bluuebunny/crossref_metadata_2025 huggingface dataset:
Study on Anti-penetration performance of metal matrix ceramic ball composite
Authors: Wang J H , Shi X M , Cui C L , Xia X , Li Y , Wang Q , Zhang L J , Shen Z , Li R , Fang X Z
Published: December 2024

Metal matrix ceramic composite plates composed of two ceramic balls -- Aluminium oxide(Al2O3) and Zirconia(ZrO2) toughened Aluminium oxide. Analogue simulation was finished by LS-DYNA software. Ballistic performance tests of 14.5mm armour-piercing incendiary (API), 30mm armour-piercing projectiles(AP), and 105 armour-piercing simulating projectiles(APSP) were conducted on metal matrix ceramic composite plates. Results showed that the maximum protection coefficient of Al2O3 ceramic balls metal matrix composite materials against 14.5mm API, 30mm AP, and 105mmAPSP are 2.63, 1.80, and 1.60 respectively. The maximum protection coefficient of ZrO2 toughened Al2O3 ceramic balls metal matrix composite materials against 14.5mm API and 105mm APSP are 2.37 and 1.77.
Critical ricochet angle of projectile penetrating into concrete
Authors: Huang C L , Wang Z Q , Zhao S J
Published: December 2024

The ricochet is an objective phenomenon when a projectile penetrates concrete at an oblique angle. The minimum incident angle at which this phenomenon happens is termed the critical ricochet angle. To enhance the consistency between numerical simulations and experimental studies of the critical ricochet angle, this research has established a numerical model of a deformable projectile penetrating a concrete target. The numerical model has been optimized by considering computational accuracy, efficiency, and practical engineering applications. Through dimensional analysis of factors influencing the critical ricochet angle, the working conditions have been designed with single variables such as impact velocity, target strength, warhead curvature radius, and projectile length. The critical ricochet angle corresponding to each working condition has been calculated by using the optimization model. The results show that the optimized model can simulate the oblique penetration of a projectile into a semi-infinite concrete structure while maintaining calculation accuracy and efficiency. The critical ricochet angle shows a positive correlation with the impact velocity, warhead curvature radius, and projectile length, and a negative correlation with the target strength. Additionally, the projectile deformation is also significant factors affecting the critical ricochet angle. The numerical model developed here is of considerable importance for advancing the methods of critical ricochet angle computation and guiding the design of concrete protection engineering.
Study on critical bounce and damage of tungsten alloy spherical fragments penetrating cylindrical concrete
Authors: Zhenning Wang , Jianping Yin , Zhijun Wang , Jianya Yi , Xudong Li
Published: December 2024

Prefabricated fragment bomb will produce a large number of tungsten alloy spherical damage elements, causing damage to a wide range of targets. The phenomenon of bouncing projectile will deviate from the trajectory of fragments and affect the damage field of explosive projectile. In order to accurately obtain the influence of bouncing projectile on the residual damage of tungsten ball fragments, the damage of concrete targets caused by bouncing projectile is analyzed. The oblique penetration of tungsten ball fragments into concrete at different angles and speeds is simulated. Through the angle-by-angle approximation of cylinders and planes with different curvature radii at 1000m/s, the critical bounce angles in each case are obtained. Based on this, the critical bounce angle of each cylinder under medium and high speed conditions is obtained. The simulation results show that the critical bounce angle decreases with the increase of curvature, and the critical angle increases with the increase of velocity. The residual velocity angle of the projectile increases with the increase of curvature. The relationship between concrete damage degree and curvature and velocity is obtained. Based on the critical angle of penetration of concrete with different fragment flight parameters, the killing range of fragments can be corrected, and the accurate evaluation of the killing ability under the condition of bouncing projectile can be realized.
Failure mode analysis and dynamic response prediction of fully confined reinforced concrete slabs under blast loading
Authors: Jiaxin Li , Jianping Yin , Xudong Li
Published: December 2024

With the development of human society, various accidental explosions and terrorist attacks have occurred frequently, posing a great threat to the safety of building structures. In order to improve the safety of building structure, the finite element model of reinforced concrete slab was established by ANSYS/LS-DYNA finite element analysis software. By comparing with the experimental results, the accuracy of the established finite element model was verified, and the failure modes of reinforced concrete slab under different scaled distances were analyzed. The effects of three damage factors: concrete compressive strength, protective layer thickness and reinforcement ratio on the dynamic response of the slab were analyzed. Based on the Π theory of dimensional analysis, the dimensionless relationship between the peak displacement of the mid-span of the plate and the scaled distance of the explosion is obtained. On the basis of a large number of numerical simulation results, the dimensionless relationship for quickly predicting the dynamic response of the plate is summarized. The results show that with the increase of scaled distance, the failure mode of the plate will gradually change from brittle shear failure to plastic bending failure. Increasing the compressive strength and reinforcement ratio of concrete and reducing the thickness of the protective layer can reduce the peak displacement of the mid-span of the slab and improve the anti-explosion performance of the slab. It is verified that the proposed dimensionless prediction relationship can better predict the dynamic response of reinforced concrete slabs at different scaled distances, so as to provide some reference for the field of structural anti-explosion.
Research on Data Recorder of Sample Return Missions Against High Overload
Authors: Liu Xinjun , Shen Na , Zhang Xiangjin , Yue Yajun
Published: December 2024

In this paper, we present the design and implementation of an ARM-based data storage system tailored to meet the extensive data acquisition, storage, and hard landing recovery requirements of aerospace sampling and return missions. The system employs the STM32 as the primary control chip and utilizes the RS422 interface to transmit two analog signals and one image data signal. Data is stored on an eMMC chip via the eMMC 5.1 protocol. Additionally, composite buffer materials were used for protection. The mechanical casing of the data recorder was simulated using the finite element software ANSYS, and its overload resistance was validated through Machete hammer impact test. Experimental results demonstrate that the system can achieve reliable data storage at 10 Mb/s, withstand overload accelerations exceeding 4000g. Experiments have demonstrated that the system operates without packet loss or bit errors, providing a solution for high-reliability, high-speed, large-capacity, and compact data storage in the high-overload environments of aerospace sampling and return missions.
A study of the kinematic response of launch vehicle subjected to a far-field blast impact
Authors: Yu Wenxin , Liu Songhan , Liu Zhipeng , Wang Yongxiang
Published: December 2024

The launch vehicle is exposed to a far-field blast wave, leading to shock displacement and attitude change, thereby posing the risk of losing its launch condition. To analyze the motion response of the launch vehicle under blast wave load, simulations are conducted based on the results of shock experiments from the shock tube. Comparing the experiment with the simulation results reveals that utilizing an equal impulse triangular wave load instead of a blast wave load can also yield relatively correct outcomes. Furthermore, by employing dimensional analysis, a similarity relationship between blast wave load and the motion response of the launch vehicle is established. The study summarizes the effects of blast wave pressure and action time on the displacement, velocity, and acceleration of the launch vehicle. Finally, the similarity law is verified through simulation. Under conditions of geometric and physical similarity, the kinematic quantities of the original size model can be predicted through the calculation of the small model of the launch vehicle. This holds significant value for research on the kinematic response of launch vehicles when exposed to explosion blast waves and related engineering applications.
Design of laser pyrotechnic device for insensitive ammunition
Authors: Cao Chunqiang , Ma Jianwei , Chen Jianhua , He Aifeng , Zheng Wei , Li Yan , Yin Guofu
Published: December 2024

In this paper, the design method of a laser pyrotechnics system for insensitive ammunition is introduced. The functional architecture, product structure and electromagnetic protection of the semiconductor laser included in the system are designed. At the same time, the principle, structure, function and advantages of the optical safety components of the magneto-optic switch are introduced in detail, and a blunt laser ignition tube is developed, the composition and charge of the explosive are described, and the slow roasting performance of the laser ignition tube is deeply studied. The research done in this paper can effectively improve the performance of the laser fire engineering system in the aspects of safety, reliability and electromagnetic environment adaptability, so as to develop a laser ignition system prototype with strong electromagnetic interference resistance and meet the requirements of insensitive ammunition, which has important military application significance.
Experimental study on the ignition mechanism of fuel tanks impacted by reactive material fragment
Authors: Peng M C , Li X D , Ji Y Z Y
Published: December 2024

Fuel tanks are vital components in military assets, such as aircraft and vehicles, where they play a crucial role in operational safety and functionality. High-velocity impacts from fragments pose significant risks, potentially causing ignition and catastrophic damage. To understand the ignition mechanisms under such extreme conditions, a series of ballistic impact experiments were conducted using tungsten-zirconium (W/Zr) alloy fragments. These experiments simulated impacts on the ullage of a fuel tank made of a 2 mm thick aluminium plate. The experiments revealed that W/Zr alloy fragments create distinct perforations in the fuel tank plates. On the front plate, the fragments produced circular holes matching their diameters. However, on the rear plate, the fragments generated much larger, petal-shaped perforations, approximately three times their diameters. Additionally, the study identified a critical ignition velocity for these impacts. When W/Zr alloy fragments impacted the fuel tank at velocities exceeding 866.9 m/s, consistent ignition was observed. As the impact velocity increased further, the intensity of ignition within the fuel tank intensified. Moreover, the location of the ignition shifted progressively from the rear plate towards the front plate, indicating a complex interaction between fragment velocity and fuel tank response.
Assessment of the lethal effect of a 500 kg deep-earth penetrating warhead striking underground confined space
Authors: Li Yin , Deng Guoqiang
Published: December 2024

As a priority military facility, underground constructions are high-value targets for earth-penetrating warheads. The lethal effect is different from that of open areas due to the confined internal space. In this study, numerical simulation and theoretical calculation are used to quantitatively and comparatively evaluate the performance of a 500-kg deep earth penetrating warhead charged with TNT, PBXN-109, and AFX-757 in a specific underground fortification. This evaluation considers the lethality of the shock wave, thermal effects, and case fragments, and the experimental data verify the reliability of the simulation results. Additionally, a three-segment simplified model is used to analyse the percentage of detonation energy for each segment and the main fragments generation ratio of the 500-kg deep earth penetrating warhead’s case. The results show that, for the shock wave, the overpressure peak at the same distance from the detonation centre is up to 7 times higher due to wall reflections, and AFX-757 has the most significant shockwave effect. For the thermal effect, AFX-757 has the highest burst temperature, followed by PBXN-109. The high temperature in the confined space lasts longer, and the damage caused by thermal effects cannot be ignored. For fragments, theoretical calculations and numerical simulations were used to determine the proportion of detonation energy in each part of the case. It was concluded that for high-velocity deep penetration warheads, the fragments generated are mainly concentrated in the middle cylindrical section. The results of this study can provide guidance for the design of earth-penetrating warheads, the damage assessment of confined space, and the designation of engineering protection standards.
Preliminary findings from experimental study on blast performance of steel-concrete composite columns
Authors: Foglar Marek , Hájek Radek , Šulc Vojtěch , Čítek David , Čítek Adam
Published: December 2024

The use of steel-concrete composites in blast resistance has gained importance in the recent years, since concrete is not able to resist higher explosive charges. The authors have designed an experimental device to test steel-concrete composite columns subjected simultaneously to axial and blast loading. The experimental device in a shape of a closed steel frame allows to test plain steel columns, composite steel-concrete columns and composite steel-using ultra-high performance fiber-concrete (UHPFRC) columns. The specimen is loaded with 800f of explosive charge while subjected to axial compressive loading. The response of the specimen is acquired using photonic-doppler velocimetry (PDV). The paper presents preliminary results from the first run of the experiment documenting the benefits of composite action on blast resistance of the tested columns. The use of UHPFRC also showed its beneficial effects.

This paper presents preliminary findings from the experimental program.
Numerical simulation on the effect of casing material on the bullet impact resistance of solid propellant
Authors: Li M Y , Yu W , Wang J
Published: December 2024

The safety of solid rocket motors under ballistic impact is significant during the working life. To compare the impact response of propellant surrounded by different shell material, D406A steel plate, carbon-fibre laminate and aramid-fibre laminate, are selected to cover the surface of the propellant as protection shell. The numerical simulation model is established for the three combined specimens, and the bullet impact response process is numerically simulated using LS-DYNA software. The simulation results show that the protection performance of the three materials are aramid fibre casing, carbon fibre casing and D406A steel casing in descending order. The steel shell is stronger than the fibre shell, but it is more likely to make the propellant react violently under the influence of the shock wave. The numerical findings in this study may benefit the propellant protection casing design.
Comparative Study on Damage Effects of Penetration-Explosive and Prefabricated-Hole Explosive Modes on Airport Runway
Authors: Rui Li , Guifeng Liu , Wanqian Yu
Published: December 2024

Based on the LS-DYNA, a numerical simulation model for warhead penetration-explosive and Prefabricated-Hole explosive airport runway was established, and the characteristic of damage airport runway was analysed. The result shows: when the detonation depth W/d from 1.0 to 25.0, the area of the runway damaged by the prefabricated-hole explosive of the warhead first increases and then decreases. At W/d = 15, the damage area reaches its peak. The damage area of airport runway caused by warhead penetration-explosive increased by 5.12% compared to prefabricated-hole explosive.
Simulation Study on the Damage Characteristics of Semiconductor Bridge Initiators during Penetrating Concrete
Authors: Wang Zhidong , Chai Kangqi , Li Chuntian , Li Lian , Shen Ruiqi , Ye Yinghua , Zhang Wei
Published: December 2024

The emergence of penetrating warheads poses a great threat to thick concrete targets. Initiators play a crucial role in the reliable and effective damage of penetrating warheads. In order to study the damage characteristics of initiators in penetrating overload environments, this paper uses LS-DYNA finite element numerical simulation software to study the damage characteristics of initiators under penetrating thick concrete conditions. By comparing and analyzing the stress, overload, and structural changes of various components of semiconductor bridge initiators at different stages. The results indicate that the overload experienced by initiators is greater than that experienced by projectiles, and their overload curves are more oscillatory. The internal structure of initiators amplifies the overload, making the penetration overload environment more severe for Initiators. Predicting the vulnerable areas of semiconductor bridge initiators during penetration provides direction for the redesign and reinforcement of initiators in the future.
Analysis of the Forming Law of Explosive Formed Projectile by Charge Asymmetry
Authors: Du Hua-chi , Tang Jing , Ren Liang , Liao Yu-gang , Zhou Shuai , Chen Xiao-hui , Liang Shuai
Published: December 2024

In this study, the influence of charge asymmetry on the forming and deflection characteristics of EFP is studied. The laser high-speed photography photos of asymmetric EFP were taken at typical moments. By establishing a geometric model based on the Lagrangian-Eulerian (ALE) algorithm, the effects of the coaxial deviation between the charge and the liner, the angle of charge with the liner and projectile axis, and the distance between the charge axis and the projectile axis on the EFP forming were analyzed. In the case of asymmetric charge, the propagation of detonation wave will be asymmetric, which will act on the liner to crush the forming asymmetry, thus leading to the asymmetry of EFP formation. The velocity and compactness of EFP decrease with the increase of the coaxial deviation between the charge and the liner, the angle between the charge with the liner and the projectile axis and the distance between the charge axis and the projectile axis, but the deflection angle and the length-diameter ratio increase with the increase. The order of the factors affecting the asymmetry of EFP forming caused by the asymmetry of the charge is the coaxial deviation between the charge and the liner > the angle between the charge with the liner and the projectile >the distance between the charge axis and the projectile axis. The research results can guide EFP design.
Study on the Overpressure Distribution of Shock Wave Fronts in Rectangular Tunnels
Authors: Luo Dan , Hu Jinsheng , Zhang Mengmeng , Yao Meili , Li Chun
Published: December 2024

To address the issue of peak overpressure distribution of shock wave fronts during propagation in rectangular tunnels, three-dimensional simulation models of explosion at the tunnel entrance were established using AUTODYN. The model’s validity was verified through conducted experiments. Initially, a comparative analysis of peak overpressure differences at various positions within the tunnel cross-section was performed. Results indicate that for explosions occurring outside the rectangular tunnel entrance, the shock wave overpressure on the tunnel roof and floor exhibits significant relative deviations. Therefore, measurement points should not be placed at these locations during tunnel shock wave testing but rather near the midpoint of the side walls. Subsequently, the relative average deviation of the peak overpressure of the shock wave front in the tunnel was introduced and calculated to characterize the uniformity of the overpressure distribution of the wave front. Finally, the effects of explosive distance X and explosive mass Q on this deviation were examined. The results indicate that these two factors have different impacts on explosions inside and outside the tunnel entrance. For external explosions, a decrease in X and an increase in Q both increase the relative average deviation and the proportional distance λ required to form a uniform plane wave. In the case of internal explosions, changes in X have negligible effects on the relative average deviation and the position required to form a uniform plane wave, while an increase in Q raises the λ needed to achieve a uniform plane wave. These findings provide significant reference for the accurate characterization of tunnel shock wave loads and the design of related experimental tests.
Numerical simulation on the response of the warhead charge under the impact of two cubic fragments
Authors: Jun-jie Xu , Wen-jin Yao , Yu Zheng
Published: December 2024

To study the response law of the warhead charge under the impact of double fragments, the LS-DYNA explicit dynamics simulation software was used to combine the Lee-Tarver ignition growth model to carry out the numerical simulation of the simultaneous impact of the warhead charge with two cubic fragments under different fragmentation distances in the form of horizontal and vertical arrangement. The results show that the JH-2 explosive charge does not have a complete detonation response under ten working conditions, and the pressure value and reactivity of the three observation points inside JH-2 decrease with the increase of distance from the impact area of the two fragments. With the increase of the distance of the two fragments, the mechanism for the impact response of JH-2 was dominated by the co-superposition of the original two fragments, which was transformed into be initiated by a single fragment. Compared with the horizontal arrangement, the vertical arrangement of two fragments is more likely to trigger the detonation of the JH-2 explosive charge. The above simulation results can provide some technical support for the detonation protection of a certain type of 122mm blast-fragmentation warhead.
Influence of lining thickness and impedance on the explosion driving of prefabricated fragments
Authors: Chen Zhao , Zhou Tong , Shi Yu-peng , Guo Xin-qi
Published: December 2024

Prefabricated fragments may deform or crack during explosion driving process, which is adverse to kinetic energy damage. Setting up lining between explosive charges and prefabricated fragments is considered to be an effective way to prevent the excessive load on fragments. This paper studied the influence of lining thickness and impedance on explosion driving of prefabricated fragments based on LS-DYNA finite element simulation. Steel lining of different thickness between 0∼14mm have been studied, as well as steel liner with Kevlar fiber. Fragments accelerated drive process were analysed from the perspective of energy conversion. The results show that the initial speed of the fragment is mainly affected by the quality of the lining and the fracture radius. The axial deformation of the fragment is positively correlated with the initial impact pressure. Steel-fiber composite lining can reduce the shock wave pressure transmitted though, which significantly reducing the initial pressure on the fragments. Low-impedance Kevlar fiber on the outside of the 4340 steel lining can reduce the initial impact pressure of the fragment by about 75%.
Research on Dynamic Response of Cylindrical Shell Structure Subjected to Underwater Explosion Considering Cavitation
Authors: Bo Yang , Jian He , Ao Zhang
Published: December 2024

When the underwater weapon explodes, not only the shock wave and bubble pulsation will cause damage to the ship, but also the collapse of the cavitation area. Firstly, tensile and SHPB tests were designed to investigate the strain rate strengthening effect of 921A steel under high speed impact and fit the C-S constitutive model. Then the finite element method is compared with the classical arithmetic example, and the simulation results coincide with the arithmetic example results. A finite element model of the cylindrical shell structure is established to consider the effects of cavitation effect and the number of impacts on the shock environment. The results show that: Under the action of high-speed impact, 921A steel will produce strain rate strengthening effect, and the parameter D = 78.67, q = 1.95 in the C-S constitutive model, the structural spectral acceleration will increase by 72% when the cavitation effect is taken into account. the damage caused by a single impact is greater when the same amount of multiple impacts is compared with a single impact.
Blast wave propagation characteristics of cylindrical charge under low pressure environment
Authors: Yuhong Yuan , Yinsheng Huang , Ye Zhong , Rui Li , Quan Wang
Published: December 2024

To address the problem of the influence of low pressure environment on the propagation of blast wave in cylindrical charges, the effects of different low pressures, aspect ratios, and azimuth angles on the peak overpressure and specific impulse of blast wave were investigated using AUTODYN finite element software. The influences of different levels of low pressure, aspect ratios, and azimuth angles on the peak overpressure and impulse of the explosive shock wave were investigated. The results indicate that the critical proportional distance for the peak overpressure of the shock wave in the region where the azimuth angle θ is less than or equal to 22.5° increases as the ambient pressure decreases and decreases as the aspect ratio of the charge increases. The influence of charge aspect ratio on the critical distance of peak overpressure in the region of θ > 22.5° is relatively small, and it increases linearly with the decrease of environmental pressure. As the environmental pressure decreases, the propagation distance required for the cylindrical charge blast wave to evolve into a spherical blast wave increases. The influence of charge shape on specific impulse is smaller than that on peak overpressure of blast wave. In explosion-proof design practices, it is recommended to prioritize the evaluation of the impact of blast wave overpressure.
Influence of Medium on Formation Effect and Perforation Performance of Annular Shaped Charge
Authors: Zhang Shenhe , Yang Shuxin , Wang Longkan , Gan Ning , Chen Longhui , Zhang Zhifan
Published: December 2024

With the continuous development of the protective structures and the upgrading of blast mitigation materials, traditional shaped charge warheads are gradually difficult to cause effective damage to heavily armoured ships. To improve the penetration capability of the warhead and achieve large aperture damage to the structures, Annular Shaped Charge (ASC) with unique geometric structure is proposed and applied. In order to investigate the damage effect of the ASC on thin-walled structures with near-field explosion, a series of numerical calculations are carried out based on the Coupled Eulerian-Lagrangian (CEL) method. The influence of the standoff distance on the penetration performance of the ASC is analysed, and the optimal standoff distance is also obtained. Moreover, the influence of medium on the penetration ability of the ASC is explored. The process of jet formation and penetration of the ASC in air medium, water medium and water with an air cavity are compared and analysed. The results show that water not only limits the formation effect of the ASC, but also significantly reduces the jet tip velocity. Accordingly, an air cavity is added in front of the liner to improve the formation effect of the ASC. As a result, both the formation effect and the penetration ability of the ASC in water are significantly improved, and the radius of the penetration hole is greatly increased.
Analysis of influencing factors on mechanical properties of rocket sled
Authors: Zhao Xiangwei , Hao Fenfen , Xie Linqing , Wang Tao
Published: December 2024

As rocket sleds advance towards hypersonic velocities, the analysis of the rocket sled mechanical environment becomes particularly important. To investigate the factors influencing this environment, provide a theoretical foundation for the new generation of rocket sleds, an Euler-Bernoulli beam element approach was employed to discretize a case study rocket sled, thereby obtaining its stiffness and mass matrices. Subsequently, the in-rail vibration equations of the rocket sled, incorporating nonlinear shoe-rail contact forces, were solved in the time domain using a central difference method, with the resulting in-rail mechanical responses validated against actual measurement data to confirm the accuracy of the algorithm. Based on these analyses, the effects of shoe-rail gap, rail irregularities, and aerodynamic loads on mechanical environment of the rocket sled were examined. Focusing on the root mean square (RMS) value of the sled’s centroidal vibration as the subject of study, the findings revealed that an increase in the shoe-rail gap led to decrease vibrations at the sled’s center of mass. Specifically, when the shoe-rail gap widened from 1mm to 5mm, the RMS value of the vibration dropped by 54%. Furthermore, there was found to be a direct proportionality between the RMS of the centroidal vibration and the level of track irregularity. Additionally, it was observed that the centroidal vibration was minimized when the overall aerodynamic lift was zero.
Study on the Dynamic Response of the Hull Beam Model under the Combined Action of Wave Loading and Impact Loading
Authors: Zou Haoyang , Zhao Yanjie , Wang Haikun , Gao Zhaoqiang , Li haitao
Published: December 2024

This paper aims to conduct experimental research on the dynamic response of hull structures under the combined action of wave loads and impact loads. Using an equivalent hull girder model as the research object, multiple sets of regular wave and impact load physical model tests were carried out. The test results show that under the combined action of wave-impact loads, the acceleration measurement points on the hull girder are mainly dominated by the dynamic response caused by the impact load at the moment of impact load application. Subsequently, within the wave period, the dynamic response caused by the impact load gradually decreases, eventually returning to the dynamic response mainly caused by the wave load. A simplified theoretical model of the hull girder was established, and the accuracy of the simplified theoretical model of the hull girder was verified by comparing the test results. The differential equations of the hull girder under the combined action of simplified wave loads and weak impact loads were established, and the accuracy of the simplified theoretical model of the hull girder was verified by comparing the test results. The research shows that under the combined action of wave-impact loads, the dynamic response of the hull structure cannot be simply superimposed by treating the dynamic responses of the two loads separately.
Influence of ice sheet on the flow characteristics of vertical high-speed water-entry cavity of a projectile
Authors: Wang Hao , Cai Xiaowei , Huang Zhengui , Liu Xiangyan , Na Xiaodong , Zhou Bingzhuo
Published: December 2024

The ice sheet will inevitably affect the dynamic cavity evolution of cross-media projectiles after breaking ice and entering water. Based on the Coupled Euler-Lagrange (CEL) algorithm, the process of vertical high-speed ice-breaking water entry of a cylindrical projectile at 100 m/s is studied. The results show that the continuous influx of external air during the ice-sheet condition delays the time for cavity closure. The velocity field distribution within the cavity becomes asymmetrical, displaying heightened nonlinear and turbulent characteristics. Furthermore, it is observed that the peak force experienced by the projectile in an ice-free environment is 69.55% of that during ice-breaking water entry. In the design of new cross-media weapons for ice-covered areas, the structural strength of the projectile head should be improved.
Experimental and numerical simulation study on the crushing of shell with central pre-formed groove
Authors: Li Weihang , Yao Wenjin , Zhu Wei , Li Wenbin , Zhang Qing
Published: December 2024

To improve the lethality of fragmentation bombs against enemy personnel and other targets, one of the primary goals is to generate as many high-speed, effective fragments as possible. A thin shell structure with central pre-formed groove, processed via selective laser melting (SLM), was designed. A shell-crushing test utilizing a water medium was conducted. The fragment formations of the parallelogram pre-formed groove grid and the square pre-formed groove grid were compared. Additionally, the AUTODYN commercial finite element software was used to simulate the influence of different grid sizes and grid angles of the parallelogram pre-formed groove grid on fragment formation. The results indicate that when the grid angle exceeds 60°, the effective fragment generation rate decreases as the grid angle increases, while the fragment conjoined rate increases significantly with the increase in grid angle. The grid size has virtually no effect on the effective fragment generation rate and the fragment conjoined rate.
Research on the Influence of Ceramic Diameter on Anti-penetration Performance under Constrained Conditions
Authors: Yang Z Z , Dang W , Wu H L , Wang L J , Luan C H
Published: December 2024

Three dimensional constraints can improve the anti-penetration performance of ceramics. According to the actual usage requirements of armor structures, a three-dimensional constrained ceramic composite structure was designed. The influence of ceramic diameter on the penetration resistance of composite structures under three-dimensional constraint conditions was studied by combining experimental and numerical simulation methods. The research results indicate that during the penetration process of long rod projectiles, circumferential constraints can effectively suppress the circumferential fracture of ceramics, while frontal constraints can suppress the fracture of ceramics along the direction of projectile incidence. Three dimensional constraints can improve the penetration resistance of ceramics. For long rod projectiles, the confinement performance of the circumferential structure on ceramics can be fully utilized when the ceramic diameter is three times the diameter of the projectile. Circumferential constraints not only suppress ceramic fragmentation, but also enhance the interaction force between ceramics and projectiles.
Experimental and numerical study on the destructive capacity of TNT contact explosions on permafrost targets
Authors: Hu Y Q , Liu H Q , Sun Q R , Wang J , Wang X Y
Published: December 2024

Several civil engineering as well as military fields are involved in permafrost explosions. To study the destructive capacity of TNT contact explosion on permafrost targets, permafrost specimens were prepared at different temperatures. The test results show that the size of the explosion crater formed become smaller, indicating worse destruction effect of the explosion on the permafrost, with the decreasing temperature. Combined with ANSYS/LS-DYNA finite element software, the numerical simulation is carried out to verify the accuracy of the model and parameters. To further study the influence of permafrost properties on the destruction effect, the temperature of the permafrost target were changed, and the relationship curves between temperature and the depth of the explosion pit were fitted. The depth of the explosion pit is linearly related to the temperature and decreases with decreasing temperature. The simulation and experimental results obtained in this study will contribute to investigation on defense design of permafrost environment.
A Method for Correcting the Shock Response Spectrum in Missile-Borne Products
Authors: Gao Peng , Li Haicheng , Jia Ziqi , Che Xiaotao , Chao Wu , Du Minglei , Sun Tianyu , Yang Hongjun , Chen Gang
Published: December 2024

Missile-borne products often encounter shock signals that include low-frequency interference. Following the detonation of initiating devices, the displacement and velocity values are non-zero, and the acceleration signal exhibits baseline drift. This phenomenon distorts the results of Shock Response Spectrum (SRS) analysis. To address these issues, we propose an enhanced method of SRS analysis based on Variational Mode Decomposition (VMD). This method uses VMD to preprocess the shock signal by decomposing it into multiple modal components. It then eliminates modes dominated by low-frequency interference based on the correlation coefficients of the positive and negative response spectra to correct the signal. The corrected signal is analyzed using SRS, and a standard spectrum type for testing is defined. Simulations demonstrate the effectiveness and accuracy of this method, showing that it can precisely eliminate low-frequency components that interfere with the signal. The revised impulse response spectrum significantly enhances both the time-domain and frequency-domain representations of the signal. By analyzing the signal measured from a missile-borne product during the launch of specific ammunition, the method is validated, effectively resolving the SRS distortion issues caused by baseline drift. This method proves to be highly valuable for analyzing the shock environments of missile-borne product and in developing test spectrums.
Research on the ballistic resistance performance of PE composite materials
Authors: Wang L , Yang B , Li G F , Yang L , Tong H , Wu Y C , Wang X D , Shen H R , Li Z L , Wei Q B , Xue X L , Guo Y Y , Zhang L , Yu X J
Published: December 2024

This article investigates the penetration of 4.5g spherical fragments into PE composite materials of various thicknesses. Based on the results of ballistic tests and theoretical analysis, the empirical relationship between the ultimate penetration velocity and areal density was determined. This relationship can be used to assess whether the ballistic resistance performance of the PE composite materials meets the requirements. Next, a lightweight ceramic-PE composite structure was designed using numerical calculation and simulation analysis. This structure can effectively protect against 12.7mm API (armor piercing incendiary) projectiles with an areal density of ≤ 70kg/mm2 and 100m/0°. The feasibility of the structure was confirmed through target testing.
Experimental and Numerical Investigation on Dynamic Response of Reinforced Concrete Shear Walls under Near-field Explosion
Authors: Chen Xionghao , Zhou Chaoyang , Zhao Qiang
Published: December 2024

The explosion test and numerical simulation of a full-size specimen were carried out to investigate the dynamic response and failure characteristics of the reinforced concrete shear walls under near-field explosion. The TNT was located at 0.55 m above the top plate center of the reinforced concrete shear wall with an equivalent of 6.4 kg and a proportional distance of 0.296 m/kg1/3. The reinforced concrete shear wall’s reflected overpressure, displacement, and acceleration were measured and analyzed. The laser 3D scanner scanned the backside failure characteristics. An LS-DYNA numerical model was established and validated by the experimental results. The effects of TNT equivalent, reinforcement ratio, concrete strength, and thicknesses on the explosion resistance of the reinforced concrete shear walls were analyzed. The study results show that increasing the reinforcement rate, using high-strength concrete, and increasing the thickness can all improve the blast resistance of reinforced concrete walls, with increasing the thickness being the most effective measure. The peak displacement values of the back of the reinforced concrete shear wall at the center 1/4 height increase with the increase in charge. Using the least square method, the corresponding fitting curve expressions were obtained. The results can provide references for blast-resistant concrete shear walls design.
Flame Propagation and Explosion Characteristics of Multi-component Natural Gas in a Low-pressure Hydrogen-doped Environment
Authors: Qi Sheng , Li Yuntao , Jing Qi , Zhang Laibin
Published: December 2024

Hydrogen is considered to be the most promising clean energy of the 21st century, and its development and application are conformed to ‘carbon peaking and carbon neutrality goals’. Hydrogen-doped natural gas pipelines, as the main means of transporting hydrogen energy, are normally laid through low-pressure areas. The influence of the low-pressure hydrogen-doped environment on the flame propagation and explosion characteristics of hydrogen-doped natural gas is not yet clear. To solve this problem, this paper configures real multi-component natural gas and experimentally obtains flame propagation as well as explosion hazard parameters for natural gas/H2/air mixtures. The tensile flame propagation velocity changes from a gradual decrease to a gradual increase with increasing tensile rate for increasing hydrogen content. The laminar burning velocity increases from 0.44 m/s to 0.66 m/s at 0.75 bar and from 0.49 m/s to 0.69 m/s at 0.50 bar. The increase in laminar burning velocity becomes more and more significant after the hydrogen content exceeds 20%. As the hydrogen content increases, the flame surface goes from smooth to cracked and gradually increases. Lewis number, flame thickness, Markstein length and critical destabilisation radius decrease with increasing hydrogen and increase with decreasing pressure. The flame stability shows the same trend. The explosion hazard of natural gas/H2/air is reinforced as the hydrogen content rises, and the reduction in pressure reduces the explosion overpressure by 70% and the flame temperature by 10%. The results of the current research could provide a scientific reference for the safe delivery of hydrogen-doped natural gas.
Experimental research on damage power of high-entropy alloy fragment penetrating spacer target plate
Authors: Zhou S , Li P Y , Xiang J A , Cai Y Q
Published: December 2024

In order to compare the damage power of different components of high-entropy alloy reactive fragments to the spacer target plate, an experimental study was carried out by ballistic gun experimental equipment. The results show that high-entropy alloy fragments cause kinetic energy and chemical energy coupling damage to the spacer target plate, and a certain degree of fragmentation in the process of penetrating the front target is conducive to improving the damage power of the fragments to the rare target. Combined with the bullet target action behavior recorded by high-speed imaging and the damage area of the rear target, the HfNiZrTiCu fragment has the greatest damage power to the spacer target plate, AlCoCrFeNi2.1 fragment, and HfNbZrTiTa fragment has the same damage power, and HfNbZrTi fragment has the least damage power. Under experimental conditions, the chemical energy released by the reaction is ranked as follows: HfNiZrTiCu, AlCoCrFeNi2.1, HfNbZrTiTa, HfNbZrTi.
The influence of initiation methods on the fragmentation characteristics of axially enhanced warheads
Authors: Lan Yuzhen , Wang Fang , Wang Tian , Wang Cong
Published: December 2024

Based on Euler-Lagrange element coupling (CEL) simulation algorithm, this paper uses ABAQUS software to simulate and analyze the fragmentation of warhead under single point initiation, two-point initiation and four-point initiation. Simulation results show that the prefabricated fragment of the warhead can cover the target in the axial region completely. Regarding the velocity characteristics of the head fragments, tungsten-zirconium alloy and tungsten alloy fragments show different average velocities under different initiation modes. At four point initiation, the average velocity of tungsten-zirconium alloy fragments is 1371m/s, and the average velocity of tungsten alloy fragments is 1366m/s. At two point initiation, the average velocity of tungsten zirconium alloy fragment is 1351m/s, while the average velocity of tungsten alloy fragment is 1344m/s. When the single point initiation, the average speed of tungsten-zirconium alloy fragments is 1329m/s, and the average speed of tungsten alloy fragments is 1330m/s. The four-point initiation mode shows the highest axial fragment velocity, up to 1,848 m/s, while the single-point initiation mode has a maximum velocity of 1691m/s, a difference of about 150m/s. Secondly, with the increase of the flying angle, the fragment velocity will decrease accordingly. It can be seen that in the case of four-point initiation, the speed of the axial reinforcement fragment can be greatly increased, which can better solve the problem of the central blind area caused by the traditional killing warhead when striking the target, and achieve the coverage of the entire damage target area under the static explosion condition.
Analysis of the Effects of Explosive Reactive Armor during the Penetration Process of Kinetic Energy Projectile
Authors: Ren Zhanping , Ding Li , Yang Junqing , Shen Peihui
Published: December 2024

For the purpose of investigating the impact of explosive reactive armors on the penetration and kinetic energy transfer of kinetic energy projectiles, a numerical simulation study was conducted on the kinetic energy projectile impacting typical tank turret armors under the effect of ERA. A numerical simulation software, LS-DYNA, was utilized to simulate the penetration of kinetic energy projectiles under three different conditions (0°, 45°, and 65°) penetrate ERA. The results indicate that the penetration depth of kinetic energy projectiles penetrate the main armor of a turret has a nonlinear decreasing tendency as oblique angle raises. When θ=0°, ERA enhances the vibrational damage capability of the kinetic energy projectile to the turret by approximately 4.2%. When θ=45° and 65°, ERA weakens the vibrational damage capability of the kinetic energy projectile to the turret by approximately 6.1% and 10.8% respectively.
An Advanced High Power Electromagnetic Pulse Generator with High Repetition Frequency
Authors: Yuan Jun , Ma Tengfei , Zhang Jie , Pan Jing
Published: December 2024

In this paper, an electromechanical pulse power source with repetitive frequency based on piezoelectric ceramic array and miniature plasma diode is introduced, which drives the piezoelectric ceramic array with an electromechanical system to generate a high-voltage pulse, which can generate strong electromagnetic radiation power after interacting with the gaseous medium plasma in the miniature plasma diode. This pulse power source can produce high output energy gain by using low-power DC power supply, and the pulse repetition frequency can be electronically adjusted by adjusting the motor speed. This pulse power source also has the advantages of compact structure and low cost, with a wide range of application prospects.
Elastoplastic Mechanical Model and Numerical Simulation for Armature Loading into Railgun
Authors: Xu G , Li B M , Zhu K Y
Published: December 2024

The initial contact state of the armature after loading directly affects the performance of initial ballistic stage, which makes it very important to design reasonable interference fit structural parameters and accurately calculate the initial state of the armature after loading. Most of the existing research used elastic constitutive model for numerical simulation. However, it was found that plastic hardening occurs in the partial area by observing the surface of the armature recovered from experiments. In this paper, the elastoplastic constitutive model was utilized to calculate the entire armature loading process. The stress, contact pressure, and engraving resistance during the loading process were obtained and compared with the simulation results based on linear elastic material model. This study can provide a reference for the design of armature interference fit structure and parameters.