Table of Content

30 April 2016, Volume 37 Issue 4

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Paper

Pressure Load Fluctuation Analysis of Torque Converter Based on Fluid-structure Interaction

YAN Qing-dong， LIU Bo-shen， WEI Wei

2016, 37(4):  577-583.  doi:10.3969/j.issn.1000-1093.2016.04.001

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The load fluctuation and vibration of blade should be analyzed in the design of high power density and compact stamping-welded torque converter. The simulation is based on fluid structure interaction and dynamic mesh. The load fluctuation and vibration in time domain are extracted by setting the monitoring points along the blade from inlet to outlet. Fast Fourier transform and modal analysis are used in frequency domain analysis. The analysis results indicate that the max load fluctuation and blade vibration are at the inlet of blade because of the hydraulic impact, and the amplitudes of load fluctuation and blade vibration decay along inlet to outlet at a certain speed ratio. As the speed of turbine is higher, the amplitudes also decay. The peak frequency of load fluctuation is between the second-order and third-order modals, and also the amplitude of load fluctuation decreases at higher speed ratio.

Multi-parameter Optimization of Volute of Cooling Fan Based on a Comprehensive Evaluation Function

LUO Qing-guo, YIN Hong-tao, NING Xing-xing

2016, 37(4):  584-590.  doi:10.3969/j.issn.1000-1093.2016.04.002

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To improve the comprehensive performance of volute, a parametric computational fluid dymamics model of a U-shaped fan volute with the radius of semicircle segment, the height of volute, the deviation of the center of semicircle segment from the center of impeller, and the distance from bottom surface of impeller to volute internal wall is established, which is verified by experiments. A comprehensive evaluation model of volute is established, where the weights of indexes in the model, such as volume of volute, power consumption of cooling fan, and 1/air mass flow rate, are calculated with entropy method. The volute is optimized using response surface method by taking the comprehensive evaluation value as objective function. The results show that the radius R of semicircle section and the height H of volute are the main factors affecting the comprehensive evaluation function. With the increase in H and R, the comprehensive evaluation function decreases firstly and then increases. After optimizing, the comprehensive evaluation function value of volute is reduced by 23.43%, of which the performance is improved significantly. The research shows the proposed method can be used for the optimization design of volute of cooling fan.

Optimized Methodfor Shift Valve Used in Integrated Transmission

JIN Bi-xuan, ZHAI Yong, GU Hong-tao, ZHANG Tao

2016, 37(4):  591-597.  doi:10.3969/j.issn.1000-1093.2016.04.003

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The pressure and flow characteristics of the shift valve in electro-hydraulic control circuit are analyzed to improve the working principle of the shift valve used in the integrated transmission. A dynamics simulation model of shift valve is established based on AMESim software. The effects of spool diameter, spring stiffness and slide lap on the dynamic respond characteristics and performance of shift valve are analyzed through simulation. The structural parameters, including spring stiffness and slide lap, of shift valve are optimized based on genetic algorithm. The simulation results are compared against the test ones. The results show that the simulation analysis with AMESim and the structure optimization with genetic algorithm are instructive, the working principle of the optimized shift valve is improved, as well as the feasibility of the proposed method is verified.

Parameter Identification of Human Body under Successive Impact

JIN Xin， ZHOU Ke-dong， HE Lei， HUANG Xue-ying， ZHANG Jun-bin

2016, 37(4):  598-602.  doi:10.3969/j.issn.1000-1093.2016.04.004

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A parameter identification method of human body under successive impact is proposed, considering the variation of the parameters over time. Orthogonal empirical mode decomposition (OEMD) and Hilbert transform are used in the method to build the analytic signals of input and output signals. The equation of analytic signals with variable parameters is derived, and the human body parameters changing with time are calculated. Surface electromyography experimental results show that the proposed method is effective. Identification result shows that the equivalent stiffness and equivalent damping parameters of human body under successive impact obtained in this paper are consistent with biology.

Research on Magnetic Field Inhibiting the Rotation of Shaped Charge Jet Particles

MA Bin， HUANG Zheng-xiang， ZU Xu-dong， XIAO Qiang-qiang， JIA Xin

2016, 37(4):  603-611.  doi:10.3969/j.issn.1000-1093.2016.04.005

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The coupling process of magnetic field and shaped charge jet is analyzed, and an equation of rotation motion of the shaped charge jet particles in the presence of magnetic field is established in the case of small angle rotation. On this basis, a simulation method is used to study the characteristics of force and torque of jet particles in magnetic field by the software Ansoft Maxwell, and the experimental verification is also carried out. The research result show that the equation of rotation motion of the shaped charge jet particles in magnetic field could well describe the process of magnetic field inhibiting their rotation, and the numerical simulation of the force and torque of particles in magnetic field also reflects the property of inhibition. The experimental results indicate that the rotation of slug is inhibited and modified under the action of magnetic field, and the axis of slug can remain aligned with the axis of crater penetrated by the jet under the action of magnetic field.

Experimental Research on the Effect of Eccentric Impact of Jet on the Impinging Atomization of Gel Propellant

DENG Han-yu， FENG Feng， WU Xiao-song， YU Xing-fei， ZUO Ying-ying

2016, 37(4):  612-620.  doi:10.3969/j.issn.1000-1093.2016.04.006

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In order to study the effect of eccentric impact of jet on the impinging atomization of gel propellant, a relative experimental system is established, and a gel propellant as well as a simulant are prepared. Jet behavior, impinging liquid sheet and droplet size distribution at different eccentricities are measured. Spray incline angle is deduced theoretically and compared to the experimental results under eccentric impingement. The results indicate that the disturbances on jets are strengthened with increase in jet velocity. However, the deformations of the jets near injectors are all very small at different jet velocities since the disturbance is limited. The development and breakup of liquid sheet are basically the same under different eccentricities. While the eccentricity exceeds 1.5/6, two darker regions with a certain angle appear at the impinging point, resulting in the enhancement of flux nonsymmetry. As the eccentricity is improved, the spray incline angle enlarges and is less than the theoretical result. The eccentricity has a little influence on the droplet size distribution of impinging atomization, but Sauter mean diameter (SMD) with eccentricity is always lower than that without eccentricity. And SMD reaches the smallest when the eccentricity equals to 0.5/6.

ZUO Ying-ying(612)Analysis of Formation Experiment and Penetration Property of Rod-like Jet of Shaped Charge with Foam

YANG Li， CHEN Chuang， ZHANG Jian， XIANG Sheng-hai

2016, 37(4):  621-626.  doi:10.3969/j.issn.1000-1093.2016.04.007

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In order to study the formation and penetration property of rod-like jet of eccentric sub-hemisphere liner shaped charge with foam, three eccentric sub-hemisphere liners are designed according to the equal mass principle, and X-ray imaging and penetration experiments are carried out. The formation effects and penetration capabilities of rod-like jets of different tapered eccentric sub-hemisphere liners are compared, and the optimal tapered liner mode for forming rod-like jet is acquired. The results show that the rod-like jet of the liner which is thick in top and bottom areas and thin in middle area has small slug, optimal formation effect, powerful penetration capability, and relatively homogenous penetration hole. The formation parameters of rod-like jet are studied by theoretical analysis, and the velocity and mass distribution of rod-like jet are obtained. Compared with traditional simple cone liner, the jet mass of the liner which is thick in top and bottom areas and thin in middle area is increased by 22%, and the tip velocity is increased by 10%.

Numerical Simulation on Interface Defeat of Ceramic Armor Impacted by Long-rod Projectile

TAN Meng-ting, ZHANG Xian-feng, HE Yong, LIU Chuang, YU Xi, GUO Lei

2016, 37(4):  627-634.  doi:10.3969/j.issn.1000-1093.2016.04.008

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A numerical simulation model for ceramic target impacted by long-rod projectile (LRP) is established to investigate the influence of several factors on the interface defeat of ceramic armor by using finite element software AUTODYN. The reliabilities of parameters and algorithms of simulation method are verified. The main factors, such as LRP nose shape, cover plate and pre-stress of ceramics, are simulated in two-dimensional computational studies. The simulated results show that three nose-shapes of LRP have significant effects on interface defeat/penetration transition velocity. The degree of damage on the ceramic can be decreased and the interface defeat/penetration transition velocity can be improved by adding a cover plate and applying a pre-stress on ceramic.

Research on Anti-frequency Sweeping Jamming of Radio Fuze Based on Support Vector Machine

ZHANG Biao，YAN Xiao-peng，LI Ping，LI Zhi-qiang，CHI Qing-xi

2016, 37(4):  635-640.  doi:10.3969/j.issn.1000-1093.2016.04.009

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Frequency sweeping jamming is a great threat to the radio fuze. The feasibility of support vector machine applied in anti-frequency sweeping jamming of radio fuze is studied. The frequency spectrum characteristics of fuze detection signal under the action of the frequency sweeping signal are analyzed theoretically with continuous wave Doppler radio fuze as an example. A feature parameter extraction method based on the Fourier spectrum is proposed. The support vector machine is used for classification and recognition of target signal and jamming signal. The experimental results show that the proposed method can be used to obtain a very high classification and recognition correct rate, and effectively improve the anti-frequency sweeping jamming ability of the continuous wave Doppler radio fuze. A good effect can be obtained by applying the support vector machine to anti-jamming of radio fuze.

Temperature Error Compensation Method Based on Adaptive Neuro Fuzzy Inference for Fiber-optic Gyro

FENG Ka-li， LI An， QIN Fang-jun， LI Feng

2016, 37(4):  641-647.  doi:10.3969/j.issn.1000-1093.2016.04.010

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According to Shupe thermally induced non-reciprocity noise theory, the mechanism of the temperature drift of fiber-optic gyro is researched, and a temperature experiment with range of -15～50 ℃ is designed. A temperature error compensation model based on adaptive neuro fuzzy inference for fiber-optic gyro is established by using the adaptive neuro fuzzy inference system and the piecewise modeling method and constructing the training sample from the measured data. The proposed model is used to solve the problem of poor model matching, and can help to shorten the time of the gyro entering into the steady state. The calculated results show that the standard deviation of the temperature drift is reduced by 75.55% after compensation with the proposed method.

Warship Formation Recognition Algorithm Based on Hough Transform and Clustering

ZHANG Yi-fei， DONG Shou-quan， BI Kai-bo

2016, 37(4):  648-655.  doi:10.3969/j.issn.1000-1093.2016.04.011

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Formation recognition is an important research task in the area of target recognition for anti-ship missile weapon systems. Perfect formation recognition capability can improve the target selection of anti-ship missiles for compact warship formation, thus enhancing the hit probability and operational effectiveness of anti-ship missiles. The formation recognition algorithm is researched base on Hough transform, which has higher recognition rate without the influence of detection noise. If the target information is polluted badly, the improved K-means clustering algorithm is used to cluster the local peaks in an accumulation matrix. The shape parameters of formation to be recognized can be extracted from the clustering results so that the adverse influence due to detection noise is restrained effectively. Even though the target information is polluted badly, the algorithm has better recognition accuracy and robustness. The complexity of the algorithm and the effect of target designation error on the accuracy of the algorithm are analyzed. The simulation results show that the proposed algorithm has the perfect capability of formation recognition.

Characterization of New 24-dinitroanisole-based Melt-cast High Detonation Velocity Explosives

LI Dong-wei， JIANG Zhen-ming， ZHANG Xiang-rong， ZHOU Lin

2016, 37(4):  656-660.  doi:10.3969/j.issn.1000-1093.2016.04.012

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In order to reveal the detonation properties of 2,4-dinitroanisole（DNAN）-based melt-cast explosives and promote the application of this kind of explosives, a computer code is used to calculate the detonation properties of three DNAN-based melt-cast explosives. A series of experiments are carried out to characterize the properties of the DNAN-based explosive (DNAN 20/HMX 80) and Octol. Electrometric method is used to test the detonation velocities and pressures of the two explosives. Explosive probability method is used to test the mechanical sensitivities of the two explosives. Laser interferometer velocimetry (VISAR) is used to test the free surface of copper bar drived by the detonation products. The results show that the detonation properties (detonation velocity is 8 436 m/s and pressure is 31.23 GPa) of DNAN-based explosive (DNAN 20/HMX 80) are better than those of Octol. The mechanical sensitivity of DNAN-based explosive (impact sensitivity is 33% and friction sensitivity is 57%) is lower than that of Octol. The speed of the copper bar drived by the detonation products is 3 045 m/s. The comprehensive performance of DNAN-based explosive (DNAN20/HMX80) is better than that of Octol. The DNAN-based explosive could replace Octol for air defense warhead, antimissile warhead, and large-caliber EFP warhead.

Multichannel Radar Signal Recognition Algorithm Based on DCS

WANG Hong-wei， FAN Xiang-yu， CHEN You， YANG Yuan-zhi

2016, 37(4):  661-669.  doi:10.3969/j.issn.1000-1093.2016.04.013

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Recognizing the radar signal in complex electromagnetic environment is the necessary prerequisite for electronic countermeasures to play a role. The priori information about signal modulation and signal parameter is limited, which cannot provide enough intelligence support for signal sorting. In addition, the mixture of signals restricts the effectiveness of signal sorting. The issue mentioned above is converted to a blind source separation. A high-order disjunction matrix is established with Givens transform, and the blind source separation algorithm with degree of cyclostationarity (DCS) based on the third-order cyclic statistics which is suitable for two channel signals is expanded to the multichannel signals with different cyclostationarity frequencies. The feasibility of the proposed method is proved by theoretical derivation, and the method for establishing the parameters of Givens matrix is derived. The features of radar signal in cyclostationary domain are extracted with cyclostationarity theory. The method is simulated with DCS separation principles. The simulated results show that the algorithm can realize the effective sorting of multichannel radar signals.

Effect of Surface Wettability on Cavitation of Sphere during Its Water Entry

SUN Zhao， CAO Wei， WANG Cong， WEI Ying-jie

2016, 37(4):  670-676.  doi:10.3969/j.issn.1000-1093.2016.04.014

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The problem of water entry of a solid sphere has challenged researchers for centuries and remains of interest to the researchers today, but how the surface condition affect the cavitation during a water entry of sphere has not been studied well. The problem of water entry of a solid sphere is investigated numerically simulated based on the Navier-Stokes equations and volume of fluid method. The numerical results show good agreement with the experimental data. Numerical results with different surface wettabilities and impact speeds are presented. The results show that the condition to create an air cavity is that the impact speed must be strictly above a critical velocity, and the critical velocity is discovered to be dependent on the wetting contact angle of sphere. That means the air entrainment is best inhibited by hydrophilic surfaces, hydrophobic spheres like making a big cavity. Four distinct cavitations are observed at different water entry velocities and contact angles: non-cavitation, deep-seal cavitation, surface-seal cavitation and surface-like cavitation. The simulation results are analyzed, and an empirical theory about the relationship between critical velocity and contact angle is presented.

Research on Double Reference Source Estimation Method for 3-dimension Space of Near-field Underwater Moving Target withLinear Track

WANG Qian, HOU Hong, YIN Shao-ping, CHEN Zhi-fei

2016, 37(4):  677-683.  doi:10.3969/j.issn.1000-1093.2016.04.015

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For the identification of noise source, the track information could be applied to Doppler compensation for the recorded noise emitted from moving vehicle. Linear track estimation of near-field underwater moving target by double pulse source (DPS) has been used successfully in 2-dimension. The use of DPS is extended to 3- dimension space in order to linearly track the target. The positioning result of double reference source obtained by the baseline positioning method is projected to a certain plane under the limitation of common perpendicular minimum length. The objective function of DPS is constructed with the known distance of double reference source. The track information in 3-dimension space is obtained by using genetic algorithm. The simulation results show that the estimated errors of azimuth and pitch angles are less than 3.8° when their trace line lies under \[-40°, 40°\] in case of 0 dB noise level. The estimated errors of abeam distance and depth difference are kept less than 5.9 m at the same time.

Combined Algorithm for Motion Parameter Estimation of Target on Underwater Static Platform

LIU Sheng-song, CHEN Shao-hua， CHEN Chuan

2016, 37(4):  684-689.  doi:10.3969/j.issn.1000-1093.2016.04.016

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For the purpose of the use of bearing-frequency target motion analysis on underwater static platform, a target motion parameter estimation method is proposed according to bearings and frequency information. The initial value in the iteration of the Kalman filter is set with the least square estimation, resulting in faster convergence and more accurate estimation results. Real test results show that the proposed method has good convergence rate and accuracy, which can be used effectively to achieve the underwater passive localization of target.

Effect of Isothermal Heat Treatment on the Semi-solid Microstructure of AM60-1Si Alloy

HU Yong， RAO Li， ZUO Tian-ping

2016, 37(4):  690-695.  doi:10.3969/j.issn.1000-1093.2016.04.017

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The effect of isothermal heat treatment on the microstructure of semi-solid AM60-1Si alloy is investigated. The results show that the semi-solid microstructure evolution of AM60-1Si alloy experiences three stages, i.e., formation of globular particles, spheroidization and coarsening, during isothermal heat treatment process. With the increase in holding temperature and holding time, the size of primary α-Mg phase decreases at first and then increases. The fine well-distributed globular semi-solid microstructure can be obtained at 605 ℃ for 45 min. The Mg₂Si phase changes from initial Chinese script shape to polygon shape during isothermal heat treatment.

The Investigation into Burnishing ForceBurnishing Depth and Surface Morphology in Rotary Ultrasonic Burnishing

ZHAO Jian， WANG Bing， LIU Zhan-qiang

2016, 37(4):  696-704.  doi:10.3969/j.issn.1000-1093.2016.04.018

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The effective burnishing time in rotary ultrasonic burnishing is determined with by analyzing machining mechanism and characteristics of rotary ultrasonic burnishing operation. The relationship between burnishing force and burnishing depth in rotary ultrasonic burnishing is firstly modelled based on the Hertz contact theory. The relational model is then applied to predict the burnishing force. Experiments of rotary ultrasonic burnishing of titanium alloy TC4 are carried out. The burnishing force is measured using a piezoelectric dynamometer, and the machined surface morphology is observed using a white light interferometer. The microstructure perpendicular to the surface of the ultrasonic burnished workpiece is observed under an optical microscope. The results demonstrate that there is a linear correlation between burnishing force and burnishing depth in rotary ultrasonic burnishing. The experimental results are in good agreement with the theoretical and predictive results. The correlation between burnishing force and surface morphology is discussed. The research results will be beneficial for the appropriate selection of burnishing depth.

Detection of Blast Point Based on Hierarchical Model of Background Subtraction via Robust Dictionary Learning

JI Hong-lei， YANG Qing-wen， QIN Xiao-yan

2016, 37(4):  705-711.  doi:10.3969/j.issn.1000-1093.2016.04.019

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For the background estimation and huge computation problems of background model in the background subtraction blast point detection method, a blast point detection method is proposed based on a hierarchical model of background subtraction via robust dictionary learning. To improve the operation efficiency, a three-tier pyramid hierarchical model is established to divide each frame image into non-overlapping blocks. The blast points are detected from the subtraction between current frame image and image background estimation by using the improved robust dictionary learning method layer by layer. Experimental results on a large number of blast point image sequences show that the proposed method has superior performance in correct detection rate, false positive rate and robustness in comparison with the existing blast point detection method.

A Method for Temperature Error Correction of Transfer Impedance of EMC Current Probe

HE Yang， GAO Wan-feng， ZHANG Jian-wei， ZHANG Chun-xi， LI Yan

2016, 37(4):  712-718.  doi:10.3969/j.issn.1000-1093.2016.04.020

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In order to improve the measuring accuracy of current probe influenced by ambient temperature in field EMC (electromagnetic compatibility) test, the mechanism of temperature affecting on the transfer impedance of current probe is analyzed, and the quantitative relations among winding resistance, distributed resistance, distributed capacitance and temperature are given. A calibration method of current probe is presented based on the temperature error compensation, the law that transfer impedance changes with temperature and the curve of temperature error compensation are given, the validity and effectiveness of the proposed method is proved by comparing the test results with the laboratory results. The results show that the method can be used to expand service ambient temperature of the current probe from -40 ℃ to 50 ℃ on the premise of ensuring measuring accuracy, and reduce the measurement error in field test.

Dynamics Analysis of a Two-stage Projection Scheme of Space Nets System

GAO Qing-yu, TANG Qian-gang, ZHANG Qing-bin, FENG Zhi-wei

2016, 37(4):  719-726.  doi:10.3969/j.issn.1000-1093.2016.04.021

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A two-stage projection scheme of space nets is proposed by using “outstretching first and opening later” idea in parachute inflation process, and a numerical simulation model is developed. In the proposed scheme, the projection process of space nets is divided into two successive courses: the first-stage of outstretching course and the second-stage of opening course, through which the process is controlled step by step to pull out the space nets regularly and ordinarily, and avoid their twining, penetration and knotting problems. Through a contrastive analysis of the numerical simulation result and the experiment result, the numerical simulation model is tested and verified. The two-stage projection scheme of space nets and the numerical simulation model developed in this paper provide a reference way to carry out optimization design of space nets.

Combined Prediction on Avionics State Optimized by MAGA

ZHAO Jian-zhong， OUYANG Zhong-hui， ZHANG Lei，ZHAO Jian-yin

2016, 37(4):  727-734.  doi:10.3969/j.issn.1000-1093.2016.04.022

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A combined prediction method based on hidden Markov model (HMM) and least square support vector machine (LS-SVM) is presented for prediction of avionics states. Multi-agent genetic algorithm (MAGA) is used to estimate HMM parameters to overcome the problem of that Baum-Welch algorithm is easy to fall into local optimal solution. The conditional probability of states is introduced into the HMM modeling to reduce the effect of uncertainty factor. MAGA is used to estimate the parameters of LS-SVM model, and the pruning algorithm is used for achieving the sparse approximation of LS-SVM in parameter estimation, thus achieving the objective of improving the generalization performance of LS-SVM. On this basis, a combined prediction model of avionics state is established. The analysis results show the combined prediction model has high prediction accuracy, calculating speed and stability.

Modelling and Simulation of Highline Cable for Replenishment at Sea

LI Nan， WEI Zhuo-bin， ZHANG Shi-yun， REN Ai-di

2016, 37(4):  735-743.  doi:10.3969/j.issn.1000-1093.2016.04.023

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The multi-body dynamics theory is used to establish a highline model, because there is not any appropriate highline model for research on sea replenishment equipment. A method for establishing multi-rigid-body dynamics model, rigid-flexible-mixed-body dynamics model and multi-flexible-body dynamics model of rope is studied. Three rope models are used to simulate the highline, and the sea dry cargo replenishment transverse process is simulated with ADAMS. The results show that the development trend of velocity, force, angular velocity and torque for three models in simulation process is basically consistent with the actual mechanical properties of highline cables, meaning that the multi-body dynamics model of rope can simulate the highline replenishment at sea; the multi-flexible-body dynamics model of rope is more closer to the actual structure of highline cable compared to the other two kinds of multi-body dynamics models of rope.

Research Notes

Research on Structural Parameters of Single-stage Multipole Field Launcher Based on Uniform Design Approach

WANG Zhi-quan, WANG Yu, YAN Zhong-ming, ZHANG Chen-ran

2016, 37(4):  744-750.  doi:10.3969/j.issn.1000-1093.2016.04.024

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Compared with the traditional electromagnetic propulsion configuration, the multipole field electromagnetic launcher (MFEL) system has numerous adjustable parameters, and the change of any parameter affects the efficiency of system. An effective method to improve the efficiency of system is proposed through the analysis of the energy coupling formula of armature. An uniform design experiment is established by taking the turns of monolayer and layers of drive coil, the thickness of armature, and spaces of drive coil and armature as variable factors. The experimental data is analyzed, and the matching pairs of optimal structural parameters are obtained. The simulation results show that the efficiency of optimization model is improved significantly. A reasonable design scheme for the MFEL major structural parameters is presented after analyzing each simulation.

A Convenient Solution Method for Kill Probability of Antiaircraft Rocket Weapon

WANG Bao-hua, PEI Yi-xuan, HUO Yong-mou, XUN Pan-pan

2016, 37(4):  751-755.  doi:10.3969/j.issn.1000-1093.2016.04.025

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A convenient solution method for kill probability of antiaircraft rocket weapon is proposed to calculate the kill capability of antiaircraft rocket weapon. On the assumption that the kill capability parameters of fragment warhead and the firing accuracy parameters of antiaircraft rocket weapon are known, a damage capability model of rocket projectile fragment is established according to the damage mechanism of antiaircraft gun AHEAD projectile against aircraft target. The kill barrage size of rocket projectile fragment is translated into an additional size of target in elevation and azimuth directions, and the hit probability of antiaircraft rocket weapon is calculated. A kill probability model of antiaircraft rocket weapon against the aircraft target is established. The kill probability to the aircraft target is computed to show the feasibility of the proposed method by And taking an antiaircraft rocket weapon for example.

Fidelity Evaluation of Electromagnetic Environment in Operational Tests of Electronic Equipment

KE Hong-fa， ZHANG Jun-qi， ZHU Ji-lu， GE Xuan

2016, 37(4):  756-762.  doi:10.3969/j.issn.1000-1093.2016.04.026

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A fidelity evaluation model of electromagnetic environment based on matrix grey relational analysis is proposed for constructing a realistic electromagnetic environment in operational tests of electronic equipment. The performance and effectiveness parameters relative to electromagnetic environment for electronic equipment are introduced. And the mechanism of action of electromagnetic environment on electronic equipment is analyzed. Two- dimension index space based on the density spectrum of electromagnetic power and the density of electromagnetic signal for fidelity evaluation of electromagnetic environment is constructed. A matrix expression model of electromagnetic environment is presented. A fidelity evaluation model of electromagnetic environment based on the matrix grey relational analysis is proposed by using the grey system theory. An example is used to show the validity and practicability of the proposed model.

Laser Target for Large-range Detection of Impact Point of Air-to-ground Attack Training Projectile from Airborne Gun

ZHU De-fang, PENG Jing-ming, CHEN Peng

2016, 37(4):  763-768.  doi:10.3969/j.issn.1000-1093.2016.04.027

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A laser target detection and positioning method based on the wide-beam and high repetition frequency pulse laser rangefinding technology is presented for a large-range detection of impact point of air-to-ground attack training projectile launched from airborne gun. The proposed method provides a layout scheme of open laser vertical target in shooting range, which is composed of four laser detecting modules. A mathematic model of calculating the projectile terminal ballistic parameters in spatial coordinates is established, and the positioning error correction is made by averaging method and linear regression fitting method. The effectiveness of laser target detection and data processing method is verified through experiment. The present paper provides afeasibe way for establishing a target scoring system which can detect the high-speed projectiles in large range field, evaluate the training records objectively, and is installed and withdrawn conveniently.