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    31 October 2025, Volume 46 Issue 10
    Electronic edition of this issue
    2025, 46(10):  0-0. 
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    2025, 46(10):  1-1. 
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    A Parallel Computing Strategy for Large-scale Numerical Simulation of Explosion Field Based on the Eulerian Method
    NING Jianguo, GAO Yi
    2025, 46(10):  250338.  doi:10.12382/bgxb.2025.0338
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    To address the issues of large computational scale and low parallel efficiency in the numerical simulation of explosion fields, a distributed shared memory parallel computing strategy based on the Eulerian method is proposed. This strategy improves the parallelization of the pMMIC3D program by constructing a cluster system with a non-uniform memory access (NUMA) architecture and using the message passing interface (MPI) and InfiniBand (IB) high-speed network, thereby enhancing the large-scale computational capability of program. The accuracy, speedup ratio, parallel efficiency and computational scale of the parallel program are tested through the simulation of the explosion in the air. The results show that the proposed parallel computing strategy is accurate and effective, significantly reducing the communication overhead and improving the computational efficiency. In addition, the applicability of this parallel computing strategy in complex scenarios is further validated through the explosion test inside a concrete building structure, and the calculated results are compared with experimental data. The calculated results show that this parallel computing strategy has the ability to handle the numerical simulation of complex large-scale explosion field and is suitable for practical engineering applications.

    A Tracking and Verification Method for Shaped Charge Jet Penetration Simulation with Application
    ZHAO Haitao, XU Xiangzhao
    2025, 46(10):  250337.  doi:10.12382/bgxb.2025.0337
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    To meet the practical requirements of swiftness and accuracy in shaped charge penetration simulation, a real-time tracking and verification software for jet penetration simulation was designed and implemented through further development of an existing simulation program. Developed based on Qt, the software tracks the simulation process and reads key results in real time, such as jet length and tip velocity. A visualized display window was constructed to enable synchronous visual tracking of target physical quantities. The software integrates quasi-steady theoretical models of shaped charge jet penetration, enabling automated verification of simulation results against predefined error thresholds. This capability allows timely detection of numerical anomalies and unphysical phenomena, thereby ensuring the scientific validity and practical accuracy of the computational outcomes. The penetration of thick steel plates by shaped charge jets was analyzed to investigate the process and the influence of cone angle and charge diameter. The results demonstrate that the software is well-suited for data tracking and verification in jet penetration simulations, ensuring the scientific validity and reliability of the computational results while improving operational efficiency. Furthermore, it provides a robust foundation for subsequent data extraction and in-depth analysis.

    Calculation of Reflected Pressure from Shock Wave Interaction with Typical Materials
    LI Yuqi, NING Jianguo, XU Xiangzhao
    2025, 46(10):  250221.  doi:10.12382/bgxb.2025.0221
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    Explosive shock waves interacting with typical materials at different angles of incidence can lead to severe reflected overpressure, posing significant threats to structures and personnel. However, the accuracy of existing reflected pressure prediction models remains limited. This study develops a theoretical model based on mass and momentum conservation equations, combined with the equations of state for air, granite, and 45# steel. A series of explosion experiments at different charge heights were conducted to measure both free-field and reflected pressures. Theoretical results were compared with experimental data, showing strong agreement. The proposed model effectively predicts reflected overpressure across a range of incidence angles and material types, offering valuable support for shock wave damage assessment and protection design.

    Numerical Simulation of Refraction of Gaseous Detonation Waves at Temperature Interfaces
    LIU Xi, MA Tianbao, LI Jian
    2025, 46(10):  250377.  doi:10.12382/bgxb.2025.0377
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    The refractive behaviors of shock waves and detonation waves during their propagation and damage processes in gaseous media are studied. A computation program with finite volume method and adaptive mesh refinement method is developed based on the reactive Euler equations coupled with a two-step chemical reaction model. The transmission and refraction processes of shock waves and detonation waves at temperature interfaces are determined through theoretical analysis and numerical simulations. The variations of the transmitted shock wave speed and post-wave state with the amplitude of interface temperature are presented, and the typical shock wave structure is obtained. The refraction phenomenon of detonation waves at the temperature interface is further studied, and then the evolution process of cellular detonation wave is analyzed using numerical schlieren and smoked foil method. The results indicate that a shock wave forms a Mach stem and oblique shock wave at the interface when it refracts into low-temperature gas, and it generates a double triple-point structure and a convex wave front when entering high-temperature gas. The cellular detonation wave forms an inclined wave front at the interface when it refracts into low-temperature gas. In contrast, when entering high-temperature gas, it generates a convex wave front and a degenerated double triple point structure. The propagation of cellular detonation waves exhibits distinct spatio-temporal evolution properties.

    Computational Model and Construction Method for Digital Human Fragment Injuries Based onExperimental Wound Ballistics
    FAN Zhuangqing, WANG Shuo, LI Xiangyu, WANG Jianmin, ZHANG Shuangbo, LI Guanhua, CHEN Jing, LU Fangyun
    2025, 46(10):  250572.  doi:10.12382/bgxb.2025.0572
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    This research has significant practical significance for enhancing defense strategies and has attracted significant attention from scholars worldwide. There is a lack of systematic research on the calculation methods and models for digital human fragment injuries based on experimental wound ballistics in China. A construction method for digital human fragment injury model is proposed, and a high-precision human geometric model is established. The injury calculation models are derived from the fragment penetration experiment and numerical simulation. The quantitative criteria for the penetrating depth and aperture of fragment into the human tissues and organs, as well as personnel injury are established. A digital human fragment injury calculation software is developed using Qt platform and OpenGL technology, and the representative cases of single fragment hitting a specific part of human body and hitting the human body at different angles are studied. The digital human fragment injury calculation method and the associated high-precision model software are proposed to offer scientific support for battlefield fragment injury assessment, casualty prediction during warhead attacks, and personnel protection strategies.

    Numerical Simulation Study on the Blast Resistance of Foam Matrix Negative Effective Mass Metamaterials
    JIA Di, CHEN Chuanqing, LI Xin
    2025, 46(10):  250505.  doi:10.12382/bgxb.2025.0505
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    The bandgap characteristics of negative effective mass metamaterials provide an effective approach for shock wave attenuation. In this study, a sandwich composite structure incorporating a foam-resonator core was numerically investigated to evaluate its dynamic response under explosive loading. The structural deformation, time-and frequency-domain characteristics of contact forces, and energy dissipation behavior under various geometric configurations and loading conditions were systematically examined. The results demonstrate that increasing the resonator size effectively reduces core layer compression. Moreover, enlarging the resonator mass lowers the local resonance frequency, thereby suppressing the propagation of mid-to-high frequency shock waves and enhancing the overall blast resistance. However, as the resonator size increases, the inertial impedance effect induced by shock loading significantly amplifies the peak contact force on the front panel, potentially leading to local damage or failure of the foam matrix. Furthermore, the analysis reveals that the structural response exhibits minimal sensitivity to different loading directions under gravity. This study provides valuable insights for optimizing the blast resistance of negative effective mass metamaterials.

    Parallel Numerical Simulation of 3D High-Speed Penetration Based on the SPH Method
    DENG Minjie, SONG Weidong, XIAO Lijun
    2025, 46(10):  250427.  doi:10.12382/bgxb.2025.0427
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    Based on the Smoothed Particle Hydrodynamics (SPH) method, a parallel numerical simulation method was developed for projectile penetration into thin metal targets to address complex physical phenomena such as large deformation, damage, and fracture involved in high-velocity penetration. To accurately describe the material’s mechanical response under high-speed loading, a simplified Johnson-Cook damage model was adopted. To tackle the high computational cost caused by the rapid increase in particle numbers in SPH simulations, the computational domain was divided into subdomains, and an MPI-based CPU parallel solver was developed and implemented to exchange particle information between them. The accuracy of the numerical method in predicting residual velocity and the penetration process was validated by comparing the simulation results with experimental data from the literature. For the 8mm and 10mm thick target plates, the maximum prediction errors were 7.86% and 5.44%, respectively. A systematic evaluation of the parallel framework's acceleration performance showed a significant improvement in computational efficiency. For a medium-scale problem involving approximately 1.79 million particles, a parallel speedup efficiency of 0.76 was achieved using 54 CPU cores. While ensuring simulation accuracy, this parallel SPH framework successfully extends the computational capability to a higher order of magnitude, enabling large-scale simulations with over 100 million particles.

    Numerical Simulation of the Behind-Target Overpressure Effect from Reactive Fragments Penetrating Thin Plates
    ZHAO Linmiao, LI Jianqiao, ZHANG Lizhong, ZHAO Shiheng
    2025, 46(10):  250429.  doi:10.12382/bgxb.2025.0429
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    Due to their pronounced post-penetration damage effects, the reaction behavior and overpressure effects of reactive fragments following penetration have garnered significant attention. This study conducts a numerical simulation of the overpressure effects resulting from the penetration of thin plate targets by reactive fragments. By integrating smoothed particle hydrodynamics, finite element method, finite volume method, and an energy release model for reactive fragments, a numerical simulation approach for analyzing the overpressure effects post-penetration is proposed. The overpressure distribution characteristics and the variation of peak overpressure with penetration velocity are determined for φ10×10mm Al/W/PTFE reactive fragments penetrating a 3mm target plate at velocities ranging from 700m/s to 1100m/s. The results indicate that the evolution of overpressure distribution inside the sealed air tank is correlated with the dispersion of energetic fragments. As the penetration velocity increases, high-pressure regions change from sparse to dense, with a significant pressure rise, reaching a transient peak of 1753.9kPa at 1000m/s. With further velocity increase, the overpressure begins to decline but at a slower rate. This study reveals the overpressure effects of energy release at different velocities, providing valuable references and numerical methods for warhead design and damage assessment.

    Ballistic Performance of Perforated Array Ceramic Armor Using FEM-SPH Adaptive Algorithm
    HE Zhifan, CHEN Tianming, LU Chengfa, YANG Yang, LIANG Bo, WANG Zhipeng, CHEN Aijun, CAO Jianwu, QIN Qinghua
    2025, 46(10):  250531.  doi:10.12382/bgxb.2025.0531
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    The perforated array ceramic plate is a new type of protective armor. The projectiles are deflected by the asymmetric forces caused by the holes in the plates, reducing the stability and penetration ability of the projectiles. In this paper, FEM-SPH adaptive algorithm was used to model the penetration of a 7.62mm armor-piercing incendiary projectile into a perforated array boron carbide ceramic target plate. The effects of impact points, angles, and projectile rotation on the ballistic performance of the perforated array ceramic plate were analyzed. It is shown that the impact points have significant influence on the projectile-target interaction, the failure mode and the ballistic performance of the perforated array ceramic plate. The active failure mode of the projectile for the impact point located at the hole edge is deflected due to asymmetric forces, resulting in the enhancement of the ballistic performance of the plate. For the oblique impact, the projectile stability is further reduced by the plate, giving rise to the enhancement of the ballistic performance and expansion of the damage area on the plate. Comparing to non-rotating projectiles, the plate has greater advantages against the rotating projectiles.

    The Mechanical Properties and Penetration Characteristics of Al/W Reactive Materials
    ZHANG Lizhong, REN Huilan, LI Jianqiao, LI Wei
    2025, 46(10):  250529.  doi:10.12382/bgxb.2025.0529
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    In order to study the mechanical properties and penetration characteristics of aluminum/tungsten (Al/W) reactive materials, Al/W reactive materials specimens were prepared by compression molding and sintering, and quasi-static/dynamic compression experiments, and ballistic gun experiments of Al/W reactive fragment penetrating the steel target were conducted. The mechanical properties and penetration characteristics of Al/W reactive materials were obtained by experiments, and the formula for predicting the ballistic terminal velocity of Al/W reactive fragments was provided based on one-dimensional shock wave theory. Combined with the high-speed photographic images of Al/W reactive fragment penetrating the steel target, the energy release characteristics of Al/W reactive fragment at different penetration speeds are qualitatively analyzed by image recognition technology. The results show that, the dynamic stress-strain curves of Al/W reactive materials show elastic-plastic deformation characteristics and obvious strain rate effects. When Al/W reactive fragment penetrate the target plate, a large amount of energy is released through the chemical reaction, and the energy release intensity and time are significantly enhanced. Compared with titanium (Ti) fragments of similar density, the high-temperature effect significantly enhance the damage capability of Al/W reactive fragment against the target plate.

    Virtual Scene Simulation of Blast-induced Impact Damage
    ZHANG Lei, XU Xiangzhao
    2025, 46(10):  250336.  doi:10.12382/bgxb.2025.0336
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    For the three-dimensional scene visualization of simulating and reproducing the explosive shock experiments, a virtual simulation system,which is designed for studying and predicting the damage process and effects of explosive shockwaves on targets, is built based on virtual simulation technology and the related explosive field calculation models. The system adopts a layered architecture, covering the scene management, interaction design, power calculation and visualization simulation, and supporting the flexible configuration of explosion parameters, dynamic loading of target models and multi-perspective interaction analysis, which can adapt to different types and scales of explosion scenes. Furthermore, based on Niagara particle system and physics engine real-time rendering technology, the system accurately characterizes the flame, smoke, shockwave propagation and target damage effects, such as concrete crushing, vehicle structure deformation, etc., and optimizes the observation clarity through the dynamic smoke concentration adjustment function. The simulation system provides a highly realistic graphical interface to observe the dynamic processes and physical phenomena of explosive shocks, and supports the multi-perspective and scalable observation in 3D scene. This enhances the intuitiveness and depth of understanding in research, significantly reducing the time and cost of actual experiments, and offering a safe, reliable and cost-effective research method.

    Research on Damage Effectiveness of Fragmentation-Explosive Warheads Against Drone Swarms
    ZHANG Kefan, ZHANG Zixuan, LI Weina, DUAN Angxuan
    2025, 46(10):  250583.  doi:10.12382/bgxb.2025.0583
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    Addressing challenges in drone swarm damage assessment—such as unclear component-level damage mechanisms and insufficient understanding of formation configuration effects—this study proposes an evaluation method integrating high-fidelity component-level damage modeling with formation dynamics analysis. By establishing a damage calculation chain of “physical damage → component failure → functional damage” for quadrotor drones, the structure-effect relationship of target vulnerability is analyzed. Combined with a fragmentation-explosive warhead blast field model, this quantifies the dynamic impact of different damage elements on drone functionality. Furthermore, considering four typical swarm formations (one character, V character, snake, round), multi-scenario simulations were conducted using the standard damage percentage criterion and warhead-target encounter conditions. Results indicate that: For single-drone targets, the number of effective fragment hits negatively correlates with burst distance; Blast waves demonstrate superior damage efficacy at close ranges, with detonation below the drone yielding optimal results; Swarm damage outcomes are influenced by both detonation position and formation type, with formation being the dominant factor—circular formations sustain the highest damage, while serpentine formations exhibit the lowest. This research provides methodological support for damage assessment of fragmentation warheads against drone swarms and offers theoretical insights for tactical formation selection.

    An Improved Efficient Parallel DSD Algorithm and Its Verification & Validation
    XIONG Jun, DAI Yijun, GONG Xiangfei, LIU Lufeng
    2025, 46(10):  250411.  doi:10.12382/bgxb.2025.0411
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    The equation of level set function based on DSD (Detonation Shock Dynamics) theory is numerically discretized and solved on uniform 2D/3D Cartesian grid. The obtained TOA (Time of Arrival) for the stable detonation front in the high explosive can be used by program burn algorithm in the hydrodynamic simulations. The boundary condition algorithm, including the selection method of boundary node stencils, and the method of boundary node sort, is simplified and improved based on the previous works. The hybrid MPI (Message-Passing Interface) and OpenMP (Open Multi-Processing) parallel code DSDLS is developed for the efficient solutions of large-scale explosive detonation problems. A series of analytic solutions, semi-analytic solutions, and explosive detonation experiments are used for verification and validation of the proposed improved DSD algorithm, which indicate that the detonation front TOA of numerical simulations conform to the exact solutions and the measured data of experiments. The results of large-scale parallel test on the grid of over 109 nodes indicate that DSDLS is of good parallel efficiency and parallel scalability.

    Numerical Research on Impact Ignition Reaction Behavior of Fluoropolymer-Based Reactive Materials
    LI Zheng, MA Tianbao
    2025, 46(10):  250060.  doi:10.12382/bgxb.2025.0060
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    To study the energy release behavior of impact ignition and deflagration reactions in fluorinated polymer based reactive materials,Based on experimental observations, cumulative temperature rise ignition mechanism and transient thermal diffusion reaction mechanism were proposed, and thermal coupling simulation of Taylor rod impact ignition process of active material was carried out, and the simulation provided the local hot spot temperature rise under the corresponding mechanism. On this basis, a heat transfer-chemical reaction model for fractured materials was constructed using the bond-based peridynamics thermal diffusion theory and combined with local hotspot information. The solution results were verified and analyzed using infrared temperature measurement experiments. The results showed that the simulation characteristics of deformation and fragmentation of the Taylor rod before ignition reaction are basically consistent with the experimental recorded images, which well reflects the inert response of the reactive material. By superimposing adiabatic shear temperature rise and friction temperature rise, a local area of the rod can form a hot spot region that meets the ignition threshold which basically corresponds to the location of the first flare, the distribution of adiabatic shear temperature rise and friction temperature rise is uneven, with significant differences in starting positions, and adiabatic shear temperature rise plays a dominant role in the total impact temperature rise, implying that the ignition mechanism of cumulative temperature rise can describe the impact ignition characteristics of materials. The simulation of deflagration reaction process proves that the temperature distribution inside the flame is directly affected by the mass and morphology distribution of impact fractured materials; Compared to the heat transfer effect, the reaction heat continuously released as the reactivity of the active site increases plays a crucial role in maintaining the high temperature state of the region.

    Molecular Dynamics Simulation of Afterburning Reactions of Aluminum Nanoparticles in the Detonation Product Atmosphere of CL-20
    ZHONG Haoyuan, SONG Qingguan, JIANG Shengli, ZHANG Lei, PANG Siping
    2025, 46(10):  250439.  doi:10.12382/bgxb.2025.0439
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    The afterburning reaction mechanisms of aluminum nanoparticles (ANPs) in the detonation product atmosphere of aluminized explosives are studied using the ReaxFF-lg reactive force field alongside reactive molecular dynamics (MD) simulations. The combustion process of a 10nm ANP is simulated in a high-temperature and high-pressure environment (2500~3500K) containing the principal detonation products of CL-20 (CO2, H2O, CO, and N2), revealing the reaction mechanism of ANP in a multi-component oxidizing atmosphere at the atomic scale. Results indicate that the formation of H—Al and H—C bonds decreases as the temperature rises, which indicates that the elevated temperatures are not conducive to the creation of hydrogen-related stable structures. Additionally, the proportion of CO2 among detonation products emerges as the primary determinant of detonation temperature. CO2 demonstrates greater reactivity than H2O and plays a pivotal role in promoting the oxidation of aluminum oxidation and the release of energy within the range of 2500~3500K. Thus, increasing the content of CO2 in detonation products can effectively regulate detonation temperature and boost the combustion efficiency of ANPs, enabling more complete energy release. These findings offer a theoretical foundation for designing high-performance aluminized explosive formulations.

    Mitigation Effects of Nanoporous Material Liquid System on losed-field Blast Loading
    ZHU Wei, YAO Wenjin, HUANG Guangyan, LI Wenbin, WANG Xiaoming
    2025, 46(10):  250468.  doi:10.12382/bgxb.2025.0468
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    To explore the application value of nanoporous material liquid systems (NMLS) in enhancing the blast resistance of fiber shells, experimental and numerical studies were conducted on the blast mitigation effects of nano-porous silica water suspensions. Internal explosion experiments were carried out to compare the blast resistance performance of three different hollow cylindrical composite structures: empty chamber-shell, water-filled chamber-shell, and NMLS-filled chamber-shell. The results showed minimal differences in fiber breakage among these three structures, indicating that neither water nor NMLS exhibited a significant blast mitigation effect. Numerical models matching the experimental conditions were established, and the mechanical behavior of NMLS was described using a compaction equation of state validated by dynamic impact experiments. The simulation results revealed that both water and NMLS significantly increased the internal blast loading on the shell, with peak pressures reaching 1.7 and 1.9 times that of the baseline (no liquid layer), respectively. The more severe loading enhancement caused by NMLS was attributed to the higher initial pressure rise experienced by the shock wave propagating through the NMLS layer under the catch-up effect. Further numerical analyses over a broader range of parameters showed that water consistently exhibits a blast-enhancing effect, while the effect of NMLS transitions from enhancement to mitigation as the standoff distance increases, the charge mass decreases, or the liquid layer thickness increases. This transition was due to a better match between the energy absorption capacity of NMLS and the blast loading, leading to greater attenuation of the shock wave pressure after passing through the NMLS layer.

    Research on Dynamic Impact Response and Energy Dissipation Mechanisms of Auxetic Metamaterial Sandwich Structures with Negative Poisson’s Ratio Based on Material Point Method
    YANG Chenchen, LIU Jun, HAN Fanghao, MEI Yue
    2025, 46(10):  250507.  doi:10.12382/bgxb.2025.0507
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    Structures with negative Poisson’s ratios (NPR) exhibit superior energy dispersion and stress homogenization capabilities under impact loading due to their unique auxetic deformation behavior, demonstrating broad application prospects in military protection. However, conventional mesh-based numerical methods such as the Finite Element Method (FEM) often suffer from reduced accuracy or even computational interruption due to mesh distortion when simulating extreme nonlinear behaviors like large deformation and fracture. To address this, the present study employs the Material Point Method (MPM) to systematically investigate the dynamic response and energy dissipation mechanisms of three typical cellular sandwich structures (regular hexagonal honeycomb, re-entrant hexagon, and chiral wave core) under impact loading. Through mesh convergence analysis and experimental validation, the MPM is demonstrated to possess good numerical convergence and physical fidelity in simulating such extreme deformation scenarios. The results indicate that the NPR effect significantly improves the impact resistance of the structures: compared to the conventional hexagonal honeycomb structure (positive Poisson’s ratio), the re-entrant hexagonal structure exhibits a 27.9% reduction in peak reaction force, while the chiral wave cellular structure achieves a reduction of 61.9%. Further mechanistic analysis reveals that the chiral structure facilitates uniform dissipation of impact energy throughout the cellular network via a multi-stage energy absorption mechanism—comprising ring rotation, ligament extension, and pore closure—thereby effectively mitigating local stress concentration and structural failure. This study provides theoretical support and simulation tools for the lightweight anti-impact design of protective equipment such as naval blast protection and personal armor.

    Study on the Damage Effect and Debris Cloud Characteristics of Reactive Fragments of High-entropy Alloys
    WANG Shengfang, CHANG Hui, JIAO Zhiming, YIN Yunfei, ZHANG Tuanwei, LI Zhiqiang, WANG Zhihua
    2025, 46(10):  250482.  doi:10.12382/bgxb.2025.0482
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    Energetic high-entropy alloys (EHEAs) hold significant promise as active fragmentation materials for enhancing the penetration, ignition, and damage efficacy of weaponry and ammunition systems. Nevertheless, a pressing need exists for in-depth investigations into their damage mechanisms and corresponding effects. To investigate the damage effects of EHEAs and the characteristics of the fragment cloud during the deflagration process, a two-stage light gas gun is employed to conduct damage experiments on spaced aluminum targets, utilizing the TiZrHfTa0.5 high-entropy alloy at varying impact velocities. High-speed photography is utilized to document the perforation deflagration behavior, and theoretical analyses are performed to elucidate the formation process of the debris cloud behind the target. Additionally, smoothed particle hydrodynamics (SPH) numerical simulations are carried out to supplement the experimental findings. The experimental results demonstrate that EHEAs exhibit intense exothermic detonation behavior upon exceeding a critical impact velocity. As the penetration velocity increases, a positive correlation is observed between the impact velocity and the diameter of the entry hole on the target, leading to an augmented penetrative and damage area on the rear target. This phenomenon can be attributed to the exponential growth in the number of fragments within the debris cloud with increasing velocity, and the velocity gradient significantly promotes the release of energetic characteristics, thereby magnifying the overall damage effects. Based on a comprehensive theoretical analysis and experimental data, a modified empirical formula for predicting the perforation diameter is proposed. Fragment size analysis further reveals that the refinement of fragments facilitates the synergistic interaction between chemical and kinetic energy, ultimately enhancing the damage performance of EHEAs.

    Dynamic Impact Mechanics Response and Deformation Mechanisms of Al15(CoCrFeNi)85 High-entropy Alloy
    LING Jing, LIANG Yanxiang, JING Lin
    2025, 46(10):  250499.  doi:10.12382/bgxb.2025.0499
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    The metastable face-centered cubic (FCC) and body-centered cubic (BCC) dual-phase Al15(CoCrFeNi)85 high-entropy alloy has significant application prospects in the field of impact-resistant structural materials. The paper aims to systematically examine its dynamic response and compressive deformation mechanisms. The quasi-static and dynamic compressive mechanical properties of the high-entropy alloy are characterized using a universal testing machine, split Hopkinson pressure bar (SHPB), electron backscatter diffraction (EBSD), and molecular dynamics (MD) simulations. The plastic stress-strain response, strain rate sensitivity, and microscopic deformation mechanisms of the high-entropy alloy are analyzed, and its strengthening mechanism under dynamic compression is elucidated. A dynamic constitutive model for the metastable dual-phase Al15(CoCrFeNi)85 is established. The high-entropy alloy exhibits strain rate sensitivity, of which the flow stress initially increase gradually and then rises sharply at larger strains. The base material is consisted of 71.4% FCC and 28.6% BCC phases. The FCC-to-BCC phase transformation under uniaxial compression is strain-rate-dependent. The ratio of FCC-to-BCC phase transformation under quasi-static loading is approximately 1∶1, whereas it is approximately 3∶7 under dynamic loading. MD simulations confirm the phase-transformation-dominated deformation mechanism. The plastic deformation shifts to full dislocation slip in BCC phases as their fraction increases. The dynamic stress-strain response is predicted using a modified Johnson-Cook constitutive model. These findings can provide theoretical guidance for the design and application of HEAs in impact-resistant structures.

    Crystal Plasticity Model of Precipitation Strengthening of CoCrNi-based High-entropy Alloys: Mechanical Properties and Texture Evolution
    ZHANG Wenwen, ZHAO Dan, ZHAO Weitao, WANG Qiang, WANG Jianjun, MA Shengguo, ZHANG Tuanwei, WANG Zhihua
    2025, 46(10):  250110.  doi:10.12382/bgxb.2025.0110
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    Based on the Crystal Plasticity Finite Element (CPFEM) framework, a modeling method for describing the mechanical behavior of CoCrNiSi0.3C0.048 medium entropy alloy with three-stage precipitated phase structure under dynamic compression was constructed. Under the loading condition of 3000s-1 strain rate, the effects of different initial textures such as random, Gaussian, rotating Gaussian, cubic, copper, and brass on the stress-strain response were studied. The results show that the random texture and copper texture exhibit higher yield strength and excellent plastic deformation ability under dynamic compression, while the comprehensive performance of the cube texture is relatively poor. At high strain rate, the precipitated phase significantly affects the strengthening effect of the material. Through the comprehensive analysis of yield strength, plastic deformation ability and hardening behavior, the influence of different initial textures on deformation at high strain rate is revealed, which provides a scientific basis for the optimization design and practical application of high entropy alloys containing precipitated phases.

    Structural Design and Experiment of 1kg TNT Equivalent Double-layer Asymmetric Explosion Protection Device
    ZHAO Shengwei, ZHOU Gang, SUN Hao, CHEN Baihan, LI Ming
    2025, 46(10):  250478.  doi:10.12382/bgxb.2025.0478
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    To study the energy release characteristics of energetic materials after excitation and ensure the safety of the test, a double-layer asymmetric cylindrical explosion protection device is designed with capability of containing 1kg TNT equivalent detonation. Through the structural design, simulation analysis using LS-DYNA finite element software, and full-equivalent detonation dynamic response test with 1kg TNT, the safety of the explosion protection device is evaluated by comparing the theoretical predictions, experimental data and simulated results. Simulated and experimental results demonstrate that the structural design of the double-layer asymmetric cylindrical explosion protection device is reasonable with a sufficient safety margin. In the full-scale 1kg TNT detonation test, the stress corresponding to the measured outer wall strain at typical positions is lower than the yield strength of shell material of the protection device. The peak reflective overpressure measured on the inner l at typical positions is within the range calculated by the empirical formulas. The explosion resistance strength of the protection device meets the test requirements. The design, analysis, and experimental methods in this paper can provide useful references for the design and verification of similar explosion protection devices.

    Design of Compressed Air-drivenVariable-sectional Shock Tube for Simulating Air Explosion Shock Wave
    WU Hao, XU Peng, CHEN De
    2025, 46(10):  250442.  doi:10.12382/bgxb.2025.0442
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    In order to develop a compressed air-driven variable-sectional shock tube test device for simulating the air explosion shock wave, the classical 1D Sod shock tube problem, compressed air-driven equi-diametric and variable-sectional shock tube tests were firstly numerically simulated based on Ansys Fluent software, respectively. The applicability and reliability of material model parameters, boundary conditions, and numerical simulation method were validated through the comparisons of simulation results with analytical solutions and test data. Secondly, the evolution processes of the pressure pulse in the equi-diametric and variable-sectional shock tubes were analyzed, respectively. It was found that the location where the rarefaction wave catches up with the shock wave is the formation location of the air explosion shock wave; the variable-sectional shock tubes with different expanded angles could generate air explosion shock waves with exponential decay, and the expanded angle of the low-pressure section has little effect on the waveform of shock wave. Further analysis was carried out to analyze the influence of the geometrical dimensions of the shock tube and initial pressure in the high-pressure section on the formation location of the air explosion shock wave and corresponding peak reflected overpressure. It was shown that the formation location of the air explosion shock wave and the above parameters have a nonlinear relationship. The peak reflected overpressure increases with the diameter and initial pressure of the high-pressure section increasing, as well as with the length of the high-pressure section and expanded angle of the low-pressure section decreasing. Finally, based on the simulation results and dimensional analysis, predicted formulas for the formation location of the air explosion shock wave and corresponding peak reflected overpressure were established, respectively. The design process of the compressed air-driven variable-sectional shock tube was given. The test loading capabilities of three typical variable-sectional shock tubes were determined by comparing them with the classical Kingery-Bulmash air explosion shock wave calculation formulas.

    A Predictive Model for Penetration Efficiency of Semi-Infinite Metallic Targets Based on Dimensional Constraints and Symbolic Regression
    CHEN Qingqing, ZHANG Jie, WANG Zhiyong, ZHAO Tingting, ZHANG Yuhang, WANG Zhihua
    2025, 46(10):  250425.  doi:10.12382/bgxb.2025.0425
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    To address the limitations of traditional penetration efficiency prediction models, such as their reliance on empirical formulas, limited adaptability, and weak physical interpretability, this study proposes a modeling approach that integrates dimensional analysis with symbolic regression. A predictive model is developed for the penetration efficiency of rod projectiles impacting semi-infinite metal targets. Based on physical prior knowledge, seven original physical variables are transformed into four dimensionless control parameters with clear physical significance. Using 819 sets of experimental data, an analytical expression between the dimensionless parameters and penetration efficiency is constructed through a symbolic regression algorithm based on genetic programming, with a penalty mechanism introduced to ensure the participation of all control variables. The Results show that the proposed model performs well across various penetration conditions, with average coefficients of determination (R2) exceeding 0.8. The model accurately captures the nonlinear influence of each parameter on penetration efficiency. Compared to traditional empirical models, the proposed method offers improved predictive accuracy and adaptability, while producing physically meaningful and structurally clear expressions that provide insight into the role of key variables in the penetration process.

    Dynamic Response of Biomimetic Gradient Double Corrugated Structure under Simulated Blast Load
    YI Xiaofei, PENG Kefeng, CHANG Baixue, ZHANG Yuanrui, LIU Jiagui, ZHENG Zhijun
    2025, 46(10):  250344.  doi:10.12382/bgxb.2025.0344
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    Sandwich structure is widely used in the field of shock protection, but the traditional cores often suffer from insufficient load stability, which limits their shock resistance performance. Inspired by the cuttlefish bone and incorporating the dynamic enhancement effect of cellular material, a biomimetic gradient double corrugated sandwich structure is proposed. A systematic study is conducted on its shock resistance performance by using graded cellular projectiles as loading means. The results show that, compared with the biomimetic double corrugated sandwich structure without gradient design, the proposed sandwich structure has excellent shock resistance, with an improvement in crushing force efficiency of 26.4%. When the gradient distribution parameters and the axial ratio are controlled within the ranges of 0.1-0.15 and 0.5-0.75, respectively, the crushing force efficiency of the structure remains stable at about 80%. This research provides novel insights and methodologies for the design and evaluation of new protective structures.

    Data-Driven Dimensional Analysis of the Dynamic Response of Low-Carbon Steel Circular Plates under Uniform Impulsive Loading
    GE Puxin, SONG Zihao, LI Zhiyang, WANG Hairen, LEI Jianyin, LIU Zhifang
    2025, 46(10):  250424.  doi:10.12382/bgxb.2025.0424
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    Under explosive loading, the key to predicting a structure’s response is to accurately establish the relationship among the input load, material properties, and mechanical response. This study proposes a method that combines data-driven modeling with dimensional-invariance analysis to identify the key dimensionless parameters governing the dynamic plastic response of circular plates under impulsive loading, and to build a deflection-prediction model. An explicit dynamic model of a clamped circular plate is constructed in ABAQUS. Data are generated by varying the plate radius L, thickness H, density ρ, yield strength σ0, and impulse I. An artificial neural network is used to fit the response surface and compute gradients; together with the exponent-matrix method and active subspace analysis, feature construction and dimensionality reduction are performed to identify the dominant dimensionless group(s). The results show that, after analysis in the principal subspace, the five original variables can ultimately be expressed as a combination of the Johnson damage number I2/(ρσ0H2) and the geometric parameter H/L, thereby reducing a multivariable input to a single core variable. The identified dimensionless group effectively characterizes impact damage and dynamic response and exhibits good applicability. The findings provide an efficient data-driven analysis tool for impact-dynamics problems and demonstrate the potential of machine learning in engineering-physics applications.

    Numerical Modeling on Explosion Protection of Sintered Fiber Network Material
    LI Yuan, WANG Tianchi, HOU Bing, SUO Tao, DOU Qingbo
    2025, 46(10):  250402.  doi:10.12382/bgxb.2025.0402
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    As a novel explosion protection material, sintered fiber network materials exhibit transversely isotropic mechanical properties, posing challenges for engineering design and application. To achieve accurate numerical simulation of sintered fiber network materials, a transversely isotropic phenomenological dynamic constitutive model was established, and a user subroutine was developed to implement the constitutive model algorithms. Constitutive parameters of the sintered fiber network were obtained by fitting experimental stress-strain curves under different loading directions. To validate the constitutive model and parameters, explosion simulation loading tests and corresponding numerical simulations were conducted, revealing the material’s shock pressure attenuation characteristics. Results demonstrate that under varying shock loading directions, the numerical simulations show good agreement with experimental results in terms of shock pressure attenuation and specimen compression deformation. The fiber network material reduces shock pressure by up to 57.4%. The established constitutive model and parameters effectively capture the mechanical behavior of the fiber network material, providing a critical simulation tool for its engineering applications.

    Study on the Shooting Vibration Characteristics of a Quadruped Unmanned Combat Platform under Impact Loads
    LIU Kun, FENG Ying, KANG Bao, WU Zhilin, SONG Jie, ZHU Tao
    2025, 46(10):  250282.  doi:10.12382/bgxb.2025.0282
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    The quadruped unmanned combat platform holds significant military application value in future warfare due to its exceptional mobility and adaptability to complex terrains. A rigid-flexible coupled launch dynamics model is established to investigate the impact of shock loads on the vibration characteristics of the platform and firing accuracy. The amplitude, angular displacement and angular velocity variations of muzzle center point around x-axis and z-axis under different shock loads are analyzed through numerical simulation. The firing dispersion characteristics are evaluated using a six-degrees-of-freedom external ballistic model, and the live-fire tests are made on unmanned combat platforms with and without a bidirectional buffering device. The results show that the amplitude of the muzzle center point around the x-axis and z-axis during five-round bursts is significantly reduced, the vibration levels decreases, and the angular velocity tends to stabilize without the continuous increase observed in fixed connections after installing the bidirectional buffering device. The radius of 100% dispersion circle (R100) is reduced to 86.4mm with a decrease of 34.6%. Live-fire test data indicates that R100 for single-shot and five-round bursts is 75.7mm and 94.5mm, respectively, with the reductions of 21.1% and 32.8%. The test data are in good agreement with the simulated results, validating the accuracy of the numerical simulations. This confirms that the designed damping device effectively suppresses firing-induced vibration, significantly improving the firing stability and accuracy of the quadruped unmanned combat platform. The research findings provide technical support for the structural optimization design of unmanned combat platforms.

    Pseudo Arc-Length Method for High-Resolution Capturing of Strong Discontinuities in Multi-Medium Flows
    LI Kun, MA Tianbao, WANG Yuanpeng
    2025, 46(10):  250420.  doi:10.12382/bgxb.2025.0420
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    In compressible multi-medium gas-liquid two-phase flow, the thermodynamic disparities between different materials lead to strongly nonlinear wave interactions in the interfacial region, significantly increasing the difficulty of numerical simulation. Particularly within the framework of hyperbolic conservation law equation, the flow field is prone to form singular structures such as shock waves, contact discontinuities (CD), and rarefaction waves, which impose stricter requirements on the accuracy, discontinuity-capturing capability, and stability of numerical algorithms. To address these challenges, this paper develops a high-order pseudo arc-length method (PALM) tailored for multi-medium gas-liquid two-phase flow. By introducing an arc-length parameter, the governing equations are transformed into an orthogonal arc-length space, thereby alleviating numerical singularities induced by strong discontinuities. A high-order reconstruction scheme is incorporated to ensure solution accuracy. For the precise description of interfacial dynamics, an evolution mechanism for the signed distance function based on the arc-length space is proposed, combined with the real ghost fluid method to rigorously define boundary conditions and maintain the continuity of physical quantities across the interface. Numerical results demonstrate that the proposed method achieves high-resolution resolution of strong discontinuities and complex wave structures.

    Research on Risk Assessment Methods for Explosion Accidents of Natural Fragmentation Warheads
    XIN Dajun, XUE Kun
    2025, 46(10):  250431.  doi:10.12382/bgxb.2025.0431
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    This study addresses the critical challenges in risk assessment of natural fragmentation warhead explosions by proposing a comprehensive parametric analytical methodology. Through systematic integration of key components including stochastic fragment generation, precise trajectory calculation, three-dimensionalh probability evaluation, and quantitative human damage assessment, we have established a multi-scale coupled risk evaluation system. In terms of fragment kinematics modeling, we developed an aerodynamic surrogate model based on artificial neural networks. By introducing fragment sphericity parameters and Mach number as dual variables, the model significantly improves the trajectory calculation accuracy for naturally fragmenting projectiles under random tumbling conditions. For hazard effect evaluation, we innovatively proposed a three-dimensional pie-shaped target model. By incorporating detailed human geometric parameters and considering the relative position between fragment trajectories and human targets, the model enables more accurate calculation of fragment hit probability on personnel. Regarding risk quantification, we constructed a multi-level probabilistic assessment framework that integrates AIS injury scales with fragment kinetic energy distribution. Validation using 155mm projectiles demonstrates that this method can not only describe fragment hazards through uniform annular safety distances but also generate two-dimensional spatial distributions of fragment hazard probability. The research achieves quantitative characterization of the entire process encompassing initial stochasticity, motion complexity, and progressive damage effects of fragments. It provides new analytical tools and decision support for dynamic safety distance determination in ammunition storage and transportation, optimized safety zoning design for firing ranges, and industrial explosion protection.

    Mechanical Characteristics and Firing Disturbance of a Lightweight Remote-Controlled Weapon Station Under Multi-Condition Operations
    WANG Yunlong, ZHAO Zhengyuan, WU Zhilin, LI Zhongxin
    2025, 46(10):  250200.  doi:10.12382/bgxb.2025.0200
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    To enhance the precision strike capability and environmental adaptability of lightweight remote-controlled weapon stations (RCWS), it is essential to study the mechanical characteristics and firing disturbances of the weapon station under firing loads. This research selects a small-caliber assault rifle as the study object. Based on the structure of a matched lightweight RCWS, a rigid-flexible coupled firing dynamics model of the system is established using ADAMS-Simulink co-simulation. The firing process under both single-shot and burst-fire conditions is simulated and analyzed. Furthermore, based on the simulation results, the clamping module of the RCWS is optimized by introducing a buffer between the weapon and the clamping structure. Live-fire tests are conducted to validate the system before and after optimization. The results show that under single-shot conditions, the response time from bullet ignition to the first peak impact torque on the motor is within 35ms, with the directional motor experiencing more significant impacts, reaching a peak torque of 182.98N·m. During burst fire, the coupling of residual energy and new impact loads causes a sudden increase of approximately 50% in the motor torque oscillation amplitude. Additionally, the inherent firing rate instability of the weapon also affects firing disturbances. The simulation results align well with live-fire test data, verifying the accuracy of the rigid-flexible coupled firing dynamics model. By introducing the buffer, the impact torque on the motor and firing disturbances are significantly reduced, with the 100-meter half-group dispersion radius decreasing by 45.8% in a five-round burst, markedly improving firing density and system accuracy.

    Discrete Element Simulation if Crack Initiation and Damage Evolution in Concrete
    TAN Rijing, REN Huilan, LI Tao
    2025, 46(10):  250111.  doi:10.12382/bgxb.2025.0111
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    To investigate the damage evolution process in concrete, numerical simulations were conducted using the Discrete Element Method(DEM) to study crack initiation and propagation evolution in pre-cracked concrete specimens under different loading modes. Based on the aggregate geometry in concrete materials, a three-dimensional discrete element model incorporating irregular polyhedral aggregates was developed. The flat-joint model was then employed to investigate crack initiation and propagation behavior in concrete specimens under four loading modes, revealing the meso-scale damage mechanisms underlying macroscopic failure in concrete. The results demonstrate that: (1) During the initial loading phase, fewer internal cracks were observed in the concrete specimen. Due to the compressive stress concentration effect, shear cracks predominantly clustered near both loading ends, while tensile cracks initiated at the pre-existing crack tip. In the later loading stage, cracks rapidly propagated along aggregate boundaries, resulting in crack deflection. Secondary cracks emerged adjacent to the loading ends and extended towards the specimen mid-section, accompanied by limited crack development within highly stressed aggregates. (2) As the loading angle increased from 0° to 28°, the proportion of shear cracks at the pre-existing crack tip exhibited an increasing trend, demonstrating the transition from tensile-dominated to shear-dominated failure mechanisms in concrete. However, tensile failure remained the predominant factor governing specimen failure across all four loading modes. (3) Within the loading angle range of 0°-28°, the crack initiation angle at the pre-existing crack tip exhibited a positive correlation with increasing loading angles. The predictions based on the generalized maximum tangential stress (GMTS) criterion showed good agreement with simulation results for pure Mode I and mixed Mode Ⅰ-Ⅱ loading conditions, while demonstrating higher predictions under pure Mode Ⅱ loading.