Acta Armamentarii

Research on Firing Phase Angle Optimization of Terminal Trajectory Correction Projectile Based on Pulse Jet Control

CAO Ying-jun, YANG Shu-xing, LI Xing-jun

2008, 29(8): 897-901. doi:10.3969/j.issn.1000-1093.2008.08.001

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The firing phase angle characteristics and residual error were theoretically analyzed on the basis of traditional firing control logic of pulse jets. It has been found that there may be a large residual error when the number of pulse jets is of shortness. An optimization strategy for the firing phase angle control was presented, which makes the number of pulse jets be minimum for the residual trajectory deviation after correction under the condition that there are not enough pulse jets, Finally, the method was verified by the 6-degrees of freedom trajectory simulation.

Study of Theoretical Model for Conductivity of Electric Exploding Foil

ZHAO Yan, ZENG Qing-xuan, LIANG Qi

2008, 29(8): 902-906. doi:10.3969/j.issn.1000-1093.2008.08.002

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The electric exploding foil is an important component of slapper plate detonator, and its con?ductivity is a key parameter of electric exploding process. The conductivity was discussed from three phases, i. e. early heated, intrinsic exploding and plasma, by analyzing the physics principle of the change of foil state. A computational model of conductivity of foil in an electric exploding process was established based on the characteristics of each phase. The simulated results of the model coincide well with the experimental results.

Simulation Study of Stagnation Charact?*istics of Heat Flux and Temperature of Millimeter Wave Fuze Antenna Radome

LIU Qing-cheng, LI Xing-guo

2008, 29(8): 907-910. doi:10.3969/j.issn.1000-1093.2008.08.003

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The heat flux and the temperature of stagnation of millimeter wave fuze antenna housing were modeled and simulated by analyzing its exterior ballistics. The simulation result shows that the polytetrafluoroethylene( PTFE) is suitable for such fuze antenna housing, but some measures should be taken to prevent the antenna housing breaking away from the warhead in ballistic flight.

3D Unsteady Numerical Simulation of Missile Launching

JIANG Yi, HAO Ji-guang, FU De-bin

2008, 29(8): 911-915. doi:10.3969/j.issn.1000-1093.2008.08.004

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The dynamic mesh update methods of computational fluid dynamics were analyzed. A new dynamic mesh update method, i.e. zone moving and dynamic layering method, was presented, and its principle was described. The method was used for the unsteady numerical simulation of 3D flow field distribution in the launching process of missile from concentric cylinder launcher to obtain the time dis?tribution of flow field parameters in 3D space. Ihe simulation results were compared with the test re?sults .The compared result shows that the method can ensure the missile launching calculation accuracy and efficiency.

The Effect of Al/O Ratio on Underwater Explosion Shock Wave of Aluminium- containing Explosives

ZHOU Lin, YANG Qi-xian

2008, 29(8): 916-919. doi:10.3969/j.issn.1000-1093.2008.08.005

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The underwater explosion parameters (shock wave energy, bubble energy and assemble en?ergy) of two kinds of aluminum- containing explosives ( RDX/Al/Wax and AP/RDX/A1) were mea?sured in the experiments. The Al/ O ratios of the explosives were calculated. It has been found that the shock wave energies of the two explosives are maximized underwater when the Al/ O ratio is about 0.4. In addition, the effect qf Al/ O ratio of RDX/1 NT/ Al/Wax explosive on the underwater shock wave energy was calculated and analyzed, and the same influencing law mentioned above was ob-tained. The research results show that the sequence oi the explosives with maximum shock wave ener?gies is AP/RDX/A1, RDX/Al/Wax and RDX/TNT/Al/Wax. The laws offer a scientific foundation to the compositions design of explosives for underwater weapons.

Design of Uncooled Thermal Imaging System Operating at Multiple Temperatures

ZHANG Jun-ju, SUN Lian-jun, CHANG Ben-kang,QIAN Yun-sheng, QIU Ya-feng, TIAN Si

2008, 29(8): 920-924. doi:10.3969/j.issn.1000-1093.2008.08.006

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The reasons why thermal imaging system consumes power were analyzed, and a design scheme of lower Dower consumption thermal imaging system operating at multiple temperatures was presented. The relation between the response characteristics and operating temperature of a-Si focal plane array detector was studied by means of formulae oF its noise equivalent temperature difference(NETD) and detectivity. The numerical analysis shows that the detectivity decreases and JNETD in?creases slightly when the operating temperature rises. This indicates the detector has a uniform re?sponse in a wide operating temperature range. A thermal imaging system operating at multiple temper?atures was designed according to the analysis. The test results of system show the power consumptign of thermoelectric controller is less than 350 mW and NETD is less than 120 mK in the range of -40℃?60℃ . It shows that the system not only outputs high-quality images but has a lower power consumption.

Study of Millimeter Wave Synthetic Aperture Imaging in Near Field

HE Yun-tao, JIANG Yue-song, LI Xiaolu

2008, 29(8): 925-929. doi:10.3969/j.issn.1000-1093.2008.08.007

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Passive synthetic aperture imaging system is to use an interference principle to sample the brightness temperature in the spatial domain and obtain the images by inverse Fourier transform. The current imaging algorithms are generally applied to airoorne and satellite-borne observation, which are the approximate imaging algorithms using the far-field condition. But the algorithms are not satisfied for near flied imaging, so it is necessary to fina a near-fiela imaging algorithm. A new imaging algo?rithm was deduced for near-field condition from 2D synthetic aperture imaging principle by correcting the geometrical errors, and the computer simulation results of the algorithm were given. The limita?tions of near field algorithm were also analyzed. Tne analysis shows that the near field algorithm has a better stability in the imaging.of a point source compared to the far-field imaging algorithm.

Entropy Weight-based Grey Evaluation of Performance of Image Segmentation

YU Feng, YANG Cheng-wu

2008, 29(8): 930-934. doi:10.3969/j.issn.1000-1093.2008.08.008

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In order to overcome the subjective limitation in traditional grey comprehensive evaluation, a new model for comprehensive evaluation, 1.e. entropy weight comprehensive evaluation model, was established by using the concept of entropy in information engineering science and the modified weignt value with differential degree of evaluation indexes. And the model was applied to evaluating the per?formance of image segmentation. All kinds of factors having influence on image segmentation perfor?mance were analyzed theoretically and quantitatively by the principle and the method of grey mathe?matics. The weight of the factor was calculated objectively by an entropy weight-based coefficient method instead of only subjective judgement. Ana the inherent information of the evaluated subject is used fully in evaluation so that the drawback of the traditional evaluation can be avoided, in which only a few indicators of process are emphasized while others are out of consideration. Thus the model is more effective and feasible.

Mechanical Analysis and Trimming of an Energy-saving Near Space Aircraft

HE Zhen, LU Yu-ping

2008, 29(8): 935-939. doi:10.3969/j.issn.1000-1093.2008.08.009

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The mechanical analysis and the trimming were performed for a novel near space aircraft which uses the variation in wind speed at high altitude to control its flight path. The flight principle of the novel aircraft was analyzed, and its parameters were determined. Because of the differences in the mechanical characteristics and relative airspeeds of the aircraft components, the forces applied on the components were analyzed separately, and a force balance equation set was established, in which a tether was analyzed in 3D space by using a segmenting analytical method. Finally for each compo?nent, the simultaneous trimming calculation of equation set was performed by using an iterative method, and the spatial profiles of the tether were plotted. The computational results show that the wind speed difference in the stratosphere can be used, to control the flight path of aircraft with the re?sult that its energy consumption is significantly decreased.

Effect of ZrQ2 on Growth Mechanism of ZrB2 in ZrB2-SiC Composites

HAO Gui-liang, XU Qiang, ZHU Shi-zhen,WANG Fu-chi

2008, 29(8): 940-943. doi:10.3969/j.issn.1000-1093.2008.08.010

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ZrB2-SiC hypertemperature ceramic composites were prepared successfully using a spark plasma sintering (SPS) technique, and the effect of Zr〇2 formed by sparking between grain particles on the grain growth mechanism of ZrB2 was studied. The results show that, for ZrB2-SiC,(l010) plane of ZrB2 is bound to (101) plane of Zr〇2 to suppress the growth of (1010) plane, and (0001) plane is a priority grown plane of ZrO2. The research provides a theoretic basis for improving the mi?crostructure and mechanical properties of ZrB2-SiC composites.

Analysis of Crack Arrest in Crl2 Alloy Steel Sample with Half-embedding In-line Crack Using Electromagnetic Heating Effect

FU Yu-ming, ZHENG Li-juan, REN Xing-Ii

2008, 29(8): 944-949. doi:10.3969/j.issn.1000-1093.2008.08.011

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A crack of standard tension test piece with prepared half-embedding in-line crack was arrest?ed by pulse current discharge from ZL-2 pulse current generating equipment. After discharging, the crack tip was melted, and a high thermal compressing stress area was formed around it, thereby passi?vating the crack tip for crack arrest. A numerical simulation was made to determine the technological parameters of crack arrest, the thermal stress and temperature fields around the crack tip at the mo?ment of pulse current discharge. The research results show that, in the case of appropriate pulse dis?charge voltage, the tip of half-embedding in-line crack can be passivated using the electromagnetic thermal effect, a thermal compressing stress field is formed around the in-line crack tip, the metal structure around crack tip is fined, and the spreading work of crack extension can be improved to solve the crack extension.

Pre-analysis of Connecting Precision of Missile Sections in Virtual Environment

XIONG Zhen-qi, NING Ru-xin, LIU Jian-hua,LIU Wei-dong

2008, 29(8): 950-955. doi:10.3969/j.issn.1000-1093.2008.08.012

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An analysis and optimization method of assembly precision in virtual environment was pro?posed for the connecting precision of missile sections. A concept of product assemoly precision pre-anal?ysis was defined, and its application in different phases of actual production was described. According to the effect of all kinds of assembly errors caused by the different connecting methods of missile sec?tions on the flight performance of missile, a product assembly tolerance model was established.The as?sembly precision was optimized based on the transfer coefficients of dimensions and the machining diffi?culty coefiicients of dimensions. The pre-analysis method of connecting precision of missile sections was verified by calculating the missile vertex offset caused with the section connecting deflection through taking a certain missile as example.

Optimal Temperature Research on Fuse Thermoelectric Peeling Process Based on finite Element Method

CHENG Sen-lin, HUANG Jian-song, WANG Jian-feng

2008, 29(8): 956-959. doi:10.3969/j.issn.1000-1093.2008.08.013

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The temperature of peeling blade has direct effect on the fuse peeling quality in fuse thermo?electric peeling process, so the research on the optimal temperature of peeling Dlade has a great engi?neering meaning. The whole fuse thermoelectric peeling process was analyzed thermodynamically based on finite element method to obtain the temperature-time curves of key nodes of fuse jacket and inner tube and the optimal temperature of peeling blade. The analysis results were verified through experi?ment .The result provides a basis for the optimal temperature choice of thermoelectric peeling fuse ma?chine design, and the fuse peeling quality can be improved at a chosen optimal temperature.

An Image Denoising Method Based on Partial Differential Equations Using B-spline Function

DU Hui-qian, GUO Lin-nan, MEI Wen-bo, REN Yan-fang

2008, 29(8): 960-964. doi:10.3969/j.issn.1000-1093.2008.08.014

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The partial differential equations (PDE) of anisotropic diffusion can be used to suppress the image noises and preserve the edges and detail features of image to some extent, but the denoismg ef?fect is still not idea. A new algorithm based on adopting a normalized third order B-spline function as a diffusion one was proposed, which can improve image edge detail besides denoising, decrease iterative order and have an effect on additive and multiplicative noises.

Reverse Measurement of TOOI Nose Compensation Radius Based on Computer Numerical Control System

ZHOU Jian-lai, ZHANG Nan-qiao, SHI Yan-ping

2008, 29(8): 965-969. doi:10.3969/j.issn.1000-1093.2008.08.015

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For the fine turning of conical and curved surfaces of weapon workpieces, a radius value of tool nose needs to be input into a computer numerical control (CNC) system to realize an accurate com?pensation .For the improved accuracy of tool nose radius value, it was presented that a necessary com?pensating radius value of tool nose was used to express a tool-nose radius wmch was input into CNC system by taking the geometric shape and size of tool nose, the contact condition between tool and workpiece, the tool wear into synthetic account, evince the necessary compensating radius value of tool nose can not be directly measured, a reverse measuring method was proposed. The method is to calcu?late a value of tool nose radius from the measured dimensions of workpiece after a chamfer or circular conical surface is turned. It gets rid of figure restriction of tool nose, and particularly can be used on line. Three types of inserts with different tool nose radii were used in experiment. The experimental tests show that the measuring method has a high accuracy and reliability for radius compensation, and can effectively enhance the turning efficency.

Research on Error Compensation Technology of Micro- displacement System

ZHANG Liao-yuan, GONG Yi-chao, LIU Yu-mei

2008, 29(8): 970-973. doi:10.3969/j.issn.1000-1093.2008.08.016

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The machining accuracy of shaft-like parts can be improved by using a piezoelectric ceramic micro-displacement actuator to control the tools for real-time error compensation. With the help of physics analysis and mathematical modeling methods, a lag mathematical model of piezoelectric ceramic micro-feed system was established. For the nonlinear characteristics of piezoelectric actuator, a correc?tion method of controlling voltage was presented, which can reduce the non-linear error of piezoelectric ceramic, improve the control accuracy of piezoelectric ceramic micro-displacement actuator, and con-tribute to the acnievement of high-precision open-loop micro-displacement control of piezoelectric ce?ramic actuator.

Method Study of Extracting the Tracer Time of Small Arms Bullet Based on Wavelet Transform

LI Yue-lin, MIN Bi-rong, PANG Wei-zheng, et al

2008, 29(8): 974-979. doi:10.3969/j.issn.1000-1093.2008.08.017

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The echo signal of continuous wave Doppler speed measurement radar was analyzed and studied on the basis of wavelet transform. The tracer times were extracted from various kinds of tracer bullets of small arms by using the wavelet transform to characterize the sudden change (transient state) of the signal. The test result indicates that the method can be used to accurately extract the beginning moment and the ending moment of tracer, and is more accurate than the traditional methods.

Leader-Follower Formation control of Autonomous Underwater Vehicles Using Position Information Only

CUI Rong-xin, XU De-min, YAN Wei-sheng

2008, 29(8): 980-984. doi:10.3969/j.issn.1000-1093.2008.08.018

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Leader-follower formation control of autonomous underwater vemcles was studied, and a formation control algorithm was presented, of which the followers only need to use the position and heading informations of leader rather than its velocity, angular velocity and dynamic model informa?tions .A reference trajectory of the followers was derived from the leader’s sailing state and the desired formation, and a virtual vehicle, which trajectory coincides with the reference route at a limited time, was designed by only using the leader’s position and heading information. An adaptive variaole struc?ture control law was proposed for the follower in consideration of the parameter uncertainty of vehicle and the ocean current disturbance. The law enables the follower to move along the trajectory of virtual vehicle to keep tke follower at a desired distance for formation purpose. Simulation results skow tKat the proposed control law is valid.

Dynamic Reliability Model of the System with Dependent Failure

WANG Zheng, XIE Li-yang, LI Bing

2008, 29(8): 985-989. doi:10.3969/j.issn.1000-1093.2008.08.019

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In consideration of the effect of common cause iailure as an important mode of dependent failure on the reliability of the system, the dynamic reliability models of systems were developed by taking advantage of the load-strength interference model, the order statistic theory and the stochastic process. The reliability models of the systems with dependent failure were built using the load-strength interference model in system-level directly. The iailure mechanism of the systems was analyzed for the multiple action of random load, and from the statistic meaning of random load action, the reliability models of the systems under random repeated load were derived using the order statistic theory. Fur?ther, the loading process was described with the Poisson stochastic process, the dynamic reliability models of series, parallel and k -out-of- n systems were established, and tne relationship between the reliaoility of the systems and time was studied. Pinally; the simulation analysis was carried out to veri?fy the reliability models proposed with Monte Carlo method, and the result shows that the proposed re?liability model is right.

A Method of Monitoring the Quantity Value Stability for Automatic Test System Based on Dynamic Revised Bayesian Model

SUN Qun, ZHAO Ying, MENG Xiao-feng

2008, 29(8): 990-994. doi:10.3969/j.issn.1000-1093.2008.08.020

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Using measurement process control principle for reference, a method of monitoring the quantity value stability was proposed for automatic test system to assure its precision in the interval of two metrological confirmations. When check data had the characters of small sample, the traditional control chart increased the probability of error alarm . Therefore, a dynamic revised Bayesian model was adopted to estimate the parameters of the distribution. Then the control parameters of traditional control chart were improved. The experiments show that the improved control parameters of control chart are optimized distinctly and the probability of “error alarm” is decreased.

Research on Battlefield Maintenance Optimization Scheduling of Mialti-requirement-point and Multi-resource

CAO Ji-ping, SONG Jian-she, ZHU Yu, GUO Jun

2008, 29(8): 995-1000. doi:10.3969/j.issn.1000-1093.2008.08.021

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In collaborative maintenance in wartime, the multitasK maintenance process is nature. How?ever resource lack and conflicts often happen in such multitask situation. Ihe characteristics and deci?sion-making target of battlefield maintenance resource scheduling of multi-requirement-point were ana?lyzed. A battlefield maintenance resource optimization scheduling model of the multi- requirement- point and multi-resource was founded, and the optimization scheduling method and algorithm based on the precedence evaluation of requirement-point were presented. The example shows that the metnod can optimize the scheduling project and reduce the mean-latency-time of damaged equipment in wartime.

Study on Platform Vibration Simulation Experimental System for Free Space Laser Communication System

TONG Shou-feng, JIANG Hui-lin, LIU Yun-qing,LIU Peng, CHEN Chun-yi

2008, 29(8): 1001-1003. doi:10.3969/j.issn.1000-1093.2008.08.022

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The half size hardware-in-the-loop simulation of platform vibration is essential to verify the key technologies of high precision compound axis acquisition/tracking/pointing (ATP) system in free space laser communication. On the basis of analyzing the vibration power spectra of platform, a simu?lation experimental system was established based on MATLAB/ Simulink. The vibration time-domain signals and power spectra of platform were given by the half size hardware- in-the-loop simulation. It was proven in CCu closed loop detection that the simulation result of platform vibration is real and available. The simulation vibration signal of platform was used as an exciting signal of ATP system to accomplish the lab verification of ATP system under the conditions of simulation vibration and move?ment.

Research on Calibration Technology and Device for Cupping Test Machines

CHEN Ji, ZHOU Zhaofeng, CAO Jiu-da,YE Jin-cheng

2008, 29(8): 1004-1008. doi:10.3969/j.issn.1000-1093.2008.08.023

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In order to solve the calibration problem of cupping test machine, a portable calibration mea?suring device was developed by a new exclusively developed multi-component force sensor, a specially designed grating gauge head and a three coordinate grating signal processing and frequency multiplica?tion card with complex programmable logic device as well as a calibration software. The calibration- measuring device can be used to measure the operational parameters of cupping test machine, such as clamping force, stamping stress, cupping indication and relative position among die mold, die pad and plunger chip, to resolve the calibration issues of clamping force and azimuth error. It was found in ex?periment that most of tne azimuth errors of clamping force are relatively large, which is consistent with the crack of test piece appearing around die mold.

Research on the Influencing Factors of Vibroacoustic Characteristics of Cylindrical Shells Based on Statistical Energy Analysis

LI Bing-ru, WANG Xuan-yin, GE Hui-Iiang

2008, 29(8): 1009-1015. doi:10.3969/j.issn.1000-1093.2008.08.024

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The statistical energy analysis is mainly used for the analysis of high frequency vibration of structure. The influencing factors of high frequency vibration and acoustic radiation characteristics of cylindrical shell were investigated based on the statistical energy methods. A statistical energy model was established for an underwater cylindrical shell system with the flute excited by external force, and the methods of determining the relevant parameters were given. The effects of the change of shell pa?rameters on the acoustic pressure of acoustic cavity in the flute, the surface vibration of cover plate and the near field acoustic pressure out of the cover plate were discussed. rhe analysis results show that the material, length, thickness and damping factor of cylindrical shell nave the great effects on the above mentioned vibro-acoustic radiation characteristics of cylindrical shell, especially its damping factor and thickness. The influencing factors should be synthetically considered in the design of acoustics struc?ture.

Optimization Analysis of Running Time of Test Software Based on Test Task Handle

WANG Cheng, WANG Wei-guo, MENG Chen

2008, 29(8): 1016-1018. doi:10.3969/j.issn.1000-1093.2008.08.025

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The major factors affecting the running time of test software were analyzed. A dynamic management method of task handle was proposed ? The method is to create all task handles dynamically and to manage them using the data structure of chain to facilitate later inquiry and utilization and to minimize the effect of frequent creation of task handles on the running time of test software greatly. This method can improve the overall design of test software, and optimize the running time of test soft?ware so that the requirements of most real time tests can be met without additional hardware design.

calculation of Bending Fatigue Strength of Helical Gear JTooth Root Based on Ship Hull Deformation and Interteeth Friction

LI Xiu-Iian

2008, 29(8): 1019-1024. doi:10.3969/j.issn.1000-1093.2008.08.026

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The hogging or sagging deformation of boat hull may be due to water buoyancy and resis?tance, gravity and inertia of ship while a ship navigates by water. The research results have shown that the deformation can result in changing the center distance of bearing supports of the gearing ar?ranged along the ship longitudinal direction. Under certain conditions, this change of the center dis?tance affects the meshing performance of helical gearing, ana leads to the reduction in the gearing life. In addition, the effect of interteeth friction on gear strength could be neglected, but it ’ s not the case for the helical gear fixed in boat. The optimal calculation equations for the bending fatigue strength of tooth root caused by the deformation of ship hull and interteeth triction were deduced by analyzing the forces exerted on the driving gear of helical gear drive. The calculation results show that the hull defor?mation and the interteeth friction have the great effect on the tooth strength.

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