bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of supercavity and shell casing on underwater energy release characteristics of armor-piercing-explosion supercavitating projectile charge
Authors: Hanxin Gong , Kui Tang , Jinxiang Wang , Yiming Ma , Xulong Hao 
Published: December 2024

Abstract
The Armor-Piercing Explosive Supercavitating Projectile (APESP) integrates explosion and armor-piercing effects, introducing a novel approach to underwater munitions. The energy release characteristic of the APESP charge underwater may differ from traditional underwater explosions due to the presence of the supercavity and shell casing. In order to investigate the effects of the supercavity and shell casing on this energy release characteristics, a finite element model of APESP charge underwater explosions is established. The deformation of the target is examined to evaluate the effects of the supercavity and shell casing. The mechanisms of these factors are further analysed theoretically. The results indicate that plastic deformation under the explosion of the APESP charge is primarily completed during the shock wave phase. Both the supercavity and shell casing influence the final deformation of the target by affecting the shock wave intensity, and the supercavity having a more significant impact. The pressure of the initial shock wave transmitted to the external medium of the charge is the highest when the charge is encased by a shell casing, and is the lowest when the charge is inside a supercavity. As the shock wave transmits through interfaces, it is amplified at the air-water interface and attenuated at both the shell-water and shell-air interfaces, with the greatest attenuation at the shell-air interface. Additionally, the presence of the shell casing reduces shock wave intensity but extends the duration of its action, thereby increasing the shock wave impulse.
Simulation Study on Adjustable Structural Shaped Charge Water Jet Forming and Penetrating Improvised Explosive Devices
Authors: Shuai Ma , Hao Xue , Chenxi Bian , Zhiyu Ma , Zhou Yang , Xinyi Shi , Xuke Lan , Guangyan Huang 
Published: December 2024

Abstract
To address the need for rapid and safe disposal of improvised explosive devices during bomb disposal operations, a method utilizing a structurally adjustable shaped water jet for the destruction of improvised explosive devices is proposed. Finite element analysis software AUTODYN is employed to develop a simulation model to study the formation process of the shaped water jet. To further explore the influence of structural parameters of the shaped charge on the jet head velocity and effective jet length, an orthogonal optimization design method is utilized. The water thickness and cone angle of the water-filled liner are selected as key structural parameters for numerical simulation, aiming to obtain the optimal parameter combination for the shaped charge structure. Based on this optimal shaped charge structure, a simulation model for the penetration of improvised explosive devices by the shaped water jet is established. Theoretical analysis and simulation results indicate that a reasonably designed shaped charge structure can generate a water jet capable of safely neutralizing improvised explosive devices without detonating the explosives.
Damage and failure mechanism of bioinspired helical layered structure under low velocity impact
Authors: Zhang Xingyuan , Sun Xin , Dong Yongxiang 
Published: December 2024

Abstract
Inspired by natural organisms, this paper employs carbon fiber epoxy resin composite thin layers to prepare a bioinspired helical layered structural material with excellent strength and toughness by imitating the internal helical layered structural of the mantis shrimp’s rods. The deformation failure and energy absorption characteristics of this material under low velocity impact loads were studied. It shows that, the helical layered structure samples with different interlayer angles exhibit complex intralayer and interlayer stress distributions during the deformation and failure processes, which significantly affect load transfer efficiency. As the interlayer helix angle changes, these intralayer and interlayer stress distributions will vary significantly, which may lead to complex failure modes such as fiber breakage, matrix cracking, fiber-matrix debonding, and delamination, and furthermore have a substantial impact on the material’s impact resistance and energy absorption. These results provide positive guidance for the internal structure design and performance optimization of lightweight, high-strength, and high-toughness materials.
Effects of density and water-entry angle on variations of the maximum impact acceleration of the projectile in water-entry process
Authors: Han Xiangdong , Wang Xiquan , Sun Yanxin , Chen Junbiao , Li Junzhi , Feng Huiyong 
Published: December 2024

Abstract
Projectile water-entry experiments under the working medium with different densities and various water entry angles were performed. Under the temperature of 30°C, mass fraction of lithium bromide solution was changed to obtain various densities. The mass fraction was 1%, 2%, and 3%. The water-entry angles were 25°, 27.5°, and 30°. Real-time variation of the impact acceleration was got by acceleration transducer. Via the analysis, the maximum impact accelerations under all conditions were obtained. Results indicated that with the increase of density, the maximum impact acceleration grew gradually. The maximum impact acceleration increased steadily with the growing of water-entry angle. Variation degree of the maximum impact acceleration indicated that effects of density were more significant than that of water entry angle.
Thermal management design and optimization of the pulse inductor for electromagnetic launch under continuous discharge condition
Authors: Ma Fuqiang , Wang Feng , Wang Sheng , Li Xianglin , Li Yuan 
Published: December 2024

Abstract
As the key component of electromagnetic launch (EML) system, insulation packaging structure and the existence of internal resistance leads to the continuous temperature rise of the pulse inductor under the continuous discharge condition, which greatly reduces the reliability and safety of the EML. This paper takes the solenoid pulse inductor as the research object and proposes a thermal management scheme that using hollow conductor to wind the coil and pumping coolant into the coil. And an optimization design method with flow resistance and thermal resistance as the objectives is proposed. By establishing coupling analysis model, it is demonstrated that the scheme can meet the temperature control requirements of solenoid inductor under continuous pulse discharge conditions. To improve the environmental applicability of thermal management scheme, the feasibility of glycol-deionized water solution as an alternative coolant at low temperature is proposed and demonstrated. The research are of great significance for promoting the engineering application process of EML.
Design and Experiment of Electromagnetic Pulse Protection Circuit for RF Front End
Authors: Jiang Dan , Li Liuhe , Su Yun , Wang Yajie , Jin Zhaoxin , Lu Hongmin 
Published: December 2024

Abstract
This paper introduces the structure and working principle of electromagnetic pulse protection circuit in VHF frequency band in detail. Based on this, a protection circuit with multilevel filtering and transient suppression function is designed. The filter function of the device is realized through a five-order coaxial filter, while the transient suppression feature is accomplished using TVS devices. In order to guarantee the power capacity, the input and output ports of the circuit use N-type connector. Due to good design, the operating bandwidth of the protection circuit exceeds 1.3GHz and the insertion loss is less than 0.5dB. The protective performance of this device was tested by sub-nanosecond solid-state pulse source. The experimental results show that the peak power of electromagnetic protection circuit is greater than 700kW, the suppression capacity is more than 33dB, and the response time is better than 1.4ns.
Study on chemical kinetics of plasma-assisted energetic material combustion
Authors: Guo J T , Yang C X 
Published: December 2024

Abstract
The combustion kinetic mechanism of C4H8N8O8(HMX) is established, with 30 components and 94 reactions. To account for the effects of plasma ignition and assisted combustion, the model incorporates reactions involving H free radicals at varying mole fractions. The thermodynamic parameters of products and combustion pathways of HMX are analysed by using Chemkin. The result of sensitivity analysis shows that the reaction of N2O+H=OH+N2 has a great influence on the ignition delay time. H and OH radicals play a positive role in ignition, while OH has higher activity than H. The sensitivity analysis of OH shows that N2O+H=OH+N2 has high sensitivity and highest reaction rate. As the mole fraction of H in the reaction chamber increases, the generation rate of OH increases. The reaction rate at 0.2 mole concentration of H is twice higher than 0.1 mole concentration. The increase of OH mole fraction increases the reactivity and decreases the ignition delay time.
Based on supercritical carbon dioxide projectile launch technology research
Authors: Tao Jie , Yang Chunxia , Han Shuyong , Wang Jian , Wang Qifan 
Published: December 2024

Abstract
In order to expand the application of compact high-velocity gas cannons in the field and hazardous areas, this paper proposes a new type of one-stage gas cannon with supercritical carbon dioxide as the gas medium. FLUENT numerical simulation method was used to study the gun bore firing process. Based on the projectile force, projectile velocity and flow field cloud diagram, the firing characteristics of the gas gun were analysed. The effects of different structures, different initial pressures and projectile masses on the firing performance were investigated. In order to verify the accuracy of the simulation model, a supercritical carbon dioxide gas cannon experimental test platform was built. The results show that the pressure in the chamber of the gas cannon with stacked arrangement structure fluctuates. Increasing the initial pressure and reducing the mass of the projectile can increase the initial velocity of the projectile. The greater the initial pressure is, the greater the pressure loss is under the stacked arrangement. There is a certain matching relationship between the thickness of the diaphragm, the filling amount of liquid carbon dioxide and the amount of heating charge. The amount of heating charge and the remaining thickness of the diaphragm have a greater impact on the launch performance of the gas cannon than the mass of liquid carbon dioxide.
Microstructural Evolution and Mechanical Property Enhancement in WAAM Components
Authors: Cheepu Muralimohan , Yenumula Padmini , Kantumuchu Venkata Charan , Annapureddy Damodara Reddy 
Published: December 2024

Abstract
Wire arc additive manufacturing (WAAM) is increasingly being recognized as a favourable method for producing large-scale products. The microstructural evolution during the solidification of molten pool in WAAM is influenced by factors such as heat input and the deposited layer sequence. In this study, the impact of different layering sequences on grain growth, microstructure, and mechanical properties was investigated by depositing Inconel 825 alloy using gas metal arc welding. Different layering sequences were employed to minimize the development of columnar grains that typically outcome from oscillating beads and bead upon bead within a single layer. The unidirectional heat flow in conventional layering techniques encourages grain growth in the direction of the heat source, with grains forming at the fusion boundaries and growing upwards. At the interface between previously solidified beads and the liquid metal, nucleation and epitaxial grain growth occur, prominent to the formation of transverse columnar grains, with their size determined by the grain structure of the preceding layer. While traditional stacking sequences tend to produce columnar grains, a zigzag layering approach was found to refine grain growth by disrupting the direction of heat flow and grain development. This resulted in smaller, more fragmented grains, which enhanced the isotropic properties of the material. The study further demonstrated that the anisotropic behavior of wire arc additively manufactured components is closely related to grain growth direction and size, both of which are significantly influenced by the layering sequence. The zigzag layering sequence not only improved hardness and tensile strength compared to conventional layering methods but also enhanced the resolution and linearity of the deposited walls.
Lightweight design of cannon frame considering dimension and topology coupling
Authors: Wang Meng , Hu Dan , Zhao Jiayu , Gong Borui , Hao Chengye , Lin Wenqi 
Published: December 2024

Abstract
The cannon frame is a primary load-bearing component of the firepower system, and lightweight design plays an important role improving the artillery’s manoeuvrability. However, the present lightweight design methods don’t consider the interdependency between dimension and topology, hindering the cannon frame from achieving the ideal stiffness to mass ratio. To tackle this issue, a novel lightweight design methodology considering dimension and topology coupling is proposed. By means of orthogonal experiment and topology optimization, various topologies of cannon frame with distinct dimensions are generated. Then the response surface method (RSM) is implemented to devise surrogate models that embody dimension, topologies, stiffness and mass mapping. Finally, global optimization is performed using particle swarm optimization (PSO) algorithm to achieve the concurrent lightweight design of dimension and topology. Compared with the original scheme, the proposed design method reduces the weight by 12.7%.
Research on the dynamic characterization of hydraulic buffer based on gene expression programming approach
Authors: Tan Tian , Dai Jin-song , Zhang Yong-tao , Meng Chao , Lin Sheng-ye 
Published: December 2024

Abstract
This paper is devoted to the dynamic characterization of the autocannon buffer through the surrogate model technique. Autocannon is usually equipped with spring hydraulic buffers, and flow field analysis based on numerical simulation is the focus of buffer characteristic research. However, commercial software is generally computationally expensive and challenging to interact with system dynamic models. To end these, this paper proposes constructing a surrogate model through the gene expression programming (GEP) approach and embedding it into the autocannon bond space model for recoil process analysis. The dataset for the GEP model is derived from the fluid pressure simulation based on computational fluid dynamics (CFD). By this, the buffer surrogate model is bonded to the firing dynamic model by a power bond formed by recoil velocity and hydraulic pressure. Moreover, an engineering example of an autocannon buffer is presented to demonstrate the validity of the proposed method; the analysis results show that the Pearson correlation coefficients between the GEP model and the training and testing sets are 0.99 and 0.98, respectively. The calculated recoil force extremum and recoil velocity are consistent with the experimental results.
Coupling Valve Opening and Closing Effects on Compressed Air Ejection System Projectile Launch Study
Authors: Tao Y , Zhang P , Yang C H , Ma W N , Zhang Z D , Zheng X L 
Published: December 2024

Abstract
Based on the working principles of high-pressure pneumatic pilot-operated valve (HPPV) and compressed air ejection device, a multi-physics simulation model of the compressed air ejection device considering pneumatic, mechanical, and leakage factors was established in AMEsim. A compressed air ejection test platform was also constructed to conduct unloaded tests. The validated simulation model investigated the impact of different initial parameters on the dynamic characteristics of the HPPV during the compressed air ejection process. The results demonstrate that the multi-physics simulation model of the coupled valve opening and closing exhibits high computational accuracy. During the compressed air ejection process, the dynamic characteristics of the HPPV still meet the requirements of the compressed air ejection device, effectively preventing ineffective gas leakage. The initial pressure of the ejection gas source and the supply pressure driving the HPPV significantly influence the dynamic characteristics of the valve during the compressed air ejection process.
FSK energy modulation integrated primer fuze technology based on S-P topology
Authors: Chang Hao , Yang Zhen , Yu Weixing , Fang Wei , Wang Guoqiang , Liu Chang , Zhang Yifan , Jiang Zhiqiang 
Published: December 2024

Abstract
The wireless energy transmission technology is utilized in the integrated primer fuze device to achieve the integrated transmission of energy and information for weapon equipment. A wireless energy and information transmission system model is designed specifically for the characteristics of energy and information transmission of integrated priming fuze. The working principle of the system under S-P magnetic coupling resonance is analyzed, and the inverter circuit and rectifier circuit are further designed. To achieve synchronous transmission of energy and information, an energy modulation/demodulation method based on FSK is proposed. Simulation verifies the feasibility of the system design, showing that while the S-P system has a simple structure and constant voltage output characteristics, it belongs to first-order resonance. When transmitting information through frequency modulation, there will be a reduction in system transmission efficiency due to deviation from the resonance point, making it only suitable for systems with small energy transmission requirements.
Research on the influence of cavitator configuration on the cavitation flow characteristics around projectiles
Authors: Qi Xiaobin , Xia Fangchao , Wang Jiawen , Liu Huan 
Published: December 2024

Abstract
In order to optimize the projectile head shape, numerical simulations were conducted on the cavitation flow field of different cavitator configurations, including inverted trapezium, hemispherical, and cylindrical cavitator configurations. The results indicate that under the same cavitation number, the inverted trapezium cavitator produces the largest cavitation profile and is more prone to cavitation generation. Cylindrical cavitator come in second place, while hemispherical cavitator are less prone to cavitation. The turbulent kinetic energy is closely related to the generation of cavities, and the turbulent kinetic energy is highest near the inverted trapezium cavitator, so its bubble size is also the largest. The diameter ratio between the smaller and larger bottom surfaces of the inverted trapezoidal cavitator has a significant impact on the high-speed cavitation flow around the projectile. As this ratio increases, the thickness of the cavity increases, but it also leads to a significant increase in the navigation resistance coefficient. Overall, the inverted trapezium cavitator is easier to generate cavitation and can provide support for the optimal design scheme of supercavitating projectiles.
A refined prediction model for the initial disturbances of the projectile in the self-propelled gun
Authors: Dong X , Rui X , Yang F , Zhang S 
Published: December 2024

Abstract
In the gun launch process, the continuous propellant combustion provides power and energy for the projectile. Due to the gap between the projectile and barrel, the high-speed motion of the former is generally accompanied by contact and collision with the latter. Meanwhile, the gun also recoils under the propellant gas. Notably, the above complex motion of the system causes the initial disturbances of the projectile and muzzle. Previous launch dynamic models usually neglect the influence of the gun recoil on the combustion and flow in the chamber. However, the gun recoil inevitably further increases the chamber’s free space, resulting in the calculation deviations of projectile and muzzle disturbances. The above deviations ultimately determine the firing accuracy and firing stability prediction. To study the in-bore projectile motion and subsequent external ballistic process more accurately, an improved coupled calculation method of launch dynamics is developed. This work combines the interior ballistic two-phase flow dynamics considering the gun recoil, in-bore projectile motion theory, multibody system dynamics, and necessary high-precision numerical schemes. The launch process of the 155 mm self-propelled gun is studied. As the results show, the calculated vibration characteristics, dynamic response, and interior ballistic performance indexes are consistent with measured ones, verifying the feasibility of the above method. In addition, the initial disturbances of the projectile with and without considering the recoil’s influence on the combustion and flow in the chamber is discussed. The work in this paper provides an accurate tool to predict the initial disturbances of the projectile.
Principle of fault direction discrimination in near area of AC grid-connected doubly-fed wind farm
Authors: Qiu Jingran , Wen Minghao , Qian Kun , Zhang Kaize 
Published: December 2024

Abstract
With a large number of new energy sources, the current characteristics of doubly-fed fans under the circumstances of AC grid connection short-circuit faults have become the focus of research. After crowbar resistance is put in, the attributes of short-circuit current become complicated. By calculating the correlation coefficient between the voltage of the AC system and the current of the doubly-fed fan, the fault direction can be accurately judged. In this paper, the research work for new energy power system fault analysis and protection provides a new thought and method. The current characteristics of the doubly-fed fan under fault state are analyzed deeply, and the principle of fault direction discrimination based on waveform correlation coefficient is proposed. The advantage of this method is that it is independent of fault types, and can be applied to all kinds of fault situations, with high reliability and practicability. Simulation results unveil that the principle put forward can judge the fault direction accurately, reliably, and sensitively when various types of faults occur in areas near an AC grid-connected doubly-fed wind farm.
Coupling mechanism for total transfer capability of transmission interface with transient overvoltage constraint
Authors: Tang Xuelin , Liu Qihui , Wu Linlin , Liu Hui , Xu Man 
Published: December 2024

Abstract
To explore the correlation between transient overvoltage (TOV) and total transfer capability (TTC), and clarify the coupling law of multi-level transmission interface TTC, this paper first analyses the mechanism of TOV under AC symmetrical faults in high-proportion power electronic systems, derives a TTC analysis model considering TOV constraints, and examines the relationship between output power and TOV. Based on this model, the coupling mechanism of the coupled interface TTC is further analyzed. The coupling laws of the interface TTC are obtained. Finally, the validity of the theoretical analysis is verified through time-domain simulations.