Table of Content

30 July 2018, Volume 39 Issue 7

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Contents

2018, 39(7):  0. 

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Paper

Research on Penetration of Asymmetrically Grooved Nose Projectile into Concrete Target

DENG Jia-jie, ZHANG Xian-feng, LIU Chuang, PANG Chun-xu, WANG Wen-jie

2018, 39(7):  1249-1258.  doi:10.3969/j.issn.1000-1093.2018.07.001

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A projectile with asymmetrically grooved nose is proposed to further improve the penetration performance of projectile into concrete target. The projectile penetrates into target with passive rotation during the penetration. The asymmetrically grooved nose projectile is geometrically characterized under the polar coordinates. An extended quasi-static cylindrical cavity expansion model with tangential shear effect is constructed to estimate the normal stress on the surface of asymmetrically grooved-nose projectile by the quasi-static cylindrical cavity expansion model. The localized interaction models (LIMs) for the ultimate depth of penetration (DOP) of asymmetrically grooved nose projectile are derived based on the predicted normal stress. Comparative experiments of the asymmetrically grooved nose projectile and the ogive- nose projectile penetrating into semi-infinite concrete target are conducted. The analysis results prove that the LIM with extended quasi-static cylindrical cavity expansion model has a preferable estimating accuracy and is suitable for prediction of DOP of asymmetric groove-nose projectile. Compared with ogive-nose projectile, the asymmetrically grooved nose projectile has a better penetration performance.Key

Study of Optimal Model and Optimizing Method for the Electronically Controlled Air Suspension System Structure

LEI Qiang-shun, PENG You-yu, WANG Guo-sheng, WANG Chao, SONG Hui-xin

2018, 39(7):  1259-1267.  doi:10.3969/j.issn.1000-1093.2018.07.002

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For non-ideal stiffness curve, different attitudes or difficult adjustment of a tracked vehicle, which are resulted from improperly designed structure and parameters, a multi-objective target model for optimization structure of electronically controlled air suspension system (ECASS) is proposed based on the analysis of the characteristics indexes of ECASS as well as influence factors and constraints. The structure and parameters are optimized reasonably. The optimization design method and evaluation method are proposed. Research shows that both multi-objective optimization target model and evaluation method reflect the various requirements for whether designing in early or field running in later. The proposed method is suitable for optimizing and evaluating the hydro-pneumatic suspension with fixed cylinder or swing cylinder. Key

An Iterative Solution of Projectile-barrel Coupling Problem

YAO Tian-le， MA Ji-sheng， TAO Feng-he， QI Zi-yuan

2018, 39(7):  1268-1276.  doi:10.3969/j.issn.1000-1093.2018.07.003

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An iterative solution method for projectile-barrel coupling vibration problem is proposed for better numerical calculation of the projectile-barrel coupling vibration model. Through the kinetic analysis of the projectile-barrel coupling vibration, the continuous process of coupling vibration is discretized by discretizing the movement time of projectile in the barrel. Based on the theory of differential equations, the iterative method is used to solve the vibration of each point on the barrel when the projectile passes through the barrel, and then the continuous vibration caused by projectile moving is solved. Under the condition of the inertia effect of projectile and the curvature change of beam, constructing a stylized process for iterative solutions makes the method easier to implement numerical calculations. The proposed method is used to numerically solve the projectile-barrel coupling vibration model. The results show that this solution can quickly and effectively solve the problem of projectile-barrel coupling vibration.Key

A Nonlinear Combined Hardening Model for Residual Stress Analysis of Autofretted Thick-walled Cylinder

FU Shi-zhong， YANG Guo-lai

2018, 39(7):  1277-1283.  doi:10.3969/j.issn.1000-1093.2018.07.004

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In order to compute the strength and fatigue life of autofretted barrel exactly, a constitutive model which can reflect the material characteristics of gun steel, including Bauschinger effect and the nonlinear relationship between stress and strain, is constructed for improving the calculating accuracy of residual stress. On the basis of a nonlinear kinematic hardening model, a nonlinear combined hardening model which is used to describe the mechanical properties of autofretted barrel and calculate the residual stress distribution is proposed. According to the proposed constitutive model and the elastic-plastic relationship among parameters, a tensor-form consistent tangent modulus related to the constitutive model is derived for increasing the convergence speed of numerical calculation. To verify the constitutive model, the material parameters are determined by combining the tension compression tests and optimization algorithm. The residual stress of autofretted barrel is calculated by utilizing these parameters and FEA method. The difference between the calculated and experimental results is small. The results show that the proposed constitutive model can reflect the residual stress distribution of autofretted thick-walled cylinder effectively. Key

Experimental Research on Fragments after Explosively-formed Projectile Penetrating into Steel Target

WANG Xin, JIANG Jian-wei, WANG Shu-you, LI Mei

2018, 39(7):  1284-1290.  doi:10.3969/j.issn.1000-1093.2018.07.005

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A series experiments that the explosively-formed projectiles (EFPs) penetrate 10-40 mm-thick mild carbon steel (45# steel) were designed to investigate the effect of behind armor debris(BAD) after EFP penetrating into steel target. The morphology and scattering characteristics of BAD are observed by pulsed X-ray photography, and the number and damage ability of BAD are obtained by measuring the perforation on witness target. It can be seen from the pulsed X-ray photographs that the shape of BAD presented as fragments is of partial ellipse with the scattering angle of about 50°. The perforation on witness plate shows that BAD could penetrate 10mm-thick aluminum plate, the perforation distribution is relatively random, and the diameter of hole on witness plate approximately conform to normal distribution. The scattering angle varies little with the increase in the target thickness, while the number of BAD increases first and then decreases, namely there is a target thickness that maximizes the number of BAD. It can also be seen from recovered fragments that EFP and steel target debris together constitute the BAD.Key

Preparation and Performances of Nano-HMX and TNT Melt-cast Explosives Based on 3D Printing Technology

XIAO Lei, WANG Qing-hua, LI Wan-hui, LIU Qiao-e, HAO Ga-zi, GAO Xiang-dong, KE Xiang, LIU Jie, JIANG Wei, QIAO Yu, TAN Cheng

2018, 39(7):  1291-1298.  doi:10.3969/j.issn.1000-1093.2018.07.006

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3D printing technology is applied in the preparation of melt-cast explosives to solve the problems existing in traditional melt-cast explosives, such as more defects, low density, and poor mechanical properties, etc. An independently developed melt-cast explosive 3D printing principle prototype was used to prepare nano-cyclotetramethylenete-tranitramine (HMX)/2,4,6-trinitrotoluene (TNT)-based melt-cast explosives by selecting the melt-cast explosive formulas and adjusting the process parameters. And the microscopic structures, density, uniformity, compressive strength and detonation velocity of two kinds of melt-cast explosives prepared by 3D printing technology and traditional casting technology are characterized and compared. The results show that 3D printing melt-cast explosives have more compacting internal structures with the density of 1.65 g/cm³, the compressive strength of 5.56 MPa, and the detonation velocity of 7 143 m/s. The density, compressive strength and detonation velocity of 3D printing melt-cast explosive are improved by 2.0%; 273% and 2.1%, respectively, compared to the traditionally prepared melt-cast explosive. Key

Study of the Energy Release of CL-20/GAP-based Quaternary Explosive

ZHANG Wei, YAN Shi, GUO Xue-yong, REN Hui, JIAO Qing-jie

2018, 39(7):  1299-1307.  doi:10.3969/j.issn.1000-1093.2018.07.007

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CL-20 is one kind of high energy explosive with wide application prospect. The explosion energy of GAP/CL-20/oxidant/combustible agent quaternary system explosive is calculated to study its potential energy. The calculated results show that lithium perchlorate can be used significantly to improve the explosion heat, but the use of it in the cast explosive needs the further research on its modification. The samples of GAP/CL-20/AP/Al explosive were prepared, and the test method of underwater explosion was used to test and estimate its underwater explosion energy. The test results show that the energy density of the quaternary explosive can achieve the maximun with a CL-20 content of 15-20 wt%, and the explosion heat of CL-20 based GAP cast explosive can achieve the maximum when the Al/O is between 0.51-0.71 with a CL-20 content of 20wt%. According to the test data, the estimated energy density of the explosive can be up to 2.88 times of TNT equivalent.Key

Research on the Viscoelasticity-viscoplasticity-viscodamage Constitutive Model of Composite Modified Double Base Propellant

WANG Hong-li, XU Jin-sheng, LIU Zong-kui, TONG Xin, ZHOU Chang-sheng

2018, 39(7):  1308-1315.  doi:10.3969/j.issn.1000-1093.2018.07.008

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A viscoelasticity-viscoplasticity-viscodamage constitutive model is derived to characterize the complicated mechanical properties of composite modified double base (CMDB) propellant. The model parameters are obtained by a series of creep-recovery tests. Creep-recovery tests under different stress levels and loading times as well as some constant loading rate-recovery tests are done to verify the model. The test results show that the viscoelasticity-viscoplasticity-viscodamage constitutive model is capable of predicting the creep-recovery response and constant loading rate-recovery response of CMDB propellant. Compared with viscoelasticity-viscoplasticity constitutive model, the viscoelasticity-viscoplasticity-viscodamage model has a significant improvement in predicting the mechanical properties of CMDB propellant. The damage variable becomes steady gradually after it slowly increases first and then rapidly increases with strain. When the strain changes more slowly, the damage variable is larger, and the difference between the predicted results of the viscoelasticity-viscoplasticity-viscodamage model and the viscoelasticity-viscoplasticity model is greater.Key

Research on the Digital Platform for Hybrid Inertial Navigation System

WANG Lei， WANG Wei， LIU Zeng-jun， SONG Tian-xiao

2018, 39(7):  1316-1322.  doi:10.3969/j.issn.1000-1093.2018.07.009

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To simplify the platform structure of hybrid inertial navigation system and improve its reliabi- lity, a full digital platform is designed, including the structure and working modes. An algorithm of control command is designed to realize the new working mode of stabilization and rotation, and the calculation process from the original output data of gyroscopes to the angular velocity of motors is proposed. The algorithm is demonstrated in a prototype of hybrid inertial navigation system. The results indicate that, in stabilization and rotation mode, the control precision of digital platform is better than 2″ in stationary state and better than 30″ during moving.Key

Study of the Fragment Mass Distribution of Tempered Glasses Subjected to Blast Shock Waves Based on Dimensional Analysis

ZHONG Wei, TIAN Zhou, SHOU Lie-feng, LI Wei-chang, HE Zeng, PU Xi-feng, WANG Zhong-qi

2018, 39(7):  1323-1332.  doi:10.3969/j.issn.1000-1093.2018.07.010

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The secondary damage effect of tempered glass subjected to blast shock waves was researched through experiments, and the statistics of mass distribution of glass fragments were done in the experiments. The mass distribution of fragments is analyzed and researched according to the statistical results. A dimensionless function of the relationship between the fragment mass and the splashing distance is derived based on the dimensional analysis. According to the dimensionless function and the experimental statistical data, a semiempirical prediction formula to calculate the fragment mass distribution is obtained by employing the least square fit. The characteristics of the formula are analyzed, and its reasonableness and effectiveness are verified. The research result shows that the mass distribution laws of glass fragments are consistent for the tempered glasses with the same thickness in the same damage mode. Key

Experimental Study of the Characteristics of Internal Explosion Pressure and Power of Thermobaric Explosive

ZHANG Yu-lei， LI Zhi-rong， JIANG Hai-yan， ZHAI Hong-bo， YUAN Jian-fei， ZHONG Kai

2018, 39(7):  1333-1338.  doi:10.3969/j.issn.1000-1093.2018.07.011

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In order to study the internal explosion overpressure and power of thermobaric explosive (TBX), the calculation models of shockwave overpressure and quasi-static pressure are established through the theoretical analysis. TBX and TNT grains are tested in explosion vessel. The result shows that the pressure effect induced by internal explosion includes shockwave overpressure and quasi-static pressure. The rise of the quasi-static pressure is accompanied by the multiple reflections of shockwave. When the reflection is over, the quasi-static pressure goes up to the maximum and lasts for a relatively long time. The overpressure peak and quasi-static pressure peak of TBX are increased by 18.0% and 62.9%, respectively, compared with TNT. The TNT equivalents of TBX which are calculated based on overpressure and quasi-static pressure are 1.18 and 1.63, respectively. Key

Mathematical Description Method for Typical Embryonic Electronic System Structure and Performance

WANG Tao, CAI Jin-yan, MENG Ya-feng, ZHU Sai

2018, 39(7):  1339-1351.  doi:10.3969/j.issn.1000-1093.2018.07.012

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A mathematical description method for a typical embryonic electronic system (EES) is proposed to analyze and research EES from a mathematical point of view. EES functional function and working state function are established by analyzing the structure characteristics and working principle of EES. EES performance function is established based on the analysis of EES self-repairing ability and hardware consumption. EES mathematical description is achieved by using the established functional function, working state function and performance function. EES mathematical description method is used for the adjustment of EES function, the analysis of EES reliability, the evaluation of EES performance, the optimization of EES structure design, the slection of EES self-repairing strategies, and the research on EES preventive maintenance strategy. Research results indicate that the proposed EES mathematical description method can effectively describe the function, performance and working state of EES, which is able to carry out EES theoretical research from the perspective of mathematics.Key

Three-layer Multiple Kernel Fault Diagnosis Model with l_p-norm Constraint for Analog Circuit

ZHANG Wei， LIU Xing, XU Ai-qiang， PING Dian-fa

2018, 39(7):  1352-1363.  doi:10.3969/j.issn.1000-1093.2018.07.013

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In order to improve the fault diagnostic accuracy of analog circuit, an improved l_p-norm multiple kernel extreme learning machine (ELM) diagnostic model is proposed based on the feature selection algorithm with one-dimensional ambiguity among fault features. In this model, the weighted classification error is incorporated into kernel ELM optimized objective function, and then a three-layer multiple kernel learning framework is constructed based on adaptive boosting (AdaBoost) algorithm, in which the training sample weights are adaptively adjusted so that the every layer in the model can focus on the different training samples. The proposed model provides an excellent strategy to improve the identifiability of classifier. Experimental results of two analog circuits show that the proposed model can achieve approximately consistent diagnostic performance under the constraints of different norms. For a fault with a single attri- bute, the diagnostic accuracy can be significantly improved, meanwhile the missing alarm and false alarm can be effectively balanced. For a fault with multiple attributes, the faults which are difficult to be identified can be accurately isolated into relevant ambiguity groups. Key

Experimental Investigation into the Cavity and Ballistic Characteristics of Low-speed Oblique Water Entry of Revolution Body

LU Li-rui, WEI Ying-jie, WANG Cong, SONG Wu-chao

2018, 39(7):  1364-1371.  doi:10.3969/j.issn.1000-1093.2018.07.014

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The oblique water entry of revolution body is experimentally studied. Cavity evolution is discussed. The influences of head form on the water entry cavity, velocity, pitch angle and drag coefficient were experimentally obtained. The experimental results show that the diameter of water-entry cavity increases with the increase in the cone angle of the head, and the cavity formed by revolution body with elliptical head is smaller than that formed by revolution body with cone-shaped head. When the angle of cone-shaped head is larger, the attenuation rate of velocity of revolution body is larger. And the velocity of revolution body with elliptical head is always higher than that of revolution body with cone-shaped head. The pitch angle of elliptical revolution body changes greatly, along with an unstable trajectory. During the water entry of revolution bodies with different head forms, the kinematic parameters change non-linearily.Key

Test and Numerical Simulation for Annular and Linear Shaped Charge Projectiles Interfering the Penetrating Process of Long RodPenetrators

ZHANG Jin-hong， LI Ru-jiang, LIU Tian-sheng

2018, 39(7):  1372-1378.  doi:10.3969/j.issn.1000-1093.2018.07.015

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A new explosive reactive armor based on the structure of annular shaped charge is designed to further improve the protective performance of explosive reactive armor and the survivability of tanks on the battlefield, which is used to intercept the high speed and large length-to-diameter ratio rod penetrators. The process of annular explosively formed projectile (EFP) interfering on the rod penetrators is numerically simulated using the finite element software ANSYS/LS-DYNA, and both the process of annular EFP forming and the mechanism of interfering on the armor piercing projectile are analyzed. Under the same conditions, the processes of interfering on the rod penetrators by linear and annular EFPs are compared. The results shows that EFP with annular shaped charge has the higher defense performance. The effective penetration depth of long rod projectile is reduced by 32.5% compared to EFP with linear shaped charge, and the length of crater is increased by 10.4%. The long rod projectile is broken and yaws under the interference of annular EFP. The simulated results are in good agreement with the test results. Key

Numerical Simulation of Dynamic Response of Laminated Glass Subjected to Blast Load

ZHANG Xiao-ying, LI Sheng-jie, LI Zhi-qiang

2018, 39(7):  1379-1388.  doi:10.3969/j.issn.1000-1093.2018.07.016

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The dynamic response of laminated glass subjected to blast load is simulated using LS-DYNA finite element software in order to study the dynamic response of laminated glass under explosive loading. The rules in dynamic response of laminated glass are studied systematically by changing the thicknesses of the external and internal glasses without change of total thickness, the interaction between explosion pro- ducts is presented, the energy absorption efficiencies of different parts of the laminated glass are analyzed, and the crack propagation process is also observed. The results indicate that the variation of glass thickness has a clear effect on the dynamic response of structure at shorter explosive distance, and the influence, however, is slight with increase in explosive distance. Explosion products damage the glass before air shock wave does. The external glass has the maximum energy absorption efficiency, the PVB glue layer has the less, and the internal glass has the least. Under blast load, the laminated glass has most circumferential cracks and relatively few radial cracks on it. Key

Experimental Study on Grinding Stability of Superabrasive Grinding Wheel for Resin Bond

FENG Ke-ming, XING Bo, SHI Chao-yu, ZHU Jian-hui, ZHAO Jin-zhui

2018, 39(7):  1389-1396.  doi:10.3969/j.issn.1000-1093.2018.07.017

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Three key influencing factors of different resin raw materials, setting time of resin and radial position of abrasive layer are investigated for the poor stability of grinding properties of superhard resin bonding abrasives, and a resin diamond grinding wheel is used to grind a cemented carbide in test. The results show that the phenolic resin raw materials have a great influence on the grinding performance of grinding wheel, the ordinary resin is not suitable for carbide grinding, the heat-resistant resin is suitable for deep grinding, and the toughening resin is suitable for micro-depth cut grinding. The store time of phenolic resin has a certain influence on grinding performance, the grinding ratio decreases slowly with the extending of store time; and the radial position of abrasive layer has a special effect on the grinding performance. When the abrasive layer is above 1.0 mm in thickness, the grinding ratio changes little; when the abrasive layer is below 1.0 mm in thickness, the grinding ratio decreases obviously. Refining of making and grinding technologies of super-hard resin grinding wheel is beneficial to improve the stability of grinding performance. Key

On-line Detection of Gas Concentration during Weapon Firing Based on Tunable Diode Laser Absorption Spectroscopy

PENG Peng, DI Chang-an, ZHANG Yong-jian, CHEN Hao-fei, SONG Wei, YIN Qiang

2018, 39(7):  1397-1403.  doi:10.3969/j.issn.1000-1093.2018.07.018

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Electrochemical gas concentration detecting system can not meet the composition and concentration detection requirements of the harmful gas generated by weapon system during firing due to its low response speed and small dynamic range. An on-line detection method of CO concentration based on tunable diode laser absorption spectroscopy (TDLAS) which is suitable for weapon launch site is presented. The detection model of the weapon emission gas concentration based on TDLAS technology is introduced, an on-line detection system of CO concentration is built. The interference of gas jet and liquid water in tank to the CO concentration measurement is avoided by selecting and controlling CO absorption peak. A method is proposed to verify the on-line dynamic detection performance of TDLAS on CO experimentally, in which less dissipation of CO gas produced by a single soldier rocket in a limited space is made use of. The test and analyzed results show that the response rate of TDLAS gas concentration detecting system is 5-15 s faster than that of electrochemical sensor, and TDLAS effective range is up to 100% (volume ratio), which can take a rapid detection for continuous shooting. In addition, non-invasive detection overcomes the influence of impact vibration on the detecting system during launching of weapon system. Key

Hybrid Reliability Analysis of Structures Based on Taylor Expansion Method

MENG Guang-wei， WEI Tong-hui， ZHOU Li-ming， LI Feng

2018, 39(7):  1404-1410.  doi:10.3969/j.issn.1000-1093.2018.07.019

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A new reliability analysis method is proposed forhybrid uncertainty with both random variables and interval variables. The expression of the upper and lower bounds of structural function is obtained based on the Taylor expansion. By means of the dimensionality reduction method, the structural function is approximated as the sum of n one-dimensional variable functions. The fourth-order central moments of limit state function of structure are derived by utilizing the Taylor expansion. The upper and lower bounds of structural failure probability are obtained by using the fourth-order moment method. In the method, the distribution of random variables is not required, and the most probable failure point of iteration needs not to be solved. Several examples demonstrate that the proposed method has higher calculation accuracy and efficiency. Key

Gait Control of Quadruped Robot Driven by Pneumatic Muscle Based on Kimura Oscillator and Virtual Model

ZHANG Yun，GUO Zhen-wu，CHEN Di-jian，WANG Bin-rui

2018, 39(7):  1411-1418.  doi:10.3969/j.issn.1000-1093.2018.07.020

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Gait control is the key for quadruped robot adapting to complex terrain, for this purpose, gait controller is proposed for robot gait planning and control. For the quadruped robot driven by pneumatic muscles, the single-leg kinematic model is established based on Denavit-Hartenberg (DH) parameters. Kimura oscillator is used to design the central pattern generator (CPG) network of the quadruped robot gait, and the mapping among oscillator outputs and joint angles is improved. The cycloid function is used to plan the foot-end trajectory. Based on biological neural reflex mechanism and virtual model control (VMC), an adaptive gait controller for gully terrain is presented by taking the swing phase of limbs and the touchdown information of the feet as state switching conditions. Adams and MATLAB co-simulation platform and physical prototype test platform are set up to verify the gait controller. Simulation and experiment show that the improved CPG gait network can reduce the coupling between gait parameters, and the amplitude and phase of the generated signal are stable. The gait control controller based on CPG and VMC can be used to realize the diagonal gait motion of robot and gully crossing with a width of 2.50 times more than the width of the robot's foot.Key

A Blind Source Separation Method for Multi-fault Modal Characteristic Signals of Rolling Bearings with Error Influences

HUANG Da-rong, CHEN Chang-sha, KE Lan-yan, ZHAO Ling, MI Bo, SUN Guo-xi

2018, 39(7):  1419-1428.  doi:10.3969/j.issn.1000-1093.2018.07.021

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The multi fault modal signals of rolling bearing are difficult to be separated due to the measurement errors and system errors. For this reason, a blind source separation method for multi-fault modal characteristic signals of rolling bearings under the influence of errors is proposed. A whitening matrix is obtained by preprocessing the fault signal, and then the fourth-order cumulant of the whitening matrix is calculated, and a fourth-order cumulant matrix is established. The eigenvectors corresponding to the larger K eigenvalues are taken as the new cumulant matrix by diagonalizing the cumulant matrix. The total least squares method is used to minimize the error function between the cumulant matrix and the target orthogonal matrix, thus estimating the fault source signal. Furtherly, the time domain correlation coefficient and the time-frequency domain bispectrum estimation are introduced to verify the feasibility and effectiveness of the proposed method. The results show that the signal derived from the proposed method has high correlation coefficient with the source signal, and the time-frequency domain bispectrum estimation is similar, so it is an effective method to separate multiple faults. Key

Reliability Analysis of Self-lubricating Spherical Plain Bearings Based on Accelerated Life Tests

QIU Ming, ZHOU Da-wei, ZHOU Zhan-sheng

2018, 39(7):  1429-1435.  doi:10.3969/j.issn.1000-1093.2018.07.022

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The reliabilities of self-lubricating spherical plain bearings are investigated with the lifetime data obtained from accelerated life tests and the reliability analysis methods for their reliability assessment under normal stress. Weibull distribution probability graph test method and F test method are used for the hypothesis test of Weibull distribution of lifetime data of self-lubricating spherical plain bearings obtained from accelerated life tests. The results show that the lifetime of self-lubricating spherical plain bearings obeys Weibull distribution. The best linear unbiased estimation method is used to estimate the lifetime data, and the reliability indexes, such as reliability, average lifetime and failure rate, of the self-lubricating spherical plain bearings under different accelerated stresses are obtained. The life reliability function of the self-lubricating spherical plain bearings under normal stress is extrapolated, and the function is verified by test results. It is found that the prediction value is close to the test result, which shows that the accelerated life tests are feasible, and can be used for the reliability analysis of self-lubricating spherical plain bearings under normal stress. Key

Influences of Preload and Assembly Deviation on Friction Torque of Aerospace Bearing

NING Feng-ping， CHEN Ran， YAO Yin-yin， FAN Xiao-qin， LIANG Jing-jing

2018, 39(7):  1436-1442.  doi:10.3969/j.issn.1000-1093.2018.07.023

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The variation law of the friction torque is explored for the friction torque of low-speed and light-load aerospace bearing. A mathematical model of friction torque of solid lubricating aerospace bearing is established, and a balance equation of bearing under load is established based on the quasi-state of bearing. The axial preload is due to axial preloading, and the radial partial load is induced by the radial assembly deviation. The situation of ball under loading is analyzed, which is caused by the assembly deviation. The influence law of axial preload and radial position deviation on the friction torque of bearing is obtained. The results show that the elastic hysteresis friction torque, micro-sliding friction torque and self-spin friction torque of bearing increase with the increase in axial preload and radial partial load. Under the axial preload, the increasing trends of elastic hysteresis friction torque and self-spin friction torque in the components of friction torque are convex downward, while the increasing trend of micro-slip friction torque is convex upward. Under the radial partial load, the increasing trend of frictional moment component growth is convex downward. The micro-sliding friction torque and the elastic hysteresis friction torque are the main components of friction torque of aerospace bearing. While the load increases, the friction torque increases. The effect of load on the differential friction torque is the most significant, followed by elastic hysteresis friction torque and self-spin friction torque. Key

A New Method for Fast Star Identification Based on Star Trace

LIU Xian-yi, ZHANG Zhi-li, ZHOU Zhao-fa, ZHANG Xi-hui, YANG Shang

2018, 39(7):  1443-1449.  doi:10.3969/j.issn.1000-1093.2018.07.024

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Digital zenith camera is a high-precision astronomical positioning instrument. It takes star images in different orientations by rotating. The stars in each star image are identified by using star catalogue. But the calculated amount is very large and the efficiency of star identification is low. Considering that there are many same stars in the star images, the trace of one star point is deduced, and the region of the same stars is studied. A new star identification method is proposed. In the proposed method, only one star image needs to be identified by using star catalogue. The identified star can be simplified as a new star catalogue, which can be used for the rest star images. Thus the efficiency and speed of the star identification get improved. The experimental result shows that the number of stars identified by the fast star identification method can meet the requirements of positioning, and its positioning accuracy is basically the same as that of star identification method. Key

Constructing Method and Application of Battle Function Transfer Function for Battle Command and Control

ZHANG Dong-jun， ZHANG Lei， LI Xiao

2018, 39(7):  1450-1456.  doi:10.3969/j.issn.1000-1093.2018.07.025

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Operational command is a process of accumulation and release of energy. A method of battle control oriented to operational experiments is proposed for effectively understanding the mechanism of winning and crack down the fog of war, and some tactics, such as combat behavior, equipment capability and potential energy transformation, are put forward in order to fully express the process of accumulation, perception, transmission and transformation of war energy. An energy transfer function for operational command and control is built, which contains the delivery and command manipulation matrix of information, operational energy, defense energy, mobile energy, which can reflect the change of operational energy with time and space in the campaign experiment of the war. And the battle function optimization control function of system combat command is put forward, the neural network algorithm is introduced, and the comprehensive influence coefficient of the command function is presented by using the real and effective training data to effectively express the dynamic game characteristics of attack and defense confrontation. Finally, as an example, the effectiveness of the proposed method is verified by a flotilla cooperative operation. Key