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    30 November 2021, Volume 42 Issue 11
    Contents
    Contents
    2021, 42(11):  0. 
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    Paper
    Burning-crack Networks Model for Combustion Reaction Growth of Solid Explosives with Strong Confinement
    DUAN Zhuoping, BAI Zhiling, BAI Mengjing, HUANG Fenglei
    2021, 42(11):  2291-2299.  doi:10.3969/j.issn.1000-1093.2021.11.001
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    A theoretical model for burning-crack networks is developed to characterize the non-shock initiation reaction growth behavior of solid explosives with strong confinement and give a quantification of reaction violence.The model is verified by comparing the calculated results with the experimental data. It is found that the stronger the confinement is,the faster the self-sustaining enhanced combustion is,and the more violent the reaction is for confinement failure. Moreover,the larger the charge size is,the longer the process of crack pressurization caused by gas flow and surface combustion at the initial reaction stage is,but the more violent the reaction is at the later self-sustaining enhanced combustion,and the greater the reaction degree is for confinement failure.The ignition intensity has no significant effect on the final reaction intensity of explosive charge.The results show that the theoretical burning-crack networks model is suitable for describing the effects of the intrinsic combustion rate of explosives,the confinement strength,the charge structure size,the air-gap volume and the pressure relief vent on the reaction growth of explosive charge,thus providing a theoretical method for the explosive safety design and the evaluation of explosives reaction violence.
    The Impact of Initiation Mode of Blast Fragmentation Warhead on the Power to Kill the Ground Target
    ZHANG Haoyu, ZHANG Shukai, CHENG Li, LI Yuan, WEN Yuquan, ZHANG Zhengwei
    2021, 42(11):  2300-2309.  doi:10.3969/j.issn.1000-1093.2021.11.002
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    In order to improve the damage power of blast fragmentation warhead to the ground target,the range static explosion test and the numerical simulation method are used to study the power of the aimed warhead under the sequential initiation network. The fragment dispersion rule of warhead under different initiation modes is analyzed based on LS-DYNA finite element program. The C language program is written to obtain the distribution density and energy distribution of the effective fragments during impacting on the ground.The effective damage area of warhead under different motion parameters (falling angle,falling speed,and falling height) was calculated by using the damage probability estimation method. The research results show that the speed gains of eccentric two lines and eccentric three lines sequential initiations in the locating direction are 20.3% and 19.8%. Sequential initiation can effectively improve the scattering angles of fragments,increase the kinetic energy and density of fragments,and further increase the damage area of warhead; the warhead by eccentric two lines sequential initiation has the highest damage efficiency,the effective damage area gain can reach up to 809.1%; and the damage area calculation method used here can better reflect the impacts of fragment density and kinetic energy on the damage efficiency.
    Capacitance-magnetic Detection Method of Armored Target
    SONG Chengtian, JIAO Yonghui, LIU Xiang, ZHAO Hongyu
    2021, 42(11):  2310-2320.  doi:10.3969/j.issn.1000-1093.2021.11.003
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    For the problem of accurate distance measurement of tank reactive armor in complex environment with low extension trajectory,a tank target detection method based on capacitance/magnetic combination is proposed, in which the distance is accurately determined through the capacitance detection,and the ferromagnetic target is identified through the magnetic detection. The composite system is used to solve the interference problem of the complex background environment of the low extension trajectory. The principle of capacitance detection is theoretically analyzed. The electrode distribution of the dual-electrode capacitance detection model is optimized through COMSOL simulation,which effectively improves the accuracy of capacitance detection. The calculation formula of tank magnetic field is theoretically deduced,and the change curve of the magnetic field intensity around the tank target is simulated. The tunnel magnetoresistance is used to design a magnetic detection circuit,which is verified by experiment. A capacitive/magnetic composite target detection and recognition method based on the state machine method is proposed,and the multiple feature quantities are used to improve the target recognition accuracy of fuze. The experimental verification of prototype was made. The result shows that the composite detection method can realize the accurate recognition of ferromagnetic target and meet the fixed distance requirements. At the same time,for the problem of insufficient detection range of the latest reactive armors,a single-electrode detection model is proposed,which can effectively increase the detection range to 2 m through simulation analysis.
    Calculation model for Operating Range of Proximity Fuze in Explosive Field of Explosive Reactive Armor
    TANG Hui, JIAO Zhigang, ZHAO Dongzhi, ZHAO Lijun, ZHU Xiaoping
    2021, 42(11):  2321-2326.  doi:10.3969/j.issn.1000-1093.2021.11.004
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    In order to effectively damage an armored target with explosive reactive armor(ERA),it is necessary to study how to avoid the explosive field of ERA.A calculation model for the operating range of proximity fuze based on the low trajectory of tank gun is established on account of the structure and action principle of ERA and high explosive antitank (HEAT) projectile. According to the geometrical relationship of the proposed calculation model,the limiting intersection position of HEAT projectile and ERA as well as the proper operating range of the first-stage proximity fuze can be worked out. The theoretically calculated value of limiting position and the relationship between the operating range of the first-stage proximity fuze and the velocity of HEAT projectile were derived by taking a HEAT projectile as an example.Experimental results show that the critical value of limiting intersection position of HEAT projectile and ERA is approximately equal to its theoretically calculated value,and the theoretical value of this calculation model has higher accuracy and has guiding significance for the actual project design.
    Dynamic Rendezvous Concentration Detection Method for FAE Secondary Detonation Fuze and Blast Cloud
    JI Tong'an, LOU Wenzhong, FU Shenghua, WANG Jinkui, LIU Weitong
    2021, 42(11):  2327-2332.  doi:10.3969/j.issn.1000-1093.2021.11.005
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    The key to the formation of maximum fuel-air cloud detonation after the dispersion of fuel-air explosive (FAE) is whether the secondary detonation fuze can detect the optimal cloud detonation concentration quickly and accurately in a very short rendezvous time.The feasibility of the method of rapidly detecting the cloud concentration by using the echo attenuation of pulsed ultrasound in cloud is verified by test and simulation tools. For the accuracy and rigor of the test results,the cloud concentration in the fuze channel detected by the fuze prototype in the high dynamic rendezvous environment can not be regarded as the same as the preset environmental concentration. The computer numerical simulation method is used to simulate the gas-solid two-phase fluid concentration distribution in the fuze and cloud rendezvous process under 100 m/s test conditions. The experimental results show that the simulated concentration of fuze channel is consistent with the attenuation rate of pulsed ultrasonic propagation in the channel in the rendezvous environment with concentration of 75 g/m3,150 g/m3 and 225 g/m3,which provides an analysis means to improve the optimal initiation of FAE weapons.
    Formation Mechanism of Large Base Fragments from Explosion in Abnormally Quenched Body of High-explosive Projectile
    PENG Jiacheng, JIANG Jianwei, LI Xiang,LI Shuaixiao,CHEN Yongheng
    2021, 42(11):  2333-2343.  doi:10.3969/j.issn.1000-1093.2021.11.006
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    The cause and related failures of large base fragments are analyzed from the flying back accident of large base fragments generated by the explosion of a high-explosive projectile. The microstructures of the normally and abnormally quenched projectile bodies and the recovered large base fragments of projectile were observed and compared by using metallographic microscope, and the property parameters of recovered fragment materials were obtained through test. The expansion and fracture processes of projectile body under different tensile failure limits were simulated to obtain the fracture state, velocity distribution and derivation of crack of the large base fragments by using AUTODYN-3D. The results show that a large number of mixed microstructures of tempered sorbite and upper bainite appear in the abnormally quenched projectile bodies and the recovered fragments, and the plasticity and yield strength of projectile body material are improved. The completely fractured projectile base generates several fragments under explosion, and a large base fragment with cracks and fracture layers is formed with the increase in the principal tensile failure stress of projectile body. The numerically simulated results are consistent with the shape and size of the recovered fragments. The fracture modes include axial collapse, lateral lamination crack and radial crack. The abnormal quenching of projectile changes the material properties, which can produce large base fragment under implosion loading, thus causing flying back accident.
    Dynamic Mechanical Properties of an Insensitive DNAN-based Melt-cast Explosive
    LI Dongwei, MIAO Feichao, ZHANG Xiangrong, XIONG Guosong, ZHOU Lin, ZHAO Shuangshuang
    2021, 42(11):  2344-2349.  doi:10.3969/j.issn.1000-1093.2021.11.007
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    The dynamic mechanical properties of explosives are important to their stability. In order to reveal the dynamic mechanical properties of insensitive 2, 4-dinitroanisole (DNAN)-based melt-cast explosives,the dynamic behavior of an insensitive DNAN-based melt-cast explosive for penetrating warhead was investigated by split Hopkinson pressure bar experiment. The stress equilibrium and constant strain rate of the explosive materials with low impedance and low strength were achieved by using the pulse shaper technique in the SHPB test,and the stress-strain curves of the explosives at the strain rates of 65 s-1,130 s-1 and 200 s-1 were obtained. Based on the experimental data obtained,the Johnson-Cook constitutive model parameters for the explosive was proposed by an improved Lesuer’s approach. The parameters of Johnson-Cook constitutive model are A=1.70 MPa,B=11.37 MPa,C=0.93,and n=0.49. The results show that the failure stress of the explosive increases with the increase in strain rate,and the explosive has significant strain rate effect. The Johnson-Cook constitutive model can be used to predict the mechanical responses of the explosive under impact load.
    Characteristics of Perforation and Fragment Group Expansion of Steel Sheet Impacted by Cylindrical 93 Tungsten Projectile at Hypervelocity
    MA Kun, CHEN Chunlin, FENG Na, YIN Lixin, LI Mingrui, ZHOU Gang
    2021, 42(11):  2350-2359.  doi:10.3969/j.issn.1000-1093.2021.11.008
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    The experimental research on the impact of 93 tungsten cylindrical projectile on thin steel plate is carried out to further study the fragment group expansion and projectile erosion of cylindrical projectile during hypervelocity impact on target plate. The empirical formula of perforation diameter of cylindrical projectile penetrating into target is given through the dimensional analysis method. The moving image of fragments behind the target is obtained by using high-speed camera,and the expansion law of fragment group and the erosion law of projectile are analyzed. The melting problems of projectile and target materials in hypervelocity impact is explored by analyzing the microstructure. It can be known from fitted experimental data that the perforation diameter of target plate,the maximum axial expansion velocity and maximum transverse expansion velocity of fragments are approximately related to the diameter of projectile,the thickness of target plate, and the impact velocity,and the projectile erosion length is also related to the projectile length-to-diameter ratio in addition to the above parameters. In the hypervelocity impact of cylindrical projectile on target plate,spallation occurs on the back surface of target plate,and a ‘tip’ of velocity greater than the velocity of remaining projectile is formed in the front of the fragment group,which can be approximately determined by the thickness of target plate being less than 0.72 times of projectile diameter. When the 93 tungsten cylindrical projectile impacts the steel target at the speed of 2-3 km/s,the fragment group behind the target is not melted in a large range,but when the fragments and the remaining projectile impact the second layer of target plate,the material near the impact zone melts in a large range.
    High-temperature Shock Resistance of Launch Container with Metal and Carbon Fiber Composite Structure
    PENG Lumei, ZHOU Chengkang, ZHANG Zhiyong, LIU Dong
    2021, 42(11):  2360-2367.  doi:10.3969/j.issn.1000-1093.2021.11.009
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    In order to solve the problem of scouring and ablation of the carbon fiber reinforced plastic (CFRP) launch container by the high temperature gas with particles generated during the launch process, a launch container is made of a thin-walled metal and CFRP composite structure, with the inner layer being the metal layer and the outer layer being the CFRP layer. The temperature distributions of the composite structures with different materials and different thicknesses of metal layer and CFRP layer were simulated using the CFD commercial software Fluent, and the linear buckling analysis of temperature was carried out using the finlte element analysis software. Finite element analysis software Ansys was used to study the buckling temperatures of steel-CFRP composite structure, aluminum-CFRP composite structure, and the composite structures with different thicknesses of metal layer. The parameters of metal-CFRP composite structure in the thermal emission environment were presented, and the actual thermal emission test results were compared and analyzed. The simulated and test results show that the thickness of metal layer is too thin to adapt to the high temperature shock in thermal launch process, and the metal layer is buckled inward; steel+CFRP composite structure has higher capacity than aluminum+CFRP composite structure for heat-emitting temperature impact under the condition of the same thickness; and steel+CFRP composite structure has lower capacity than aluminum+CFRP composite structure for heat-emitting temperature impact under the condition of the same mass.
    Cross-validation and Optimization of SWIR Star Catalogue in Celestial Navigation
    ZHANG Geng, LI Chonghui, ZHANG Chao, DU Xingzhen, LIU Changhao
    2021, 42(11):  2368-2378.  doi:10.3969/j.issn.1000-1093.2021.11.010
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    Continuous day and night star surveys in the short-wave infrared band are expected to realize all-time celestial navigation in near-earth space,which is of great significance for improving the usability and continuity of celestial navigation systems.A short-wave infrared star catalogue with complete information is an essential foundation for all-sky celestial navigation. Since there is a lack of the information about the motion of stars necessary for celestial navigation and the extremely uneven distribution of stars, the existing infrared star catalogues,such as two micron all sky survey (2MASS) and wide-field infrared survey explorer, cannot be directly applied to astronomical positioning and orientation. Based on the analysis of the current main star catalogues,2MASS infrared star catalogue and the visible light Tycho-2 catalogue are certified and a short-wave infrared star catalogue containing complete information of the stars themselves is presented.Then the quasi-uniform star catalogue division method is used to analyze the characteristics of the cross-validated star catalogue. The star catalogue is optimized using the “angle distance + magnitude” weighted screening method. The short-wave infrared star catalogue is obtained with an average star distribution density of 0.5 stars per square degree and a coefficient of variation of 0.14 throughout the sky.
    A Statistical Hot Spot Reaction Rate Model for Shock Initiation of PBX
    BAI Zhiling, DUAN Zhuoping, HUANG Fenglei
    2021, 42(11):  2379-2387.  doi:10.3969/j.issn.1000-1093.2021.11.011
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    A statistical hot spot reaction rate (SHS) model for shock initiation and detonation of heterogeneous solid explosives is developed to describe the formation,growth or disappearance of hot spots,combustion after nucleation and rapid transition to detonation. The pressure-time histories in both HMX-based PBX9051 and TATB-based LX-17 are calculated by using the SHS model, and the numerical results are found to be in good agreement with the experimental data. It is found that the void size should be controlled as small as possible to improve the safety during the synthesis of insensitive high explosives. The results indicate that the shock initiation behavior of the HMX-based PBX has the accelerated reaction characteristics,and the TATB-based PBX has a stable reaction characteristic.
    Wide-area Cooperative Detection Algorithm of Missile-borne Image Detector
    LOU Wenzhong, SU Zilong, WANG Jinkui, LIU Weitong, ZHAO Fei
    2021, 42(11):  2388-2395.  doi:10.3969/j.issn.1000-1093.2021.11.012
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    The wide-area cooperative detection algorithm of missile-borne image detectors is studied for the effect of cooperative detection allocation scheme on the target information gain. The issues of the dispersion correction of missile-borne image detector and the target allocation are studied for the purpose of obtaining the most effective damage information. The complete dynamic model and target equivalent model of image detector are proposed to simulate the collaborative detection environment of multiple detectors. The ability of the image detector system to obtain damage information through effective information entropy is described, the correlation equations between damage information entropy and the system and target are derived, and the evaluation criteria is established for cooperative detection capabilities. Based on the Kuhn-Munkres algorithm and the Runge-Kutta algorithm, an optimal solution method is proposed for solving the optimal correction timing of image detector and the optimal observation target allocation, and the algorithm flow is given to solve the optimal allocation problem of collaborative detection of missile-borne image detector. The results show that this algorithm has higher information gain compared with the random allocation of image detectors, and the target information entropy gain is increased by 24% when the image detector crosses a detected target.
    Information Consensus-based Distributed Cubature Kalman Filtering Algorithm with Intermittent Observations
    WANG Ning, LI Yinya, QI Guoqing, SHENG Andong
    2021, 42(11):  2396-2408.  doi:10.3969/j.issn.1000-1093.2021.11.013
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    For nonlinear target tracking of distributed fire control systems with intermittent observations,an information consensus-based distributed cubature Kalman filter (ICDCKF) algorithm is presented to improve the estimation accuracy of tracking system and ensure the consistency of estimated results of each sensor node. The modified cubature Kalman filter with intermittent observations is presented for nonlinear systems. Considering the correlation between local estimation information of sensor nodes,the covariance intersection method is firstly utilized in the nonlinear consensus filtering algorithm,and the estimation accuracy is improved under the condition of unknown cross-covariances. Specially,the condition for guaranteeing the convergence of estimated results of ICDCKF slgorithm with intermittent observations is derived for the feasibility. In this condition,the boundedness of the estimation covariance is proved strictly in theory. The proposed ICDCKF algorithm is applied to an electo-optical sensor network. The results show that the proposed ICDCKF algorithm can greatly improve the estimation accuracy of tracking system with the consensus estimation compared with CKFI, CKF_CI and KCF_Me algorithms.
    On the Delay Time of Induced Electrostatic Discharge of Metal Electrode under the Action of ESD EMP
    ZHANG Jianping, HU Xiaofeng, LIU Shanghe, WEI Ming
    2021, 42(11):  2409-2417.  doi:10.3969/j.issn.1000-1093.2021.11.014
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    For the problem about electrostatic discharge induced by strength electromagnetic field, the delay time of electrostatic discharge of metal electrode is studied to further explore the changing law of its electrostatic discharge under the action of strong electromagnetic field. The electrostatic discharge rule of metal electrode under the action of strong electromagnetic field is emphatically analyzed from the formation process of discharge channel and the mechanism of electrostatic discharge induced by electromagnetic field. The test results show that enhancement in the magniude of radiated field strnegth results in the shorted delay time of induced discharge under the action of strong electromagnetic pulse radiation field, and the voltage between metal electrodes and the air pressure all have impact on the delay time of induced discharge under the action of strong electromagnetic pulse. The delay time of induced discharge gradually shortens and the dispersion of time delay also becomes gradually smaller with the increase in metal electrode voltage, radiated field strength or air pressure.
    Deep Learning-based Color Compensation Method for Projected Images in Combat Assistant System
    ZHANG Feng, ZHANG Chao, YANG Huamin, WANG Fabin
    2021, 42(11):  2418-2423.  doi:10.3969/j.issn.1000-1093.2021.11.015
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    A deep learning-based color compensation method for projected images is proposed to realize the visual display of large-scale data in arbitrary complex color plane.The proposed method is aimed to realize the rapid deployment of display system in complex environment and improve the mobility of field command system in modern war. The method is used to avoid the inherent defects of multiple modules in deep learning based on an end-to-end deep learning network,a model and an objective function. The number of image features extracted from the training model is increased by deepening the layers of CompenNet. The improved loss function SSIM+Smooth L1 is used to calculate image similarity,which enhances the robustness and stability of the loss function while speeding up the convergence of the network. The experimental results show that the PSNR and SSIM average values of the images generated by the improved CompenNet after 1 000 training iterations on the same 24 data sets are increased by 5.54% and 0.14%, respectively,the RMSE average value is decreased by 0.14%, and the subjective perception projection effect of human eyes is also better.
    Depth Face Recognition Algorithm Based on Adaptive Circle Margin
    CAI Hua, SUN Jun, ZHU Ruikun, ZHU Xinli, ZHAO Yiwu
    2021, 42(11):  2424-2432.  doi:10.3969/j.issn.1000-1093.2021.11.016
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    Face recognition is an important research direction of computer vision,and the effective loss functions play a vital role in face recognition. In view of the fact that the existing loss function does not consider the marginal situation to result in a limited model convergence and a low generalization ability is for unbalanced samples,AdaCMloss (Adaptive circle Margin Loss) loss function method is proposed for studying the margin itself.Through the self-adaptive learning of the margin,the unique margin can be learnt for different categories,and the self-adaptive circle margin is generated. A more margin is learnt for a small number of samples,so that the intra-class compression of the data of a small number of samples is more compact and the model generalization ability is stronger. The common face recognition benchmarks Megaface, IJB-C, LFW, LFW BLUFR and YTF are extensively analyzed and experimentally varified. The results show that the proposed method is used to improve the convergence accuracy of existing methods by 0.5% in unbalanced data sets and enhance the model generalization ability effectively, and has a clear convergence state.
    Magnetic Vector Gradient Anomaly Detection Based on OBF
    MA Jianfei, YAN Bing, LIN Chunsheng
    2021, 42(11):  2433-2443.  doi:10.3969/j.issn.1000-1093.2021.11.017
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    The conventional scalar orthogonal basis function (OBF) detector is used to obtain limited magnetic field information,while the vector OBF detector is significantly influenced by the swaying motion of magnetic field of the earth. To solve above problems,an OBF detector with rich magnetic field information and anti-swaying performance is presented for vector magnetic gradient detection. When measurement noise obeys Gauss's independent distribution, the vector OBF detector has the lower false alarm rate compared with scalar OBF detector,and the spatial sampling length is the main factor affecting the performance of OBF detector. The simulated and experimental results show that the vector magnetic gradient OBF detector has better detection performance than traditional detector, and the performance of the detector can be improved by shortening the spatial sampling length. In addition, based on the vector magnetic gradient signal retrieved by the vector magnetic gradient OBF detector under the condition of low signal-to-noise ratio, the position parameters and magnetic moment parameters of target can be obtained by the particle swarm optimization (PSO) parameter estimation algorithm.
    Underwater Acoustic Target Recognition Algorithm Based on Generative Adversarial Networks
    XUE Lingzhi, ZENG Xiangyang, YANG Shuang
    2021, 42(11):  2444-2452.  doi:10.3969/j.issn.1000-1093.2021.11.018
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    In the practical application of underwater acoustic target recognition,one of the main factors restricting the recognition results is the insufficient quantity of labeled samples. For the small sample properties of underwater acoustic target noise,a generative adversarial networks(GAN)-based recognition algorithm is proposed based on deep learning theory. It can be used to learn more effective features with more discriminative information from the game between generated model and adversarial model,and it is compared with deep auto-encoder(DAE) network and deep belief network(DBN) models. The experimental results illustrate that the recognition performance of GAN network model is higher than those of DBN network and DAE network models when the number of samples is limited,and the recognition performances of the three deep learning models are better than the conventional approach of extracting Mel frequency cepstrum coefficient(MFCC) features and then classifying by Softmax. In addition,GAN network model is superior to DBN network and DAE network models in recognition rate when using training samples and test samples with different SNRs. The smulation experimental results indicate that the GAN network model is more robust to noise.
    Bullet-proof Performance and Mechanism of New Ultra-high Molecular Weight Polyethylene Film
    FU Jie, LI Weiping, HUANG Xiancong, LIU Qiang, LIU Xiaolin, MA Tian
    2021, 42(11):  2453-2464.  doi:10.3969/j.issn.1000-1093.2021.11.019
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    Ultra-high molecular weight polyethylene(UHMWPE) film is a new type of bullet-proof material that has appeared in recent years. It has the different structural characteristics from UHMWPE UD.1.1 g standard simulation fragments,Type 51 7.62 mm steel armored lead-core bullets and 9 mm Perabellum copper armored lead-core bullet are used to conduct shooting tests on two types of UHMWPE material laminated targets.The influences of the molecular weights,crystallinities,mechanical characteristics and ballistic efficiency coefficients of the two types of materials on their ballistic limit v50 values,specific energy absorption value and depression depth are studied. Their bullet-proof performances are theoretically analyzed. And the bullet-proof mechanisms of the two types of materials are compared and studied from the morphology of the impact point. The results indicate that the molecular weights,crystallinities,tensile strengths,tensile moduli,and ballistic efficiency coefficients of the two types of materials are positively correlated with their bullet-proof performances,and a smaller elongation at break is more conducive to reducing the depression depth.Analysis of the bullet-proof mechanism found that the tape structure of film is more conducive to the bearing stress of material,energy transmission and energy dissipation.Therefore,UHMWPE film has good application prospects in the field of bullet-proof protection.
    Equivalent Method for 921A Steel and Q345 Steel Target Plates Based on Plate Thickness Compensation Model under thePenetration of Truncated-oval Nose Projectile
    WANG Yinan, ZHANG Jianwei, WANG Zhi, YAO Xiongliang, YANG Nana
    2021, 42(11):  2465-2475.  doi:10.3969/j.issn.1000-1093.2021.11.020
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    The special shipbuilding steel is expensive and its test cost is high for the test of projectile penetrating into the ship target. Thus the equivalence of replacing shipbuilding steel with ordinary shipbuilding steel is studied to determine the equivalent relationship between different target plates.Based on the equivalent principle of residual velocity,the dimensional analysis method and compensation model are used,and a design formula for material equivalent engineering based on the compensation model is proposed. In the formula, the ratio of equivalent plate thickness to prototype plate thickness and the ratio of equivalent plate yield strength to prototype plate yield strength meet the power exponent relation, and the power exponent coefficient needs to be determined by experiment or simulation. The process of truncated oval projectile vertically penetrating into the 921A steel and Q345 steel target plates was simulated using finite element analysis software LS-DYNA. The result shows that the calculated results are in good agreement with the test results,thus verifying the correctness of the numerical simulation method.The empirical formula for the equivalent plate thickness and the dynamic yield strength of two target plates is presented by fitting the calculated equivalent plate thickness, and the validity of the compensation model formula is verified.
    Characteristics of Quadrotor UAV in Forward Flying Mode
    YE Jianchuan, WANG Jiang, LIANG Yi, SONG Tao, WU Zeliang, XU Chao
    2021, 42(11):  2476-2490.  doi:10.3969/j.issn.1000-1093.2021.11.021
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    To study the characteristics of quadrotor unmanned aerial vehicle (UAV) in the forward flying mode, an aerodynamic model of rotor and fuselage is established through the mechanism analysis (blade element method) and wind-tunnel experiments. The nonlinear dynamic model and the state-space model of quadrotor UAV were acquired with considering the previous aerodynamic models and verified through wind tunnel test. The result shows that the aerodynamic characteristics of a rotor in forward flying mode are quite different from that in hovering mode; and the coupling of pitch channel and vertical channel,and the coupling of roll channel and yaw channel exist in the forward flying mode.
    Optimal Design of an Upper Limb Rehabilitation Robot with Generalized Shoulder Joint
    YAN Hao, WANG Hongbo, CHEN Peng, ZHANG Leilei, LI Yungui
    2021, 42(11):  2491-2502.  doi:10.3969/j.issn.1000-1093.2021.11.022
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    The shoulder joint is an important part of upper limb movement, and the range of shoulder joint rehabilitation training is one of the essential considerations to determine the rehabilitation effect of patients. A rehabilitation robot with a generalized shoulder joint is designed to help the patients with upper limb disability do rehabilitation training. The robot has six degrees of freedom (DOF) in the shoulder joint, which is coordinated with the shoulder girdle composite structure of human physiological system. In order to solve the problems that the existing rehabilitation robot arm shoulder joint has a small workspace and many joint motors, the included angle of shoulder joint axis of robot arm under the given workspace is optimally designed. The forward and inverse kinematic equations of three rotation pairs of rehabilitation robot glenohumeral joints are solved by using the exponential product formula and the Paden-Kahan subproblem calculation method, respectively. An angle evaluation index is proposed to optimize the included angle of rotation axis. The interference between the body and the robot's glenohumeral joint is analyzed by the software MATLAB, and the optimal installation position and orientation of robot relative to the body are determined. Finally, the forward and inverse kinematic equations of 6-DOF shoulder rehabilitation robot are derived. The experiment verifies that the optimized robot glenohumeral joint can reach more motion space under the same installation space compared with the traditional orthogonal structure. The result shows that the optimized 6-DOF shoulder rehabilitation robot structure has a smaller installation space and larger moving space.
    Evaluation Model of Land Force Weapon Equipment System Combat Capability Based on Improved SEM
    SHEN Binzhen, MIAO Jianming, LI Xiaofei, JIA Guangwei
    2021, 42(11):  2503-2512.  doi:10.3969/j.issn.1000-1093.2021.11.023
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    The combat capability evaluation of weapon equipment system is significant for its development and operational applications,and the construction of evaluation model is the most critical aspect of combat capability evaluation. The evaluation steps of land force weapon equipment system combat capability were analyzed based on improved structural equation modeling (SEM),an evaluation index system of weapon equipment system combat capability was constructed,and the SEM was improved by reducing the dimension of multidimensional capability index system of land force weapon equipment system combat capability based on linear weighted sum method. The computational efficiency of SEM is increased,and the fast calculation and comprehensive evaluation of combat capability is realized by using the improved SEM. The entropy weight method and the analytic hierarchy process method are used to calculate the weight of aggregation index in the improved SEM,and the capability evaluation results of two kinds of weight aggregation indexes participating in the improved SEM are compared with those of SEM. The simulated results show that the change trends of the evaluated results are basically the same,thus validating and analyzing the accuracy and timeliness of the improved SEM.
    Dynamic Super-network Model of Task-oriented Naval Fleet “Cloud Combat” System
    NIE Junfeng, CHEN Xingjun, SHI Hongquan
    2021, 42(11):  2513-2521.  doi:10.3969/j.issn.1000-1093.2021.11.024
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    For the new operation mode of “cloud combat”,a analysis model of naval fleet “cloud combat” system is proposed,which includes operational mission domain,logical function domain, resource entity domain, intelligence reconnaissance network,active assistant decision network and fire strike network. The functional nodes,information relations and association mapping rules of naval fleet “cloud combat” system are abstractly represented,and a dynamic super-network model of task-oriented naval fleet “cloud combat” system is constructed. The feature parameter space of dynamic super-network of naval fleet “cloud combat” system is constructed based on the features of super-network elements,super-network association and super-network elasticity. The model is simulated for the typical combat task of air defense. The simulated results demonstrate that the dynamic super-network of naval fleet “cloud combat” system has good robustness and network elasticity,and the “cloud combat” system has better invulnerability and attack efficiency compared to the traditional combat system. This method can solve the modeling problem of naval fleet “cloud combat” system scientifically and effectively.
    Research Notes
    Design of Dynamic Derivative Test System for Projectile/rocket Model in High-speed Wind Tunnel
    XUE Dong, LIU Jin, WANG Huan, YIN Jintao, JIANG Chunmao, YUAN Xianshi
    2021, 42(11):  2522-2530.  doi:10.3969/j.issn.1000-1093.2021.11.025
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    Wind tunnel test is one of the most important methods to obtain the dynamic derivatives. A test system for the high-speed wind tunnel was developed to simulate the actual flight motion of projectile/rocket in the wind tunnel and improve the measuring level of dynamic derivatives. The system includes a control subsystem, a data acquisition subsystem, a data processing subsystem, and three different test devices, i.e., small and medium slenderness ratio model test device, large slenderness model pitch oscillation test device and spinning projectile model test device. For the small and medium slenderness ratio (L/d<15) models, the traditional forced vibration method is used to establish the roll, yaw and pitch oscillation test devices. For the small caliber and large slenderness ratio (L/d≥15) model, the tail-forced vibration method is adopted for test device. For two-degrees-of-freedom spinning projectile model, a motor is used as driven device. The entire system was validated through wind tunnel test with standard model. The results show that the measured results of the small and medium slenderness ratio models obtained at different Mach numbers and angles of attack have high accuracy. Compared with domestic and foreign experimental data and CFD data, the experimental results here are within acceptable error range. The dynamic derivative test devices for large slenderness ratio and spinning projectile models have high engineering application value.