In order to improve the damping performances of suspension systems for tank and armored vehicle, a basic structure with"inerter-spring” quasi-zero stiffness is proposed. Dynamic simulation and parameter optimization of inerter continuous control and inerter on-off control are carried out with the parallel structure of inerter, spring and damper as suspension system. The results show that the vibration acceleration of vechile body is greatly reduced and the ride comfort is obviously improved with the quasi-zero stiffness control strategy. At the same time, the damping coefficient is reduced and the damping efficiency is improved. By analyzing the instantaneous power of each component in the process of suspension damping, it is found that the controllable inerter plays an role in energy compensation so that a part of the vibration energy can be transferred and converted dynamically and repeatedly between the spring and inerter, breaking through the traditional damping mechanism of spring buffer energy storage and damping heat generation energy consumption, and achieving better damping efficiency.

To solve the problem of large initial lead angle or significant change in lead angle when missile terminal guidance starts, a 3D time-to-go（TGO）estimation method for lead angle is designed for various missile guidance laws. The missile velocity and target velocity projections are decomposed to establish the relationship equations of relative motion between missile and target on Oxy and Oxz surfaces of ground coordinate system. Based on this, a three-dimensional missile-target relative motion model is established. A first-order nonlinear differential equation is established by using the relative motion equation and proportional navigation control equation of missile and target. The relationship between missile-target distance and lead angle is analyzed. The first-order nonlinear differential equation is solved by using McLaughlin formula. An appropriate inner frame angle is selected based on the change in line-of-sight angular velocity to compensate for the lead angle, and the median average filtering method is used to reduce the error caused by the fluctuation of lead angle. The simulation experiments are conducted by using the proposed three-dimensional missile-target relative motion model. The simulated results show that, when the small angle assumption cannot be established, especially when the angle control of guidance law results in significant changes in the lead angle, the convergence time and maximum error value of estimated error of the lead angle TGO estimation method are smaller than those of other TGO estimation methods.

Gravity dam is a kind of common large concrete hydraulic construction. In order to explore a calculation method for the reflected pressure of shock wave applicable to the near area of hydraulic structure, a method for calculating the reflected pressure of shock wave of the underwater explosion on the rigid wall with clear physical connotation is derived strictly by using the three conservation basic relations of mass, momentum and energy on the shock wave front and the equation of state of condensed medium. Based on the relationship between shock wave velocity and particle velocity in continuous medium, the determination method of the state parameter k of water is given, and the law of state parameter k decaying exponentially with incident shock wave pressure is revealed. It is found that the change of k value has a significant impact on the calculation result of reflected pressure of shock wave when the incident pressure is above 725 MPa. By comparing with the calculation methods proposed by Cole^\[12\], Henrych^\[14\], and Luo, et al^\[15\], and the numerical simulation, the results show that the proposed calculation method has a wider application scope and higher calculation accuracy, and it also reveals theoretically for the first time that the reflection pressure coefficient of underwater explosion shock wave ranges from 2.00 to 4.49.

The near-field blast wave characteristics(0.06m/kg^1/3<Z<1m/kg^1/3)of typical charge structures(sphere and cylinder)are investigated for supporting the protection of sympathetic detonation through near-field explosion experiment and numerical simulation.The load of near-field blast wave of cylindrical charge is experimentaly investigated,and a numerical caculation model of near-field explosion is established,The near-field blast wave structures and spatial distributions for peak parameters of spherical and cylindrical charges are analyzed.The results show that the near-field explosion loads are affected by the detonation products,and the reflected overpressure histories exhibit multi-peak and jagged form,which are due to the effects of multiple reflection waves and the complex flow of detonation products after the Mach region.The inverse of pressure and density gradient between detonation products and shock wave interface leads to the Rayleigh-Taylor instability effect.The generated interfacial microjets of detonation products promote the complexity of multiple reflection wave structure,resulting in large uncertainty of measured results of near-field reflected loads.The near-field incident overpressure curve shows a typical double-peak structure,which comes from the air shock wave and detonation products.Due to the structural effects of charge,the incident wave loads of cylindrical charge distribute non-uniformly along the axial and radial directions.The spatial distribution of incident parameters drastically varies when the azimuth angle is between 30°-60° because of the bridging wave effects.The modified predictive model can capture the incident peak overpressure and impulse in the range of 0.06m/kg^1/3<Z<1m/kg^1/3 for cylindrical charge(L/D=0.8)with center initiation under arbitrary azimuth angle,and the relative deviations among predicted results and numerical results of incident peak overpressure and impulse are less than 20%.

Traditional coating layer for underwater vehicles mainly depend on material renewal and structure optimization, which is difficult to cope with low-frequency active sonar detection. A lightweight, thin and low-frequency broadband underwater acoustic emission unit with high pressure resistance is designed based on the giant magnetostrictive material. The design and optimization process of the core components are analyzed emphatically, and the finite element simulation results are verified by the PSV-400 laser vibriometer. The optimal boundary constraints of the active emitting element are determined through the modal analysis of a fixed radiation panel. Compared with the performance of the emission unit in the original configuration, it is found that, under the premise of maintaining good directivity of underwater acoustic emission, the highest resonance frequency below 2 000 Hz is reduced by more than 10% based on the finite element analysis. Based on the acoustic structure coupling analysis, the maximum radiation source level of active emission unit in the low frequency range is 147.48 dB, which is increased by 4.65%. The frequency bandwidth of transmitting unit exceeds 1 500 Hz when the sound source level is higher than 100 dB. This means that there is a higher sound power level in this frequency bandwidth range. The emission unit can provide technical support for the application of array in the large-scale acoustic cladding. It has certain academic research value and broad engineering application prospect.

For solving the problems of nitrogen escape and splash in the droplet transfer process of high-nitrogen steel additive manufacturing, the experiment of droplet transfer in an ultrasonic frequency pulsed gas metal arc (UFP-GMA) additive manufacturing is carried out, and the influences of different ultrasonic frequency pulsed current superposition modes and pulse current frequencies on the stability of high-nitrogen steel droplet transfer are studied, The process parameters that can realize the stable droplet transfer of high-nitrogen steel additives were obtained. The experimental results show that the of one-pulse-one-droplet transfer can be realized under the pulsed gas metal arc (P-GMA) process conditions, but the transition stability is poor and the splash is obvious. Superimposing the ultrasonic frequency pulse current at the base current stage of P-GMA or both at the base and peak current stages is not conducive to the droplet transfer, and the problems such as short circuit and droplet explosion are prone to occur. When the low-frequency (20 kHz) pulse current is applied during the peak stage, its effect on droplet transfer is minimal. However, the medium-frequency (40-60 kHz) pulse currents can be superimposed to inhibit the generation of large particle splash, leading to improved stability in droplet transfer, but many small splashes will be formed during the transition when the frequency exceeds 60 kHz.

Thermobaric explosive is an fuel-rich explosive that can inflict severe damage to facilities and personnel in confined spaces due to the long-term pressure generated by explosion and combustion, as well as high-temperature fireballs. Thermobaric explosive involves the propagation of detonation waves in the charge, the scattering of fuel particles in space, and the subsequent combustion process of fuel particles. The coupling process of multi-scale, multi-material, multi-factor and multi-physical field causes the thermostatic damages, which is a significant area of damage research. This paper primarily discusses the research advances in the theoretical underpinnings of formulation design, the impact of formulation's primary components on thermobaric explosive performance and the performance evaluation of thermobaric explosive. It highlights that the future developments in thermobaric explosives will focus on the high chemical potential metal fuels and energy release techniques.Models for simulating the performance of thermobaric explosives should also be highly regarded. In conclusion, the formulation design based on large-scale data from simulations and tests will be a mainstay for driving the development of thermobaric explosives.

With the development of weapons and equipment towards diversification, versatility and systemization, modern warfare requires the increasingly high levels of command and decision-making in terms of overall planning, timeliness, and scientificity. The construction of task planning systems for major military powers is urgently needed and developed rapidly. In order to better promote the research of task planning systems, a comprehensive review is conducted on the tactical-level task planning methods. This paper reviews the development history of task planning systems and the methodological framework of tactical-level task planning, with a focus on summarizing the main implementation methods and future development directions of tactical-level task planning. In terms of the main implementation methods, the main methods involved in various aspects such as task description, task decomposition, task allocation and scheme evaluation are overviewed and analyzed. In terms of future development direction, the suggestions on standardization, universality, credibility, and other aspects are put forward.

In order to enhance the maximum dispersal speed of fuel during the explosion of fuel-air explosive (FAE) devices and achieve a more uniform speed distribution, the paper investigates the influences of detonation methods on the radial maximum speed of fuel dispersal in FAE device. Numerical simulation techniques are employed to analyze the influences above while maintaining the overall structure of the existing device. Specifically, the ALE algorithm implemented in LS-DYNA software is utilized to numerically simulate the fuel dispersal in a frustum-shaped FAE device. The changes in radial dispersal speeds of nodes located at identical positions under the conditions of single point initiation, multi-point initiation and approximate line initiation, are compared. The results demonstrate that positioning the initiation point closer to the unit exerts a restraining effect on the dispersal motion of the fuel within that specific element. Additionally, for a certain point on the fuel, the adoption of the approximate line initiation method proves effective in achieving a more uniform dispersal of fuel cloud and mist. This finding serves as a foundational step towards the further refinement of numerical simulations concerning FAE explosive fuel dispersal.

The magnetic gradient tensor system (MGTS) is the application basis for detecting the full tensor gradient field of magnetic target. Regional magnetic anomalies leads to a magnetic gradient tensor field, which MGTS uses as an information source to achieve the magnetic gradient tensor measurement through the differential calculation between vector magnetic sensors. Compared to the magnetic total field and vector field detection equipment, MGTS has high resolution, large information content, and strong anti-interference ability, which can obtain more potential physical property information of targets. The progress of target detection technology based on MGTSs worldwide is studied to provide theoretical reference and technical support for the modernization and informatization construction of magnetic detection equipment in China. The development process and stages of modern magnetic detection technology are elaborated, and then the two types of MGTSs based on superconducting technology and flux gate method, as well as their applications areintroduced and summarized. The calibration, compensation, noise reduction, magnetic target positioning and recognition technologies of MGTSs are reviewed. Finally, the design ideas for future high-precision magnetic gradient tensor detection instruments are prospected, and the current problems and development trends of various key technologies for magnetic gradient tensor detection are summarized.

To support the theoretical design of the hypersonic missile's terminal effect and meet the development demand of penetration mechanics theory of non-circular projectiles, the penetration mechanism of non-circular projectilesis a key scientific problem required to be solved. A comprehensive review is conducted on the penetration behavior, penetration mechanism, ballistic stability, and structural response of non-circular projectiles.It is a review and summary of the existing research work, aiming to establish a basic framework for researching the penetration problem of non-circular projectiles.Moreover, the new phenomena and mechanisms introduced by the structural changes of non-circular projectiles are highlighted. Three suggestions for the future research of the non-circular projectiles are put forward for the reference of relevant researchers.

When using infrared imaging to detect the scenes of flames generated by high-temperature combustion of objects and high-temperature fragments generated by object explosions,the rapid increase in scene temperature within the infrared imaging field of view leads to an increase in the dynamic range of infrared imaging,the image saturation,the loss of detail information,and the submergence of weak targets by high-temperature backgrounds.Therefore,it is urgent to develop an anti-fire interference high dynamic infrared imaging detection technology.This article briefly introduces the current development status of high dynamic infrared imaging technology with anti-fire interference capability.On this basis,the development trend of high dynamic infrared imaging detection technology with anti-fire interference capability is analyzed.

The temperature rise of the high-speed permanent magnet synchronous machine (PMSM) for aviation aircraft supplied by PWM voltage might be significant because of its high loss density and poor heat dissipation condition. What's worse, high temperature increases the demagnetization risk of Halbach-array magnets, which impairs the reliability of operation. In allusion to above problems, a multi-objective optimization method of high-speed PMSM based on Nelder-Mead algorithm is proposed. The loss and temperature rise are selected as optimization objectives. Field-circuit coupled finite element analysis method is used to calculate the loss of the machine powered by T-type three-level converter, thus calculating the temperature rise. The optimal design areas are searched by using the optimization algorithm, and the optimal solution is achieved. The flux density distribution and eddy current loss in the Halbach-array magnet are analyzed, and then the design of magnets is optimized to suppress eddy current loss and demagnetization. A 300 kW, 30 000 r/min high-speed PMSM was designed and manufactured. Simulated and experimental results show that the proposed design method could realize multi-objective optimization and suppress demagnetization effectively.

Explosive smoke bombs are of great significance in countering the infrared-guided weapons and protecting the high-value military targets. At present, most of the smoke simulation models do not take into account the vector information of explosion and the near-ground particle diffusion effect, and the authenticity of the explosion smoke simulation is low in the near-ground scene where the wall effect and the air turbulence phenomenon are significant. For the poor simulation accuracy of explosive smoke bomb in near-earth scene, a simulation method of explosive smoke bomb structure model in near-ground scene is proposed. This method uses the particle position information to replace the life cycle of the particle model. Based on the Gaussian puff model, a near-ground smoke explosion model considering the explosion flying direction of bomb and the wall effect is constructed to improve the simulation accuracy of near-ground smoke bomb explosion scene. The structural similarity (SSIM) analysis is used on the simulated image. After the best parameter selection experiment, the SSIM value reaches 0.944 3 and the standard deviation is ±0.000 5. The SSIM value of the proposed model is 0.011 2, 0.132 9 and 0.006 3higher than those of the particle system-Gaussian smoke model, ellipsoid explosion model and explosive smoke bomb model，respectively.The experimental results shows that the proposed model has clear direction information in smoke simulation, stronger ability to express the details of smoke turbulence and wall effect, and higher accuracy in the simulation of near-ground smoke bomb explosion scene.

The overload signal of penetrating projectile is of vital importance to reflect the physical process of penetration, which further helps to reveal the mechanism of penetration resistance and the structural response of projectile. It is also an important basis for designing the projectile-fuze system and achieving the precise target strikes.The overload signal is divided into four components: rigid body deceleration, structural response of projectile, response of connection structure and interference signals of sensors. The sources and characteristics of the four components are introduced, and the modeling and evaluation methods for the vibration and sensor-related signals of projectile-fuze system are discussed. For analyzing the components of overload signals, the low pass filtering, mechanical filtering, modal decomposition, wavelet transform, and blind source separation methods are discussed respectively. The accuracies, adaptabilities, real-time performances, and applicabilities of the methods above are also compared. The real-time requirements for overload signal processing, the signal reconstruction methods, the form of rigid body deceleration in complex penetration environments and the challenges brought by high-speed penetration scenario are discussed. Based on the current research status of overload signals processing of penetrating projectiles, the existing problems and possible future research directions are summarized.

Three-dimensional woven preform (3DWP), because of its better formability and significant interlaminar bearing capacity, is expected to achieve the integrated molding of helmet curved surfaced, and reduce the waste of cut and raw materials. Because of the structure characteristics of ballistic helmet with multiple curved surfaces and high curvature, it is important to study the deformation mechanism of 3DWP during curved surface forming for the integrated forming of helmet. The curved surface formability of a layer-to-layer interlock 3DWP with stuffer yarns under high curvature and large deformation is studied systematically. The deformation mechanism and wrinkle defects formation mechanism of 3DWP are described comprehensively from in-plane/inter-layer dimensions and macro/mesoscale. The results indicate that significant in-plane shear deformation of 3DWP can be observed along the 45°direction at the same latitude. The maximum in-plane shear angle of the concave surface is 38°, which is greater than that of the convex surface. The maximum inter-layer shear angles of 3DWP warp and weft rows are 34.83°and 27.76°, respectively. After forming, 3DWP has reached 62° intra-ply shear locking angle, which induces the buckling of yarns microscopically and forms the ridged wrinkles macroscopically. In the wrinkle area, the maximum in-plane shear angle is only 4.8°, and the maximum inter-layer shear angle is 18°. This conclusion has guiding significance for structure selection and forming process of reinforced fabric for ballistic helmet in practical application.

The tracked vehicle dynamics model serves as a foundation for the design of vehicle structure optimization and the development, testing and calibration of control algorithms. However, the user is unaware of the dynamic equations and gradient information of the model created using commercial software, which significantly lowers the efficiency of the optimization of structural parameters and control parameters. Additionally, the poor real-time performance and low solving efficiency of the currently available commercial software have an impact on the development and porting of control algorithm. An improved dynamic model of tracked vehicles, which can satisfy the needs of vertical and horizontal coupling motion simulation, is constructed and simulated based on the derivation of multibody dynamics in order to address the aforementioned issues. A dynamic model of vehicle body considering the three-dimensional coupling motion of space and a dynamic model of track chain including track link are established. By calculating the interaction force between the track links and other components, the vehicle body model, the track chain model and the ground are related, and finally a track vehicle dynamic model with 190 degrees of freedom is constructed. It was compared to the ADAMS Tracked Vehicle Toolkit (ATV) in terms of acceleration, braking, and steering. The simulated results of the proposed simulation model are remarkably compatible with those of commercial software, confirming the accuracy of the approach.

Powdered fuel has broad application prospect prospects as fuels or additives in detonation propulsion systems due to their high energy density and excellent stability. Based on the classification of fuel types for gas-solid two-phase detonation and the application of powder detonation propulsion technology, the theoretical research progress on the detonation initiation and propagation characteristics of powdered fuel in oxidizer gas and gas fuel/oxidizer gas at domentically and internationally is reviewed. The theoretical and engineering aspects of heterogeneous detonation and hybrid detonation are summarized, highlighting the key factors affecting the initiation and propagation characteristics of gas-solid two-phase detonations, as well as important conclusions. Furthermore, the two-phase detonation engines are reviewed from the perspectives of application prospects, propulsion performance, difficulties and challenges, etc. Based on the summary of the numerical and experimental research status of powder detonation engines, the future research work that needs to be carried out is prospected.

Maritime manned/unmanned collaborative systems play a crucial role in enhancing naval operational effectiveness and represent a significant direction in the development of modern naval equipment. This paper focuses on the development of maritime manned/unmanned collaborative systems, reviews the current developing status and relevant foreign projects, clarifies the main characteristics of the systems, condenses and analyzes the scientific issues and key technologies involved, and ultimately provides a comprehensive survey on the development of maritime manned/unmanned collaborative systems. In the future, intelligence, modularity and sparsity will become the important directions for the development of maritime manned/unmanned collaborative systems. However, due to the contradictions between system autonomy and controllability, the development of intelligence and maritime constraints, and the features of manned/unmanned collaboration and existing collaborative frameworks, the system will also face challenges in scale, diversity, security, and intelligence-related aspects.

Linear focusing fragment warhead makes the fragments disperse at an equal velocity and focus linearly by taking advantage of the design of charge generatrix and fragment arrangement, which can exert structural cutting damage to a target. In order to study the influence of structural parameters of linear focusing fragment warhead on the dispersion characteristics of fragments, the fluid-structure interaction (FSI) algorithm is used to numerically simulated the focusing process of fragments. The numerically simulated results reveal the linear focusing mechanism of linear focusing fragment warhead. The typical linear focusing process includes fragment driving stage, fragment focusing stage, focusing completion stage and fragment dispersion stage. The effects of warhead size, fragment arrangement, fragment mass and intersection velocity on the dispersion and spatial distribution characteristics of fragments are further obtained by numerical simulation. The results show that, with the increase in charge length from 0.3 m to 0.5 m, the standard deviation of fragment velocity increases from 125 m/s to 147 m/s, the focusing completion time is 490 μs, 585 μs and 590 μs, respectively, and the width of perforation dense distribution increases from 135 mm to 234 mm. When the fragment arrangement increases from 15 columnsto 18 columns, the standard deviation of fragment velocity increases from 117 m/s to 125 m/s, the focusing completion time is 470 μs and 490 μs, respectively, and the width of perforation dense distribution increases from 235 mm and 135 mm respectively. When the fragment mass increases from 4.08 g to 9.21 g, the standard deviation of fragment velocity decreases from 137 m/s to 125 m/s, the focusing completion time is 380 μs and 490 μs, and the width of perforation dense distribution is 156 mm and 135 mm, respectively. When the interaction speed increases from 0 m/s to 1 000 m/s, the focusing completion time is 490 μs, 480 μs and 469 μs, respectively, the width of perforation dense distribution increases from 135 mm to 138 mm, and the density of fragment distribution decreases from 640/m² to 630/m²with a rate of about 2%. The research results can provide guidance and reference for the design of focusing warhead.

The temperature fluctuation and magnetic noise in the alkali-metal vapor cell are key factors that restrict the sensitivity improvement of spin-exchange relaxation-free atomic spin gyroscopes. To deal with these two issues, a laser heating method is proposed to perform non-magnetic heating for the vapor cell, thus fundamentally eliminating the magnetic noise, and the graphene films are deposited on the heating surface, and adjacent upper and lower surfaces of the vapor cell for photothermal conversion, thermal conduction, and stray-light interference avoidance. The combination of linear active disturbance rejection control (LADRC）and thermal management technology is used to improve the temperature control accuracy and stability of alkali-metal vapor cell. A linear active disturbance rejection controller based on temperature control system is designed. A thermal structure is designed and graphene film is selected in consideration of heat conduction, thermal convection and thermal radiation. An experimental platform was built for the temperature control system of alkali-metal vapor cell. The result shows that the temperature control accuracy of temperature control system of alkali-metal vapor cell using LADRC and thermal management technology is ±0.003 ℃, and the temperature control stability is 6 mK. This lays the foundation for improving the sensitivity of atomic spin gyroscopes in the future.

Kinetic energy missile is a new type of anti-armor weapon that combines the effects of kinetic energy strike and armor penetration, but there is currently no relevant theoretical model available for reference regarding the load characteristics and influencing factors of impact process. The load characteristics of the impact process of kinetic energy missiles are studied. By considering the missile-target action behaviors in different velocity ranges, a calculation model for the impact load of kinetic energy missile body is established. The calculated results indicate that the impact load of missile is directly related to the geometric characteristics, impact velocity, density, strength, and other properties of missile. The change in the impulse of missile is relatively small at low velocity, but at high velocity, the rebound of the shattered mass significantly increases the impulse, and the impulse contribution of the shell accounts for a larger proportion of the impact impulse. The amplitude of impact load curve increases with the increase of shell strength and density, but the influence of density on the load waveform characteristics is more obvious. At the same velocity, the influence of shell strength on the momentum transfer factor of missile is relatively small, but the influence of shell density has a significant effect on it. At the same velocity, the influence of shell strength on the momentum transfer factor of missile is relatively small, while the shell density has a greater impact on it, The transfer factor curve shows a trend of increasing first and then decreasing with the increase in density.

Unexploded ordnance refers to ammunition that has been disarmed, detonated, ignited or otherwise prepared for use or has been used, and has not exploded due to fuze failure, functional failure, design defects or other reasons after igniting, throwing, launching or burying for various reasons. The research status of safety disposal technology of unexploded ordnance at home and abroad is described,the unexploded ordnance detection technologies, such as magnetic detection, sound-magnetic compound detection and optical detection, and the non-contact disposal and destruction technology principles, such as burning treatment, blasting destruction, cutting treatment, are analyzed, and the advantages and disadvantages of different detection and disposal technologies and their application scenarios are summarized. At last, it is pointed out that the detection and disposal technologies of underwater unexploded ordnance are the focus of the current national defense field, and also the research hotspot. The research on key technologies of safe disposal of unexploded ordnance can provide theoretical basis for unmanned, safe and environmentally friendly detection and disposal of unexploded ordnance in the future.

With the wide application of intelligent collaborative algorithm and autonomous technology in the field of air,space and sea equipment,the multi-domain cluster distributed collaborative autonomous control technology has also been deeply studied,and significantly improved the degree of intelligent autonomy of unmanned equipment.Based on the development needs of distributed intelligent autonomous control technology of multi-domain cluster,this paper reviews the relevant references related to multi-domain cluster distributed intelligent autonomous control technology and the research status at home and abroad.The relevant strategies,key research directions and advanced methods of multi-domain cluster collaborative autonomous control technology are deeply analyzed.The relevant key technologies and methods are summarized,and the future development trend is discussed.This paper provides a reference for improving the collaborative autonomous control ability of unmanned cluster system.

Polarization can improve the autonomous reconnaissance capability of unmanned aerial vehicle, but it is easily interfered by the variation of detection angle and target materials, which affects the robustness of polarization detection. In this paper, a real-time low-altitude camouflaged target detection algorithm of YOLO-Polarization based on polarized images is proposed. The coded image fused with multi-polarization direction information is used as input, the 3D convolution module is applied to extract the connection features from the different polarization direction images, and a feature enhancement module (FEM) is introduced to further enhance the multi-level features. In addition, the cross-level feature aggregation network is adopted to make full use of the feature information of different scales to complete the effective aggregation of features, and finally combined with multi-channel feature information output detection results. A dataset consisting of polarized images of low-altitude camouflaged targets (PICO) which include 10 types of targets is constructed. The experimental results based on PICO dataset show that the proposed method can effectively detect the camouflaged targets, with mAP_0.5:0.95 up to 52.0% and mAP_0.5 up to 91.5%. The detection rate achieves 55.0 frames/s, which meets the requirement of real-time detection.

To explain the paradox between the experimental and theoretical results of equivalent full charge (EFC) conversion coefficient, which can be used to convert the number of firing under various firing conditions to the number of EFC firing, a computational method of that coefficient is investigated on the basis of the thermo-chemical erosion model of the barrel. Supposing that the thickness and composition of the white layer on the inner wall of barrel change periodically after several firings, the relationship among the thermo-chemical erosion volume at the beginning of the rifling and the erosivity of the propellant and the transient temperature field of the inner layer of the barrel is established with the help of the mass diffusion law. During the firing process, the gas temperature in the space behind the projectile and the forced convection coefficient at the innerwall surface of barrel are provided by the classical interior ballistic theory. Hereafter, the model to calculate the transient temperature of the barrel can be developed. In addition, the effect of gas with relative high temperature during the after-effect period is also considered. Eventually, focusing on the firing rate, the charge mass and the charge temperature which have an essential effect on the interior ballistic process, erosion volumes under different firing rates, charge numbers and charge temperatures are calculated. Accordingly, the EFC conversion coefficients under various firing conditions are obtained. It is found that a more severe erosion of the barrel is often related to a faster firing rate, a more charge mass and a higher charge temperature.The EFC coefficient of the supercharge is up to 2.131. The reasonability of the proposed model is verified by using the practical firing data of a 155 mm barrel.

In order to improve the rotation robustness of the traditional UAV infrared target recognition algorithm to the input image, an infrared image target recognition algorithm with rotation equivariant is proposed. An infrared image is expanded into a three-channel image to enrich the details and edge information of the input image by referring to the visible-light three-channel structure. The standard rotation equivariant convolution FBL and rotational residual FSP modules are designed and implemented based on the rotation equivariant convolution, which can highly retain the rotation characteristics of the image, so that the FC-YOLOv5 model is robust to the rotation of the image and the target in the image; The SE attention mechanism is added to learn the importance of each channel adaptively, and the channel contribution in the feature map is weighted according to the needs of the task, so as to extract the important feature information and suppress the unimportant feature information. The performance of the model is verified on APOPV data set and SAS data set, and the benchmark model YOLOv5s and the models YOLOv8s and NanoDet used in common lightweight target recognition tasks are used as the control models. The experimental results show that the mean average precision of the proposed algorithm can be improved by 2%-4% compared to the benchmark model, and when the input image has different rotation angles, the FC-YOLOv5can recognize more rotating targets with fewer recognition errors than those of the control model.

The high-speed switching of switch modules in the high-power electric drive system of armored vehicle power system will generate a series of high-voltage transient pulses and broadband harmonic interference, thus posing a serious threat to the highly electrified vehicle system. A system level constructing method for a conducted interference prediction model is proposed to address the lack of digital detection and analysis of conducted interference generated by high-power electric drive systems. Firstly, the models of electrical components, such as high-voltage battery pack, inverter, and load motor, of the electric drive system are constructed independently; secondly, based on the multi-conductor transmission line method, each model is cascaded through transmission lines that characterize the parasitic effects of the system, thereby forming a complete distributed system-level conducted interference prediction model; and finally, the accuracy of the proposed prediction model is test and verified through bench test. The verified results indicate that the proposed prediction model has a simulation accuracy of better than 8 dB in the frequency range of 10 kHz to 100 MHz, which can provide effective support for the forward design of electromagnetic compatibility of electric drive armored vehicle, and is innovative and practical.

Ducted-fan unmanned aerial vehicle(UAV)can realize take-off,landing and hovering,which has a simple and reliable structure and high safety coefficient.In view of the restricted take-off and landing environment,redundancy of folding wing mechanism and low aerodynamic efficiency of conventional water-air amphibious UAVs,a new dual ducted fan water-air amphibious trans-media UAV is designed.The fuselage is optimized with reference to underwater unmanned underwater vehicle(UUV)and UAV,and the tilting dual ducted fan power system is used.Based on the improved blade element momentum theory,the theoretical formula for calculating the lift of small ducted fan is derived.The structural vibration pattern of UAV as a whole under the mechanical physical field is analyzed,and the aerodynamic performance of the whole vehicle is verified by flow field finite element simulation.The analyzed results show that the calculated results of the improved small ducted fan lift calculation formula are basically consistent with the wind tunnel test results,with the maximum error between the two results is 4.5%,and the designed small ducted fan can provide 20% of additional lift with high aerodynamic efficiency.Through the modal analysis,it is found that the UAV fuselage structure is more stable,and the vibration pattern is reasonable.The wind tunnel test and the test flight verification of the ducted fan water-air amphibious UAV in different media are completed,which proves the feasibility of the UAV design scheme.

Time series matching technology is widely used in vehicle handling consistency evaluation.An evaluation method of vehicle throttle control action consistency based on segmented dynamic time warping (DTW) is proposed for the motion consistency evaluation of a coach vehicle in the process of cooperative driving.On the basis of the inconsistent number of sample data points in the cooperative control test of coach vehicle and the slope constraint of dynamic bending path, the traditional DTW rectangular search area is transformed into a parallelogram search area to reduce the area of the search area by changing the slope of search path, thus greatly reduce the calculation amount.Four groups of typical throttle action curves are selected to carry out 50 rounds of iterative experiments for verification, and the DTW distance matrix between the action curves of real vehicles A and B is calculated by segmented DTW method.A minimum deviation leveling method is used to combine the cluster objects for the actions of vehicles A and B, so as to complete the consistency evaluation of throttle action data.The experimental results show that the average matching accuracy of the improved DTW algorithm in each throttle action can reach 89.2%, which is about 3.2% higher than that of the single DTW algorithm, and the average matching time is about 92.45s, which is about 12.6% lower, thus verifying the feasibility and superiority of the segmented DTW algorithm in the consistency evaluation of throttle action.

Based on the application research background of large aircraft impact,the experimental research is conducted on the impact of flying object on a prestressed reinforced concrete target plate.The scaled samples equivalent to flying object and prestressed reinforced concrete target plates are designed using a geometric scaling ratio of 1:6.Finite element analysis software is used to construct the collision models and calculate the impact damage effects of two scaled samples with different structures on the target plate at different speeds.A physical loading test is conducted using an air cannon,and the critical penetration velocity of two scaled samples on 200mm thick prestressed reinforced concrete is obtained by comparing the test results with simulated results.This provides basic data for intuitive prediction/evaluation of the impact response and failure mode of prestressed reinforced concrete containment in nuclear power plants,and also provides design references and basis for prototype collision test schemes.

Personnel are a critical factor in warfare.The damage effects of three types of damage elements,namely,shock wave,thermal effect and fragments,against personnel,are assessed based on the anti-personnel criterion through numerical simulation,experiment and theoretical computation tools.A damage zone of shockwave overpressure against personnel is delineated,and the relationship between scaled blast distance and personnel damage level is established,resulting in the minimum scaled blast distance of damage to personnel being 8.155m/kg^1/3.The spatial distribution of explosion thermal effect is calculated,and the free-field non-fuel air explosive or thermobaric bombs are not suitable for separate assessment of thermal effect on the personnel killing effect is put forward.The generation process of fragments is numerically simulated to obtain the quality,quantity and velocity of fragments.The simulated results are compared with the theoretically calculated results to assess the damage effect of the specific kinetic energy of fragments to personnel.The conclusions can provide reference for the design of warhead and the protection of battlefield personnel.

The effect of particle injection velocity on the two-phase flow field of a rotating detonation engine fueled by aluminum powder and air is studied. The two-dimensional rotating detonation combustion for the aluminum particles with the injection temperature of 300 K and the high temperature air with the total inflow temperature of 900 K is simulated by using the discrete phase model, one-step surface reaction including kinetic/diffusion-limited rate surface combustion model and multiple-step gas phase decomposition reaction model and considering the devolatilization of incompletely unburned particles. Results show that the particle injection velocity near the inlet is lower than that of air, which results in an incomplete overlap between the air triangle and the particle triangle. As the particle injection velocity increases from 1 m/s to 100 m/s, the detonation velocity and temperature first decreases and then increases. There is a significant temperature difference between particles and air injected into the combustion chamber, which leads to unstable detonation wave propagation. The detonation wave has the best stability when the particle injection velocity is 70 m/s.

The development of military intelligence systems has a great influence on the fighting mode and winning mechanism of modern war. However, these systems are easily affected by haze and other bad weather conditions, resulting in blurred and degraded images, which brings challenges to the subsequent combat missions such as identification and tracking. Therefore, it is essential to restore the haze-free images on the battlefield. Since it is hard to capture the paired clean/hazy images, most existing methods adopt synthetic data for training. However, the gap between the real and synthetic hazy images will lead to the poor generalization of a model trained on synthetic data in the real world. To this end, a Transformer-CNN-based multi-feature aggregation algorithm is proposed for real battlefield image dehazing. This network adopts a semi-supervised framework to train the model with synthetic and real hazy images so that the model can better deal with the real hazy images. The algorithm applies a two-branch feature aggregation architecture to aggregate the local features extracted by CNN branch and the global features extracted by the Transformer branch to further improve the dehazing ability of the model. Moreover, a hazy battlefield image dataset is constructed to simulate the real battlefield hazy conditions. The experimental results show that, compared with 8 state-of-the-art image dehazing algorithms, the proposed algorithm performs well on both synthetic data and real images.

A real-time simulation system for the hydrodynamic characteristics of amphibious vehicles is designed to solve the problems of dificultly acquiring the hydrodynamic parameters and slowly predicting the motion attitude of amphibious vehicles. It can realize the driving of simulation models, motion attitude prediction, data monitoring and output. The numerical calculation method(CFD) is used to correct the vehicle dynamics coefficients, which significantly improves the accuracy of real-time simulation system. In addition, a test amphibious vehicle is developed to verify the accuracy of real-time simulation system under different working conditions. The results show that the real-time simulation system can be used to accurately and efficiently simulate thehydrodynamic characteristics of amphibious vehicles, and predict the motion attitude of the vehicle quickly and accurately. It is also applicable to various complex working conditions and has universal applicability for attitude prediction. The system has strong application value and application prospect in the development stage of amphibious vehicles, driver training, semi-physical simulation exercises and complex environment simulation.

Under the development trend of unmanned warfare, the cultivation and application of unmanned combat force have become an important expansion direction in the fields of test and training. The technical characteristics of marine unmanned combat systems and the generation attributes of new unmanned combat capabilities are comprehensively analyzed. On the basis of this, an overall framework of marine unmanned test and training system is constructed. Focusing on the organization and implementation of unmanned marine test and training tasks, the developmental background of the field is elaborated， and the key measures to promote the rapid development of the field are explored. Facing the requirements of actual combat-oriented and systematic organization implementation for test and training missions in the new era, this paper discusses the overall planning and general ideas for constructing the marine battlefield test training resources and the sea test training blue army under the development background of informationization and unmanned technologies, and forms a methodology for organizing and implementing the unmanned marine test and training tasks and the system support from sea battlefield test training equipment. The The research results can provide reference for the implementation of related activities, such as the organization and implementation of marine unmanned test and training tasks, the construction and management of equipment, the organization and application of test and training blue army, and so on.

Tungsten fiber reinforced zirconium-based bulk Metallic Glass matrix composite (WF/Zr-MG) is widely used in the field of kinetic energy penetration due to their high density, high strength and high adiabatic shear sensitivity. The static and dynamic micro-in-situ compression test platforms are set up to accurately characterize the influence of different armor-piercing attitudes on the armor-piercing properties of composites during forward and oblique armor-piercing. The compressive mechanical behaviors of WF/Zr-MGs with 6 different fiber arrangement angles of 0°, 10°, 25°, 45°, 65° and 90° are studied by in-situ mechanical properties test and microscopic image analysis. The change of the failure strength of the composite with the arrangement angle of fibers is obtained. According to the test results, the failure strength envelope of WF/Zr-MG considering strain rate and fiber arrangement angle is defined. It provides a reference for a safe stress state range of materials under different armor-piercing attitudes and loading rates, which is of great significance for the development of armor-piercing materials.

In order to obtain the threshold value of membrane breaking pressure of 1Cr18Ni9Ti steel high-pressure diaphragm in the two-stage light gas gun and explore the influence of grooving parameters on the pressure threshold value, the static loading experiments of high-pressure diaphragm under hydraulic loading are carried out to obtain the membrane breakjng pressure and damage pattern. On the basis of the experiments, a theoretical model of the high-pressure diaphragm under pressure is established through the large-deformationtheory, and the method of calculating the ultimate load value is derived. The finite element simulation is carried out by utilizing the LS-DYNA software, the change rule of effective strain in the breaking process is analyzed, and the simulation research is made on different grooving depths, angles and grooving shapes.The results show that the breakage pressure threshold obtained by the large-deformation theory is in good agreement with the static load experimental results, and the calculated results are very close to the static load experimental results.The changes of grooving depth, angle and shape have an effect on the breakage pressure threshold, and the decrease in the grooving depth and angle, and the groove type of arc will cause the increase in the breakage pressure threshold.The destructive position of high-pressure diaphragm is changed when the grooving depth is less than a certain value.

Active rigid lower limb assisted exoskeleton system is an intelligent device worn on the human body that can improve the load capacity and mobility of individual soldiers. The current research status and development of active rigid lower limb assisted exoskeletons at home and abroad are summarized. The key technologies, such as sensing, mechanical structure, actuator, and control technology, that affect the development of lower limb assisted exoskeletons, are analyzed and summarized based on existing research. Special consideration is given to the technical difficulties of exoskeletons for special groups, such as soldiers, providing valuable insights for the development of active rigid lower limb assisted exoskeletons for soldier equipment.

To solve the problem that the trans-media flight vehicle will be subjected to large impact load in the process of entering water, a topology optimization design method for anti-impact structure with of negative Poisson's ratio based on engineering requirements is proposed. A star-quadrangular honeycomb (SQH) structure with negative Poisson's ratio which meets the requirements of impact resistance is obtained by adding the elastic modulus and Poisson's ratio into the objective function of topology optimization design. Based on the theoretical analysis model of SQH structure, the analytical formula of plateau stress under impact load is deduced and verified by numerical simulation. Compared with the specific energy absorption of star-circle honeycomb (SCH) and other negative Poisson's ratio structures, the specific energy absorptions of SQH structure under low-speed, medium-speed and high-speed impact are 28.74%, 45.2% and 7.03% higher than that of SCH structure, respectively. Through the fluid-solid coupling simulation analysis, the designed SQH sandwich structure is studied for load reduction by water- entry impact, and the influence of the main size parameters of SQH sandwich structure on the impact characteristics of water entry is further discussed. The results show that, within the allowable range of size, the increase in the inclination angle and wall thickness of SQH unit will reduce the peak acceleration of the structure and the transformation of kinetic energy into the deformation energy of the structure, which verifies the effectiveness of the negative Poisson's ratio structure topology optimization design for engineering requirements.