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.

Microbially induced calcite precipitation (MICP) is effective to strengthen the calcareous sand foundation of reef fortifications via in-situ construction,dynamic response,and the dynamic characteristics and numerical model of MICP-treated calcareous sand are essential to the reef defense design and damage evaluation.The MICP cementation experiment is conducted on calcareous sand from the South China Sea.The strain rate effect of MICP-treated calcareous sand is evaluated through quasi-static uniaxial compression and dynamic mechanical testing of a split Hopkinson pressure bar (SHPB).A user subroutine VUMAT is developed based on the microplane model M7 for calibrating the material parameters.Compared with the calcareous sand penetration experiments,the numerical simulations demonstrate an increase in the penetration resistance of calcareous sand.The results reveal that the unconfined uniaxial compressive strength of MICP-treated calcareous sand specimen is 12.31MPa,and the dynamic increase factors are 1.117,1.485,and 1.828,respectively,at strain rates of 426s^-1,1150s^-1,and 1712s^-1 on the Hopkinson bar.Strain rate effect has a negative influence on the penetration depth of M7 constructive model by 4.2% DOP contribution.Compared with ordinary calcareous sand,the depth of penetration of MICP-treated calcareous sand is reduced by 40.11% on average,and the average target static resistance increases from 5.21MPa to 11.89MPa,indicating a significant increase in the resistance to penetration.These findings provide the experimental data and simulation model reference for damage analyses of reef fortifications subjected to high-impact loadings.

In order to clarify the injury mechanism of human head under blunt ballistic impact,a finite element model fitting the characteristics of Chinese 50th percentile male adult heads is constructed by the material parameter optimization,proportional scaling and fluid-structure interaction methods based on the total human model for safety (THUMS) model.LS-DYNA (Livermore software technology corporation's dynamic analyzer) is taken as a simulation platform,and the arbitrary Lagrangian-Eulerian algorithm is used to define the fluid characteristics of cerebrospinal fluid,optimize the elastic-plastic material parameters of skull and brain tissue,and realize the localization of head size and anatomical structure through mesh deformation technology.The biomechanical response of the model is verified by comparing the data of Nahum cadaver experiment and THUMS model for the typical vulnerable parts,such as forehead,parietal wall,occipital and posterior fossa,of human body.The results show that the peak values of intracranial pressure in the vulnerable area of the improved model are 150kPa,75kPa,53kPa and 69kPa,respectively,and the error between the improved model and the experimental data is 4%-10%,and the shape of the dynamic response curve is consistent.The maximum von Mises stress of brain tissue (29.5kPa) and the principal stress of skull (18.7kPa) are close to the threshold of Marjoux and Yoganandan simulation experiment,which verifies that the proposed model could effectively predict the risk of craniocerebral injury.The assessment based on NATO AEP-103 standard indicates that the peak value of the forehead intracranial pressure under typical impact is 511.1kPa,far exceeding the threshold of skull fracture (150kPa),which highlights the optimization needs of existing protective equipment.The proposed model has strong applicability and can provide reference and theoretical support for head injury assessment and safety protection under blunt ballistic impact.

Amphibious vehicle is a mobile platform capable of operating in both terrestrial and aquatic environments,and has significant application value and development potential in both military and civilian fields.The development history of amphibious vehicles is reviewed,and the characteristics and development trends of different types of amphibious vehicles are compared and analyzed.The key technologies for the navigation of amphibious vehicles on water are expounded from three aspects:modeling and simulation,high-speed amphibious vehicle design,and navigation control.The difficulties and challenges in achieving the unmanned operation of amphibious vehicles on water are discussed based on the research progress of unmanned technology for amphibious vehicles,and the future research direction of amphibious vehicles is prospected.

To address the challenges of extreme scale variations，dense occlusion of small targets，and complex background interference in unmanned aerial vehicle （UAV）-based target detection，this paper proposes a cross-layer dynamic detection network based on an improved YOLOv10 for the detection of small target via UAV aerial photography.A dual-branch cross-layer feature fusion pyramid network for replacing the original pyramid network is designed to resolve the problem of insufficient detail preservation for small targets in traditional methods.A channel-shuffling depth-wise upsampling module is developed，which combines channel shuffle operations with depth-wise separable convolutions and enhances the edge features of small targets through high-frequency residual connections.An end-to-end dynamic detection head is adopted to replace the original detection head，and a dynamic weighting mechanism is introduced，which enables the adaptive adjustment of feature representations at each position based on contextual information.Experimental results show that the proposed detection network achieves mAP0.5 of 53.3% and mAP0.5：0.95 of 33.2% on the VisDrone 2019 validation set，which are improveed by 12.7% and 9% ，respectively，compared to YOLOv10s，while reduces the model parameters by 23.7% and achieves an FPS of 79.The proposed algorithm significantly enhances the detection accuracy while maintaining excellent inference speed.

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.

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.

In order to study the variation law of the penetration power of shaped charge jet under lateral disturbance,the finite element models of the dynamic penetration of shaped charge jet are established,and the evolutionary process of jet penetration from static to dynamic conditions is analyzed.Based on the virtual origin theory and dimensional analysis method,a virtual source is introduced to characterize the jet in the dimensional analytical model.An engineering prediction model for dynamic jet penetration depth,which considers lateral disturbance,jet and target plate strength,is established.A jet dynamic penetration test based on a rocket sled is designed and conducted,and the numerical simulation and prediction models are validated.The research results indicate that the dynamic penetration depth of shaped charge jet decreases exponentially with the increase in the lateral disturbance of target plates.The numerically simulated results,prediction model,and experimental results are in good agreement with each other,and both the prediction model and numerical simulation have a certain degree of accuracy and effectiveness.The proposed prediction model can describe the influence of lateral disturbance on the penetration power of shaped charge jet,thus providing a basis and reference for evaluating the dynamic damage power of formed charges.

The complex nature of missions executed by the Armed Police Force imposes higher requirements on the precision and control of strike effects of firearms.This paper focuses on the design and key technologies of intelligent non-lethal electromagnetic constant kinetic energy strike weapon systems.A “human-weapon integration” precision strike model is constructed by integratiing artificial intelligence，electromagnetic launch，and constant kinetic energy strike theories to achieve the dynamic control of non-lethal kinetic energy output.A hierarchical framework and operational mechanism based on the “perception-decision-execution” architecture are proposed by reviewing the global development status of intelligent firearms and analyzing the design necessity and intelligent connotation of weapon systems.Key technologies including line-of-sight stabilization，trajectory computation with terminal energy threshold，and electromagnetic launch control are thoroughly analyzed.The future development directions and potential contradictions of weapon systems are presented，transitioning from theoretical research to practical combat applications and providing effective support for equipment upgrading and operational effectiveness enhancement of Armed Police Force.

The mixing process,as a crucial step in the fabrication of solid propellants,typically involves the incorporation of particulate phases such as aluminum (Al),ammonium perchlorate (AP),and RDX into a polymeric binder matrix.The binder slurry is applied onto the solid particles through mechanical kneading and stirring.The dispersion accompanied by dynamic blade kneading during the co-mingling of solid particulate phases in a mixer is simulated based on the Mixture solid-gas-liquid multiphase flow model.Dynamic rheological measurements of slurries with varying solid contents (0%-95%) are performed to construct a rheological model of propellant slurry.Considering the dynamic changes in granular concentration and their impact on local rheological properties,the mixing dynamic processes at different granular injection flow rates are simulated.The analysis focuses on the temporal patterns of granular concentration,pressure fields,and torque under various operating conditions.The results indicate that the proposed numerical simulation method is in good agreement with experimental results in Ref.[39] with an average error of less than 15%.The study reveals that the greatest pressure occurs at the tips of the near and far blades,while a low-pressure zone exists in the middle of the blades.During mixing,the blade torque exhibits a serrated fluctuation,and gradually increases with the addition of the particulate phase.A slight increase in the granular injection flow rate results in a minimal torque change.However,a significant increase in flow rate could lead to a torque increase of up to 90%.In the continuous feeding mixing process,the torque value at the farthest blade from the axis of rotation continues to rise,eventually reaching an average value 19 times that at the initial stage.This research provides insights for enhancing the efficiency and safety studies of solid propellant mixing processes.

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 TiZrHfTa_0.5 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.

The ceramic/fiber composite ballistic plates are widely used in personal protection equipment. Studying the performance of ballistic plate subjected to multi-impacts is of great significance for reducing the number of casualties in the battlefield.This paper investigates the Al₂O₃/UHMWPE composite ballistic plate,focusing on numerical simulations conducted for various bullet impact points.The reliability of the simulated results is validated by comparing with the experimental results.The relationship between the energy absorption and damage characteristics of the ballistic plate is derived from the ceramic and fiber damage results,and the penetration probability of the next impact is effectively calculated.The results indicate that the damage patterns of ballistic plates are roughly the same and the impact resistance of ceramic layer at the joint decreases.when the impact point of the first bullet is located at the center of a ceramic plate,within the gap between two plates,or at the gap of quadrilateral jointing.Specifically,when the impact point of the first bullet is located at the center of ceramic plate,the subsequent bullets tend to penetrate through the gap between adjacent plates.As the proximity between successive impacts decreases,the energy absorption by the ceramic layer diminishes while the energy absorbed by the fiber layer increases.When two impact points are located parallelly and diagonally apart,the middle ceramic plate does not suffer macroscopic damage due to the joint structure.When the first impact point is in the center of the ceramic plate,the penetration probability of the second impact is 1.04%.When the first impact point is in the center of the ceramic plate,and the second impact point is in the horizontal adjacent center,the four corners of the gap,or the diagonal adjacent center,the penetration probability of the third impact on the ballistic plate is 5.45%,7.35%,and 5.05%,respectively.This method can be used to quickly evaluate the resistance of damaged equipment to multiple penetrations.

It is required to fastly and accurately predict the exterior ballistics and impact points of mortars on the modern battlefield.A mortar exterior ballistics prediction method based on Transformer-long short-term memory (Transformer-LSTM) hybrid neural network is proposed.The Transformer network is utilized to extract the intrinsic joint features of mortar’s velocity and three-dimensional coordinates at the moments from T to T+K,and the LSTM network takes these time series features as an input to map the three-dimensional coordinate information at the moment of T+K+1.In order to optimize the network model,the effects of different sliding window step sizes on the convergence performance of the exterior ballistics prediction model are investigated and analyzed.The proposed hybrid network is compared with GRU and LSTM networks in terms of single-step,multi-step and impact-point prediction.It is found that the prediction accuracies of the proposed hybrid network for the three-dimensional coordinates of exterior ballistics can reach up to 99.78%,99.72% and 99.81%,which are better than those of GRU and LSTM networks; and the single-step prediction of the exterior ballistics of the proposed hybrid network consumes only 1.2ms,which significantly improves the prediction accuracy and efficiency.The method enables accurate and fast prediction of exterior ballistics and impact point,providing more response time for mortar interception missions.

Aircraft aerodynamic configuration design has long adhered to an experience-driven design philosophy,where the aerodynamic performance of the baseline shape often determines and limits the performance improvements achievable through shape optimization.This traditional design approach is incapable of yielding disruptive aerodynamic configurations.In recent years,with the emergence of aerodynamic topology design concepts,aerodynamic topology optimization methods have gained attention and are expected to be applied to the design of novel aircraft aerodynamic configurations.Focusing on aerodynamic topology optimization methods,this paper reviews their development in terms of topology representation methods and optimization algorithms,and analyzes typical application cases of existing methods in the design of novel aircraft aerodynamic configurations.First,the historical development of aerodynamic topology optimization methods is outlined.Second,recent advances in the application of aerodynamic topology to novel aircraft configuration design are summarized.Subsequently,the challenges and difficulties faced by aerodynamic topology optimization methods are discussed,including difficulties in handling high-speed compressible turbulent flows and insufficient smoothness at fluid-solid interfaces in aircraft flow topology.Finally,future research directions in this field are prospected.

In complex geographical environments such as uncertain area，hostile environment and restricted area on the battlefield，conducting the search and rescue operation for persons in distress faces numerous challenges including low efficiency and poor positioning accuracy.How to utilize emerging equipment such as unmanned aerial vehicles （UAVs） to improve the efficiency of search and rescue operations for the persons in distress has become a research hotspot across the world.A searching and positioning UAV micro-swarm system composed of three multi-rotor UAVs is designed.This system is mainly composed of quadcopter UAVs，electro-optical search payloads，broadband ad hoc network radios，and UAV ground stations，etc.The day and night search and collaboration control are realized by single UAV and muliti-UAV collaboration.The miniaturized design of UAV makes it easy for the operator to carry with a backpack，facilitating forward reconnaissance to determine the locations information and the condition of the injury.The system can precisely locate the persons in distress and has the advantages of being less restricted by terrain and environment and having high search efficiency in the area.UAVs can achieve multi-mode networking communication among multiple unmanned platforms，and the ground control station has the functions of mission planning，setting the mission routes for multiple UAVs，and controlling UAVs to fly in formation，which can enhance the efficiency of battlefield search and rescue through the multi-UAVs collaboration.

On the vast ocean，some islands and reefs are scattered and far apart from each other.The traditional energy power generation mode is facing prominent problems such as difficulties in power supply guarantee，and high operation and maintenance costs，etc.In order to fully develop renewable energy in the ocean and build a sustainable offshore energy supply system，the offshore wind power generation technology is gradually becoming a strategic choice to solve the problem of power supply in remote islands and reefs.As a new type of electromagnetic energy conversion device based on advanced magnetic field modulation theory，the permanent magnet vernier motor (PMVM) has demonstrated unique advantages in the fields of ship propulsion and offshore wind power generation due to its excellent low-speed and high torque characteristics，and is particularly suitable for use as the core power generation unit of offshore island microgrids.A multi-node magnetic circuit analytical model system is structured for tangential excitation PMVM.An accurate analytical solution for the air gap magnetic field in this structure is obtained through rigorous mathematical modeling.Based on the theory of magnetic field modulation and the principle of electromechanical energy conversion，the quantitative relationship among the core electromagnetic parameters such as air gap magnetic field，no-load back electromotive force，electromagnetic torque and armature inductance with the size of motor are systematically established.Taking into account the bilateral slotting effect，the error of the core electrical parameters is controlled within 2%.Specifically，the direct current attenuation method is used to achieve the high-precision experimental calibration of motor inductance parameters.The error between the predicted values of the analytical model and the measured data is controlled within 3%，fully verifying the effectiveness of the theoretical model.This study provides a complete theoretical analysis framework and engineering practice guidance for the rapid design and optimization of tangential excitation structure PMVM.The accuracy and engineering applicability of the analytical model are confirmed through the comparative verification of finite element simulation and prototype experiments.

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.

The reactive filling structure exhibits a unique behavior of self-distributed deflagration and energy release,along with mechanically and chemically coupled dynamic characteristics when penetrating multi-layered plates.This results in a multi-peak,long-duration deflagration overpressure behind the plates,featuring a complex evolution and waveform mechanism of the deflagration process.To better understand this distinctive energy-releasing behavior,overpressure signals were recorded during experiments that involved the reactive filling structure penetrating multi-layered plates at various velocities.An equivalent deflagration position model and theories for deflagration overpressure were developed to clarify the waveform characteristics of deflagration shock wave.Experimental results show that the third collision produced the maximum peak overpressure.,which increased from 0.0607MPa to 0.246MPa as the velocity rose from 594m/s to 819m/s(the impact stress in the range of 2.54GPa to 3.92GPa).The equivalent deflagration model indicates that the intense deflagration reaction occurred within a distance of 20.73mm behind the plates.The peak deflagration overpressure is influenced by several factors,including thickness of the structure's head,the impact velocity,and the thickness of plates,all of which affect the effective initiated mass of the reactive filling.The analytical model aligns well with the experimental results,providing credible support for further investigations into the after-effects of the reactive filling structure.

To address the challenges of multispectral feature mismatch，complex scene interference，and insufficient detection accuracy in drone aerial vehicle target detection，this paper proposes Multi-Scale Gated Fusion Network（MSGF-Net），a YOLOv10-based multi-feature space joint optimization network.First，the network employs a dual-stream feature extraction network and introduces a gated local-global fusion （GLGF） module into the backbone.This enables effective interaction and joint optimization of visible and infrared features across mult-feature spaces，thereby mitigating the impact of feature mismatch and enhancing feature representation.Subsequently，after the feature pyramid network，MSGF-Net incorporates a cross-modulation block （CMB） module to perform the pixel-wise weighted fusion of multi-feature space information，further improving the complementarity between different spectral features.Experiments on the public DroneVehicle dataset demonstrate that MSGF-Net achieves 83.4% mAP_0.5and 63.9% mAP_0.5：0.95，showing a significant improvement compared to the single-channel model YOLOv10n.Furthermore，compared to leading multi-modal fusion algorithms like C2Former and TSDADet，MSGF-Net increases the mAP_0.5：0.95 by over 9 percentage points，providing compelling evidence of its superior accuracy and robustness.

To address the issues of the lack of structural synergy between ceramic plates in existing spliced ceramic bulletproof plates and the poor dissipation of impact energy,a biomimetic topological interlocking ceramic splicing scheme based on the exoskeletal structure of phloeodes diabolicus is designed.The numerical simulation research is made on the protective performance of the designed bulletproof plates under the impact of bullets. A non-standard bulletproof ceramic plate with a phloeodes diabolicus exoskeletal structure is designed based on the microstructure of biological materials and the principle of topological interlocking in engineering structures.The accuracy of the simulation model is verified through 3D-DIC testing,and the penetrations of 5.8mm DBP 10 rifle bullets into square,hexagonal and biomimetic topological interlocking ceramic spliced bulletproof plates are simulated.The results show that the biomimetic topological interlocking ceramic blocks can effectively enable the surrounding ceramics to dissipate the impact energy,The back bulge height of the biomimetic topological interlocking ceramic bulletproof insert after being penetrated is reduced by approximately 8% compared to that of the hexagonal ceramic bulletproof insert.An individual soldier protective insert plate based on the biomimetic topological interlocking ceramic configuration is designed,and the numerical simulations are conducted on the blunt trauma effects of M80 rifle bullet penetrating the human torso of the protected individual soldier.The results indicate that the blunt trauma energy is primarily borne by the muscles and thoracic ribs,and the peak stress on thoracic ribs reaches 30.7MPa,which potentially leads to bone fractures.The maximum stress in the heart is 930.2kPa,and the maximum stress in the lungs is 777.5kPa,potentially causing myocardial injury and lung soft tissue contusion.

The influence of aluminum powder content on the energy output characteristics of RDX-based aluminized explosives is studied.The free-field static explosion tests are conducted on aluminized explosives with aluminum powder contents of 20%,30%,and 40%.The overpressure-time curves of free-field and ground shock waves are measured using overpressure sensors,and the propagation processes of incident waves,reflected waves,and Mach waves,as well as the changes in the explosion fireball are captured using a high-speed camera.The JWL-Miller parameters of the aluminized explosives are calibrated based on the test results.The test results show that the peak overpressure and specific impulse of ground reflected wave of the aluminized explosive are slightly affected when the aluminum powder content increases from 20% to 30%.When the aluminum powder content increases from 30% to 40%,the peak overpressure of ground reflected wave is decreased by 2.17% to 7.81%,and the specific impulse is decreased by 0.29% to 12.17%.When the aluminum powder content increases from 20% to 40%,the maximum diameter of explosion fireball increases from 6.48m to 7.12m,and the time when the explosion fireball begins to shrink increases from 20ms to 60ms.The maximum errors of the blast shock wave parameters (peak overpressure and specific impulse) of 30% and 40% aluminized explosives predicted using the JWL-Miller parameters are 16.75% and -8.51%,respectively,compared with the test results,and the average absolute percentage errors are 6.76% and 4.14%,respectively.This study can provide reference and guidance for the prediction of the power field of aluminized explosives.

A cooperative encirclement interception method based on virtual aiming points is proposed for intercepting the high-speed maneuvering targets in near-space in three-dimensional scenarios.A calculation method for the ideal interception time of interceptor groups is derived by analyzing the maneuvering envelope of target and considering the guidance characteristics of the interceptors.Thus,the problem of intercepting the high-speed maneuvering targets is transformed into a problem of hitting a specific point on a fixed spatial plane at a predetermined time and angle.Based on the ideal interception time and angle of attack,the virtual aiming points are selected in space to guide the interceptors,ensuring that the impact angles meet the head-on interception conditions,thereby reducing the requirement for the speed of interceptor.The interception tests are conducted on two typical C-type and S-type maneuvering targets through numerical simulation.The results demonstrate that the proposed method is used to successfully intercept C-type and S-type maneuvering targets with different maneuvering intensities,achieve a minimum group miss distance of less than 3 meters,and enable the impact angle meet the requirements of head-on interception angle.

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.

In order to study the explosion driving characteristics of shell fragments driven by cylindrical charge with cavity and reveal the mechanism of the influence of shaped charge structure on the initial velocity of shell fragments,the explosion driving process and initial velocity distribution of shell fragments under different cavity cone angles are studied through the numerical simulation.The initial velocity distribution function of shell fragment along the axial direction is fitted by analyzing the rarefaction wave propagation path,velocity loss coefficient and fragment acceleration process.The relative error between the calculated and simulated results is less than 15%.The results show that the earlier generation of rarefaction wave and the decrease in cross-section ratio of mass of charge to shell are the main factors contributing to the decrease in the initial velocity of fragments.The initial velocity of the fragments near the non-detonation end decreases with the decrease in the cone angle of cavity and the increase in the cone top height of cavity.The rarefaction wave reflected from the non-detonation end is an approximately planar wave and is at a certain angle to the cavity surface.The instant when rarefaction wave reaches shell is linearly and positively correlated with the axial position of the shell.The cross-section ratio of mass of charge to shell has a quadratic function relationship with k,where k is the ratio of the distance from the cross section to the non-initiating end to the height of cavity cone top.The velocity loss coefficient decays exponentially with the decrease in k.The research can provide a useful reference for the overall structural design,material selection and structural optimization of anti-armour and anti-personnel composite warheads and the deformable fragment warhead with cavity charge structure.

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.

To address the issues of slow convergence and poor path planning associated with the Deep Q-Network (DQN) algorithm for mobile robot path planning in large-scale complex unknown environments,a path planning algorithm combining Ant Colony Optimization (ACO) and DQN,termed ACOG-DQN,is proposed.Initially,the pheromone mechanism of ACO is introduced to facilitate the selection of potential paths with the goal of reaching the destination,thereby reducing the number of ineffective environmental explorations and determining the optimal path.Concurrently,the previous path selection experiences are filtered using a threshold to form a sample set for training the Q-network,which is then utilized to determine the optimal path for the mobile robot in the current environment.Finally,a path selection mechanism is designed where the weight of the Q-network’s optimal path increases over time,using the optimal paths determined by ACO and the Q-network,as well as those determined by random exploration,as candidates.This mechanism selects the current action,aiming to achieve a path that is ultimately decided entirely by the Q-network.Simulation and physical experiments conducted in three different complex environments demonstrate that the proposed ACOG-DQN algorithm exhibits superior performance in terms of convergence speed,path quality,and algorithm stability compared to the DQN algorithm,thereby validating the effectiveness of the proposed algorithm.

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-dimensional_h 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.

To evaluate the performance of tracked vehicles,a multiple road surfaces-three-dimensional driving cycle construction method based on micro-motion segments is proposed.This method aims to address the issues of various types of road surfaces,longer short-trip segments,and the numerous dimensions of influencing factors in the construction of driving cycles for tracked vehicles.The collected driving data of tracked vehicles is processed,and the three-dimensional data such as speed,angular velocity,and ground resistance coefficient are extracted.The K-means clustering method is used to categorize the driving segments into three typical road surfaces:paved road,gravel road,and undulating dirt road.The short-trip segments are divided into micro-motion segments based on their minimum weighted three-dimensional variation rate,and the feature extraction and clustering analysis are made for the short-trip segments.A three-dimensional driving cycle is constructed using the Markov transition probability of the micro-motion segments,and a corresponding comprehensive evaluation system is proposed.The total duration of the constructed driving cycle is approximately 2000 seconds,and the average feature coverage rate of three types of road surfaces is up to 94.63%.This driving cycle accurately reflects the driving characteristics of tracked vehicles and serves as an effective tool for simulation and bench testing of tracked vehicles.

Ballistic helmets are critical protective equipment designed to mitigate craniocerebral injuries caused by ballistic impacts and blast shocks.The cushioning system within the helmet plays a vital role in attenuating the damage effects from such impacts.To enhance the overall protective performance of headgear,a novel cushioning material—EVA/SSG composite foam—was developed by incorporating Shear Stiffening Gel (SSG) into ethylene-vinyl acetate (EVA) foam.Using a ballistic impact testing platform and a synthetic head model,comparative ballistic tests were conducted on helmets equipped with conventional EVA pads and those with the EVA/SSG pads.The temporal variations in impact force on the headform surface and the acceleration at the centroid of the head model during impact were investigated.Additionally,finite element simulations of the ballistic impact were performed.Both experimental and numerical results demonstrate that,under ballistic impact conditions,the helmet with EVA/SSG foam liners reduces the peak pressure on the headform surface and the peak acceleration at the centroid by more than 20%,thereby significantly lowering the probability of head injury.

Magnetic field-modulated fractional-slot permanent magnet motor utilizes the magnetic field modulation effect to eliminate the need for the gearbox structure in traditional electric propulsion system，which simplifies the electric propulsion system architecture and reduces mechanical noise.Furthermore，magnetic field -modulated fractional-slot permanent magnet motor is particularly suitable for the electric propulsion of AUVs due to their high power density and high torque density.Magnetic field -modulated fractional-slot permanent magnet motor can utilize multiple harmonic components of the excitation magnetic flux density to work cooperatively，significantly enhancing the motor’s torque density.However，this type of motor simultaneously modulates certain low-order harmonic components of the armature magnetic flux density.This leads to the issues such as low power factor，high harmonic losses，and significant torque ripple in magnetic field-modulated motors，negatively impacting the stealth capabilities and operational efficiency of AUVs.This paper focuses on the control strategies for torque ripple suppression，power factor improvement，and efficiency optimization from the perspective of motor optimization control.Finally，the current state of technology regarding the application of such motors in new energy power generation is summarized，marine propulsion，and electric vehicles，followed by a discussion on the key technologies and future development directions for their application in AUVs.

In view of the problem that there is no effective online monitoring means in the process of blade high-cycle fatigue crack damage,an acoustic emission technology is adopted to study the online monitoring test of blade high-cycle fatigue crack acoustic emission under the action of fixed amplitude load,and explore the evolution law of blade crack initiation and propagation signal characteristics.The acoustic emission parameters and frequency spectrum characteristics of high-cycle fatigue crack are studied,and a crack activity coefficient index (CAI) is proposed.The high-cycle fatigue cracks in blades are divided into three stages,i.e.,crack initiation,metastable propagation,and rapid propagation.At the end of crack initiation and the rapid propagation stage,the crack activity coefficient significantly increases,which can achieve early warning of cracks.The generalized S transform is used to analyze the frequency spectra of acoustic emission signals at different damage stages,The results show that the signal energy is concentrated at 90-160kHz during crack initiation,the signal energy is mainly concentrated at 80-180kHz during the crack propagation,and a distinct energy peak at 120kHz appears during rapid crack propagation,The signal energy is the highest during rapid crack propagation,the energy is higher during crack initiation,and the energy is the lowest during crack metastable propagation.

Regarding the issue of hypervelocity impact on ship-stiffened plate structures,the research has predominantly focused on the information about residual projectile and the characteristics of target plate breaches,while there has been a lack of research on the formation and distribution of fragment cloud.In this study,the finite element-smoothed particle hydrodynamics (FE-SPH) adaptive method,incorporating the Johnson-Cook failure criteria and the maximum tensile strain failure criteria is used to simulate the formation of the fragment cloud produced by cylinder projectile impacting a stiffened plate.Simulated results indicate that the cylindrical projectile forms a fragment cloud with double-saddle shape due to the influence of stiffeners during the impact process,and the main part of the fragment cloud is concentrated at the front end,including hazardous fragments on the inside and small fragments on the outside.Moreover,the distribution of fragments is consistent with the experimental result.The impact process is divided into three stages based on the cbharacteristics of fragment distribution,and the formation and propagation of fragments at each stage are discussed.The topographic characteristics of fragment cloud under various stiffener configurations are presented by varying the impact location of cylindrical projectile.Finally,the characteristic parameters,such as mass and kinetic energy,of the hazardous fragments in the fragment cloud are studied,and the degrees of influence of different impact locations are discussed,which is used to assess the damage ability of hazardous fragments to the rear plate.The analyzed results show that the fragments concentrate towards specific areas to form double-saddle shape and saddle shape due to the influence of the stiffeners.The generation of hazardous fragments is primarily influenced by the main stiffener.

Infrared small target detection has extensive applications in military fields such as infrared guidance and tracking systems and is an important area of infrared image processing.Due to the limitations in detection equipment and the lack of inherent information about infrared small targets,the existing detection methods are difficult to meet the practical performance requirements.In order to explore a lightweight and highly accurate infrared small target detection model,a lightweight and efficient YOLOv10n infrared small target detection model (L-YOLOv10n) is designed based on YOLOv10n.The SCDown module in YOLOv10n is replaced by a lightweight spatial-channel decoupled downsampling (L-SCDown) module to enhance the key features of infrared small targets with a low computational cost.A lightweight Cross-stage partial convolution with Two Fusion layers (L-C2f) module is used to replace the C2f module,thereby enhancing the edge information of small targets and extracting the multi-scale features while reducing computational cost.To address the issues of infrared small targets with few pixels and an imbalance between foreground and background,Focal Loss and a focaler intersection-over-union (Focaler-IOU) loss function are introduced,thus allowing the model to better focus on the difficult-to-detect targets.Experimental results on the public datasets SIRST-V2 and NUDT-SIRST demonstrate that L-YOLOv10n significantly outperforms the detection-based models in both detection performance and resource consumption.The detection performance of L-YOLOv10n is slightly lower than that of Transformer-based segmentation models,but its resource consumption is significantly better than those of other models.Its generalization performance on the NUDT-SIRST dataset is also significantly higher than those of most infrared small target detection models.These results demonstrate that the proposed model strikes a balance between resource consumption and high-precision detection,demonstrating its practicality.

To address the limitations of existing traversability analysis methods,which often suffer from incomplete obstacle recognition and poor generalization in complex off-road environments,this paper proposes an obstacle recognition method based on open-vocabulary semantic segmentation.The method extracts the semantic labels of obstacles and terrain around the vehicle,enabling effective identification of previously unseen obstacles in unstructured environments.The method is validated on the datasets in real-world experiments,demonstrating its stability and comprehensive recognition capability.On this basis,a multi-layer 2.5D map is constructed by integrating semantic labels with 3D point clouds.The traversability level of a terrain is preliminarily classified according to semantic labels.And then the terrain smoothness is quantified based on ground elevation,and the geometric parameters of special environmental features (e.g.,vertical wall) are measured.Furthermore,the driving posture of vehicle is predicted by incorporating the geometric configuration of a tracked vehicle,thereby quantifying the coupling relationship among static slope stability,semantic terrain categories and geometric attributes.A cost function is then designed to jointly assess the traversal risk and cost of vehicle,ultimately generating a vehicle-centric traversability map.The effectiveness and reliability of the proposed method are verified by comparing it with similar methods,which enhances data support for decision-making,planning,and control of unmanned tracked platforms.

Since the concept of kill chain was proposed，the kill chain in various combat domains，especially the aerial kill chain，has played an increasingly important role in the informationized and intelligent battlefield.The construction of the aerial kill chain includes link design，link connectivity，and link verification，which requires the coordination of various human and material resources to be completed.It has strong system characteristics and engineering practicality.However，most of the existing researches related to aerial kill chain remain at the theoretical level，and the verification methods are mostly theoretical derivation or simulation deduction，which are unable to effectively guide the practical construction of aerial kill chain.In view of this，an aerial kill chain construction method is proposed based on the system engineering principle and practical experience.The SWOT analysis method is used to study and analyze the aerial kill chain and refine the basic principles of link construction.A Hall three-dimensional structural model of the aerial kill chain is established to clarify the basic logic of link construction.And then an interpretative structural model is used to design the aerial kill chain to clearly reflect the structural characteristics of the system.The case verification is made on the proposed aerial kill chain construction method，and an information transmission network is established to connect the equipment nodes.The orthogonal experiment and evaluation index system are designed.The results such as link closure time，link availability，node matching and target damage degree are obtained through experiment.It is proved that the aerial kill chain construction method based on system engineering principle can effectively and reasonably guide the construction practice of aerial kill chain.

The negative obstacles pose a significant threat to the driving safety of unmanned ground vehicles (UGVs) when they operate in unstructured environments.However,in the existing research on negative obstacle detection,the camera-based detection methods are not well suited for the detection of negative obstacles in unstructured environments with poor lighting conditions and complex backgrounds; and LiDAR(light detection and ranging)-based detection methods are mostly designed based on the characteristics of mechanical LiDAR harnesses and have poor universality.Therefore,a highly compatible and scalable negative obstacle detection method is proposed,which can adapt to different types of LiDAR and achieve high-precision negative obstacle detection.The proposed method involves preprocessing the point cloud data,extracts the ground regions of interest,and performs point cloud pose correction.The adaptive resolution polar coordinate rasterization technology is used to enhance the spatial representation capability of point cloud data.A negative obstacle grid feature descriptor is designed,and the potential negative obstacle regions are extracted from multiple features such as the hollow characteristics,height differences,and minimum height of point clouds.A multi-frame fusion strategy is introduced,and the high-precision negative obstacle surface occupancy range is outputed through map reprojection and Bayesian rule-based probability updates.The experimental results show that the proposed method is applicable to LiDARs with different scanning modes,and can effectively identify the negative obstacle areas in complex unstructured environments.

Rolling bearing is a key component in a large number of rotating machines，and its remaining useful life (RUL) prediction is related to whether an equipment can operate safely and stably.In order to solve the current problem of low accuracy of RUL prediction，a prediction method combining temporal convolutional autoencoder (TCAE) and Informer (TCAE-Informer) network in frequency domain is proposed for RUL of rolling bearings.The method designs a TCAE for the frequency-domain signals of different time samples of rolling bearings，and adaptively extracts the depth features that better reflect the full-life degradation law of rolling bearings.An Informer network model is built，and with the help of its learning advantage in long sequence information，the mapping relationship between the depth features and the RUL of rolling bearings is effectively fitted to realize the RUL prediction function of rolling bearings.XJTU-SY bearing dataset is used to compare and validate the evaluation indexes of three RUL prediction results.The results show that the proposed method is able to achieve more accurate RUL prediction effect under different working conditions compared with many existing methods，which proves that it has superior RUL prediction ability and generalization ability.The anti-interference test is carried out for different methods.In the test，the proposed method shows better RUL prediction effect under different noise conditions，which proves that it has superior anti-interference ability of RUL prediction.

The operational safety and catalytic efficiency of hail-suppression and rain-enhancement shells,as critical tools for weather modification,are directly affected by the fragmentation characteristics formed after self-destruction.This paper investigates the mechanism of shell material mechanical properties effecting on fragment formation through experiments,theories and numerical simulations.The differences in fragment mass distribution,morphological characteristics and energy dissipation among S20 steel,9260 steel,D60 steel,and 823 steel are analyzed.The results reveal that the strength-toughness synergy of shell materials plays a decisive role in fracture patterns.High-strength materials (e.g.,9260 steel) generate uniform fine fragments (>60% of 1-5g fragments) but exhibit localized energy concentration due to insufficient toughness.Low-strength high-toughness materials (e.g.,D60 steel) produce irregular agglomerated fragments (32% of more than 10g fragments) due to significant plastic deformation.In contrast,823 steel demonstrates optimal brittle-ductile fracture coordination under explosive loading due to its unique mechanical properties (1000-1200MPa tensile strength and 40-60 J impact toughness),with 85% of less than 5g fragments and over 90% of ≤10g fine fragments,which fully complies with national safety standards (Class B,≤10g) and significantly reduces ground safety risks.The research provides theoretical guidance for optimizing the hail-suppression and rain-enhancement shell materials and holds substantial engineering value for enhancing the weather modification safety.

Bottom mines are typically deployed on the seabed and are designed to damage the surface ships and submarines during underwater explosion.The casing of bottom mine is the key factor influencing the energy output structure of charge underwater explosion (UNDEX).Based on the theory of UNDEX,the coupled Euler-Lagrange (CEL) method is used to establish a numerical model of the UNDEX of cased charge near the seabed.The characteristics of shock wave loads generated by the underwater explosion of cased charge are studied and the effects of various factors,such as charge shape,detonation mode,casing configuration,casing thickness ratio,and casing-to-charge mass ratio,on the characteristics of shock wave loads generated by underwater detonation of charges are analyzed.Furthermore,a casing with a variable wall thickness suitable for near seabed conditions is proposed,which significantly enhances the shock wave load.The results show that the constraint characteristics of the casing can cause the slower attenuation in the shock wave due to the underwater explosion of charge with distance.The casing with variable wall thickness has an enhancing effect on the shock wave load due to the underwater explosion of charges.The peak pressure of shock wave at 800 mm significantly increases with the increase of δ,and the growth rate can reach 9.74%.It can provide reference for the design of underwater weapons.

Addressing the issue of low recognition rates for complex multi-class radar signal modulation types under low signal-to-noise ratio,a radar signal modulation recognition method based on time-frequency fusion features and multi-scale dual attention network is proposed.By applying three time-frequency analysis methods,namely,smoothed pseudo Wigner-Ville distribution,Fourier synchrosqueezed transform and Hilbert-Huang transform based on variational modal decomposition,and the denoising preprocessing technique,the radar signals are transformed into three-channel time-frequency feature maps,which significantly enhances the robustness and expressive power of the features.A multi-scale dual attention network is designed to realize denoising preprocessing technique the cross-scale information fusion and noise suppression through the multi-scale channel attention mechanism.The time-frequency structure of radar signals is adaptively perceived by utilizing the multi-scale spatial attention,and the information is further integrated through gated fusion and residual connection.The experimental results show that the method achieves an average recognition rate of 98.99% for 12 types of typical radar signal modulation modes under the condition of a signal-to-noise ratio of -10dB,showing good robustness.