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    28 February 2025, Volume 46 Issue 2
    Electronic edition of this issue
    Electronic Edition of this issue
    2025, 46(2):  0-0. 
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    Contents
    Contents
    2025, 46(2):  0-0. 
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    Dynamic Response of UHPFRC Beams with Different Strengths under Blast Loading
    ZHANG Qiyue, LIU Yan, YAN Junbo, XU Yingliang, WANG Baichuan, HUANG Fenglei
    2025, 46(2):  240390.  doi:10.12382/bgxb.2024.0390
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    The damage effects of ultra-high performance fiber reinforced concrete (UHPFRC) beams with different strengths subjected to blast loading are studied,with a focus on protecting typical architectural components from explosion.The influences of fiber content and longitudinal reinforcement type on the failure mode and dynamic response of UHPFRC beams are studied througth experiment.The results show that the increase in the fiber content and the use of high-strength steel (HSS) longitudinal reinforcement can improve the bending resistance of UHPFRC beams.A finite element model for UHPFRC beams under blast loading is developed to expand the research on damage effect.The parameters of the K&C constitutive model are calibrated using the single element test method,considering the factors like strength planes,equations of state,shear dilation,damage evolution,and strain rate effects.The quasi-static experiments demonstrate that the modified constitutive model parameters provide a more precise description of the mechanical characteristics of UHPFRC.Furthermore,the accuracy of the finite element model is also validated based on explosive experimental data.Finally,the influences of concrete strength,steel reinforcement type,and charge masses on the damage effects of UHPFRC beams at close range are further analyzed through parameter analysis.

    UAV Air-to-ground Attack Task Assignment Method Based on Damage Assessment Results
    HOU Peng, GE Yuxue, PEI Yang, YUE Yuan, AI Junqiang
    2025, 46(2):  240212.  doi:10.12382/bgxb.2024.0212
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    To improve the combat effectiveness of multi-UAVs cooperative air-to-ground attack task and the efficiency of cooperative task assignment,a task assignment method based on the result of combat unit damage probability is proposed.Three kinds of typical ground target damage eveluation models are established,and the damage probability of each target under different strike directions,as the data support for task assignment,is calculated.In view of the typical scenario of each UAV carrying different weapons to strike ther ground targets,an improved hybrid particle swarm optimization algorithm is proposed to solve the task assignment problem.The crossover and mutation operations of genetic algorithm are used to update particle positions.The crossover operation and mutation operation are improved,and the particle inversion operation is introduced to increase the diversity of particles and avoid falling into local optimum.The proposed method is verified by simulation examples.The simulated results demonstrate that,after using the damage assessment model to calculate the damage probability of ground targets,the proposed method can be used to obtain a task assignment scheme that meets the constraint conditions while meeting the damage requirements,and improve the overall combat effectiveness of the multi-UAV system.

    A Path Planning Algorithm for Mobile Robots Based on Angle Searching and Deep Q-Network
    LI Zonggang, HAN Sen, CHEN Yinjuan, NING Xiaogang
    2025, 46(2):  240265.  doi:10.12382/bgxb.2024.0265
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    deep Q-network algorithm has the limitations of long learning time and slow convergence speed when solving path planning problems.A path planning algorithm that combines angle search strategy and deep Q-network,called AS-DQN algorithm is proposed.A search domain is set to control the search direction of mobile robot and reduce the traversal of grid nodes,thus improving the efficiency of path planning.In order to enhance the collaboration ability of mobile robots,an internet of things information fusion technology model is proposed,which can integrate multiple scattered local environmental informations into a global information to guide multi-robot path planning.Simulation experimental results show that AS-DQN algorithm can take less time to find the optimal path to the target point for mobile robots compared with the standard DQN algorithm.Combining IIFT model with AS-DQN algorithm for path planning is more efficient.The physical experimental results show that AS-DQN algorithm can be applied to the Turtlebot3 unmanned vehicle and successfully finds the optimal path from the starting point to the target point.

    Analysis of Weapon System Capability Requirements Using an HF-DEMATEL-TOPSIS-based Enhanced QFD Method
    ZHAO Qingtian, LI Liwei, ZHANG Yangming, HOU Lizhi, LEI Zhen
    2025, 46(2):  240333.  doi:10.12382/bgxb.2024.0333
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    A new method is proposed for the analysis of capability requirements for the weapon systems,which enhances quality function deployment (QFD) by using the decision-making trial and evaluation laboratory (DEMATEL) method and the technique for order preference by similarity to ideal solution (TOPSIS) methods under a hesitant fuzzy environment.The proposed method utilizes the hesitant fuzzy theory-based DEMATEL method to analyze the interrelationships among the mission requirements of equipment system,thereby determining the importance of these requirements.Based on the importance of mission requirements,a hesitant fuzzy TOPSIS-based optimal model is established for equipment capability requirements.The relative importance of mission requirements is calculated from an improved weighted Hamming distance.The effectiveness of the improved QFD method is validated using an intelligent urban warfare equipment system as a case study compared to traditional methods.This improved method effectively addresses the shortcomings of traditional QFD method in handling the hesitant fuzzy information,providing new tools for the analysis of capability requirements of equipment systems.

    Adaptive Terminal Guidance for Hypersonic Gliding Vehicles Using Reinforcement Learning
    XIAO Liujun, LI Yaxuan, LIU Xinfu
    2025, 46(2):  240222.  doi:10.12382/bgxb.2024.0222
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    Addressing the uncertainty of dynamic model parameters in the terminal guidance phase of hypersonic gliding vehicles and the slow convergence speed of traditional reinforcement learning algorithm,an adaptive guidance algorithm based on reinforcement learning is proposed.The terminal guidance problem for hypersonic gliding vehicles under nominal conditions is converted into an optimal control problem,which is solved using the sequential convex optimization algorithm to generate a dataset of state-control pairs.The dataset is fitted through supervised learning to obtain a corresponding guidance model.The disturbances such as aerodynamic parameter deviation,uncertainty in control response delay coefficient,and state measurement noise are introduced,and the guidance model is further optimized based on the reinforcement learning framework through numerous interactions between the vehicle and the current environment.Numerically simulated results indicate that the proposed guidance method exhibits better robustness and accuracy compared to the supervised learning guidance method.

    Guidance-Tracker:An Adaptive UAV Siamese Tracker for Visual Guidance
    YANG Xuqi, TAN Qifan, SU Hang, TAN Hao
    2025, 46(2):  240284.  doi:10.12382/bgxb.2024.0284
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    Object tracking is an important part of UAV visual guidance,and the tracking accuracy determines the combat effectiveness of UAVs on the battlefield.There are many problems with general object tracking in UAV guidance:fast scale change,large appearance change,slow inference speed and lack of dataset.In order to solve the problems,this paper proposes Guidance-Tracker,an adaptive UAV siamese tracker for visual guidance.The adaptive search region mechanism adjusts the search region to fit the fast scale change by analyzing the guidance process,and the adaptive template updating mechanism updates the template feature to fit large appearance change.Besides,FasterNet Block and anchor-free mechanism are respectively introduced in the backbone network and the tracking head to speed up the inference time.In addition,an object tracking test dataset Guidance UAV for visual guidance,which contains 12 videos, is constructed to evaluate the performance of trackers in visual guidance.The experiment results indicate that Guidance-Tracker is not only suitable for use on the general UAV tracking dataset UAV123,but also achieves state-of-the-art performance on the Guidance UAV,while maintaining a speed of 15f/s on the onboard device Jetson Xavier NX.The indoor guidance experiments shows the effectiveness of the Guidance Tracker.

    Attitude Control Method of Serial Wheel-legged Robot
    XIE Jingshuo, HAN Lijin, LIU Hui, REN Xiaolei, HOU Hongyu, SHANG Qingyi
    2025, 46(2):  240183.  doi:10.12382/bgxb.2024.0183
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    To address the precise attitude control of a serial wheel-legged robot,a motion control framework with offset-free model predictive control as the core is proposed.Firstly,a concentrated center-of-mass dynamics model is established,which considers the mass distribution of body,legs,and wheels.Based on the concept of active disturbance rejection control,the unmodeled characteristics of the model are treated as disturbances,and an extended state observer is established to estimate and compensate for the unmodeled characteristics.Furthermore,the joint control is introduced to solve the problem that the wheels are easy to roll and cause leg abduction during attitude adjustment,and an additional wheel control strategy is designed to assist in constraining the leg state.The hardware experiments are conducted on the serial wheel-legged robot.The results show that the proposed motion control framework can accurately track the desired attitude signal,effectively suppress the terrain disturbances and external force disturbances,and ensure the driving stability and disturbance resistance capability of the robot.

    A CNN-SVM-based Adapter Drop Point Prediction Algorithm
    SU Zhengyu, YANG Baosheng, YANG Jing, TANG Jingnan, JIANG Yi, DENG Yueguang
    2025, 46(2):  240016.  doi:10.12382/bgxb.2024.0016
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    To address the prolonged processing and resource consumption challenges in the launch process adapter drop point prediction algorithm,a adapter drop point prediction model with convolutional neural network and support vector machine (CNN-SVM) is proposed.The adapter dynamics and motion models are established by utilizing Euler angle representation,and the fourth-order Runge-Kutta method is used to numerically solve the motion trajectory of adapter to provide the extensive motion state parameters and drop point information.The CNN-SVM-based adapter drop point prediction model uses the Adam optimizer to optimize CNN network performance,and determines optimal SVM hyperparameters through mesh searching.Simulated results show that the proposed model has high solution accuracy and robust generalization performance for adapter drop prediction,achieving R2 values exceeding 0.99 for both training and test sets and the mean absolute error (MAE) less than 0.1m.The solution time of the proposed method is only 8.5% compared to that of the traditional numerical integration method under the conditions of equivalent resources and the required prediction accuracy.The proposed model offers an efficient solution for rapidly predicting the adapter separation drop point during the launch process.

    Impact Resistance and Energy Absorption Properties of CFRP Thin-walled Circular Tube with Porous Arrays
    JIN Yue, MIAO Fuxing
    2025, 46(2):  240074.  doi:10.12382/bgxb.2024.0074
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    In order to improve the impact resistance and energy absorption of thin-walled circular tube,a carbon fiber reinforced composites (CFRP) thin-walled tube with porous array is designed to investigate its impact resistance and energy absorption performance under axial and transverse impact loads,respectively.A finite element model of CFRP thin-walled tube with porous arrays under impact loading is established based on the finite element method (FEM).The effects of different lay-up angles on the impact resistance and energy-absorbing properties of the structure are analyzed.Numerical results show that CFRP thin-walled circular tube with porous arrays has higher specific energy absorption and peak load,which are too high for the protected structure.But the peak impact load and specific energy absorption values can be changed by varying the lay-up angle of CFRP in order to enhance impact damage resistance.The maximum compression load within the effective compression displacement is reduced by about 10.1% and the specific energy absorption value is increased by about 15.1% when the lay-up angle of thin-walled circular tube with porous arrays is changed from [90°/45°/90°/0°]2S to [90°/0°/90°/0°]2S under axial impact loading.The preliminary results will be a guide for the engineering application of lightweighting and impact resistance enhancement of CFRP thin-walled tube.

    Study on the Damage Behavior of Reactive Composite Jet Based on Multi-layer Spaced Target Experiment
    WANG Zaicheng, PENG Yucheng, JIANG Chunlan, HU Rong
    2025, 46(2):  240086.  doi:10.12382/bgxb.2024.0086
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    To study the behind-target damage enhancement effects and mechanism of the reactive material double-layered liner (RM-DLL) shaped charge penetrating into the target plates,the penetration and deflagration behaviors of composite jet impacting a multi-layer spaced target are studied.The damage behaviors and mechanism of the reactive composite jet against multi-spaced target plates are investigated through experiment,numerical simulation and theoretical analysis.The experimental results show that the reactive composite jet can effectively damage the multi-layer spaced target composed of 8 mm thick steel targets and 10 mm thick aluminum plates.it can penetrate into 7-9 layers of target plates within the standoff range of 1.0-1.5 CD.The petal shaped edge damage and large opening damage of 8 mm steel targets are the most serious within the penetration depth range of 2.0-2.7 CD.The maximum damage area diameter of the steel target is 2.5 CD.At a penetration depth of 1-4 CD,it causes a petal shaped edge damage and large openings on 8 mm steel plates,with a maximum opening diameter of 2.5 CD.The simulated and calculated results indicate that the collapse effect of detonation waves,the material and structure of liner,and the penetration process determine the energy release behavior of reactive composite jet.The deformation energy changes of target plates at different positions are basically consistent with the distribution of reactivation mass of reactive materials.The metal jet of the composite jet head penetrates on the target plate in advance,which can avoid wasting a large amount of energetic materials in the early stage of penetration.Most of the reactive materials are brought into the interior of the target,fully utilizing the reaction energy release of the reactive materials,and achieving the enhanced damage effect inside the target through the combined action of penetration and deflagration.By adjusting the action conditions of jet,it is possible to control the position of reactive materials to enhance target damage as needed.The maximum energy release of ractive materials is achieved within the depth range of 2.3~3.0 CD,achieving the best damage effect.

    A Lightweight Recognition Method for Low Altitude Targets in the Battlefield
    XU Tunan, GAO Ang, CHEN Yucheng, YAN Shoucheng, DENG Bin
    2025, 46(2):  240170.  doi:10.12382/bgxb.2024.0170
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    In the process of intelligent radar target detection,the real-time recognition of targets by edge devices is particularly important.Considering the resource constraints inherent in embedded devices,the need for lightweight target recognition networks has become increasingly prominent.To address the challenges of limited battlefield target images and low contrast,a battlefield low-altitude target recognition algorithm named YOLOF is proposed.This algorithm is based on the YOLOv5s network model and incorporates a cycle-generative adversarial network (CycleGAN) for image enhancement.By integrating the RepVGG module and SiLU activation function,the algorithm enhances the feature extraction capability and inference speed of model through structural reparameterization and more efficient activation functions.Additionally,a pruning algorithm based on filter importance is employed to accurately evaluate and remove the filters with low weight impact,thereby optimizing the model’s structure and improving the computational and storage efficiencies.Furthermore,the knowledge distillation based on feature layers allows the transfer of knowledge from the teacher model to the student model’s feature layers,thus maintaining the high performance of the pruned model.Experimental results demonstrate that the proposed YOLOF algorithm,compared to the original YOLOv5s algorithm,achieves network lightweighting while ensuring high-precision target recognition.Specifically,the parameter count is reduced to just 3.6×106,and the mean average precision (mAP) reaches 86.3% on a custom dataset,meeting the requirements for battlefield low-altitude target recognition.

    Combat Intention Recognition of Air Cluster Targets Driven by Data and Knowledge
    LI Yangjun, HUANG Qilong, YANG Li, CHEN Xu
    2025, 46(2):  240113.  doi:10.12382/bgxb.2024.0113
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    Aiming at the diverse spatiotemporal characteristics of cluster targets and the excessive reliance of traditional data driven models on empirical samples,this paper proposes an algorithm for combat intent recognition driven by both data and knowledge.A cluster feature vector based on the virtual envelope and minimum bounding rectangle of target formation are constructed to enhance the feature expression of enemy situation data,which takes the cluster characteristics,such as the spatial form of cluster targets,into account.A knowledge model based on military expert experience and a long short-term memory (LSTM) network model with attention mechanism are established then.The knowledge model generates the intent pre-recognition vectors based on constraint rule,while the LSTM network model predicts the residual of intent probability distribution.The fusion ratio of both models is adaptively adjusted by utilizing a learnable residual estimator structure.A multi-objective loss function is designed to control the influence weights of the dual models.Ultimately,the fusion of the dual models overcomes the contradiction between the high accuracy of traditional data models and the insufficient data samples.Experimental results indicate that the proposed method improves the recognition accuracy to about 5.34% and 4.98% compared to LSTM and Attention-LSTM,respectively,and has significantly lower dependence on sample size than traditional data-driven methods.

    Study on Shock-induced Phase Transition of CsPbBr3 through Pulsed Discharge of Cylindrical Wire Array in Water Medium
    ZHANG Xueying, GAO Xin, XIAO Zeqi, LIU Kaiyuan, YUE Lidan, QIN Zhiqi, CHEN Pengwan
    2025, 46(2):  240276.  doi:10.12382/bgxb.2024.0276
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    Perovskite is regarded as one potential material for next-generation photovoltaic devices owing to its outstanding photoelectric characteristics which can be easily adjusted by phase transitions.However,the technology for intercepting and preparing the metastable perovskites is still in its infancy.The impact loading method has a significant advantage of high quenching rate,and enables the capture of metastable phases and facilitating their subsequent recovery and preparation.To achieve the impact phase transition treatment of CsPbBr3,the cylindrical converging shockwaves are generated by the pulsed discharge of cylindrical wire array in water medium for studying the shock-induced phase transition of CsPbBr3.The delicate control of shock pressure is applied to act on CsPbBr3 powder by adjusting the charging voltage.After experiments,the samples are recovered and characterized.The characterized results reveale that the shock waves generated by pulsed discharge can induce phase transition in CsPbBr3 powder under appropriate shock pressures (above 2 GPa).Additionally,the typical phenomena such as grain refinement,lattice distortion and nano-defects are observed in the recovered samples after shock-wave treatment.This study demonstrates that pulsed discharge of cylindrical wire array in water medium is a feasible converging shock wave loading technique,providing a novel approach to shock-induced phase transition loading.

    Fault Diagnosis of Planetary Gearbox Based on Frequency Slice Wavelet Transform and Attention-enhanced ConvNeXt Model
    CUI Suxiao, WU Zhe, CUI Yanping, ZHANG Qiang, ZHAO Yuejing
    2025, 46(2):  240329.  doi:10.12382/bgxb.2024.0329
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    The excessive reliance on experts prior knowledge in traditional manual fault feature extraction leads to incomplete information extraction,low efficiency,high cost,and missed or misdiagnosed cases.A fault diagnosis method based on frequency slice wavelet transform (FSWT) and attention-enhanced ConvNeXt is proposed for planetary gearboxes.This method integrates the convolutional block attention module (CBAM) into the ConvNeXt model,enabling the network to focus more on key regional features and reduce the interference from irrelevant targets.The one-dimensional vibration signals are transformed into the two-dimensional time-frequency spectrum images by applying FSWT,which are then input into the improved network for automatic feature extraction.A mapping relationship between the feature space and the fault space is established to accurately distinguish different fault modes.The proposed method is validated experimentally using the data from a dynamic drive simulation experimental platform.The results show that compared to other network models,the improved ConvNeXt model can accurately identify specific types of gear faults and exhibit good robustness even under noise interference.The research findings provide valuable reference for intelligent fault diagnosis of planetary gearboxes.

    An Acoustic Emission Source Localization Method Based on Basic Theta* Algorithm
    ZHANG Lizhong, REN Huilan, LI Tao
    2025, 46(2):  240234.  doi:10.12382/bgxb.2024.0234
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    For large concrete,rock and other structures,the elastic wave bypasses the empty zones inside the structure to propagates along a non-linear path due to the empty zones,so the traditional time difference of arrival (TDOA) localization method based on linear paths has large errors.In order to improve the localization accuracy of acoustic emission (AE) sources in the structures with empty zones,an AE source localization method suitable for such structures is proposed based on Basic Theta* algorithm.This method is verified by pencil lead break test on the surface of concrete slab containing circular empty zones,and the effects of the number of sensors,the position of sensors and the AE source location on the AE source localization error are discussed.The attenuation law of wave velocity with propagation distance in the concrete slab is obtained by multi-channel AE testing system.The localization results of single and multiple AE sources indicate that,compared with the traditional TDOA localization method and A* localization method,the proposed localization method effectively reduces the effect of elastic wave propagation around empty zones on localization,and substantially improves the localization accuracy and efficiency of AE sources in the concrete structure with empty zones.

    Effect of Desensitized Coating on Electrostatic Interaction between Energetic Explosive Particle and Conducting Wall
    FENG Yue, ZHOU Zilong, WU Chengcheng, GUO Xueyong, ZHANG Bo, WANG Hao, WANG Shuo
    2025, 46(2):  240189.  doi:10.12382/bgxb.2024.0189
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    This paper aims to study the electrostatic safety threshold of energetic explosive particles in the production process.A theoretical model of electrostatic interaction between coated energetic explosive particle and conducting wall in the cylindrical coordinate system is established using the re-expansion method.The boundaries of charge density and electric field threshold for electrostatic discharge between coated energetic explosive particle and conducting wall are defined based on the modified Paschenŋ’s law.The influences of particle structure and key electrical properties on electrostatic safety threshold are discussed.The results show that the conducting wall remains electrostatic attraction to particles with arbitrary charge and gap.The maximum electric field is located at the particle-wall gap.The electric field between the conductor particle and the metal conducting wall tends to infinity when they contact with each other.The electrostatic discharge risk of ractive metal particle is much higher than that of single-component explosive particle.The coating layer with small gap can increase the gap electric field of dielectric-core particles,but decrease the gap electric field of conductor-core particles.When the dielectric constant of the coating layer is 7.5ε0(ε0 is the dielectric constant of vacuum),the peak gap electric field of the coated dielectric-core particles with a surface charge density of 40μC/m2 is increased by 29.5%,reaching the discharge threshold.However,the peak gap electric field of the coated conductor-core particle with a surface charge density of 1.0μC/m2 decreases from infinity to a value below the discharge threshold.Although,the coating layer improves the intrinsic electrostatic safety of active metal conductor particle but reduces the electrostatic safety of single-component dielectric particle,the coated active metal conductor particle possesses less electrostatic safety than that of coated single-component dielectric particle.

    Study on Ballistic Characteristics of Variable Cross-section Projectile Obliquely Penetrating Two-layer Spacer Steel Target
    JIANG Teng, WU Haijun, DENG Ximin, QUAN Xin, DONG Heng, HUANG Fenglei
    2025, 46(2):  240019.  doi:10.12382/bgxb.2024.0019
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    The influence of the structural characteristics of variable cross-section projectile on the ballistic characteristics during obliquely penetrating the two-layer spaced steel targets is studied.The elliptical and variable cross-section projectiles obliquely penetrate a two-layer spaced steel target at an initial velocity of 1020m/s and an impact angle of 5° in the experiments.The trajectories,velocities,deflection angles,longitudinal displacements and longitudinal accelerations of circular and elliptical equal cross-section projectiles,and circular-and elliptical-variable cross-section projectiles during obliquely penetrating the steel target are compared by numerical simulations,and the physical mechanism of which the structural characteristics of variable cross-sectional projectile affect the stability of its trajectory is revealed.The results indicate that,when the initial impact velocity of projectile is high,the cross-sectional area at the shoulder of projectile remains consistent,and the variable cross-sectional angle is within the range of 0° to 2.5°,the velocity variations of projectiles with different cross-sectional shapes and variable cross-sectional angles during obliquely penetrating two-layer spaced steel targets are very small.For the variable cross-section projectile,a critical variable cross-section angle can be found by changing the structural characteristics of variable cross-section projectile,which makes the longitudinal displacement of the projectile penetrating the first-layer target plate basically zero.Different cross-sectional shapes of variable cross-sectional projectiles have different sensitivities to longitudinal motion and attitude deflection after penetrating the steel target at variable cross-sectional angles.The greater the ratio of long axis to minor axis of cross-sectional shape is,the greater the influence of variable cross-sectional angle on the deflection angular velocity is.Variable cross-section angle has an affect the force direction of the projectile during the process of penetrating the target,which may lead to the reversal of force on the projectile.The relevant studies have good guiding value for the optimization of structural characteristic parameters of variable cross-sectional projectile and the prediction of trajectory characteristics of variable cross-sectional projectiles during obliquely penetrating two-layer spaced steel targets.

    Parameter Selection and Optimization Algorithm for Low-overload Compressed Air Launch of Small Unmanned Aerial Vehicles Based on Particle Swarm Optimization
    ZHANG Fenglin, DONG Yihao, XIN Jianshe, GUO Liping, GU Xuechen, QU Jiaqi
    2025, 46(2):  240014.  doi:10.12382/bgxb.2024.0014
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    To further improve the internal ballistic characteristics during the compressed air launch process of unmanned aerial vehicles (UAVs),an internal ballistic model of the launch process is established by utilizing the thermodynamics and gas dynamics theories based on the structure and working mechanism of the compressed air launch system.The validity of the model is verified through simulation calculations and launch tests.The variation patterns of internal ballistic performance parameters with respect to the area and full-open time of pulse valve and the initial volumes of high- and low-pressure chambers are studied.An improved particle swarm optimization (PSO) algorithm based on the submunition principle is used to optimize the launch parameters,and the effectiveness of the optimized results is analyzed and verified.The results show that the pulse valve area has a positive correlation with the peak overload of UAV and significantly affects the mass flow rate of gas.The peak overload of UAV can be effectively reduced by increasing the full-open time of pulse valve.The volume of high-pressure chamber mainly influences the internal ballistic performance by altering the gas mass flow rate,and a larger volume of high-pressure chamber results in more noticeable changes in the pressure difference between the high-and low-pressure chambers.Reasonably increasing the low-pressure chamber volume can effectively reduce the peak acceleration while having a minor effect on the exit velocity of UAV,thereby enhancing the stability of UAV during launch process.The improved PSO algorithm effectively optimizes the parameter selection for low-overload compressed air launch of small UAVs.The research outcomes provide theoretical guidance for the selection,design,testing,and engineering application of compressed air launch parameters of UAVs.

    A Design Method of Vibration Accelerated Excitation Based on Feedback Approximate Damage
    FENG Yunwen, YANG Rongji, XUE Xiaofeng, LIU Jiaqi, GAO Tao
    2025, 46(2):  240138.  doi:10.12382/bgxb.2024.0138
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    The method for formulating the high-acceleration profiles for electromechanical products has some problems,such as unclear correlation between key element of profile and excitation failure mechanism,low fault excitation efficiency,and high testing costs.To establish a correlation mechanism between the cumulative damage and the key elements of vibration test profile,a vibration acceleration excitation design method based on feedback approximate damage is proposed.The refined design of vibration test profile is achieved through the dynamic control of damage increment.By integrating the analysis of vibration damage mechanism and the frequency-domain analytical technology of power spectral density,the mapping relationship between vibration excitation and cumulative damage is quantified,and a vibration excitation-damage corresponding model (CM-VED) is established.The validity of the proposed method is verified by taking the high-acceleration step vibration test of a fuse as an example.The research findings indicate that the obtained high-acceleration vibration test profile enhances the excitation accuracy of failure limit by 60% compared with the standard fixed-step method,and the time is shortened by 33.33% compared with that of the equal division method while ensuring high excitation accuracy.The proposed CM-VED can provide a theoretical basis for establishing the correspondence between excitation and damage.The proposed vibration acceleration excitation design method based on feedback approximate damage can reduce the test cost while guaranteeing the excitation accuracy,providing technical support for the design of the high-acceleration vibration test profile of electromechanical products.

    Effect of Divergent Section Contour of Supersonic Nozzle on Oscillation Characteristics of Underwater Jet Propulsion
    WANG Deyou, LI Shipeng, GUO Baojun, ZHANG Beichen, WANG Ningfei
    2025, 46(2):  240103.  doi:10.12382/bgxb.2024.0103
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    The effect of the divergent section contour of supersonic nozzle on the multiphase flow and propulsion performance of underwater rocket propulsion nozzle is studied by a series of numerical simulations.The underwater flow processes of conical and parabolic nozzles with different divergent section contours under still water,variable depth and over-expanded conditions are simulated.A numerical model of underwater supersonic gas jet is established based on the volume of fluid(VOF)multiphase model.The influence laws of the contour types and key parameters of divergent section on the nozzle near-field flow structure,flow separation characteristics,and thrust oscillation characteristics are analyzed.The results show that the separation shock structure in the nozzle operating in deep water is highly unstable.The gas-liquid separation may also occur at the separation point in the divergent section,and the nozzle thrust oscillates on the basis of the full-flow value.There is a dynamic transition of flow separation patterns in parabolic nozzles,and the gas-liquid separation phenomenon is not significant under the restricted shock separation(RSS)pattern.The effect of contour type is more pronounced than that of contour parameters,with the parabolic nozzles having more moderate thrust oscillations than the conical nozzles,and the difference is more significant at greater water depths.At a depth of 90 m,the maximum difference in average thrust of the nozzles with different contours reaches 10.13% of that of the basic parabolic nozzle.

    Static and Dynamic Mechanical Behaviors of Bouligand-type Biomimetic Composite Materials
    YANG Fan, QIN Zishang, LI Dacheng, HU Zhaocai, XIE Weihua, MENG Songhe
    2025, 46(2):  240118.  doi:10.12382/bgxb.2024.0118
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    The Bouligand structure found in arthropod exoskeletons had been shown to be the key factor to improving their dynamic mechanical properties.It is expected to provide innovative solutions and ideas for high-performance aerospace materials by designing the microstructure of fiber reinforced composites (CFRP) with the help of the concept of structural bionics.In this paper,the dynamic and static mechanical behaviors of Bouligand-type biomimetic materials and quasi-isotropic laminated materials are studied by means of SHPB and mechanical testing machine.The experimental results show that,with the increase of strain rate (≮1850s-1),the toughness of can be improved by at least 17.4% at a small helical angle,and the energy absorption capacity under quasi-static compression reaches 21.25J/g,which is improved by at least 42.4% compared with the quasi-isotropic configuration,all of which can be attributed to the plastic strengthening ability of Bouligand configuration specimen.The simulated and test results of drop weight impact further show that the bionic configuration can obtain excellent energy dissipation and impact protection characteristics.

    Research on Motion Blur Object Detection Technology for Imaging Guidance
    ZHAO Chunbo, MO Bo, LI Dawei, ZHAO Jie
    2025, 46(2):  240376.  doi:10.12382/bgxb.2024.0376
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    To enhance the accuracy and efficiency of motion-blurred image object detection in missile-borne imaging guidance,this paper proposes a lighter and more effective motion-blurred image object detection (LEMBD) network.The causes of motion-blurred image are analyzed,and a dedicated motion-blurred image dataset is constructed based on the imaging mechanism.Without increasing network parameters,a shared-weight siamese network design is adopted,and the prior knowledge is introduced to extract the features of blurred images by the feature learning of clear images,thereby enabling the simultaneous detection of both clear and blurred images.Additionally,the partial depthwise separable convolutions are introduced to replace the standard convolutions,which significantly reduce the parameter count and computational cost while enhancing learning performance.To further improve the feature fusion quality,a cross-layer path aggregation feature pyramid network is designed to effectively leverage both the detail information of low-level features and the semantic information of high-level features.Experimental results demonstrate that the proposed LEMBD network achieves superior performance in detecting the targets within motion-blurred images compared to conventional object detection and state-of-the-art motion-blurred detection methods,which can provide more accurate relative positional information for precision guidance tasks.

    An Anti-cloud Backscattering Method Based on PSAF-LMS Algorithm for Circumferential-scanning Laser Fuze
    ZHA Bingting, XU Guangbo, QIN Jianxin, ZHANG He
    2025, 46(2):  240264.  doi:10.12382/bgxb.2024.0264
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    Cloud backscattered signals superimposed on the target echo is an important factor affecting the ranging accuracy of laser fuzes.Aiming at the problems of poor adaptability and low time-efficiency of the current anti-cloud and fog interference methods,this paper proposes a nonlinear backscattering filtering algorithm based on the pauseable spline adaptive filter-least mean square (PSAF-LMS) with variable step size,and designs a Zynq implementation scheme of the algorithm.According to the characteristics of laser detection echo signals in cloudy environments,a variable learning step function with positive correlation with the time error is proposed.A filtering algorithm pause module based on threshold detection is set to retain the original change trend of target echo and improve the moment discrimination accuracy and anti-jamming ability of laser fuse.The,simulations and environmental tests are carried out to verify the filtering effect by using the echo signals with different signal-to-noise ratios.The results show that the proposed algorithm can effectively filter out the back scattering within 34.85μs and retain the original change trend of the target waveform,and the signal-to-noise ratio before and after filtering can be improved by more than 25.15dB on average.

    Sample Imbalanced Fault Diagnosis Method Based on Multi-channel Data Double Augmentation
    GUO Yiming, TONG Yifei, HE Fei, XIE Zhongqu, SONG Shida, HUANG Jing
    2025, 46(2):  240012.  doi:10.12382/bgxb.2024.0012
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    In complex manufacturing processes,it is crucial to collect and analyze the multi-channel data for condition monitoring and fault diagnosis.The existing methods are used to difficultly handle the problems of complex spatial-temporal correlation and sample imbalance of the multi-channel data.To solve these problems,a sample imbalance fault diagnosis method based on multi-channel data double augmentation is developed.The proposed method has the advantages of two-stage data augmentation and global optimization.It first learns the fault features,and then converts them into the multi-channel data for the data augmentation.The distribution difference evaluation mechanism is introduced to effectively describe the correlation between different channels,and a multi-objective global optimization strategy is designed to improve the quality of generated data.The effectiveness of the proposed method is verified by studying a real-world case.The experimental results show that the data double augmentation method can effectively expand the multi-channel data with small samples,and the global optimization strategy can improve the performance of generated data in the fault diagnosis.Compared with existing methods,the proposed method has higher fault diagnosis accuracy in various sample imbalance scenarios.

    Identification of Viscoelastic Constitutive Parameters of Acrylic Thin Plates Using Complex Virtual Fields Method
    WANG Gangting, GUO Baoqiao, LIU Han, LUAN Kedi, GU Yuansen, CHEN Pengwan, ZHOU Jiangfan, LIU Zhanwei
    2025, 46(2):  240051.  doi:10.12382/bgxb.2024.0051
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    To investigate new methods in the field of material parameter inversion,a complex virtual fields method is proposed for solving the elastic constants of orthogonal anisotropic composite materials.To lay the groundwork for the inversion of orthogonal anisotropic constitutive parameters,an isotropic material,polymethyl methacrylate (PMMA),is initially used as an experimental specimen.Based on thin plate theory and deflectometry,a vibration loading test is conducted on a thin plate specimen to acquire the full-field deformation of the specimen surface.The measured deformation field is processed using C3 continuity Hermite finite elements,resulting in the out-of-plane displacement and curvature fields of the thin plate specimen.The complex virtual fields method is then used to calculate the viscoelastic constants of material.The inversion results are compared with the elastic parameters measured by the three-point bending test and the damping coefficients measured by the cantilever beam hammer impact test.The experimental results show that the measured errors of the elastic modulus and damping coefficients are all within 0.3%.This confirms the feasibility of the proposed method in the inversion of isotropic constitutive parameters and lays the foundation for the subsequent inversion of anisotropic material constitutive parameters.

    Experimental Study on Acoustic Property of Solid Rocket Motor under Pulse Triggering
    ZENG Jiajin, LI Junwei, LI Qiang, LI Tao, ZHANG Wenhao, LU Jiancheng, WANG Ningfei
    2025, 46(2):  240162.  doi:10.12382/bgxb.2024.0162
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    In order to study the influence of external excitation on the stability of solid rocket motor,an experimental model system for the acoustic property of solid rocket motor is built,and the axial and radial excitation experiments of solid rocket motor are carried out.The influences of throttle aperture and trigger mode on the experimental results are studied.The natural frequency and attenuation coefficient of each order oscillation are obtained.The acoustic speed in the combustion chamber measured by cross-correlation analysis is 604.2m/s,and the frequency error predicated upon the measured acoustic speed is 10.1%.The oscillation of the system can be divided into two stages according to the attenuation speed.When the throttling aperture increases,the frequency of pressure oscillation input into the motor by a pulser and the oscillation amplitude of each mode increase,and the first-stage attenuation becomes faster,while the second-stage attenuation becomes slower.The oscillation attenuation of the axial excitation is faster than that of the radial excitation on the combustion chamber head in the first stage,and it has stronger nonlinear characteristics.

    Design and Simulation of Bionic Composite Shock Absorption Structure for Imaging Fuze
    ZHANG Cong, LU Junhua, YUE Mingkai
    2025, 46(2):  240021.  doi:10.12382/bgxb.2024.0021
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    The optical components in the trajectory correction fuze can not be subjected to the high launch overload of a projectile.A shock absorption method for the optical system of the fuze is proposed based on the bionic concept.The macro-and micro-structures of bamboo are applied to a metal thin-walled tube,and two kinds of metal thin-walled sleeves with the characteristics of bamboo structure are designed for the optical system.And also a shock absorption device composed of rubber pad and disc spring is designed.The finite element analysis software is used to carry out dynamics simulation to verify the shock absorption efficiency of the designed structure model.The simulated results show that the proposed shock absorption method can be used to alleviate the impact on the optical system and reduce the deformation value.The peak strains of two lens outer cylinders are reduced by 40% and 72%,respectively,and the peak strain of the optical sensor is reduced by 68.21% and 52.49%.It is proved that the proposed shock absorption method has a good shock absorption effect.This strategy provides a new idea for the application of optical components in high overload fuze.

    DOA Estimation for Underwater Acoustic Sensor Arrays Using Jensen-Bregman LogDet Divergence on Positive Definite Matrix Manifolds
    WANG Zhuying, YAN Yongsheng, ZHANG Hongwei, SUO Jian, HE Ke, WANG Haiyan
    2025, 46(2):  240225.  doi:10.12382/bgxb.2024.0225
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    Because the covariance matrix is a nonlinear space,the traditional method using Euclidean space does not reflect the difference between covariance matrices,resulting in information loss.To address this issue,a DOA estimation method based on Jensen-Bregman LogDet divergence (JBLD) is proposed,which transforms the target orientation estimation problem into the geometric distance problem between two points on the matrix manifold.It is concluded that the angle corresponding to the minimum geometric distance is the incidence angle of target,and two robust matrix manifolds are constructed to complete the establishment of matrix information DOA estimation theory model.The proposed method is verified by simulation and measured data.The results show that the proposed method has better estimation accuracy in low SNR environment than the existing MVDR and MUSIC algorithms.The proposed method has specific practical significance and application prospects,and can provide a solid technical support for underwater target positioning in marine defence and the civil field.

    A Point Cloud Splicing Method of Rectangular Fragment Interception Target Based on Euclidean Space Transformation
    REN Jie, JIANG Haiyan, JI Jianrong
    2025, 46(2):  240178.  doi:10.12382/bgxb.2024.0178
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    Three-dimensional laser scanning technology can be used to acquire the high-precision point cloud data of fragment interception target directly.The damage characteristics such as holes and pits formed by fragments on the target can be identified and extracted.However,the positions of local point clouds collected by the laser scanner at multiple positions and angles are independent of each other,making it difficult to reflect the overall structure of a large-scale target array.A point cloud splicing method of rectangular fragment interception target based on Euclidean space transformation is proposed.The rotation matrix and translation vector are constructed based on the corner coordinates and position relationships of local point clouds.Through multiple rotation and translation transformations,the angle and posture of multiple local point clouds are adjusted to splice them into an overall point cloud of the rectangular fragment interception target.Compared with the size of the target array,the average relative errors of the height and length of overall point cloud acquired by this splicing method are 2.035% and 1.192%,respectively.This study fills the research gap of target array laser point cloud splicing method in the field of fragment dispersion distribution testing technology.On this basis,the 3D reconstruction of fragment field dispersion distribution of warheads based on laser point clouds can be studied with fragment feature recognition technology in the future.

    Sensorless Control of High-speed Permanent Magnet Synchronous Motor Based on Adaptive Synchronous-frequency Tracking Observer
    XU Guxuan, ZHAO Feng
    2025, 46(2):  240121.  doi:10.12382/bgxb.2024.0121
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    At high rotational speed,the inherent chattering,low-pass filter (LPF) delay,and dead zone effect of the rotor position and speed estimation algorithm of the traditional sliding mode observer have become the main factors affecting the control accuracy of sensorless control system for high-speed permanent magnet synchronous motor.A sensorless speed estimation algorithm based on an adaptive synchronous-frequency tracking observer is proposed to improve the observational accuracy of rotor position.In this observer,the quasi-proportional-resonance control can be used to realize the adaptive tracking of stator current estimation error during frequency change,and a fundamental wave back electromotive force is obtained by the adaptive harmonic elimination,instead of the convergence function and LPF of the traditional SMO to eliminate the chattering and phase delay,which can realize the high-precision estimation of the rotor position and speed.In order to minimize the influence of the error voltage caused by the deadtime at high frequency on the angle estimation,an accurate voltage estimation model based on the reconstruction of deadtime voltage is adopted to further improve the dynamic performance and position estimation accuracy of the sensorless estimation algorithm in the low-speed domain.Simulated and experimental results demonstrate the superiority of the proposed method applied to the full-speed domain of high-speed permanent magnet synchronous motor for gas turbine.