Table of Content

31 July 2010, Volume 31 Issue 7

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Paper

Research on Mobile Survivability of Integrated Missile-Gun Air Defense System

HUANG Da-rong， JIANG Hui

2010, 31(7):  881-886.  doi:10.3969/j.issn.1000-1093.2010.07.001

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A new method to evaluate the mobile survivability of integrated missile-gun air defense system was researched by analyzing the structural model of the indexes of system of air defense weapon system in detail and using the analytic hierarchy process (AHP) and the matter element theory. Based on the definition of its mobile survivability, the index-evaluation system of its mobile viability was constructed according to the system structure. The evaluation model of its mobile survivability was established based on the basic concept and evaluation rules of element theory and AHP. Its mobile survivability was simulated to validate the rationality and validity of the evaluation model according to the empirical data in actual engineering application. The simulation results show that the model can provide the effective basis for mobile survivability assessment of air defense weapon system.

Numerical Simulation of Airflow and Structure Optimization for Shutters of Tracked Vehicles

SUO Wen-chao， BI Xiao-ping， LV Liang-dong

2010, 31(7):  887-891.  doi:10.3969/j.issn.1000-1093.2010.07.002

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For reducing the pressure drop and the weight, enhancing the barrier capability

Experimental Research on Heat-transfer Characteristics of Ethanol Solution at Room Temperature

WU Jiang-hong， LI Cheng，XIAO Fei， WANG Xi-hui， TANG Yong-bai

2010, 31(7):  892-895.  doi:10.3969/j.issn.1000-1093.2010.07.003

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Based on the research on rotating magnetic refrigerator prototype developed by Sichuan University，it experimentally studied the heat transfer characteristics of ethanol-water and water in the active magnetic regenerator(AMR), discussed the thermal storage mechanism of room temperature magnetic refrigerator of which the heat transfer fluid has different physical properties, and analyzed the temperature distribution of AMR wheel which was effected by refrigerant disk rotational speed，heat transfer fluid flow，temperature and other parameters. It is concluded that the ethanol-water used to replace water as a heat exchanging fluid is conducive to increase the permeability of porous media，so the temperature of the wheel decreases，a larger temperature gradient is achieved at the cold-side of the system and the system's cooling power is increased by 6%. When the ethanol-water with 10% concentration is replaced with the ethanol-water with 50% concentration，the system cooling capacity can be higher than 20 W and the cold-side temperature drop can be higher than about 0.3 K.

Application of the Level Set Method for Propagation of Non-ideal Detonation Wave

JIANG Yang, ZHONG Min, SUN Cheng-wei, LI Ping, BAI Jin-song

2010, 31(7):  896-900.  doi:10.3969/j.issn.1000-1093.2010.07.004

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In order to compute the propagation of non-ideal detonation wave

Target Identification of High-Resolution Millimeter Wave Radar

LUAN Ying-hong， LI Yue-hua

2010, 31(7):  902-905.  doi:10.3969/j.issn.1000-1093.2010.07.005

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Since fractional Fourier transform（FrFT）is a mixed expression of signal in time-frequency domain, the discrete fractional Fourier transform（DFrFT）and relevance vector machine were introduced into one-dimension range profile identification of high-resolution millimeter waves（MMW）radar. The order α of discrete fractional Fourier transform was confirmed by Fisher criterion. The features of range profiles were extracted by discrete fractional Fourier transform at order α and classified by the relevance vector machine（RVM）network. The experimental results show that the method is feasible and has higher recognition probability.

Decentralized Adaptive Sliding Mode Decoupling Control Scheme for Bank-to-turn Missile

ZHANG Ying-xin， DONG Chao-yang， WANG Qing， CHEN Yu

2010, 31(7):  906-910.  doi:10.3969/j.issn.1000-1093.2010.07.006

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For the strong kinematic，pneumatic and inertia coupling among three channels of bank-to-turn（BTT）missile, a decentralized adaptive sliding mode control scheme is proposed. Based on the idea of decentralized control, the BTT missile control system is divided into three associated subsystems. A model reference adaptive sliding mode controller based on the local measurement was designed for each subsystem. Considering the conjunction of the three channels, a coordination loop was designed and the parameters of local decentralized controllers were regulated to guarantee the global asymptotic stability and realize the decoupling control. The adaptive sliding mode controller has strong adaptability and robustness for the modeling uncertainty and the pneumatic parameter variation under a high angle of attack flight condition. Compared to traditional decoupling control method, the decentralized control does not need extra measurement of the coupled item, which is beneficial to the practical application. The simulation results demonstrate that the system tracks the maneuver commands well and satisfies the requirements of BTT control.

Autopilot Robustness Analysis of Air-to-Air Missile

ZHANG Min， CHEN Xin， LU Yu-ping

2010, 31(7):  911-915.  doi:10.3969/j.issn.1000-1093.2010.07.007

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The uncertainty and disturbance models were established using μ-syntheses for the large envelope, complex flight environment and dramatic changing aerodynamic parameters of next-generation air-to-air missile. The performance weighting function was selected for the non-minimum phase characteristics of overload control. The nominal performance, robust stability and robust performance of PID controller, H_∞ controller and μ controller were analyzed according to a unified robustness criterion. Autopilot performances in the frequency domain and time domain were compared. The results show that the μ-synthesis autopilot has the best overall performance.

Research on the Leak Current Fault Diagnostic Technology for Launch Vehicle

ZHAO Gang， HUANG Da-rong， HUANG Xi-yue

2010, 31(7):  916-921.  doi:10.3969/j.issn.1000-1093.2010.07.008

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A new leak current fault diagnosis method of Launch Vehicle (LV) was researched by combining connection number of set pair analysis and fault tree analysis（FTA）. Every kind of factors, which could make the leak current fault of LV, was analyzed in detail. Then a fault tree model of LV leak current was constructed according to every possible combination way of these factors, which can impact on LV leak current fault. An attribute significance model of factor influencing leak current fault was presented, and a leak current fault diagnostic technology of LV was established by introducing the intermediate probability and the theory of connection number of set pair analysis. An example of LV leak current fault diagnosis was given to verify the reliability and effectiveness of the model. The simulation results show that the model was easy to find the weakness of system, so it has better updating capability and applied prospect.

The Envelope Soliton in a Elastic Cylindrical Shell Subjected to Axial Compression and Its Existent Conditions

ZHOU Yi-qing， ZHANG Shan-yuan

2010, 31(7):  922-926.  doi:10.3969/j.issn.1000-1093.2010.07.009

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A nonlinear partial differential equation governing the transverse axial symmetrical motion of a elastic cylindrical shell in axial compression was derived using circumferential logarithmic strain definition. The reductive perturbation method was used to derive a nonlinear equation from the nonlinear flexural wave equation. It follows that the existence of the envelope soliton in the cylindrical shell is possible under certain conditions. The bright and dark solitons can be formed depending on the situated sections of load-parameter λ and wave-number k in λ－k plane.

Research on the Structure and Wear Resistance of Colmonoy 6 Alloy Coating Cladded on Austenitic Stainless Steel by Laser

SHI Yan， ZHANG Hong， XU Chun-ying

2010, 31(7):  927-932.  doi:10.3969/j.issn.1000-1093.2010.07.010

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It investigates cladding Colmonoy 6 powder on AISI316L austenitic stainless steel by CO₂ laser in order to improve its wear resistance property. And its microstructure, microhardness, the friction and wear characteristics were systematically studied by means of SEM, EPMA, XRD, microhardness tester as well as friction and wear tester. It is found that preheating is necessary for preventing cracking in the laser cladding procedure and 450 ℃ is the proper preheating temperature. the microstructure of the laser clad layer is featured with densities and composed of γ-Ni, M₂₃(CB)₆, BNi₃ and CrB. The friction and wear test reveals that the clad layer has not only low friction coefficient, but also high wear resistance compared to those of substrate, which reveals that laser cladding layer plays roles on wear resistance.

Properties of Laser Cladded Ceramic Composite Coating on Plastic Mould

LUO Fang， CHEN Zhi-jun， LOU Cheng-hua， CHAI Guo-zhong

2010, 31(7):  933-938.  doi:10.3969/j.issn.1000-1093.2010.07.011

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In order to improve the micro-hardness and wear resistance of clad layer, the ceramic composite of amorphous nano Al₂O₃，WC，TiC is pre-placed on P20 base metal and then treated by a CO₂ laser. The microstructure, micro-hardness and the wear resistance of the laser cladding composite layer were studied respectively. The results show that the elements of the base and clad layer diffuse and react each other, which lead to the formation of hard phases of WC, Al₂O₃ and FeSi in clad layer with great hardness and good wear resistance. The worn surface of the clad layer has the fine scratches on it, which appears a grain abrasion.

Comprehensive Review

Research Progress of Intelligent Control Systems of Aerocrafts

KE Fang， Neusipin K A

2010, 31(7):  939-949.  doi:10.3969/j.issn.1000-1093.2010.07.012

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The research progress of intelligent control systems of aerocrafts was analyzed and summarized. The varied types of adaptive control systems of aerocrafts based on dynamic expert systems and the “advice” control systems of aerocrafts widely used currently were discussed. The development trends of intelligent systems were analyzed, and the most perspective intelligent system based on theory of functional systems proposed by Anokhin P K was suggested. The scheme diagram of intelligent system was given. The constructional problems of prediction and control algorithms, target synthesis and dynamic expert system, which are the key blocks of intelligent control system, were discussed in detail. The latest sucsesses of functional-intelligent system for control of aerocrafts were presented with description of system scheme and realization process of key parts. The simulation results of system performance was demonstrated. The developing advices of effective intelligent control system which has a favourable performance in actual application were proposed based on the analysis of the structure and algorithms of intelligent control system.

A Review on the Mass Loss of Projectile

HE Li-ling， CHEN Xiao-wei， XIA Yuan-ming

2010, 31(7):  950-966.  doi:10.3969/j.issn.1000-1093.2010.07.013

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The underground targets are usually protected by reinforced concrete and rocks. When they are attacked by projectile, the structure of projectile should keep integral, therefore, an assumption of non-deformable projectile is usually employed in the analysis of terminal ballistics. However, with the impact velocity increasing, the mass loss of projectile becomes unavoidable and it is not proper to treat it as rigid any more. The mass loss of projectile may induce the instability of terminal ballistics of penetrator, and lead to its damage or structural failure. Therefore, it is necessary to study the mechanism of mass loss of projectile. Abrasion and local erosion are supposed as the main reasons of mass loss. A review on mass loss of penetrator, including experimental results, empirical and theoretical analyses and numerical simulations, is presented as it penetrating into cementitious target (concrete, rock, etc.). Finally, some research proposals are given for the further study.

Research Notes

Numerical Simulation and Analysis on Power of Anti-Tank Belly Mine

GUO Shi-gui， ZHANG Zhong-ying， LIU Zi-li， LIU Yun-jian

2010, 31(7):  967-970.  doi:10.3969/j.issn.1000-1093.2010.07.014

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The effects of the secondary fragment groups at three energy levels, the fragment groups at different parameter level and the fuse on mine power as well as the anti-mine ability of vehicles were quantitatively analyzed using the anti-tank belly mine power calculation software based on the former test and the assumed data. The power estimate formula was set up according to the third energy level diameter. In general, the fragment group parameter level is in proportion to the power, and the third energy level has a remarkable effect on power. Now, 3%～5% power is offered by fuse, new belly material can reduce the power effectively.

Condition Detection of Diesel Engine Cylinders Based on Continuous Wavelet Transform

FAN Xin-hai， WANG Zhan-jun， AN Gang， FENG Fu-zhou

2010, 31(7):  971-974.  doi:10.3969/j.issn.1000-1093.2010.07.015

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To realize the non-disassembly detection of working diesel engine cylinders of armored vehicle，the misfire fault was simulated in an actual vehicle，noise signals nearby a vent in different states were measured. The low frequency component of periodical exhaust noise with obvious characteristics of amplitude demodulation was acquired by using continuous wavelet transform (CWT) under appropriate scale. Hilbert transform amplitude demodulating approach was used to extract the variance of the maximal amplitude normalized envelope signal as characteristic parameter，and a new method was presented for the working uniformity evaluation and misfire detection of diesel engine cylinders. The experimental results show that this method is effective and feasible.

A Study on the Mechanism of Ceramic Composite Target with 3D Constraints Against Non-Central Impact of30mm Projectile

LIU Fei， JIANG Zhi-gang， SHEN Zhi-qiang， ZENG Shou-yi

2010, 31(7):  975-981.  doi:10.3969/j.issn.1000-1093.2010.07.016

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The penetration process of ceramic composite target with 3D constraints against non-central impact of 30mm projectile was simulated based on ballistic experiments. Emphasis was laid on the effect of impact point on the anti-shell capability and mechanisms. The study shows that, in the effective protective area, the impact point has little effect on the penetration resistance and the energy dissipation of backing plate, thus it has a little effect on the limit velocity, and that both the penetration resistance and the energy dissipation of backing plate decrease with the increase in the eccentric ratio beyond the effective protective area, so the anti-shell capability decreases rapidly.

A New Estimation Algorithm of Direction-of-Arrival

CUI Wei， TAO Jian-wu， XU Hui-bin

2010, 31(7):  982-986.  doi:10.3969/j.issn.1000-1093.2010.07.017

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Most existing direction-of-arrival (DOA) estimation methods based on long vector for electromagnetic sensor generally need a high-dimensional searching process. Since the searching process is complex, these methods are limited in practical applications. A new estimation algorithm of DOA was proposed based on quaternion model in this paper. The signal output model based on quaternion was set for electromagnetic sensor. Based on the quaternion model, only DOA parameters rather than polarization parameters exist in the direction matrix. Thus, the high-dimensional searching process is replaced by the low-dimensional process in the proposed DOA estimation algorithm so that the amount of computation is heavily reduced. The effectiveness of the algorithm was confirmed through computer simulation.

Research on Attitude Algorithms for Spinning Projectiles

LI Hai-tao， CAO Yong-hong， ZU Jing

2010, 31(7):  987-990.  doi:10.3969/j.issn.1000-1093.2010.07.018

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An integrated test system with accelerometers and magnetometers was proposed to solve the problem of the accelerated accumulation of navigation errors in the attitude measurement of spinning projectiles. An attitude algorithm based on quasi-Newton method was used for a twelve-accelerometer configuration. The simulation results show that the algorithm can suppress the accumulation of errors effectively and meet the requirement of navigation accuracy.

Research on Laser Welding of 30CrMnSi Steel

SHI Yan， LIU Jia， ZHANG Hong， LIU Shuang-yu

2010, 31(7):  991-997.  doi:10.3969/j.issn.1000-1093.2010.07.019

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The laser welding technology of 30CrMnSi steel welded by CO₂ laser was studied in order to reduce its welding deformation and improve its welding efficiency. The microstructure, microhardness and tensile strength of the welding joint were systematically studied by means of SEM, microhardness tester as well as material testing machine. It is found that the welded joint is divided into five parts, such as welding seam zone, heat affected zone, matrix and interface zone between welding seam and heat affected zone, interface zone between matrix and heat affected zone. The microhardness increases from the center of welding joint to the two sides, and is maximized at the interface between the welding seam and heat affected zone. Then it begins to decrease fast at the interface between the heat affected and matrix zone. And the microhardness is minimized at the matrix. The faster the welding speed is, the higher the microhardness of welding seam is, and the narrower the width is. The deformation decreases with the increase in welding speed. The deformation within 100mm length is about 0.1 mm when the laser power is 4 kW and welding speed is 8m/min. The tensile strength of the welded joint is 110~170 MPa higher than matrix. The matrix bears a ductile fracture, and the fracture presents a dimple. A brittle fracture appears in the heat affected zone , and the quasi-cleavage fracture is presented. The tensile strength of the heat affected zone has a decrease tend with the increase in welding speed.

Research on the Maintainability Information Model Based on VR

YU Hai-quan， PENG Gao-liang， LIU Wen-jian

2010, 31(7):  998-1002.  doi:10.3969/j.issn.1000-1093.2010.07.020

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In order to solve the problem that maintainability design is lagged behind struc

Experimental Research on the Determination of Human Body Surface Reachable Grade

DONG Da-yong₁， WANG Li-jing₁， YUAN Xiu-gan₁， CHEN Xiao₂， ZU Yuan

2010, 31(7):  1003-1008.  doi:10.3969/j.issn.1000-1093.2010.07.021

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A concept of human body surface reachable grade was presented according to the s