good process performance, mass preparation, and can be applied to the thermite system of most metal oxides (such as Bi2O3, Fe2O3).
Damage performance of a shaped charge liner fabricated from Ti-29Nb-13Ta-4.6Zr alloy
Authors: Wang C T , Hu X B , Ji C , Guo Z P , Guo L , He Y
Published: June 2023

The change of the liner material directly affects the penetration and damage performance of the shaped charge. In this paper, Ti-29Nb-13Ta-4.6Zr (TNTZ) was used as the charge liner. Autodyn software was used to analyze the jet formation of TNTZ liner, then static explosion test was conducted to analyze the penetration and damage performance of charge liners. The following conclusions were obtained: A charge liner structure was proposed for TNTZ alloy, the simulation shows that a jet with acceptable L/D ratio was formed, and the jet head velocity was around 6000 m/s. The TNTZ charge liner successfully ignited fuel tank after penetrating steel target due to chemical reaction. For the tests on C35 concrete targets, the TNTZ liner has horizontal damage effect which leads to penetration tunnel with large diameter, however the penetration depth is smaller compared to Cu liner. Such behavior makes TNTZ liner a good candidate as forward shaped charge of tandem warheads.
Research on ignition and reaction characteristic of PTFE-based reactive materials
Authors: Xie Zhi-yuan , Wang Yan-xin , Xu Rui-ze , Xiao Jian-guang
Published: June 2023

In order to study the ignition characteristic of PTFE-based reactive materials (RMs), Al/W/PTFE RMs with different W powder contents were prepared and split Hopkinson pressure bar (SHPB) test was carried out under different loading conditions. The temperature rise of three RMs were calculated theoretically. The material model parameters of the three formulations were calculated by using the mixture equation of state theory and Johnson-cook model, and the impact process was numerically simulated by using AUTODYN dynamics software. The results showed that the Al/PTFE (26.5/73.5) formula material has ignition reaction when the impact speed is 27.47m/s, and Al/W/PTFE (7.94/45.33/46.73) formula material is 28.68m/s. Al/W/PTFE (5.29/80/14.71) only has weak ignition reaction under experimental conditions. The ignition reaction of RMs is related to the impact temperature rise. Under the impact condition, local high temperature induced ignition occurred at the crack of RMs.With the increase of W powder content, the overall temperature rise of RMs decreased, and the reaction degree of RMs decreased.
Ignition delays of two ADN/GAP mixtures irradiated by a CO2 laser: atmospheric experiments and numerical calculations
Authors: Li H , Hao H X , Li M , Zhang Y
Published: June 2023

The ignition experiments of two ADN/GAP mixtures irradiated by a CO2 laser were conducted to investigate the dominant mechanism of ignition induced process. The power law exponents of experimental curves for ignition delay versus laser power density are all closed to -1. Two reduced numerical models were employed to calculate the ignition delay times against the experimental data. The analysis suggested that the ignition delays of ADN/GAP mixtures related to the corresponding burning rates and the ignition delay behaviours followed a fixed energy pattern approximately. The calculation results indicated that the measured ignition delay time might be mainly dominated by the formation of preheating layer for steady state burning.
Density distribution characteristics of the explosively formed reactive material jet
Authors: Guo H G , Zhang J H , Liu C Z , Wang H F
Published: June 2023

The density evolution behaviour and distribution characteristics of the explosively formed reactive material jet were studied based on the SPH algorithm. Numerical simulations show that the reactive material jet has obvious expansion phenomenon under the shaped charge effect. Especially, the expansion and divergence of the jet head are obvious. In general, the density deficit occurs in the whole reactive material jet, and the density increases from the jet head to the tail. Compared with the initial density of the reactive liner material, the density of jet head decreases by about 30%. In addition, the effect laws of the reactive liner thickness, the liner cone angle, and the type of explosive on the jet density distribution were investigated. With increasing of the reactive liner thickness, increasing of the liner cone angle, and decreasing of the explosive detonation pressure, the proportion of the high-density area on the reactive jet and the average density of the jet head increase.
A unified method for studying impact particle relation and spallation under shock loading
Authors: Ma R. , Ren K.R , Chen R.
Published: June 2023

Spallation is the phenomenon that under impact loading, the material interior reaches the tensile failure limit instantaneously due to the tensile effect of two sparse waves moving in opposite directions, and cracks are formed in the interior. The specimen of a certain alloy was taken as the research object, and the planar impact experiment was carried out by a 20mm caliber one-stage light gas gun. The free surface particle velocity curve of the alloy specimen was obtained. The Hugoniot state parameters, spallation strength, unloading strain rate and other experimental data were obtained through theoretical analysis. The results show that: The spall strength of the alloy is proportional to the tensile strain rate in the loading range: σs
= 0.37 × 10-4

ε

·

(GPa); the alloy has higher wave impedance and spallation strength compared with C10100. The experimental parameters of Hugoniot state are smaller than those calculated by the mass average method because of the special internal structure of the alloy. The state parameters of the sample can be obtained at the same time by using the material with known Hugoniot state parameters as the flyer.
Theoretical analysis for the axial tensile response of the mesoscopic model for filament-wound composites
Authors: Yin Dongmei , Li Zhenxiao
Published: June 2023

A theoretical analysis approach of the mechanical response of mesoscopic model of filament wound composites under the axial tension is provided in this work. In this method, a rhombus representative volume element (RVE) is selected according to the winding patterns, which is further divided into several length scales. Based on the iso-strain and iso-stress assumptions, combining bridging theory and homogenization, equivalent stiffness matrix of the structure in each scale is obtained. Then theirs’ three dimension (3D) equivalent elastic constants can be forecasted. Some elastic constants of the macro structure are compared with those gained by experiment and classical laminate theory (CLT) model. The comparison results verify the reliability of this model to a certain extent. According to the equivalent stiffness matrix of the structure in each scale, the equivalent stresses and strains of these structures under the axial tensile load are calculated. Stresses of fiber tows and matrix in each unidirectional layer are computed by using the bridging model. Considering the stress concentration factors of matrix, the damage of the mesoscopic structure is obtained based on the failure criteria of constituents. The locations of damage are verified by the numerical simulations in the references.
Properties of Aramid Fibers And Their Composites Based on Atomic/Molecular Scale Simulation Technology: A Review
Authors: Jingli Xu , Shuhu Li , Jianfen Guo , Haiyan Zang , Jianqin Zhang , Haiyun Zhang , Danyong Wang , Yiwei Chen
Published: June 2023

Atomic or molecular simulation technology is gradually used in the performance simulation of organic ballistic fibers and their composites, to reveal their various performance mechanisms and evolutionary mechanisms from the molecular point of view. Atomic or molecular simulation technology in the mechanical properties, thermal properties, aging properties, properties of aramid fiber composite fibers, and interface properties of aramid fiber-reinforced composites are summarized in this paper.
Thermo-Structure Approach to Dissimilar Explosive Cladding with Interlayer
Authors: Saravanan S.
Published: June 2023

A thermodynamic model capable of predicting the change in internal energy, work done, and thermal energy required during aluminum-stainless steel explosive cladding is presented. The mathematical model is instrumental in determining the temperature and pressure developed at the interface, which characterizes the interface microstructure, compared with the numerical simulation. Numerical simulation is implemented by the Smoothed Particle Hydrodynamics method available in ANSYS Autodyn. Furthermore, the effect of different interlayers, such as Al 1100, copper, and SS 304, on kinetic energy utilization and deformation work is discussed. The increase in ram tensile and shear strengths is also reported.
The composite laminate design and manufacture based on wrapped ply
Authors: guo Jianfen , zhang haiyun , jia huamin , gao shouzhen
Published: June 2023

This paper analyzes the layup design and manufacture of composite laminate with inserts on the surface of revolution, and points out that both the interior surfaces and the outer surfaces should be laid as a full-body ply. Utilize 3D design software Catia and composite design software Fibersim, carry out digital layup and producibility simulation of the product, design wrapped plies for the interior surface and outer surface with complex structures, simulate and adjust the laying process, and make the fiber deformation of the entire surface reasonable. Flat patterns of the plies are provided for material cutting. For the layup of thicker area and transition area of the product, the layup design and production data and suggestions are also given. The scheme and data of layup are well used in guiding production and improving production efficiency and product quality.
Research on key technologies for autonomous vehicles
Authors: Yu Duan , Fanqing Gao , Bu Lü , Xulin Chen , Xundong Yang
Published: June 2023

With the advancement of science in the world, Artificial Intelligence is also developing rapidly. Currently, the traditional automobile industry is making significant efforts to develop autonomous driving technology based on the development of AI. The research focuses on key technologies for autonomous vehicles, systematically analyzing environmental perception, behavioral decision-making, path planning, and vehicle lateral or longitudinal motion control systems.
Quantitative Investigation of Ballistics Flow Fields by Background Oriented Schlieren Technique
Authors: Moumen A , Laboureur D , Gallant J , Hendrick P
Published: June 2023

The ballistics field is known by the presence of several complex phenomena such as muzzles and flying projectiles flow fields. Consequently, numerical simulations are commonly used to model these complicated flows. However, the validation process of these codes has proven to be problematic due to the lack of experimental quantitative data. In this context, the present paper describes the application of the Background Oriented Schlieren technique (BOS) as a quantitative investigation tool in the ballistics field. We illustrate that BOS can accurately capture the main characteristics of the studied configurations: Firstly, we discuss the visualization and the density field reconstruction around a Bullet Simulated Projectile BSP flying at supersonic velocities and a sniper projectile flying at supersonic and transonic velocities. We demonstrate that these fields are in satisfactory agreement with the results of Taylor and Maccoll’s equation and numerical simulation. Then, the findings of the BOS visualization of the precursors and the propellant flow fields are presented. To this end, the salient features accurately captured by the BOS technique such as vortex rings, shock bottles, Mach, and blast wave are described both qualitatively and in terms of density profiles. Two improved approaches that are essential to the aforementioned analysis are proposed: the first is related to density field reconstruction based on Abel inversion and the second approach is a phase separation procedure.
Low-light image enhancement based on simulated multi-exposure fusion
Authors: Han Yongcheng , Zhang Wenwen , He Weiji
Published: June 2023

We propose an efficient and novel framework for low-light image enhancement, which aims to reveal information hidden in the darkness and improve overall brightness and local contrast. Inspired by exposure fusion technique, we employ simulated multi-exposure images fusion to derive bright, natural and satisfactory results, while images are taken under poor conditions such as insufficient or uneven illumination, back-lit and limited exposure time. Specifically, we first design a novel method to generate synthesized images with varying exposure time from a single image. Thus, each image of these artificial sequences contains necessary information for the final desired enhanced result. We then introduce a flexible multi-exposure fusion framework to achieve fused images, which comprises a weight map prediction module and a multi-scale fusion module. Extensive experiments show that our approach can achieve similar or better performance compared to serval state-of-the-art methods.
Segmentation Clustering Algorithm for Point Cloud Processing of Targets on The Ground
Authors: Huang Jinbo , Zheng Zhen , Zhang Yifei , Zhou Yu
Published: June 2023

After the ground extraction algorithm, there are multiple objects, including the target in the non-ground point cloud. To effectively extract the features of individual objects and overcome the dependence of the traditional algorithm based on the normal vector and curvature of the region growing point cloud segmentation method on the initial point, the normal vector angle in the neighborhood, and the curvature threshold selection. In this paper, we propose a fast clustering segmentation method for region-growing point clouds based on neighborhood density. The test results show that the point cloud segmentation algorithm proposed in this paper has better performance than the traditional Euclidean clustering point cloud segmentation algorithm and region growing point cloud segmentation algorithm in terms of timeliness and correct segmentation rate. This new segmentation clustering algorithm can quickly implement automatic point cloud clustering segmentation of ground objects.
Point Cloud Target Registration Algorithm Based on Local Feature Description
Authors: Wang Chengjun , Zha Binting
Published: June 2023

Point cloud data has received extensive attention in the field of target recognition and target tracking due to its rich target information, and point cloud registration is one of the basic tasks in point cloud applications. Aiming at the problem that the feature descriptor in the traditional registration algorithm is complicated to calculate and cannot sufficiently describe the features of the point cloud, this paper proposes a local feature descriptor that integrates the local normal vector angle features, projection distance features, and distribution density features of the point cloud. The feature similarity is introduced to determine the corresponding point pairs between the template point cloud and the target point cloud, and the point cloud registration task is completed based on local feature matching. Experiments show that the feature descriptor in this paper is simple to calculate and can sufficiently describe the local features of the point cloud, a good correspondence between points can be established based on the feature descriptor, and the algorithm has good robustness. The registration algorithm proposed in this paper can provide a reference for the fields of target recognition and target pose estimation, etc.
Impact of Air Quality on Millimeter Wave Transmission Performance
Authors: Wu Hongming , Wang Ningbo , Wang Yelong , Wang Jinkuan
Published: June 2023

In this paper, we use millimeter wave radar to conduct outdoor experiments under different air quality conditions and analyze the degree of millimeter wave transmission attenuation. The radar we use operates at 94 GHz with a bandwidth of 1 GHz, a distance resolution of 15 cm, and a maximum detection distance of about 150 meters. We mainly use PM2.5 and PM10 indices as air quality criteria and find that the reflected signal strength of millimeter wave from 90m to 150m decreases by 0.38dB when the air quality rises from 136 to 250, indicating that the weaker the air quality, the weaker the millimeter wave signal strength. This provides an experimental basis for the field of millimeter wave communication.
Multisensor-Based Maneuvering Target Tracking Algorithm under Non-Gaussian Measurement Noise
Authors: Zhou Yu , Qin Jianxin , Zha Bingting
Published: June 2023

The UAVs have become a huge threat in the battlefield. The excellent maneuverability makes them competent for the actual combat operations such as investigation and strike. Therefore, accurate tracking of UAVs is critical. Centralized radar/IR fusion system has been widely concerned to track the UAVs because of the complementary characteristics between these two sensors. The appearance of non-Gaussian measurement noise produces a negative impact on tracking accuracy. This paper proposes a novel IMM-CMCSCKF algorithm which can improve the tracking accuracy of radar/IR fusion system for maneuvering target under non-Gaussian measurement noise. The heterogeneous measurements from radar and IR are firstly fused. Then, CMCSCKF algorithm is presented based on MCC to deal with non-Gaussian measurement noise. To improve maneuvering target tracking accuracy, CMCSCKF is embed into IMM algorithm. Numerical simulation verifies the effectiveness of the proposed IMM-CMCSCKF.