bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Research on Dilute Polymer Solutions Cavitating Flow through Venturi and Cavitation Induced Vibration Acceleration Characteristics
Authors: Yu L F , Zuo Zh G , Li L , Lu X X , Wang Zh X 
Published: July 2020

Abstract
The present work deals with an original study of vibration signals induced by unsteady cavitating flow of polymer solutions through a Venturi section. A blow-down Venturi experimental rig was utilized to generate cavitation in polymer solutions. The cavitating flows through the Venturi tunnel were captured by high-speed photography. The accelerometer was mounted on the upper wall of Venturi tunnel to gather the cavitation induced vibration accelerations. Results show that the morphologies of cavitation bubbles in polymer solutions are different from that of filtered water. Cavitation bubbles with bigger size and less number are observed in polymer solutions cavitating flow. It is observed that the peak value, kurtosis and the root-mean-square of vibration acceleration increase in polymer solutions. Meanwhile, a broader frequency band and a higher power spectral density level is observed in spectrogram of polymer solutions. It is inferred that the collapse of the vaporous cavity clouds with high void fraction developed in polymer solutions is responsible for this alteration.
Numerical simulation on continuous penetrating/blasting behavior of multi-projectiles against concrete target
Authors: Wang S P , Tan J Z , Su C H , Zheng Y F 
Published: July 2020

Abstract
Deep digger weapon system uses continuous kinetic energy and chemical energy of the penetrating/blasting projectiles to dig the concrete target. In the present paper, numerical simulations are conducted to study the continuous penetrating/blasting effects of multi-projectiles against concrete target. The simulation results show the KE penetration produces the crushing and rupturing zone, providing conditions for subsequent damage due to explosions. Then, the explosion further increases the diameters of the crushing and rupture area, and the cracks propagate inside the concrete target. The second penetration and blast further increase the depth and the damage area, achieving deep digger behavior to the concrete target. However, the throwing effect of secondary penetration/blast is slightly weaker than that of first one. Moreover, the simulation also shows the continuous penetrating/blasting behavior is influenced markedly by impact velocity.
Study on the air shock wave effect and engineering algorithm in the tunnel after the damage of protective door under different explosion conditions
Authors: Liu F , He X , Sun G J , Ren X J , Wang X , Chen L 
Published: July 2020

Abstract
In this study, the effect of an air shock wave discharged into a tunnel when an explosion occurs in front of a protective door was experimentally examined and the actual air shock waveforms in the tunnels with and without a protective door were analyzed and compared. It was found that both the waveform structure and the characteristic parameters of the air shock wave, such as the peak and the action time, were significantly changed after a protective door was installed. Moreover, by combing with dimensional analysis results, some detailed engineering algorithms of the residual shock wave effect, namely, the engineering algorithm of the overpressure peak of the residual shock wave in the tunnel, the equivalent explosive coefficient in the case without protective door, and the shock wave reduction coefficient with and without a protective door, were derived.
Numerical study on anti-penetration performance of metal packaged ceramic structure
Authors: Sun X , Tian Ch , Sun Q T , An X Y , Dong Y X 
Published: July 2020

Abstract
The anti-penetration performance of traditional layered ceramic composite structure is limited by the properties of the materials and the layered structure is difficult to resist the multi-hitting. Considering these two characteristics of the layered structure, the lightweight metal packaged ceramic composite structure is investigated to improve the anti-penetration performance by experiments and simulation. The finite element model was verified by ballistic range test, so it can well simulate the process of the penetrating and the result has high reliability. The metal packaged ceramic composite structure exhibits 50% higher anti-penetration performance than that of the equivalent titanium alloy plate and 20% higher than the layered ceramic composite structure. In metal packaged ceramic composite structure, the metal packaging interlayer can reduce the projectile energy by 55% and plays the most important role in the anti-penetration process. It is also found that the metal packaging increases the erosion of the projectile by confining the ceramic material and restricting the broken ceramic debris flying out. Thus, it can improve the anti-penetration performance of the composite structure. Moreover, metal packaging can also limit the propagation of cracks in the ceramics, thereby improving the ability of the composite structure to resist the multi-hitting. The metal packaged ceramic composite structure is less affected by the projectile penetration position.
Time-frequency characteristics of the strain signal of the metal shell under internal explosion
Authors: Wei D , Gan YD , Zhang Q M , Su J J , Long R R , Chen P W , Liang H Z 
Published: July 2020

Abstract
In this paper, the empirical mode decomposition-Hilbert Huang transform (EMD-HHT) was used to characterize the strain signal within metal cylindrical shell structure under internal blast loading. The received vibration frequencies of signal were closely consistent with FT characterization results. Through the EMD-HHT, instantaneous energy spectrum, marginal energy spectrum and Hilbert energy spectrum were determined, and these reflected the change in trend of signal energy in time domain, frequency domain, and time-frequency domain, showing the instantaneity and locality of explosion signal. The frequency components of the signal at any time were also determined, which proved that signals generated by the metal shell were the result of the superposition of different frequency signals under internal blast loading. This paper explains more clearly the time and frequency characteristics of blast signal, providing the theoretical basis for the study of antiknock in structures.
Study on jet forming characteristics of shaped charge with truncated-liner structure
Authors: Ji L , Zu X D , Xu M W , Wang P , Wang G C 
Published: July 2020

Abstract
In order to verify the jet forming characteristics of the shaped charge with a truncated-liner, numerical simulation and X-ray experimental research were carried out. The behavior of the truncated-liner and the top velocity, diameter and morphology of the jet were obtained, and the outcomes were compared with the characteristics of the jet formed by the traditional shaped charge. The results show that the numerical simulations are almost consistent with the results obtained by the X-ray test. The morphology of the two is nearly the same, and the data deviation is less than 6%. The truncated-liner can effectively improve the velocity of the jet head, which can reach more than 10km/s by structural optimization. In addition, the truncated-liner can decrease the diameter of the slug, meanwhile, increase the length of the jet and the quality utilization of the liner.
Effect of ultrasonic-electric surface modification on metal material
Authors: Liu D , Zhao J Z , Gao Y , Liu J B , Shen Y L , Meng C 
Published: July 2020

Abstract
With the demand for the materials are increasing in the field of military and civilian application with each passing day, an ultrasonic-electric surface modification treatment was employed to improve the surface properties of metal material with different heat-treated conditions. The surface properties of the specimens after conventional cutting and ultrasonic-electric surface modification treatment were characterized, respectively. A grain refinement layer was formed on the surface of different heat-treated specimens after ultrasonic-electric surface modification treatments. The average grain size on the top surface was refined into the submicrometer or nanometers scale. This is caused mainly by two aspects: one is the accumulation of initial tiny particles during deformation; the other is that the ferrite is smashed into pieces due to micro-fatigue damage. Moreover, it was found out the specimens after ultrasonic-electric surface modification treatment had shown the optimal surface properties and friction-wear properties.
Effect of interfacial microstructure and mechanical properties of steel/copper casting bimetal by active protective agent
Authors: Kang Y Y , Zhang G W , Xu H , Niu J W 
Published: July 2020

Abstract
This article study on the 45#steel/high-lead tin bronze bimetal that were prepared by solid-liquid casting. Effect of interfacial microstructure and mechanical properties by active protective agents were investigated including Na2B4O7, H3BO3, AlPO3 and NaF. The results show that the effect of the single component active protective agent on the binding interface is Na2B4O7>H3BO3>AlPO3>NaF. The multiple components optimal ratio of the active protective agent is Na2B4O7:H3BO3:AlPO3:NaF=60:25:10:5(wt.%)after mixing, which make the interfacial bonding strength reach 168.4 MPa and diffusion distance of the Fe/Cu interface attain 12.4μm. When the thickness of Na2B4O7 is lower than 60%, FeP transition layer is precipitated at the interface, which depress the interface shear strength.
Quantitative study on SLIP model parameters based on multi-rigid-body dynamics
Authors: Han D L , Zhang R , Wen L G , Dong W C , Li T , Jiang L , Li J Q 
Published: July 2020

Abstract
The spring-loaded inverted pendulum (SLIP) model is often used to describe the interaction between hindlimbs and the ground during the locomotion of animals or humans. This model is frequently adopted to qualitatively explain the flexible deformation of legs and feet and the trajectory change of center of mass (COM), caused by the impact between hindlimbs and the ground. However, such research cannot provide precise reference on the structural parameters, spring and damper selections and their collocations for the design of robotic legs and feet. In this study, an SLIP model was established on the multi-rigid-body dynamics software Adams. The main influence factors on the SLIP model were determined by targeting at the touchdown-phase duration of animal or human locomotion. Then the main factors were quantitatively studied by combining a multivariate orthogonal polynomial regression design. Simulation showed that spring stiffness coefficient (Z1), damping coefficient (Z2), swing angular velocity (Z3) and initial swing position (Z4) were the main factors affecting the trajectory of COM. Multivariate orthogonal polynomial regression analyses showed the relationship between the COM fluctuation (y) and the main factors satisfied the following equation: y = 217.33 - 16.25 Z1 + 0.3975 Z12 - 194.6 Z2 - 0.953 Z3 + 0.755 Z4 + 8.1 Z1 Z2 + 0.043 Z1 Z3 + 0.6 Z2 Z3 - 0.0055 Z3 Z4.
An improved algorithm for target trajectory prediction in the active protection system based on converted measurement Kalman filter
Authors: Wang J L , Song H P , Chen R M , Zhang Y N 
Published: July 2020

Abstract
Fast and accurate prediction of the trajectory is the prerequisite for the successful interception of the incoming target by the active protection system (APS) of armoured vehicles. The traditional least-squares algorithm is susceptible to large errors in the initial stage of the tracking process, and the prediction of interception points converges slowly. This paper proposes an interception point prediction algorithm that combines the Kalman filter and least-squares estimation. By dynamically determining the convergence of the least-squares prediction, a converted measurement Kalman filter is used in the initial tracking stage to obtain higher prediction accuracy of the interception point. Simulations are performed in the scenario of the interception process of the APS. The results prove that the algorithm can effectively accelerate the convergence of the interception point prediction process.
Millimeter-wave radar image analysis for the traffic sensing
Authors: Wu H M , Qi F , Wang J K , Wang Y 
Published: July 2020

Abstract
Millimeter-wave(MMW) radar sensing is one of the most promising technologies to provide safe navigation for autonomous vehicles due to its expected high-resolution imaging capability However, driverless cars have higher request for different environment and light conditions. Therefore, millimetre-wave imaging is of paramount importance for complex load scenario. In this paper, we have built models of pavement pits and bulges and analysed their with differences ways of antennas. A comparison of the imaging performance of experimental systems operating at a MMW radar and a Lidar is presented with the analysis of features for initial image interpretation Experimental images of the complex road surface are made by a 94GHz frequency-modulated continuous-wave (FMCW) radar technique with 3mm wavelength.
Dynamic Analysis and State Estimation of Wearable Extra Robotic Limbs for Physical Assistance and Load Reduction in Missile-mounting
Authors: Li H B , Guan X R , Li Zh , Zou K F , Shi Y F , Xia X H , Guan L Sh , Zhu M , Zhang L F 
Published: July 2020

Abstract
In order to fully exploit the potential in the field of human augmentation, to help the wearer fulfil the task of physical assistance and load reduction, a new type of wearable robot that can perform tasks in close coordination with the wearer and assist the wearer with extra arms and legs secured around the body is presented. The system, named extra auxiliary robotic upper limbs-lower extremity exoskeleton (EARUL-LEE), consists of two additional robotic arms worn through a backpack around the upper body and two exoskeleton legs attached to the lower body tightly. The EARUL-LEE can assist the wearer by holding objects, lifting weights and streamlining the execution of a task. If the EARUL-LEE performs movements closely coordinated with the wearer and exhibits human-like dynamics, it might be incorporated into the body representation and perceived as parts of the wearer’s body. The EARUL-LEE can work closely with the soldier by supporting and securing the human body when lifting a missile, and more. Although the EARUL-LEE control performance is hindered by unpredictable disturbances due to involuntary motions of the soldier, which include postural sway and physiological tremor, the dynamic analysis the human-EARUL-LEE hybrid system include the models of human-induced disturbance based on biomechanics literature, extra auxiliary robotic upper limbs and lower extremity exoskeleton and state estimation method based on an orthogonal least squares for the EARUL-LEE, aimed to perform the missile-mounting for aircrafts on the ground or decks in tight coordination with the soldier as a close co-worker are presented here. Via the current study, the orthogonal least squares (OLS) filter is constructed to estimate the state and its performance is evaluated in terms of error covariance. The simulation results show that the orthogonal least squares filter can tracking desired trajectory and its convergence is better than without any filters. The results can be used to control the EARUL-LEE accordingly with the used end effectors and provide a method for improving the accuracy and stabilizing the human body and the EARUL-LEE.
A study of blockchain technology development and military application prospects
Authors: Zhu Y , Zhang X , Ju Zh Y , Wang Ch Ch 
Published: July 2020

Abstract
Once blockchain technology is successfully applied, it will certainly trigger revolutionary changes in the military development and combat mode, which are beyond the traditional military command and management scope. In the future, blockchain technology, by combining with military artificial intelligence, Internet of things, cloud computing and big data, will have priority to be applied in military management, support, security and even command. It is of great significance to excavate the military application potential of blockchain technology and scientifically predict its impact and influence on the military field, so as to improve the combat effectiveness of the army and promote its transformation and development.
A method of simulated motion tracking control based on lyapunov vector field
Authors: Huang D G , Sun J , Liu D 
Published: July 2020

Abstract
For the problem of irregular formation in aircraft cluster planning, this paper proposes a simulated motion tracking control of cluster planning. The simulated motion is the expected motion trajectory for one aircraft provided by the planning system. Using Lyapunov vector field guidance and omnidirectional speed control method, this paper realizes the tracking control of the simulated motion for the aircraft. The simulation results demonstrate that the proposed method can realize the tracking control of the simulated motion and achieve the expected effect, which lays a foundation for the cluster planning.
Research on anti UAV swarm system in prevention of the important place
Authors: Hao Q , Li W Z , Qiu Z K , Zhang J L 
Published: July 2020

Abstract
With the rapid development of artificial intelligence (AI) technology, UAV swarm has become possible. It has become an urgent problem that how to realize the effective counteraction to the UAV swarm in the important target security defence, or in the important place prevention in the war. In this paper, by analysing the development status and combat characteristics of UAV swarm, as well as existing anti-UAV technology, the countermeasures and technologies applicable to UAV swarm is combed. Then the further construction of anti UAV swarm control system is built to realize the effective anti UAV swarm in the key prevention and control.
Research on 100kJ pulsed power module for electromagnetic launch
Authors: Zhang Y Z , Li Y M , Yang L , Zhao B 
Published: July 2020

Abstract
With the development of the electromagnetic launch (EML) technology, the requirement of the pulsed power supply is increasing. Capacitor-based pulsed power supply usually consists of several hundred kilojoule level pulsed power modules (PPM) in parallel. The PPM for EML system requires the capability of continuous working ability, high energy storage density and high peak current. A 100kJ compact PPM with rated operational voltage 10kV was designed, the output peak current was about 90kA, and the continuous working ability was 6 times per minute. The design and selection of main components in the module were simulated. At last, the PPM was used in the testing of the coil gun. It provides transient pulse current test platform and technical support for the subsequent construction of megajoule level pulsed power supply.
A Non-Lethal Electric Shock Generator with Wireless Control Function
Authors: Yang Chunxia , Wan Gang , Liu Jian , Zhang Wenxuan , Tian Hui , Li Zhenxiao , Jin Yong , Li Baoming 
Published: July 2020

Abstract
A Non-lethal electric shock generator is presented and tested. This non-lethal electric shock generator without trail wires, is different from Taser series stun guns or Husha TX series electric shock guns which all have trail wires. And the intensity of electric shock can be adjusted by remote control device according to the status of the target. This no-lethal electric shock generator extends the range of application of electric shock from about 9 meters to 30 meters. The manner of using electric shocks of single intensity is also changed by telecontrol adjustment. It can provide electric shocks of different intensities for different conditions, such as different distances from special electrodes to targets, different targets with different clothes and different height or weight. Basic functions of the non-lethal electric shock generator are tested. Results show that the prototype projectile can be launched from a barrel stably, and the flight range is over 30 meters. When it captured the target, it can be triggered via the telecontrol adjustment. The prototype projectile can support a series of pulses at a rate of 20 r/s with the peak voltage of 30kV.
Numerical study on aerodynamic characteristics of rotating missile launched vertically under strong transverse wind
Authors: Xu Yihang , Chen Shaosong , Zhou Hang 
Published: July 2020

Abstract
Numerical simulation of low speed high Angle of attack rotating missile was carried out by using different turbulence models, and the numerical simulation results were compared with the experimental results. The results show that the SST-DDES model can well simulate the aerodynamic characteristics of the rotating missile at low speed and high Angle of attack. Under the condition of low speed and high Angle of attack, the difference of the lateral force produced by the missile’s tail fin is small, and the variation of the total missile lateral force mainly depends on the variation of the projectile body lateral force. When the Angle of attack increases from 40.1° to 60.1°, the direction of the missile’s lateral force changes. This is because with the increase of the Angle of attack, the fluid velocity perpendicular to the projectile increases, resulting in the interaction and fusion of asymmetric vortexes on the leeward side, resulting in the change of lateral force direction.
Fault diagnosis of missile refrigeration system based on the belief rule base
Authors: Liu Zh Zh , Xiao M Q , Zhu H Z , Li J F 
Published: July 2020

Abstract
In order to diagnose the fault of missile refrigeration system, aiming at the complex nonlinear relationship between the causes and symptoms of missile refrigeration system, we propose a method for fault diagnosis of refrigeration system based on the belief rule base (BRB). The method can use quantitative and qualitative information to establish a nonlinear model between input and output, and diagnose the system through optimization model. BRB can make comprehensive use of expert knowledge and historical data, which is more suitable for fault diagnosis. In order to address the problem of parameter inaccuracy in the initial BRB given by experts, combined with the information type of the failure of the refrigeration system, we use the chaotic particle swarm optimization learning model to train the initial BRB parameters given by experts to achieve the diagnosis of refrigeration faults in the refrigeration system. The experimental results show that the BRB after parameter optimization can better identify the state of the missile system and improve the accuracy of fault diagnosis.
Research on ignition process of micro solid rocket motor in vacuum
Authors: Wen J J , Deng H Y , Zheng K , Liao W H 
Published: July 2020

Abstract
Aiming at the ignition process of micro solid rocket motor in space, the effects of different structure on the ignition gas filling process were investigated by means of experiment and numerical simulation. By establishing numerical simulation model and the mass flow rate model of ignition chamber for black powder, pressure establishment process was researched under different parameters (the igniter quantity is 0.2g and 0.5g, outlet size of ignition chamber is Φ4mm and Φ7mm respectively). Meanwhile, the ignition experiment was conducted in vacuum (the ambient pressure is 16Pa) that pressure curve and vacuum plume phenomenon were obtained. The results indicate that simulation value of pressure establishing process relatively consistent with experimental one, so the mass flow rate model of ignition chamber for the black powder is evidently efficient. Therefore, the numerical method proposed in this paper can provide a theoretical basis for further research on the ignition process of micro solid rocket motor.