bluuebunny/crossref_metadata_2025_split huggingface dataset:
Prediction of creep performance during long-term storage of composite directors based on nonlinear viscoelasticity
Authors: Sun T S , Yu C G , Wang Q , Yang W C , Zhong J L 
Published: July 2020

Abstract
In order to investigate the long-term storage creep performance of composite directors for multiple launch rocket systems, E-glass fiber reinforced epoxy matrix composite laminates were prepared and the 60/60-minute creep/creep-recovery tests were carried out at different stress levels. The master curves of long-term creep compliance were obtained by shifting the short-term creep compliance based on the superposition principle, and then the parameters of linear-transient creep compliance model were obtained by a curve fitting procedure. The functional relation between the Schapery’s nonlinear parameters and the average matrix octahedral shear stress was developed by an analytical procedure. Finite element method and the user-defined material subroutine (UMAT) are used to establish the long-term storage numerical analysis model of composite directors, and the creep deformation after 15-years stacking storage was predicted.
Prediction of three-dimensional elastic behavior of filament-wound composites based on the bridging model
Authors: Yin D M , Li B M , Ch Xiao H 
Published: July 2020

Abstract
With the high specific stiffness, specific strength and designable ability, filament-wound composites have been widely applied in many industries, such as aerospace, energy and transportation, and they are also the one of more ideal choices for the lightweight structural design of weapon system. However, their complex structures, which including the cross-overs, undulations, and overlaps between different winding passages of the fiber bundles, make it difficult to obtain their macro mechanical properties. And this work will provide a method to predict the three-dimensional equivalent elastic properties of the filament-wound composites based on the multi-scale homogenization principle. The representative volume element (RVE) in the meso-scale is defined on the basis of the filament winding pattern, which characterizes all the micro-architecture details of the filament wound composites, such as fiber undulation, winding angle and lamination arrangement. Referring to the principle of volume average in the analysis method of braided composites, a theoretical prediction model for the three-dimensional equivalent elastic constants of the filament wound composites is established by adopting the bridging model. Through this method, the results obtained for the previous experimental model are in good agreement with the experimental ones, which verifies the reliability of this model. In addition, the effects of some winding parameters, such as winding angle, on the equivalent elastic behavior of the filament-wound composites are analyzed. And the rules gained can provide a theoretical reference for the optimum design of filament-wound composites.
The full version of this extended abstract will appear in Defence Technology in 2020.
Study on single-lap joints tensile properties under fire and thermal conductivity of Z-pin reinforced thermal protection composites
Authors: Li L S , Li Y , Huan D J 
Published: July 2020

AbstractQuartz fiber reinforced phenolic (QFRP) resin composites were often used in thermal protection structures such as the engines and tip of missiles or rockets, but its anti-erosion performance needs to be further optimized. Z-pin technology can improve the anti-erosion performance because Z-pin effectively improved the inter-laminar shear strength of composite materials. However, it will increase the through-thickness thermal conductivity (TC), resulting in a decrease of its thermal protection performance. This paper successfully established the equation about through-thickness TC of Z-pin reinforced composites based on theoretical analysis and experimental results and tested the single-lap joints tensile strength of the samples compared with the blank and Z-pin samples under fire which characterized the interlayer performance of Z-pin reinforced thermal protection composites at high temperatures. Research showed that the through-thickness TC of the composite increases regularly with the TC and content of Z-pin, and this is because the pins act as a thermally conductive pathway. The TC increases by 13.19%, 12.34% and 12.13% when the Z-pin implantation volume fraction is 2.18%, 0.785% and 0.401%, respectively. Z-pin samples have an increase in shear strength of 63.85%, 78.97% and 88.31% compared with blank samples when the ablation time is 20s, 40s and 60s, respectively, indicating that Z-pin technology effectively could reduce the shear strength of single-lap joint with the increase of ablation time. These results prove the controllability of the through-thickness TC enhancement and effectiveness of interlayer strength by Z-pin, and guide the structural design of Z-pin reinforced thermal protection composites.
Optimization in the multi-cycle densification technology for manufacturing of the high density carbon fiber reinforced carbon
Authors: Ilyushchanka A Ph , Kryvanos A K , Prokhorov O A , Kryvulenka M U 
Published: July 2020

Abstract
Carbon fiber reinforced carbons (CFRC) are used to work in extreme environments because of their erosion resistance, ablative ability, and high mechanical characteristics at extremely high temperatures. The production of such materials includes several cycles of gas-phase or liquid-phase densification of initially porous carbon fibers reinforcement. The paper analyzes the main process parameters and densification routes, and their role in the manufacture of CFRC with high performance. A method for calculating changes in the density and porosity of CFRC during a multi-cycle densification has been developed. The results of the experiments confirmed the adequacy of this method.
Tests of thermal insulation properties of bakelite and glass-epoxy composite
Authors: Rybakiewicz L , Sokolowsk D 
Published: July 2020

Abstract
This paper presents tests results of thermal insulation of bakielite and epoxy resin with glass fibre. The tests were carried for the same thicknesses of different type of insulation materials and taking over the temperature through a steel plate under insolated material was measured. Based on the tests results material with better thermal insulation properties was chosen.
Special software design for data acquisition and experi-mental database management of electromagnetic launch system
Authors: Tian H , Xia Y , Huang F , Jin Y , Wan G , Ni Y J , Li B M 
Published: July 2020

Abstract
Electromagnetic launching system is composed of the Electromagnetic Railgun (EMRG) and the large-scale Pulse Power System (PPS). According to the different test requirements of PPS and EMRG, the special master-slave distributed data acquisition software for electromagnetic launching system is designed by using LabVIEW graphic language. The test host and the sub-machines are multi-channel transient data acquisition systems based on PXI bus. The host PXI is used to measure the comprehensive parameters of the EMRG in multi-physical field. All sub-PXIs are used to diagnose the discharge current signals of each Pulse Forming Unit (PFU). The database management software uses C# programming language to design a friendly human-computer interaction interface, and uses SQL Server software to establish and manage the database, which realizes the comprehensive management of experimental data, tasks and resources involved in the EMRG experiments. The experimental information and experimental data are classified and filed, and the experimental data can be queried, and the experimental results can be analyzed and compared. The data acquisition and experimental database management software has perfect functions, friendly user interface, convenient operation, good versatility, and can also be used in other experimental occasions.
Researches on the trigger pulse width’s compression of high power thyristor
Authors: Luo H G , Gu J L , Xia Y , Ge Ch M , Li X , Wang Sh Y 
Published: July 2020

Abstract
The width compression phenomenon of the trigger signal in triggering high power thyristor was first observed in the experiments. The trigger pulse was measured by the oscilloscope in the experiments. The experiments showed that with the increase of the voltage supplied to the thyristor from 1kV to 7kV, the width of the trigger pulse was compressed gradually from 70us(the width with no compression) to 45us. Then with the increase of work voltage from 7kV to 10kV the width of the trigger pulse was not compressed further. This research is very valuable for the design of the thyristor trigger signals.
Analysis on the Influence of Breech Voltage on the Pulsed Discharge Characteristics of Capacitive Pulsed Power Supply in EML
Authors: Li Zhenxiao , Hao Shuangpeng , Ma Fuqiang , Li Baoming 
Published: July 2020

Abstract
Corresponding to the different gradient of the ideal working current, the movement process of the armature in the railgun bore can be divided into rising phase, stable phase and decreasing phase. Based on the load characteristic and the lumped-element equivalent circuit of the railgun, the characteristics of the railgun’s breech voltage in above three phases were analysed. Under the condition that the size of the launching system is close to the same, the change ranges of the breech voltage of the augmented railgun is much larger than that of the simple railgun, and the breech voltage of the augmented railgun is a very high forward voltage in the rising phase. The influence of the breech voltage on the discharge characteristics of the capacitive pulsed power supply was studied. In the rising phase, the high breech voltage of the augmented railgun has a significant adverse effect on the pulsed discharge characteristics of the capacitive pulsed power supply whose pulsed forming net consists of a large number of pulsed forming units with small energy storage and high resonance frequency. As a result, part of the stored energy of the capacitive pulsed power supply cannot be used effectively, which leads to the decrease of the working efficiency of the launching system. Using the launching system with a 13-MJ capacitive pulsed power supply and a medium calibre augmented railgun, the launching simulation and test were completed, and the analysis was verified. The research has important enlightenment for improving the match between the capacitive pulsed power supply and the railgun.
Study on dynamic characteristics of micro gas turbine with load mutation of pulse generator
Authors: Liu Jiaxing , Fu Xin 
Published: July 2020

Abstract
Because of the sudden load phenomenon of the pulse generator, it is required that the gas turbine, as the primary energy source of the pulse generator, not only has certain stability, but also has good dynamic performance. In this paper, based on AMESim, the dual rotor micro gas turbine pulse generator set is modeled, calculated and studied the dynamic characteristics of the micro gas turbine in the case of sudden change of fuel quantity, and the effects of fuel increasing speed on the dynamic characteristics of gas turbine are studied with three different fuel supply strategies (a), (b) and (c).
Characteristic analysis of inductor in pulsed power supply changing with shape ratio
Authors: Hao Shuangpeng , Li Zhenxiao , Ma Fuqiang , Li Baoming 
Published: July 2020

Abstract
Solenoid inductor is an important component of pulse power source, its volume, electrical performance, stress and magnetic field generated during discharge directly affect the relevant parameters and performance of pulse power source. This paper presents a calculation model for solenoid inductor in pulsed power supply, given the inductance value and the wire, the volume, stress, resistance and external magnetic intensity of the five inductance values inductor under different shape ratio are calculated by changing the number of turns, and discusses and analyzes the changes and extremum in the volume, resistance, stress, and magnetic intensity of inductor with shape ratio. This article has certain guiding significance for the design of solenoid inductors.
Research on high-rate and repeat frequency discharge lithium battery for electromagnetic launch primary power supply
Authors: Ren Ren , Zhiqiang Dong , Jingang Liu , Weisheng Ye , Zizhou Su 
Published: July 2020

Abstract
Lithium battery with excellent comprehensive performance can effectively improve the firing frequency of railgun, firing times of railgun, system integration and security of electromagnetic launch weapon system. The development of lithium-ion batteries were introduced in this paper, mainly from the material system of lithium battery, analyzes all kinds of lithium battery, combined with electromagnetic emission weapon system for high voltage cascade characteristics of primary lithium battery power supply demand, points out the advantages and disadvantages of the lithium battery materials system, determine the improved after optimization of high ratio of lithium iron phosphate battery as primary power battery components. Two kinds of lithium batteries have been tested by high power discharge test, which proves that the high power lithium iron phosphate batteries have better performance. The high power lithium iron phosphate battery with soft package, high discharge rate, high power density and good security, can meet the requirements of high power, high power density and good integration of the primary source of electromagnetic emission.
Experimental Study on Plasma Ignited Single-base Propellant using SEM and EDS
Authors: Yang Chunxia , Jin Yong , Li Haiyuan , Yang Yong , Ni Yanjie , Li Zhenxiao , Li Baoming 
Published: July 2020

Abstract
To explore the reaction mechanism in the plasma-propellant interaction, plasma ignition and conventional ignition experiments are carried out on a single-base propellant. The samples after ignition are analyzed by scanning electron microscopy (SEM) and X-ray energy dispersive spectroscopy (EDS). Results show that the plasma jet brought a variety of high enthalpy flows into the propellant and deposited them on the surface of the propellant. These high enthalpy particles reacted with the propellant on the surface rapidly and produced voids and cracks different from the surface melting mode in the conventional ignition process. These voids provided microchannels for ignition and heat transmission. The area of ignition and combustion increased accordingly.
Research on armature vibration characteristics of electromagnetic gun’s extreme sliding electrical conta
Authors: Li Xiangjun , Wang Jun , Zhang Xianchun , Wang Sheng 
Published: July 2020

Abstract
The electromagnetic railgun is a new launch method that uses electromagnetic force to drive payloads and accelerate objects to super high speeds. In the electromagnetic railgun system, the armature is a key component that converts electrical energy into kinetic energy of projectile. It will vibrate when it moves between rails, and the vibration characteristic is the behavior when the armature slides along the rail. Armature vibration will affect firing accuracy, damage integrity of rail, and affect life of rail. Armature vibration may also cause arc discharge, which will damage the armature, consume energy, and reduce the launching efficiency of the electromagnetic railgun. In order to provide a more reasonable design for the armature, based on the finite element simulation software ANSYS, a modal analysis was performed on the armature during the launch process, and the possible modes of its free vibration were simulated. The analysis found that the vibration modes are mainly divided into translational movements along the X, Y, and Z directions and torsional movements along the X, Y, and Z axes. Whether or not the prestress is loaded on the armature and the magnitude of the prestress does not significantly affect its vibration mode. Changing the armature structure and materials will affect the vibration mode of the armature accordingly.
Analysis of firing after shortest distance between target and anti-aircraft gun
Authors: Wang J , Chang S F , Fan X C , Li X J 
Published: July 2020

Abstract
In order to make full use of the performance of high-muzzle-velocity anti-aircraft weapon, make full use of the target firing segments on the entire route of the target, fully grasp all the firing opportunities, and reduce the possibility of a target breaking through the defense, the original pre-navigation firing (firing before shortest distance between target and anti-aircraft gun) method based on a muzzle velocity below 3ma cannot meet the needs mentioned above. Based on the establishment of high-muzzle velocity projectiles, this paper aims at the current situation of less post-navigation firing (firing after shortest distance between target and anti-aircraft gun), verifies the feasibility of post-navigation firings by analyzing the relative remained velocity required to penetrate the target, and verifies that with the gradual increase in projectile muzzle velocity, its firing range and timing can increase simultaneously. It provides a theoretical basis for post-navigation firing, increases the firing opportunities for the target on the entire route, and provides a reference for the demonstration, design and testing of the new anti-aircraft fire control system.
An investigation on plastic deformation of rotating band for large caliber gun projectile during engraving process
Authors: Guo J H , Yao X F , Qiao J M , Li Y L , Zhang X D 
Published: July 2020

Abstract
The projectile engraving process of a large caliber gun is investigated by adiabatic process simulation based on smoothed particle hydrodynamics (SPH) and finite element method (FEM). The acceleration, velocity, displacement of the projectile are obtained, and the resistance force and moment applying on the projectile by the gun bore are also obtained. The resistance force varying with the travel of projectile is obtained and the curve reveal a peak in the particular position. At the beginning stage of the deformation, the force increased rapidly and then exhibits a slight transitional drop. The deformation process, equivalent stress, equivalent plastic strain, temperature and damage variable distribution of rotating band are obtained by numerical simulation. In order to visualize the simulation results, two kinds of post processing method are proposed. The frequency distribution of particles was get by particular variables, and the result showing that the maximum temperature of rotating band increment due to plastic deformation can be 150 degrees. Only few material can accumulated to the failure threshold, which indicates that large plastic deformation occurrences in rotating band while ductile fracture does no happen. The second method is to interpolate the field variable on a specified section by developing a program. The results show that the maximum equivalent stress is about 300MPa, the stress triaxility is less than zero, which indicates that most material under compression, and the maximum value of J3 related parameter is 0.5 located at rotating edge, which indicates material under shear loading, which agrees with the function of rotating band.
Numerical Study on Hydrogen Detonation Initiation through an Inhomogeneous Thermal Explosion
Authors: Da Chen , Jianguo Ning , Jian Li 
Published: July 2020

Abstract
Detonation initiation through an inhomogeneous energy source is studied using one-dimensional simulations. The energy source is divided into two segments, called segment A and segment B. The initial temperature and the length of two parts energy source are varied to provide different auto-ignition delay time and strength of the leading shock. Detailed chemical reaction mechanism is used for a stoichiometric hydrogen/oxygen mixture diluted by 70% Argon. According to the initial thermodynamic parameters, four different regimes of detonation initiation were found in the present study, namely high-critical, low-critical, low-subcritical and high-subcritical regimes. The critical temperature and internal energy in the inhomogeneous energy source to initiate the detonation are analyzed. It was found that, as we fix the length and temperature of segment B, by changing the temperature of segment A, there are two critical temperatures, called high critical temperature and low critical temperature. When the temperature of segment A higher than the high-critical temperature or lower than the low-critical temperature, there is no detonation occurs. As we change the length ratio of segment A and B, the same results was found. In addition, the relationship between the length ratio of segment A and B and the energy to initiate detonation are also studied.
Numerical simulation of the formation behavior of coated explosive formed projectiles
Authors: Yu Q B , Cun H , Xie J W , Wang H F 
Published: July 2020

Abstract
The formation behavior of coated explosive formed projectiles (CEFP) with different structure and material liners were numerically simulated by AUTODYN-2D. There are many factors affecting the coating effect of CEFP, the numerical simulation results show that the structure and liner material have remarkable influence on the velocity and forming effect of the CEFP. For the coating effect, the liner thickness has an optimum range. When the liner thickness is small or large, the explosive balls will deform seriously or not be wrapped sufficiently, and the EFP velocity decreases with increasing the axial thickness of the liner, when the liner thickness is 4.5mm and 5mm, the coating effect is the best. The curvature of liner also has an optimum interval, when the curvature of liner is small or large, the explosive balls will be lengthened or retrogradely compressed and destroyed, and the EFP velocity increases with the decreasing the curvature of the liner. When aluminum, iron, copper and tungsten are used as liner materials, the density and ductility of the material will affect the coating effect. The high density copper liner can achieve a good coating effect and well penetration performance.
A study on combat process simulation and casualty forecasting based on system dynamics
Authors: Peng B , Xu L , He Zh 
Published: July 2020

Abstract
The traditional casualty prediction method is of low accuracy, and there is no prediction of the detail time and place of the casualty. Moreover, there is no consideration of the real combat environment. This study uses system dynamics method to build casualty forecasting model, based on the dynamic combat process of red and blue troops to predict the temporal and spatial distribution of casualty. The simulation results are similar to the one actual case. Results show that the modern combat has short duration and the total number of casualties declined over the past but the casualty is concentrated in a short period of time, and attributed in wider areas. Air forces and relative military strength are the key influence factors for casualty. The use of system dynamics model for casualty prediction can significantly improve the pertinence and effectiveness of medical support.