Table of Content

31 January 2011, Volume 32 Issue 1

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Paper

Investigation on Dynamic Response of Sandwich Plate to the Impact of Cellular Metallic Projectile

SONG Yan-ze， WANG Zhi-hua， ZHAO Long-mao， ZHOU Zhi-wei

2011, 32(1):  1-7.  doi:10.3969/j.issn.1000-1093.2011.01.001

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Dynamic response of the clamped sandwich plate impacted by cellular metallic projectile was investigated using experimental and finite element methods. Effects of the projectile impulse, the faceplate thickness, the thickness of core player and different core layers on the shock resistance performance of structure were discussed. The results indicate that the permanent deformation of the back faceplate is effectively controlled to improve the shock resistance capability of sandwich plate by increasing the thickness of faceplate or core layer. It is also found that the improved shock resistance capability can be obtained by increasing the thickness of core layer rather than the thickness of faceplate. The results obtained reveal that the sandwich plate is superior to the monolithic solid plate with the same mass in shock resistance, and the sandwich plate with honeycomb core layer is superior to the aluminum foam sandwich plate with the same mass in shock resistance.

Theoretical Research on Structures and Detonation Performance for Nitro Derivatives of Triazole

LEI Feng-bin， ZHU Jia-ping， CAO Duan-lin

2011, 32(1):  8-16.  doi:10.3969/j.issn.1000-1093.2011.01.002

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Twenty-one nitrotriazole compounds and its derivatives were calculated by density functional theory. Their optimized geometries and electronic structures were computed at the B3LYP/6-31+G (d, p) level. The optimized geometries of these compounds show that they have no imaginary frequencies, and they are stable on the potential energy surface. The heat capacity and enthalpy of some representative compounds at different temperatures were obtained by statistic thermodynamics. In order to calculate the standard enthalpies of formation for the derivatives of nitrotriazole, the isodesmic reactions were designed. The average molar volume and theoretical density were estimated using the Monte-Carlo method based on 0.001 e·bohr^-3 density space. Furthermore, the detonation velocity and pressure of the derivatives were estimated using the Kamlet-Jacbos equation. The results show that the ring of triazole has some aromaticity and the detonation velocities of these compounds are between 7.08 and 9.53 km/s. Detonation performance shows that these compounds are very good candidates for energetic material.

Method for Solving Integrated Evaluation Problems of Multi-criteria Indicator Based on Diversity Projection

LI Ming-hui， XIA Jing-bo， HAN Zhong-xiang， TAO Xiao-yan

2011, 32(1):  17-22.  doi:10.3969/j.issn.1000-1093.2011.01.003

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The multi-criteria integrated evaluation problems with known weight information were investigated. Based on the diversity projection, a new integrated double weights evaluation method was proposed. This new method was used to analyze the problems of the diversity and projection aspects, integrating the real number, interval number and triangular fuzzy number, and creating the indicator evaluation matrices. Firstly the weight matrix was acquired according to the weight vector, then the standard indicators required based on the predominance and the diversity coefficient were figured out, and the diversity evaluation matrices were got. Then all the alternatives were ranked according to the projection of idea points. The evaluation principle and implementation steps of the method were given. Finally, a numerical example of military communication network running quality integrated evaluation was given to illustrate the method very effective.

The Effect of Phase Difference of Linear Signal and the Control Signal on the Periodical Mean Force

WANG En-de， ZHU Feng， XIAO Yang-hui， TONG Xin-xin， ZHU Dan

2011, 32(1):  23-27.  doi:10.3969/j.issn.1000-1093.2011.01.004

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The method of single channel control is often used in spinning missile. It expatiated on the causation of the periodical mean force, and gave the specific ways to get the direction and the magnitude of the force. The current linear method for controlling the spinning missile was also described. By analyzing the effect of phase difference between the linear signal and the control signal on the periodical mean force, it is concluded that the magnitude and the direction of the periodical mean force are both affected by the phase difference, and the period is π, further more, it gives out the precise changing rule, the maximum bias angle of the periodical mean force is 8.8°, and the maximum amplitude of the period mean force is 3 times of the zero phase difference condition. The conclusions are the important theoretical basis for the reasonable control of missile.

Research on Effect of Seeker Disturbance Rejection Rate with Phase Lag on Stability of Parasitical Loop

DU Yun-li， XIA Qun-li， QI Zai-kang

2011, 32(1):  28-32.  doi:10.3969/j.issn.1000-1093.2011.01.005

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In order to analyze the effect of disturbance rejection rate on stability of the guidance system, the conception of seeker disturbance rejection rate parasitical loop was presented. A model of parasitical loop of seeker disturbance rejection rate was established based on the phase lag of seeker disturbance rejection rate. When the parasitical loop is feedforward and feedback, the stability zone of the parasitical loop is obtained based on the Routh criteria and the normalized model. The effect of phase lag on stability zone was analyzed in complex frequency domain. Simulation results show that the phase lag of seeker disturbance rejection rate reduces the stability zone. The smallest stability zone occurs at about -140° phase lag instead of -180°. As a result , it is helpful for the engineers at the preliminary stage of missile design.

Error Analysis and Compensation Methods for Geomagnetic Signal Detection System

HUANG Xue-gong，WANG Jiong

2011, 32(1):  33-36.  doi:10.3969/j.issn.1000-1093.2011.01.006

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High-precision, high-resolution magnetic signal detection is the basis of geomagnetic matching navigation. A three-axis magnetic sensor error model and the synthesis error model for hard -iron and soft-iron magnetic interference were built based on the analysis of the error sources of the geomagnetic signal detection system. An ellipsoid fitting correction algorithm based on the character that the geomagnetic vector is constant at a fixed point was presented. The experimental results show that the ellipsoid fitting method can suppress and compensate the errors caused by the geomagnetic sensor and the external environment effectively, including errors caused by zero offset and scale factor, nonorthogonality and misalignment errors, and the hard-iron and soft-iron magnetic interference around the geomagnetic sensor.

Numerical Simulation and Performance Analysis on Start Process of Missile Turbojet Engine Windmill

YANG Xin-yi， SHEN Wei， LIU Hai-feng， DONG Ke-hai， WANG Yong-hua

2011, 32(1):  37-44.  doi:10.3969/j.issn.1000-1093.2011.01.007

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A new simulation strategy was proposed for the start process of missile turbojet engine windmill according to its characteristic. The simulation consists of two phases: the windmill process before ignition and the acceleration process after ignition. The former is simulated using radial basis function networks (RBFN)，and the latter which model is a set of nonlinear equations is solved using particle swarm optimization (PSO) algorithm. The introduction of PSO helps to solve the divergence problem of nonlinear equations caused by traditional iteration method when the initial condition is far from real solution. The results are in agreement with test data, which shows that the presented model has a higher accuracy. The start processes at the different ignition times were simulated, and the results were analyzed synthetically. The analysis shows how the ignition time affects the acceleration performance of the engine windmill start, which provides a theoretical foundation for igniting time optimization.

Fuzzy Logic Adaptive Compensation Control of End-effect Montion and Flexible Vibration for Space-basedFlexible Manipulator

LIANG Jie， CHEN Li

2011, 32(1):  45-57.  doi:10.3969/j.issn.1000-1093.2011.01.008

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It discusses the control problem of space-based flexible manipula

Effect of Loading Rate on Dynamic Fracture Behavior of Mg-8%Li Alloy

SHA Gui-ying, YU Tao, WANG Hong-shun, WANG He-nan， SUN Xiao-guang

2011, 32(1):  58-62.  doi:10.3969/j.issn.1000-1093.2011.01.009

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The dynamic fracture experiments of Mg-8%Li alloy were carried out with the Hopkinson pressure bar, and the dynamic fracture behavior and its loading rate effects of the alloy under high-speed impact were investigated. The results show that the fracture micro-mechanism of Mg-8%Li alloy is ductile fracture under high-speed impact condition, and there are a lot of dimples in the fracture surface. With the increase of loading rate from 14.27 m/s to 21.33 m/s, the dynamic fracture toughness of the alloy reduces gradually, and the number of secondary crack in fracture surface increases obviously to make the alloy behave brittle fracture tendency at high loading rate.

Optimization Method of Heat Treatment Parameters for Austempered Ductile Iron

WANG Hong， GUO Xu-hong ， WANG Wei

2011, 32(1):  63-68.  doi:10.3969/j.issn.1000-1093.2011.01.010

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Austempered ductile iron (ADI) is a performance designable material. The optimization design of its heat treatment parameters is the key to develop a good performance ADI material. The fuzzy subtractive clustering function model about the heat treatment parameter and mechanical properties was built using experiment data on the base of no changing the production conditions of heat treatment, various ADI samples with test data of different mechanical properties were made at the different austempering temperatures and time. The heat treatment parameters were chosen by taking tensile strength, impact toughness and hardness as objective of customer's demand, taking austempering temperature and time as designable variables, and using the NSAGⅡgenetic algorithm as optimization algorithm. The results show that this method can satisfy the parameters of heat treatment required by mechanical properties ASTM grade 3 and 4，and can get the best prediction austempering temperature and time ,which are respectively 333 ℃，136 min and 312 ℃，132 min.

Instantaneous Correlation Integral Algorithm and Application in the Detection of the Line Spectrum

ZHANG Guang-pu， LIANG Guo-long， FAN Zhan， FU Jin

2011, 32(1):  69-73.  doi:10.3969/j.issn.1000-1093.2011.01.011

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A new method of the line spectrum detection was derived from the Wigner-Vill transform. The principle of the instantaneous correlation integral algorithm was illustrated. The effect of the algorithm on the line spectrum component and noise component under high speed movement condition was analyzed theoretically. The process gain of the algorithm was analyzed. The results of simulation and lake trial proved that the instantaneous correlation integral algorithm can eliminate the effect of Doppler and the cross-term interference effectively. The algorithm can be applied to the detection and estimation of the line spectrum widely.

Theoretical Calculation and Experimental Study of Load Sharing for Double Helical Gears

WANG Cheng₁， FANG Zong-de₂， JIA Hai-tao₃

2011, 32(1):  74-77.  doi:10.3969/j.issn.1000-1093.2011.01.012

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According to transmission feature of double helical gears, based on tooth contac

A New Fusion Method for Conflicting Evidence

PENG Ying， SHEN Huai-rong，MA Yong-yi

2011, 32(1):  78-84.  doi:10.3969/j.issn.1000-1093.2011.01.013

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A new method of evidence fusion with high degree of conflict was proposed for the deficiency of conflicting handling by Dempster's rule. Evidence is classified into three categories: evidence of reliability, evidence of no conflict, evidence of conflict. The influence of these three categories of evidences on fusion results when discounted are analyzed respectively. On these bases, belief distance and conjunctive conflict are utilized in a sequence to distinguish the evidence of reliability and the evidence of no conflict. The discounting factors of these two categories of evidences are set to one, which keeps the evidences hold the right hypothesis to a great extant and makes the fusion results focus onto the right hypothesis more strongly. Examples of some missile fault diagnosis show the superiority of the new method in fusing conflicting evidences as well as reliable evidences. The new method improves the reliability and rationality of fusion results compared with traditional methods.

Mechanism Dynamics for Satellite Antennas Based on Spatial Operator Algebra Theory

YOU Bin-di, ZHAO Zhi-gang, WEI Cheng, ZHAO Yang

2011, 32(1):  85-90.  doi:10.3969/j.issn.1000-1093.2011.01.014

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The two-axes position mechanism of a satellite antenna is a free-floating space rootless and multi-body system. Based on the need of dynamics real-time simulation and control system design, spatial operator algebra (SOA) theory is applied to the multi-body systems modeling and simulation. The dynamics recursion and solution algorithm of SOA is proposed, and the object-oriented idea is utilized to define the data structure of the multi-body system, and to design the flow-chart of the dynamical calculation. This method is heuristic, easy to derivate, and has clear physical sense and O(n) computational efficiency. Through comparison with Simpack simulation results, it shows that, the multi-body dynamic algorithm of SOA has higher simulation accuracy and faster computation speed.

Target Tracking Based on Modified Particle Filter Algorithm in Glint Noise Environment

LIU Wang-sheng, LI Ya-an

2011, 32(1):  91-95.  doi:10.3969/j.issn.1000-1093.2011.01.015

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Due to strong nonlinear and non-Gaussian nature of the target tracking system, a strong tracking particle filter (STUPF) algorithm is presented. The algorithm adopts a new proposal distribution combining the unscented Kalman filter (UKF) with the strong tracking filter (STF), the filter gain matrix can be adjusted on line according to the change of innovation, and the ability of tracking saltatory state is improved. The STUPF is applied to track several kinds of typical target moving model tracking systems based on the glint noise statistical model, compared with UKF and UPF. The simulation results show that STUPF algorithm is valid in target tracking system in glint noise environment, and it indicates higher reliability and better accuracy compared with UKF and UPF algorithm.

Research Notes

Parametric Design on High Speed Aerocraft Composite Heat Insulation Layer Based on Genetic Algorithm

LIU Feng， LIN Bin， WANG Zhan-bin

2011, 32(1):  96-100.  doi:10.3969/j.issn.1000-1093.2011.01.016

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The heat insulation layer of composite materials for spacecraft was studied, and an optimization design proposal for its structure was presented based on the genetic algorithm and the finite element analysis (FEA) parameterization analysis. In the genetic

Design of Multi-point Ring Initiator for Shaped Charge

DUAN Zhuo-ping， WEN Li-jing， SHEN Jian， ZHANG Lian-sheng， WANG Qing-tao

2011, 32(1):  101-105.  doi:10.3969/j.issn.1000-1093.2011.01.017

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A multi-point ring initiator applying for shaped charge was developed

Effect of Structure Characteristic Parameters and Strain Rate on the Compressive Mechanical Properties ofAluminum Foams

WANG Yong-gang, WANG Chun-lei

2011, 32(1):  106-111.  doi:10.3969/j.issn.1000-1093.2011.01.018

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A series of uniaxial compression experiments of open-and close-cell aluminum foams were conducted by using a MTS hydraulic pressure machine and a split Hopkinson pressure bar (SHPB) at different strain rates. Results show that the quasi-static compressive behaviors of aluminum foams depend on the aspect ratio of the sample. With the decrease in the aspect ratio of the sample, the plastic yield stress becomes higher and the plastic yield plateau becomes smaller in length, which is attributed to the influence of the friction force between the end face of sample and the loading plateau. The density of aluminum foams has a significant influence on the quasi-static compressive behavior and results in the appearance of the smooth plastic plateau phase. With the increase in the density, the deformation mechanism is changed from the localized plastic collapse to the whole plastic yield. The plateau stress of aluminum foams shows an apparent strain rate dependence.

Synthesis and Characterization of BaFe₁₂O₁₉ Nanofibres Via an Electrospinning Technique

FAN Li-jia，DONG Xiang-ting，GAO Xv-bo，WANG Jin-xian，LIU Gui-xia

2011, 32(1):  112-117.  doi:10.3969/j.issn.1000-1093.2011.01.019

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PVP/\[BaCl₂+Fe(NO₃)₃\] composite fibers were synthesized by electrospinning, BaFe₁₂O₁₉ nanofibers were fabricated by calcinating of the prepared composite nanofibers. Thermogravimetric-differential thermal analyzer（TG-DTA）analysis revealed that the water，organic compounds and inorganic salts in the PVP/\[BaCl₂+Fe(NO₃)₃\] composite nanofibers were decomposed and volatilized totally, and the weight of the sample kept constant when sintering temperature was above 450 ℃, and the total weight loss percentage was 90.5%. X-ray diffraction （XRD）and Fourier transform infrared spectroscopy（FTIR）results showed that PVP/\[BaCl₂+Fe(NO₃)₃\] composite nanofibers were amorphous in structure, and pure phase BaFe₁₂O₁₉ nanofibers were obtained by calcinating of the PVP/\[BaCl₂+Fe(NO₃)₃\] composite fibers at 900 ℃ for 5 h. Scanning electron microscope（SEM）analysis indicated that the diameter of the prepared BaFe₁₂O₁₉ nanofibers was about 80nm, and its length was greater than 200 μm. The formation mechanism of the BaFe₁₂O₁₉ nanofibers was preliminarily discussed. This method can be applied to the preparation of other ferrite material nanofibers.

Research on Friction and Wear Testing of Pad Materials of Water-lubricated Thrust Bearings

WU Zhu-xin， LIU Zheng-lin， WANG Jun， YANG Jun

2011, 32(1):  118-123.  doi:10.3969/j.issn.1000-1093.2011.01.020

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The shipboard thrust bearing lubricated with water instead of lubricant has the advantages of energy saving, environment protection and extensive application. 3 kinds of materials, such as Ferofrm, ACM, and SF-1, were selected for the friction and wear tests to explore their different tribological performances in the various working conditions in order to screen out the pad materials of the water-lubricated thrust bearings. The test results indicate that the friction coefficients of these materials are evidently affected by load and rotation speed in dry friction. At a certain rotation speed, the wear amount of 3 kinds of materials enhances with increase in load, and the wear amount of ACM is least among them. In wet friction, their friction coefficients are significantly affected by rotation speed, but not clearly affected by load.

Optimal Switching Sequence for a Kind of Switched Systems

FANG Zhi-ming， XIANG Zheng-rong₁

2011, 32(1):  124-128.  doi:10.3969/j.issn.1000-1093.2011.01.021

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Referring to the relation between optimization and stabilization of sun-systems and whole-system, a kind of switched system with arbitrary number of sub-systems are investigated, in which, the switching number, switching sequence and switching instants are variable. It is indicated that the optimal switching sequence is the key of switched system optimal control. A kind of cost function which contains the switching number, switching sequence and switching instants is proposed. The cast function can be solved by using genetic algorithms and a group of switching number, switching sequence and switching instants, which make the cost function to be minimum, is obtained. A numerical example is provided to demonstrate the effectiveness of the proposed method.