Table of Content

31 July 2007, Volume 28 Issue 7

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Paper

Fluid-Structure Interaction Finite Element Analysis of Dynamic Structural Strength on Gearbox’s Housing

XIANG Chang-le, JIAO Kai-he, WANG Wen-ping, LIU-Hui

2007, 28(7):  769-773.  doi:10.3969/j.issn.1000-1093.2007.07.001

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The mathematical representation of fluid-structure interaction was deduced for a gearbox housing of composite transmission of a certain vehicle. And the fluid-structure interaction finite ele?ment model of a complex gearbox’s housing was built. The effect of the oil height on the modal of the housing was analyzed, the exciting forces of the housing were analyzed and applied to the model; the vibration of the housing was calculated by the model, and the strength of housing was analyzed by the fourth material strength theory; according to the calculated results, the housing was strengthened by reinforcing ribs and the vibration of the modified housing was calculated. The calculated results show that the stress and vibration amplitude of the modified housing are lower.

A Study on Various Models for the Prediction of Technical States of Vehicular Engines

LIU Jian-min, LIU Yan-bin, QIAO Xin-yong

2007, 28(7):  774-777.  doi:10.3969/j.issn.1000-1093.2007.07.002

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The penalty tendency for engine technical states was predicted by the grey model, AR time sequence model and the grey-time sequence model respectively, and the predicted precisions were com?pared among the three models. The results of the prediction show that the grey-time sequence model can reflect the tendency and fluctuation of change in character, realize high precision in prediction, lay the basis for engine life prediction and has thus more practical meanings.

A Comparison Study on Optimal Configuration Methods of Naval Gun Weapon Systems

SUN Shi-yan, QIU Zhi-ming

2007, 28(7):  778-781.  doi:10.3969/j.issn.1000-1093.2007.07.003

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SAW, TOPSIS, ELECTRE Ⅲ and PROMETHEE Ⅱ are typical ranking and choice meth?ods for optimal configuration of naval gun weapon system. The methods have their own advantages and limitations, and need to be analyzed critically in application to practical problem. JLach ranking method was evaluated in three phases ： constructing the attribute preference model; constructing the alternative preference model; ranking the alternatives. In the unified frame, SAW, TOPSIS, ELECTRE Ⅲ and PROMETHEE Ⅱ were compared and analyzed by taking a naval gun weapon system for example, leading to some valuable results.

Study on Photoelectric Measuring Systems for the Swaying of Rocket and Artillery Systems

YAN Yu-feng, LI Yang, BAI Su-ping, ZHENG Ping-yi

2007, 28(7):  782-784.  doi:10.3969/j.issn.1000-1093.2007.07.004

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The scheme of measuring the swaying of rocket and artillery systems was proposed by means of a laser beam simulating the axis of the barrel and a photoelectric rotary encoder measuring the sway?ing, and the principle of the scheme was illustrated. A photoelectric measurement system composed of the automatic force application equipment, angular measurement equipment and the photoelectric de?tection screen was designed. Measurement accuracy of the system was analyzed. I He measurement er?ror of the system is equal to or less than 17.3″（0.08 mil).

Structural Optimization 0f Machine Gun Based on Dynamic Stability Concept

LI Yong-jian, WANG Rui-lin, ZHANG Ben-jun

2007, 28(7):  785-788.  doi:10.3969/j.issn.1000-1093.2007.07.005

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Improving the firing accuracy is the final aim in the structural optimization of machine guns. The main factors which affect the dispersion accuracy of machine guns were analyzed. Based on the concept of dynamic stability, a structural optimization model was built up and the sensitivity of disper?sion accuracy to design variables was analyzed. The optimization results of a type of machine gun show that the method is valid, feasible and can be used as a guide to the structural optimization of other au?tomatic weapons.

Numerical Simulation of a Twophase Flow Interior Ballistics Model of Variable-Burning Rate and High-Density Charges for a Certain Light Caliber Cannon

WANG Jing, YUAN Ya-xiong, JI Xin-yuan

2007, 28(7):  789-792.  doi:10.3969/j.issn.1000-1093.2007.07.006

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A two-phase flow interior ballistics mathematical model was established, in which the effect of the variable-burning-rate is concerned in a high-density gun and numerical simulation was conduct?ed. The simulation results show that the variable-burning-rate and hign-density charge have obvious effects on improving the muzzle velocity under controlling pressure in the chamber, and the insensitivi?ty layer thickness oi the propellant grain and primer powder quantity affect the interior ballistics per?formance obviously. Simulation results for the shape of pressure waves in the chamber are of benefit to the safety analysis of gun shooting.

Models of Laser Detector and Target Azimuth for Terminal Correction Mortar Projectile

XU Jin-xiang

2007, 28(7):  793-795.  doi:10.3969/j.issn.1000-1093.2007.07.007

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The operational principle of laser detector of terminal correction mortar projectiles(TCMP) was studied, the correction zone of laser detector was analyzed, the coordinate transformation formula between ground coordinate system and laser detector coordinate system was deduced, the target az?imuth model of laser detector was established, and the method of solving target azimuth angle and track error angle was researched by means of target facula. The simulation computation results show that lower body rotation speed may cause the missing of target in the detecting process, hit precision can be greatly improved by using low cost course correction technology. The established laser detector model and target azimuth moael lay the foundation for trajectory model and exterior ballistics simula?tion of TCMP.

Application of Dynamics and Kinematics of Parachute-Bomb System in Target Identification for a Target Sensitive Projectile

TANG Qian-gang, WANG Yu, ZHANG Qing-bin, ZHANG Xiao-jin, YANG Tao

2007, 28(7):  796-799.  doi:10.3969/j.issn.1000-1093.2007.07.008

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For a smart munitions system with parachute, a target identification algorithm of terminal sensing device is key factor having influence on attack precision. The nine-degree of freedom dynamic model of the parachute-bomb system was developed to simulate the trajectory and the dynamic behavior of the system. By using the principle of dynamics of the parachute-bomb system, a new method was used for the target identification of a target sensitive projectile. The simulation program was developed and used to remove the influence of wind gust. Successful airdrop tests demonstrate that the target i- dentification algorithm combined with bomb kinematics is valid and reliable and can improve hit preci?sion of smart munition system.

Study on Reliability Evaluation Methods of Guided Ammunition

WANG Wei, CAI Rui-jiao, JIAO Qing-jie

2007, 28(7):  800-803.  doi:10.3969/j.issn.1000-1093.2007.07.009

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The problem of prior information fusion was investigated. In order to avoid that a small amount of field test information would be obliterated by a large amount of prior information, a Bayesian method with mixed Beta distribution was used. The applicable condition of the method was analyzed, and the method was generalized to the situation of multiple prior information. By using the result, the general method of the reliability evaluation of the guided ammunition was given. The com?parison of reliability lower boundary with an example among the method, the classical method, and Bayesian method with Beta distribution shows that the method is reasonable and the feasible.

Static Test Method for the Dynamic Imbalance Degree of the Projectile

ZHANG Xin-ming, WANG Li-ming, YANG Jian-dong, SHANG Chun-min

2007, 28(7):  804-807.  doi:10.3969/j.issn.1000-1093.2007.07.010

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Aiming at improving the limitations of the traditional test method for the dynamic imbalance of projectile, a new static test method for the dynamic imbalance was presented. Formulas of calcula?tion of dynamic imbalance were deduced and the relation between the dynamic imbalance and product of inertia as well as the test method of product oi inertia Ixy and Ixz were analyzed. It was proved that the essence of the test of dynamic imbalance of projectile is to test the product of inertia of the projec?tile theoretically. The experiments show that the test result of the traditional method is identical with that of the new static method; the latter can reduce the cost of equipment, simplify the test procedure, spare human resource, and get more reliable test precision.

Study on Features Extraction of Pseudo Code PM-Carrier FM Combined Signal Based on the PWD Transform

LI Ming-zi, ZHAO Hui-chang

2007, 28(7):  808-811.  doi:10.3969/j.issn.1000-1093.2007.07.011

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The features of pseudo code PM-carrier FM combined signal include the pseudo code and the modulation frequency. The pseudo Wigner distribution(PWD) transform was used for extracting these features. The feature of the pseudo code was extracted by the amplitude output of PWD and correlative filter technology. The feature of the frequency modulation was extracted by the way of PWD trans?form on the signal which was processed by anti-phase operation according to the extracted feature of pseudo code 1.e. position of phase changed abruptly.丄he simulation result shows that both the feature of FM and the feature of phase changed position caused by the pseudo code PM can be extracted effec?tively in SNR = 3 dB.

The Optimum Method and Its Application of the Integrated Relation for FPA Thermal Imagers

MAI Lü-bo, JIN Wei-qi

2007, 28(7):  812-816.  doi:10.3969/j.issn.1000-1093.2007.07.012

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The large-scale system theory and the principles of generalization, serialization and unitiza?tion were used to solve the discrete, non-numeral and fuzzy problems of tne integrated relation opti?mum for thermal imaging systems. The generalization optimum model system, optimum operation procedure, knowledge models, relation models, mathematics models, particle models and target mod?els for thermal imaging systems were built up by above theory and principles. The schemes oi integrat?ed relation optimum, basic detector, detector module generalization, infrared optical module serializa?tion and cooler module serialization of FPA thermal imagers were obtained with the optimum model system. The schemes can be used to guide the optimum development of military FPA thermal imagers, to reduce the product types, producing cost and development cycle and to increase logistical support ability.

Influence of Velocity-Height Ratio of Satellite on the TDICCD Camera

FAN Chao, LI Ying-cai, YI Hong-wei

2007, 28(7):  817-821.  doi:10.3969/j.issn.1000-1093.2007.07.013

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In the nigh-resolution satelliteborne remote sensing TDICCD camera, angular velocity of the image is changed with variation of the velocity-height ratio ( v/H) of the satellite, and the image quality of camera is deteriorated seriously. Thus, the variation rule of the v/H was studied at the imaging of satelliteborne TDICCD camera. Influence of v/H on the image quality was studied from two variations oi imaged ground scenery latitude and IDICCD camera scroll angle . The interval of reg?ulation of the row integration time and the range of the scroll angle at the imaging were computed based on the given oroital parameters. The effect of the field of view on the image quality was finally- analyzed .

Study on Fabrication of Superluminescent Diodes by Anodic Oxidation

GAO Xin, BO Bao-xue, ZHANG Jing,LI Hui, QU Yi

2007, 28(7):  822-825.  doi:10.3969/j.issn.1000-1093.2007.07.014

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InGaAs/AlGaAs non-uniform well-thickness multi-quantum well superluminescent diodes were designed and successfully fabricated, the output properties of light power and spectrum were measured and analyzed. An output power higher than 10 mW with spectrum width about 18 nm was obtained under driving current less than 150 mA.

Target Recognition Method of MMW Radar Based on Gabor Atom Transformation and Support Vector Machine

YANG Guo, LI Xing-guo

2007, 28(7):  826-829.  doi:10.3969/j.issn.1000-1093.2007.07.015

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In order to improve the ability of target recognition of millimeter wave radar, a method of target recognition based on Gabor atom transform and support vector macmne(SVM) was proposed. The Gabor atom transform’s validity in signal expression and the SVM’s advantage in signal classilica- tion are fully utilized m the method. The features of echo signals of raaar were extracted by Gabor atom transform and classified and recognized by SVM. The results of experiments show that the method is feasible and has higher recognition probability.

A Frequency Domain Switching-Beam Algorithm

SU Wei, HUANG Jian-guo, WEI Zhou-fang, LEI Ji-sheng

2007, 28(7):  830-833.  doi:10.3969/j.issn.1000-1093.2007.07.016

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Traditional time domain switching-beam (TDSB) algorithm is incapable of tracing the DOA while the SNR of the received signal is low. The algorithm is not suitable for underwater acoustic telecommunication system of UUV. In order to solve this problem, a frequency domain switching- beam (FDSB) algorithm was proposed. The principle of the proposed algorithm is that the beam is se?lected and switched by comparing amplitudes among output signal frequency spectrum peak values in frequency domain. The performance simulation with the proposed algorittim and the lake test were completed by using the acoustic receiving array of designed UUV. The simulation results show that the beam is switched steadily and correctly by FDSB algorithm under the condition of array element re?ceiving SNR of — 10 dB. The results of the communication test of underwater in the lake at the dis?tance of 25 km show that the beam is selected ana switched by FDSB algorithm and the code error rate is less than 10-4 at the condition of existing relative displacement between UUV and signal transmis?sion end.

Research on Discrete Fractional Fourier Transform-Based Detection Algorithm for LFM Echo of Underwater Moving Target

CHEN Peng, HOU Chao-huan, LIANG Yi-hui

2007, 28(7):  834-838.  doi:10.3969/j.issn.1000-1093.2007.07.017

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The mismatch between echo and replica caused by underwater moving target (UMT) ’s radi?al velocity degrades the detection performance of matched filter (MF). By using the focusing property of fractional Fourier transform (FRFT) to linear frequency modulation (LFM) signal, a discrete frac?tional Fourier transform (DFRFT)-based detection algorithm for UMT’s LFM echo was proposed. The algorithm is less affected by target's radial velocity compared with the other MF detection algo?rithm utilizing zero radial velocity replica (ZRVR)，and the mathematical relation between the output peak positions of these two algorithms is present in the case of existence of target echo. The algorithm can also estimate the target distance by using this mathematical relation. The simulation and experi?ment data analysis show that the algorithm’s detection performance is better than or equivalent to that of the other MF detection algorithm utilizing ZRVR for the LFM echo of UMT with unknown radial velocity under reverberation noise background.

An Analysis on the Detectable R^ion for Bistatic Sonars

YANG Li, CAI Zhi-ming

2007, 28(7):  839-843.  doi:10.3969/j.issn.1000-1093.2007.07.018

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Bistatic sonar, which inherits the merits of active and passive monostatic sonars to some ex?tent, has the advantage of extending detectable area. But it can’t obtain the desirable detectable area at all angles, and the detectable area may be inferior to what the equivalent monostatic sonar has at some angle. Based on the energy relationship, the model of detectable region for the bistatic sonar was established, and the relation between the detectable range and the azimuth angle at different baseline length, equivalent raidius and detectaole area was analyzed. Ihe notion of advantage region and advan?tage angle was put out. The optimal configuration of bistatic sonar were put forward under some cir?cumstances .

Missile LFT Model and Its Application in H∞ Gain-Scheduled Autopilot Design

YU Jian-qiao, LIU Li, JIN Dong-ya, XU Cheng-dong

2007, 28(7):  844-848.  doi:10.3969/j.issn.1000-1093.2007.07.019

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The missile linear fractional transformation(LFT) model was established by the graph ap?proach, and the missile’s dynamics was separated into certainty part and uncertainty part. Based on the LFT model, the linear parameter varying (LPV)/p. control structure was established, and the H00 gain-scheduled autopilot was designed by use of D-K-D iteration. The designed controller with the LPV/fi technique, which takes account of the time-varying nature of missile explicitly, can automati-cally gain-schedule the parameters in the course of missile flight, adapt to the variation of the missile dynamics characteristics, and stabilize autopilot dynamics characteristics over its entire operation range. Simulation results show that the LFT model can describe the missile’s dynamics exactly, and the dynamics of H00 gain-scheduled autopilot are independent of the flight conditions.

Movement Model and Design of Variable Structure Attitude Control System for Low Speed Spinning Ballistic Missiles

WANG Zhi, ZHOU Jun, ZHOU Feng-qi

2007, 28(7):  849-853.  doi:10.3969/j.issn.1000-1093.2007.07.020

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The spin is a new method for ballistic missile’s penetration. It can reduce the dwell time of the beam on a particular point of the missile and counter laser antimissile effectively that ballistic mis?sile makes a flignt in spinning during the first booster phase. The missile spinning can lead to the cou?plings of control, inertia and aerodynamics, especially the control mode based on composite of force vectors makes pitch and yaw movements interact. Thrust vector control mode and movement model of spinning ballistic missile were proposed. A robust variable structure attitude control system was de?signed, and some useful conclusions were drawn.

Estimation of the Attitude of a Rolling Missile Based on Strong Tracking Filter

ZOU Yi-min, WANG Bo

2007, 28(7):  854-858.  doi:10.3969/j.issn.1000-1093.2007.07.021

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A scheme to estimate the flight attitude of a rolling missile based on strong tracking filter (SfF) was proposed. To get the attitude of an experimental missile, a telemetry scheme based on two-axis liquid-driven rate gyroscope was studied. The telemetric data was processed by STF to recon?struct the attitude of missile, thus offering a basis for further analysis on the flight dynamics perfor?mances and the effectiveness of the control and guiding system. Using the dynamic attitude model of low rate rolling missile, a group of iterative filter equations based on sub-optimal multi-fading extended Kalman filter (SFEKF) were educed. With the robustness to model unfitness and the strong tracking ability to state variety, the SFEKF was introduced to improve the precision of attitude estimation. Simulation example shows the effectiveness of proposed algorithm.

Study of Successive Test Data Distribution of the Strapdown Inertial Measurement Unit Based on the Bayesian Method

XU Jun-hui, WANG Li-xin, QIAN Pei-xian

2007, 28(7):  859-862.  doi:10.3969/j.issn.1000-1093.2007.07.022

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Aiming at the small sample of strapdown inertial measurement unit (SIMU) successive test data, a Bayesian method was used to study its statistical characteristics. Prior and posterior distribu?tion of SIMU successive test data was set up by the method and the information of pretest, sample and population. Some statistical inferences can be made with the posterior distribution, it can reduce the error of statistical analysis in the case of small samples.

Unsteady Supercavitating Flow on Cone Cavitator

WEI Xi-bin, WANG Cong, RONG Ji-li,ZHANG Jia-zhong, YANG Hong-Ian, ZHANG Xue-wei

2007, 28(7):  863-866.  doi:10.3969/j.issn.1000-1093.2007.07.023

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Based on an integral equation method, the unsteady supercavitating flow past slender body was studied. The shape and length of supercavity was calculated respectively using a finite difference time discretization method. The characteristics of tne shape and length of supercavity varying with the cone’s angle and cavitation number were investigated respectively. It obviously shows that super cavi?ty ’ s change has retardancy and waviness.

Treatment of Wastewater of Recovery RDX by Fenton and Photo-Fenton Process

ZHANG Dong-xiang, XU Hang, LI Han-sheng, XU Wen-guo

2007, 28(7):  867-871.  doi:10.3969/j.issn.1000-1093.2007.07.024

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Fenton process and photo-Fenton process were employed to treat the wastewater formed during the recovery of RDX. The effects of Fe2S〇4 dosage, H2O2 dosage, pH, reaction time and tem?perature on removal efficiency of chemical oxygen demand (COD) the wastewater were investigated. The results show that the optimum FeS〇4 dosage and pH value are 700 mg/L and 2.5, respectively, and that the COD removal efficiency of the wastewater increases with the rise of H2O2 dosage but de-creases with the rise of temperature. Under the conditions with H2O2 dosage of 100 mg/L and the re?action temperature of 15℃，the best removal efficiency of COD is obtained at 82.07% . In the photo- Fenton process, FeS〇4 dosage could be reduced sharply to 50 mg/L.

Reduction of Cross-sectional Curves for Easier Helmet Design by Wavelet Analysis

LIU Hong, ZHOU Hong, LI Zhi-zhong, ZHENG Li

2007, 28(7):  872-875.  doi:10.3969/j.issn.1000-1093.2007.07.025

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The curved surface modification is often conducted by repeatedly modiiymg the three direc?tion cross-sectional curve cluster of the surface. It is a hard work and needs much experience. An algo?rithm for reducing cross-sectional curves in curved surface reconstruction was presented. The original cross-sectional curves were given and the curved surface was created by skinning. For replacing the original cross-sectional curves, the new cross-sectional curves were regenerated by the low-resolution control points that are the outcome of the original control points by wavelet decomposition. A new curved surface can be fitted to the lower number of cross-sectional curves by skinning to a given toler-ance. The problem of huge amounts of control points produced in curved surface skinning can also be avoided. Helmet design example shows that tne algorithm is efiicient and easy-to-use.

Analysis of Magnetic Leakage Fields Based on 3D FEM

JI Feng-zhu, WANG Chang-long, CHEN Zheng-ge,ZUO Xian-zhang

2007, 28(7):  876-879.  doi:10.3969/j.issn.1000-1093.2007.07.026

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3D finite element method (FEM) was adopted to analyze the magnetic leakage fields (MLF) because of the drawbacks of magnetic dipole model and 2D FEM. The mathematical models for MLF were established based on the Maxwell，s equations and 3D finite element theory. The models were used for simulating and analyzing MLF data sets. The vector plot of 3D magnetic flux and the surface plot for the radial component of magnetic flux density were obtained, which could show the feature of the MLF near defect expressly. The effects of the defect length, the lift-off and the path po?sition on the peak-peak values for magnetic flux leakage signals were studied. It is the base for further studying on magnetic flux leakage inspection.

An Analytical Method for the Network of Warship Combat Systems

WU Xiaofeng, LI Xu-yong, CHEN Ye

2007, 28(7):  880-884.  doi:10.3969/j.issn.1000-1093.2007.07.027

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A new method for optimizing and evaluating the network of warship combat systems was proposed. By analyzing the characteristics of network in an operations process, it was discovered that the network of warship combat systems belongs to an evolution network. By using complex network theory, an evolution network model suitable for the network of warship combat systems was obtained. Two measures of performance (MOPs) for the complexity of network, the average path length and the average clustering coefficient, were introduced. Mathematical models for these measures were estab?lished .The measures of network were then simulated along with the combat procedure by means of the models. Influences of the measures on the rapidness and robustness of the network in the operations were analyzed.

Prediction for Crankshaft's Fatigue Crack Growth Using ε-machine

ZHOU Xun, YU Xiao-li

2007, 28(7):  885-888.  doi:10.3969/j.issn.1000-1093.2007.07.028

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Propagations of mechanical components’ fatigue cracks are usually staged. As a process of system dissipation, in each stage of the crack propagation, a slightly shifting of pattern will occur. If the abnormal measurement, which is correspondent to the original state, derived from these features can identify shifting patterns and predict the coming behavior features in real time dynamically, the referential basis is to be provided for preventing destructive fatigue failures and establishing reasonable maintenance and repair schedules. As one of the anomaly detection algorithms based on hidden pat?tern, e-macmne was utilized to process the vibration acceleration data that were recorded in the fatigue test of engine crankshafts, in order to make identification and prediction for the fatigue crack growth behavior patterns. By comparison with the test results of crack growth rate, the prediction capability of the method for crack growth behavior pattern was discussed.

Angular Shift Calibration for Rudders Based on Monocular Vision

HE Sen,HOU Hong-lu,WANG YAO

2007, 28(7):  889-892.  doi:10.3969/j.issn.1000-1093.2007.07.029

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A calibrating method was put forward based on computer monocular vision for the angular displacement sensors of aileron, flap, jaw rudder and elevator, etc, rotating around a fixed axis. The pictures of the double-circle target fixed on a jaw rudder surface and parallel to its axis were taken by a stationary digital camera. The coordinates of four characteristic points were found out by digital image processing. Analytical solution of the double-circle ’ s normal direction cosine was obtained according to perspective projection principle without calibrating camera parameters, then the relative direction of the double-circle’s normal was found besides relative positions of the circles’ centers. The rudder’s an?gular shift can be expressed with the parameters above. Simulation results show that the calibration is a simple and real-time process and can also be used to measure rendezvous and docking spacecrafts’ rel?ative positions and attitude parameters in real time.

Research Notes

Wind Tunnel Experiment for Aerodynamic Characteristics of Diamond Back Wings

LEI Juan-mian, WU Jia-sheng

2007, 28(7):  893-896.  doi:10.3969/j.issn.1000-1093.2007.07.030

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A series of wind tunnel experiment models with various Diamond Back wings were designed with a modularized method, and 6-component measuring experiments were conducted to study the aerodynamic characteristics of the Diamond Back wings under the coditions of Ma =0.4-0.8, a —— 2°?12° and δz = -5° . The experimental results indicate that the Diamond Back wing is suitable for gliding extended range of unpowered guided bomb unit based on high lifting force,CL/CD≥5 and high gliding extended range ability; the local slope of CL - a curve reduces rapidly under the condition of a >6° ; the attack angle of gliding flight should be selected according to maximum CL/ CD.