bluuebunny/crossref_metadata_2025_split huggingface dataset:
Research on joint simulation technology of fire dynamics and servo control of self-propelled antiaircraft gun during moving
Authors: Gao X K , Gu B , Zhou C J , Liu J 
Published: July 2020

Abstract
Taking self-propelled anti-aircraft gun as the research object, this paper presents a joint simulation method of shooting dynamics and servo control during the course of self-propelled anti-aircraft gun. Aiming at the matching between structural parameters and servo control parameters of self-propelled anti-aircraft gun, an evaluation and optimization design method is proposed. The platform of the joint simulation system of dynamics and servo control is mainly composed of road-body-turret dynamics model, fire control module, elevation control compensation module, azimuth control compensation module and motor module. The control compensation module realizes the control strategy by PID (Proportional-Integral-Differential) control of position and speed loop. The motor module achieves the system control torque output through the current loop and the motor. These modules constitute the joint simulation design model of dynamics and servo control. By comparing the output of the simulation system with the actual firing test results of self-propelled antiaircraft gun, the effectiveness of the method is verified by the firing line error analysis under different experimental conditions. This method can be used to evaluate the tracking accuracy of the system at the design stage, which is helpful to reduce the development cost and shorten the development period.
Numerical simulation for high speed oblique water entry of different density projectiles
Authors: Mu Q , Xiong T H , Wang K J , Yi W J , Jun G 
Published: July 2020

Abstract
To explore the effects of material density on the cavitation flow field of a projectile entering water at an oblique angle at 300m/s, numerical simulations were conducted. The model was based on the finite volume method, VOF (Volume Of Fluid) multiphase model, Schnerr-Sauer cavity model, SST(Shear Stress Transfer) k-ω turbulence model and dynamic mesh method. The evolution laws of cavity shape, motion characteristics and hydrodynamic characteristics of water entry are analyzed. The research results show that the numerical calculation method can effectively simulate the change of cavity shape during the water entry of the projectile. The larger the density is, the smaller the diameter of the cavity formed after entering water is; the longer the cavity is, and the smaller the diameter of the cavity opening is; The peak value of pressure on the surface of projectile with different density is the same at the moment of entering water, but the projectile with larger density experiences a slower rate of the surface pressure decline; Moreover, the larger the density, the smaller the acceleration peak value of the projectile at the moment of entering the water, the slower the velocity decay after entering the water, and the deeper underwater at the same time.
Continuous sliding mode control for gun position servo system
Authors: Zhang Gaosheng , Zhang Zhipeng , Han Chongwei , Gu Shuanghao , Wang Tianshi , Zhang Pengfei 
Published: July 2020

Abstract
With the development of military technology and changes in the war situation, modern warfare has higher requirements for the accuracy and speed of gun firing. The control performance of the gun position servo system directly affects the accuracy and speed of the gun firing. In order to improve performance of the gun, the sliding mode control is investigated for the gun position servo system. Sliding mode control has advantages of simple structure and good robustness against uncertain system parameters and disturbance. But discontinuous sign function in the classical sliding mode control method will lead to chattering of the system. To address the shortcoming of chattering in the traditional sliding mode control, a continuous sliding mode control algorithm is investigated in this paper. Finally, numerical simulations are performed to illustrate the efficiency of the theoretical results.
Research on muzzle dynamic analysis of an overhead weapon station with the viscoelastic elastomer damper
Authors: Mao B Q , Wang Z Q , Chang L , Yang Y Y , Xu Z H , Han X P 
Published: July 2020

Abstract
Live firing tests are difficult to realize, thus it is not clear whether the viscoelastic elastomer damper can effectively reduce the recoil force and recoil displacement, which determines the firing accuracy of the overhead weapon station. This paper constructed a rigid-flexible coupling dynamics model of overhead weapon station with the viscoelastic elastomer damper. The dynamic simulation parameters of the damper were determined according to the static pressure test results. A characterization method of the firing dispersion of the overhead weapon station was then proposed. Additionally, the influences of the viscoelastic elastomer damper and the spring damper on the muzzle dynamic characteristics and firing dispersion of the overhead weapon station were studied. The results show that: the recoil displacement and the recoil-return time with the viscoelastic elastomer damper were respectively reduced by 69.83% and 33.50% compared to the spring damper; By contrast the spring damper, the horizontal and vertical dispersion standard deviations of the overhead weapon station with the viscoelastic elastomer damper at different firing conditions were respectively decreased an average of 39.48% and 43.68%, while the firing dispersion was increased by an average of 41.89%. These results prove that the viscoelastic elastomer damper can significantly reduce and shorten the recoil displacement and the recoil time of the machine gun overhead weapon station, effectively reduce the muzzle jump and improve the firing accuracy of the overhead weapon station.
New evaluation method for shared firing table of two ammunition types
Authors: Zhongxiang’ Xu , Lixin Chen 
Published: July 2020

Abstract
In this paper, a statistical function is proposed for the test of Shared Firing Table of two ammunition types, regarding the problems of two common evaluation methods of Shared Firing Table in evaluating Shared Firing Table of two ammunition types, based on basic concept of Shared Firing Table and the difference in characteristic values of dispersion ellipses of two ammunition types at drop point, and the maximum allowable value between two dispersion ellipse centers and the criterion of test evaluation are derived from the preset probability value of two ammunition types group dropping into dispersion ellipse overlapping region; through application of relevant sample size calculation formula and OC (Operating Characteristics) curve (OC curve), the relationship between the test efficiency and the minimum test sample size is solved, so as to provide an effective means for the decision and planning of sample size before test and the determination of test efficiency after test; and the validity and practicability of Shared Firing Table evaluation method established herein are verified by comparing the shooting test results of 1 group x 7 shoots, and the firing table of basic howitzer type - explosive warhead bomb.
Simulations on the reactive material projectile coated by explosively formed penetrator
Authors: Ma H B , Guo H G , Su Ch H , Zheng Y F 
Published: July 2020

Abstract
A typical shaped charge structure enhanced by reactive material projectile is established by AUTODYN-2D software. The formation and penetration processes of reactive inner core-wrapped compound EFP are simulated and analyzed. The results show that the segment liner with thick axis and thin edge becomes a penetrator with a lower velocity in the axis and a higher velocity in the edge under the shaped charge effects, which leads to EFP flipping forward and coating the reactive material projectile. The impacts between liner and reactive material projectile further increase the velocity difference between the axis and the edge, resulting in a better coating effect. The formation process is divided into three phases, including impact, coating and stretching. Then, the damage process contains penetration and deflagration of the following reactive material projectile. The liner thickness difference, curvature radius of the segment liner and radius of the reactive sphere all have important influences on formation and penetration of the reactive inner core-wrapped compound EFP.
Study on the functional rule of exploding foil multi-point synchronous explosive
Authors: Qin G Sh , Wang K X , Cao H Y , Wang Y , Zhou M , Tong H H 
Published: July 2020

Abstract
In order to study the effect of series initiation and parallel initiation on multi-point synchronous initiation of EFI (Exploding Foil Initiator, EFI), two-point series and two-point parallel electric explosion, three-point series and three-point parallel electric explosion of exploding foil were tested in this paper. The electrical explosion parameters for synchronous initiation of exploding foil two-point in series and two-point in parallel were tested also. The electric explosion parameters of exploding foil varies with the initiation voltage were analyzed. The effects of series initiation and parallel initiation on the performance of exploding foil multi-point synchronous initiation were obtained. The initiation sensitivity test of three-point series EFI and four-point hybrid EFI was carried out. The experimental results agree well with the analysis law. The research results show that series initiation is beneficial to improve the consistency of initiation conditions at each point on the condition of exploding foil multi-point initiation, is beneficial to improve the synchronization of multi-point initiation. But it’s adverse to the full release of system energy when the number of series initiation points is large. Parallel initiation is beneficial to improve the system energy utilization. But the explosion synchronization relatively poor when system energy is low. The explosion synchronization of exploding foil will be better when system energy increase. It’s benefits to increase the consistency of initiation conditions at each point of exploding foil, benefit to increase the system energy utilization and reduce system firing energy that adopt reasonable combination of series and parallel, when the number of initiation point is large and system energy is sufficient.
Explosive synthesis: novel intrinsically safe method and application with micro-channel reactor
Authors: Weifei Yu , Zhiyong Wei , Ruijuan Xu , Mei Feng , Sen Li , Guangcheng Yang 
Published: July 2020

Abstract
Novel Micro-channel method was introduced into explosive synthesis process. The method was discussed hereby with its intrinsic safety including marvelous inner-structure, high heat-transfer efficiency, and high mass-transfer efficiency compared to traditional kettle-based method. Micro-channel reactor for explosive synthesis was established with high precision control, the temperature difference of oil flow between import and export of micro-channel reactors was measured to be no more than 3°C, and the flux fluctuation of reactant flow were measured to be no more than 0.1ml/min. Micro-channel reactor was experimented with TATB explosive synthesis process. Nitration reaction showed no residue of raw material PG and 91.62% HPLC area of target material TNPG, alkoxylation reaction showed no residue of raw material TNPG and 98.01% HPLC area of target material TETNB, amination reaction showed 5.28% HPLC area of raw material and output of target material TATB. It was concluded to be verifiable including micro-channel method, the apparatus, and application in TATB synthesis process
Experimental study on thermomechanical behaviour of polyurea under dynamic compressive loading
Authors: Liu Q , Wang Ch J , Zhang Y L , Chen P W , Su J J , Zhang F 
Published: July 2020

Abstract
Polyurea is one kind of protective materials, which has been extensively used to enhance the survivability of structures under blast loading. To study the thermomechanical behavior of polyurea, compressive tests are conducted using a split Hopkinson pressure bar (SHPB) apparatus at high strain rates. An infrared thermograph is employed to observe the temperature rise. The experimental results show that the compressive stress strain response of polyurea presents a sensitivity of strain rate and strain. In addition, the deformation energy can transform to heating resulting in temperature increases under dynamic loading. Thus, the thermal softening decreases the mechanical behavior of polyurea, corresponding to temperature rise. The strain rate and length of strike bar can remarkably influence the variation about temperature rise.
Numerical simulation to determine the shaped charge jet-slug interface
Authors: Jing Y D , Chen Q , Chang B , Xue B , Tang Ch , Shu D Y , Liu F W 
Published: July 2020

Abstract
In order to determine the interface of shaped charge jet-slug, numerical simulation of the shaped charge jet forming process is carried out by non-liner finite element numerical simulation. A plurality of gauge points is arranged in the thickness of the liner, and the velocity and pressure time history of different gauge points is obtained in the jet forming stage. The result show that in the process of shaped charge jet formation, obvious velocity and pressure difference in gauge point is observed. By dividing the boundary between the slug and jet of different sets of gauge points, the corresponding area of jet and slug can be determined on the liner. The numerical simulation to determine the shaped charge jet-slug interface can be used to evaluate the performance of different shaped charge design and provide guidance for shaped charge design.
The fluid-based structure for human body impact protection
Authors: Pacek Dawid , Gieleta Roman 
Published: July 2020

Abstract
The article presents results of research and analysis of the currently conducted project aiming at the development of a flexible impact protector. The need to carry out the work results from the necessity of the ever-wider and more frequent use of body armours, including those resistant to blunt impacts, by the army, police and other public security services as well as a demand for impact protective elements in the civilian market. In the first part, the assumptions regarding the protective coverage under development and the origin of the topic with reference to earlier work on the use of non-Newtonian fluids in body armours are indicated. Next, the requirements for impact protectors and a review of the state of the art in the scope of this type of protective elements are presented. Finally, the results of the impact tests of armour samples are shown.
Experimental study on ignition reaction evolution of pressed PBX-B in long thick wall cylinder confinement
Authors: Qiu T , Wen S , Li T , Hu H , Fu H , Shang H 
Published: July 2020

Abstract
In order to explore the possibility of deflagration to detonation transition (DDT) of pressed HMX-based PBX inside long thick wall steel tube initiated by ignition composition, a new experiment apparatus was designed based on traditional DDT tube, in which strength at specific locations enhanced, and multichannel PDV probes and high speed photography were used to diagnose the expansion process and rupture characteristics of tube wall. Compared with the results initiated by detonator in the same explosives and confinement, the reaction durations of detonation and ignition differed by orders of magnitude; the pressure evolution measured by tube wall velocities, and the propagation process of tube wall movement were significantly different in two reaction. Analysis shows that the convective flow of reaction products along the seam between tube wall and explosives, high temperature and pressure, dominated the reaction evolution of PBX-B initiated by ignition composition under strong confinement, and appeared as laminar burning on explosive surface and structural response of confinement. There is no reaction activated in explosive bulk by the ramp wave caused by upper stream non shock initiation reaction, least of all DDT.
A study of the ballistic protection mechanism of two kinds of structure against 7.62×54 mm ball ammunition
Authors: Li G F , Yang L , Xu H , Guo Y Y , Wang Zh W , Wang L , Miao Ch , Wu Y Ch 
Published: July 2020

Abstract
In this work, the protection mechanism of two kinds of structure was studied using 7.62×54 mm ball ammunition, which still played an important role in the threat spectrum of military vehicles. The tested one structure is consisted with silicon carbide (SiC) ceramic and Ultra-High Molecular Weight Polyethylene (UHMWPE), and the other is UHMWPE only. Silicon carbide ceramic was chose as strike face material for the reason of its widely using in Light Weight Vehicle Armor. And the UHMWPE was widely used for personnel body armor, because of its high protection ability and low density. These two kinds of structure were tested with 7.62×54 mm ball ammunition using a 7.62 mm powder gun launching system. After the ballistic experiment, the target plate was evaluated, and the residual steel core was recovered and measured. It was found that the main effect of ceramic strike face was eroding the steel core, rather than breaking it in the scene of defeating AP round ammunition. Otherwise, there is a critical thickness with the ceramic strike face to erode the steel core in the ceramic/UHMWPE combination, for the reason of the presence of two intermediate parts, the jacket and lead filler, between the core and ceramic target. Furthermore, compared to the ceramic/UHMWPE structure, single UHMWPE laminate is more effective, because that is strong enough to mushroom the core and absorb the energy.
Simulation analysis of the effect of conical cap on the piercing performance of projectile
Authors: Niu G J , Shi X H , Li J C , Qian L X , Yu C X 
Published: July 2020

Abstract
To study on the effect of conical cap on the piercing performance of projectile( Φ 150mm) when penetrating three-interval-layer steel target ( target thickness: 20mm+20mm+20mm, the center of distance between adjacent targets is 1.5m ), the FEA model of penetrating performance of the projectile with conical cap was built by using Ls-dyna, and the attitude change law, velocity change law and impacting acceleration change law of projectile in the process of piercing the targets were analyzed under the different impact velocity(500m/s, 600m/s, 700m/s, 800m/s) and impact angle(0°, 25°, 50°) condition. The simulation results show that: with the increase of impact velocity and impact angle, the time of the conical cap separating from the head of projectile and breaking is earlier, and the breakage of the cap is also more severity. Under the same impact angle and different impact velocity condition, the maximum axial acceleration variation of projectile penetrating into each target is inconsistent, which is closely related to the separation of the cap from the projectile and the breaking of the cap. After the cap separating from the head of projectile, the cap will impact on the target firstly, which can reduce the axial acceleration when the projectile penetrates the target. Under the same impact velocity condition, the residual velocity of the projectile decreased with the increase of impact angle; and under the same impact angle condition, the velocity change after the projectile penetrates the target gradually decreases with the increase of the impact velocity of projectile. The amount of kinetic energy change of projectile increases with the increase of impact velocity of the projectile, that is to say, the higher of the impact velocity, the more of the kinetic energy loss in process of projectile penetrating target.
Dynamic mechanical response and weldability of high strength 7A62 aluminum alloy
Authors: Zhou G X , Lang Y J , Du X Zh , Mao H , Li J B , Wang Sh , Qiao L , Cai H 
Published: July 2020

Abstract
The 7A62 as one kind of Al-Zn-Mg alloys is the highest strength weldable aluminum alloy currently. Plates and forgings of 7A62 alloy have been widely used in the defense system and main bearing parts of special vehicles. The microstructure, dynamic mechanical response and weldability of 7A62 aluminum alloy were investigated by OM, TEM, SHTB, DSC, microhardness and other tests. The morphology and mechanical test results showed that the 7A62 aluminum alloy strengthened by trans-scale precipitates had high strength, high hardness and good plastic toughness. The mechanical responses of the 7A62 aluminum alloy were found to be strain-rate sensitive and the dynamic response behavior was significantly higher than that of the 7A52 aluminum alloy through the SHTB test. In addition, for the as-welded 7A62 the tensile strength reached a scope of 260 MPa-305 MPa, which is considerably higher than the tensile properties reported when using ER5356. Because the weld of 7A62 alloy was free of macroscopic imperfections. The grains were highly equiaxed and homogeneous throughout the melting zone, showing smooth grain boundaries. Compared with 7A52, the lower melting point, low thermal enthalpy and low specific heat capacity of 7A62 alloy are more conducive to weld performed.
Investigation on formation process of a Ta-based dual phase alloy EFP liner
Authors: Hu X B , Wang C T , He Y , He Y , Guo Z P , Ma Y 
Published: July 2020

Abstract
Explosively formed projectile (EFP) has advantages of insensitive to the height of explosion, small interference from reactive armor and large penetration diameter. In this paper, a Ta based dual phase alloy was employed as the charge liner material. The software AUTODYN was used to simulate the formation of EFP under the conditions of different curvature, liner thickness and curvature radius. The following conclusions were obtained:(1), the ratio of length/diameter of EFP decreases with increase of liner thickness.(2) The liner with unequal thickness was proposed, the liner thickness is reduced from the top along the generatrix. The formed EFP from such liner has higher length/diameter ratio, compared to liner with the uniform thickness and the same internal curvature radius. (3) The formed EFP of Ta-based alloy liner could penetrate steel target, the chemical reaction caused by residual mass of EFP could release a large amount of chemical energy.
Study on the energy release rule of sniper projectile penetrating soft protective target
Authors: Li J M , Yan W M , Dong F D , Qu Y J 
Published: July 2020

Abstract
In order to investigate the penetrating mechanism of one sniper bullet against the gelatin target with soft armor under the condition of low speed, using gelatin as the imitation of biological targets, the energy release and transfer law were paid more attention. First of all the ultimate penetration velocity of the sniper projectile penetrating soft protection was carried out, with the ultimate penetration velocity was obtained, experiments and numerical simulation were carried out on the impact of the sniper projectile to soft protective gelatin below the velocity. The simulation results and test results were compared with the sniper projectile deformation and penetration of soft protective layer, gelatin bulging size, verified the accuracy of the numerical simulation. Thus further analysis with the result of numerical simulation, the stress, energy transfer and energy changes of soft protective gelatin penetrated by sniper projectile under non-penetrating conditions were analyzed, and the absorb energy law and the energy dissipation law of soft protective and gelatin in the process were obtained. The results showed that the main reason for the energy dissipation was bullet deformation. Under direct penetrating conditions, the energy of soft protective and gelatin increased with the increase of velocity, while the energy dissipation of sniper projectile also increased. The larger the penetration angle, the energy absorption of gelatin decreases with the increase of the penetration angle, energy dissipation of sniper projectile and energy absorption of soft protective were increased. The results can provide technical guidance for bullet design and individual soldier protection design.