Table of Content

28 February 2011, Volume 32 Issue 2

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Paper

Dynamic Response Analysis of Gearbox Housing Under Multi-source Dynamic Excitation

LIU Hui, ZHANG Xi-qing, XIANG Chang-le

2011, 32(2):  129-135.  doi:10.3969/j.issn.1000-1093.2011.02.001

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A dynamic finite element model of gearbox housing is established. The internal and external dynamic excitations of gear transmission system are calculated by numerical simulation method, considering the gear time-varying meshing stiffness, damping and meshing error in the internal dynamic excitation, and the torque ripple of engine, bearing time-varying stiffness and damping in the external dynamic excitation. The dynamic forces of housing bearing seats are obtained by simulating and analyzed the rigid and flexible coupled multi-dynamics of inner gear transmission system. On this basis, the dynamic response analysis of housing is carried out using a mode superposition method, and according to the results of constrained modal analysis, the dynamic response characteristics of housing are studied in the time and frequency domains. The results show that the housing structure design is relatively conservative, the various response amplitudes are small so that the sympathetic vibration is not occurred in the use process, and it is sufficient for application requuirement.

Approach to Assess Tank Diesel Cylinder Wear By Analyzing Its Relation to Start Current

QIAO Xin-yong, ZHANG Xiao-ming, XIE Xiao-yang, LIU Chun-hua

2011, 32(2):  136-140.  doi:10.3969/j.issn.1000-1093.2011.02.002

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In order to assess the technical state of tank diesel engine, a method for measuring the start current of diesel engine is designed, analyzed the relation between start current wave and cylinder wear as well as cylinder air pressure, explored the nature of start current fluctuation. Measured start current signals in experimentations on tank engine, made pretreatments by means of singular data elimination and wavelet analysis, and so that extracted the feature wave of the start current. Cut the current signal into divisions according to cylinder work order, calculated the integral of the upwards half in each division, made this compression work done by start motor as an assessment parameter to assess cylinder wear. By means of dynamic clustering algorithm determined an assessment standard to assess cylinder wear asymmetry of tank engine.

A Finite Element Analysis of Blade Wheel Strength of a High-powered Torque Converter's

YAN Qing-dong, LIU Shu-cheng, YAO Shou-wen， LI Jin

2011, 32(2):  141-146.  doi:10.3969/j.issn.1000-1093.2011.02.003

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To solve the strength problem of blade wheel of a high-power torque converter used on tracked vehicle, a analysis model is set up for the blade wheel strength of torque converter based on the one-way fluid solid interaction (FSI) theory. A globally conservative interpolation algorithm is used to convert the fluid pressure load from flow field mesh nodes to structure mesh nodes. In the light of inertial centrifugal load, the statics method is used for a finite element strength analysis of a blade wheel of torque converter under the two loads, and its stress distribution and deformation state are obtained. Two hazardous working conditions-the starting working condition and the maximum power working condition—are analyzed in detail. An effective method is provided for the strength analysis of blade wheel.

The Application of a Local Homogenous Medium Model in the Ventilated-supercavitation FlowComputations

SHI Su-guo, WANG Guo-yu, QUAN Xiao-bo, YU Zhi-yi

2011, 32(2):  147-154.  doi:10.3969/j.issn.1000-1093.2011.02.004

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In order to simulate the ventilated-supercavitation flow more accurately, a local homogeneous medium model based on the state equation is proposed and embedded in commercial software. The two-phase flow model in the commercial software and the software+local homogenous medium model are used to simulate the ventilated-supercavitation flows around a disk-cavitator respectively. The simulated results are compared with the experimental data on bubble shape, flow structure, drag characteristic and so on. Since the local homogenous medium model considers the compressibility of the gas-liquid, it can simulate the ventilated-cavitation more acculately, and the bubble shape and the drag force coefficient computed from the model are more accordant with the experimental results.

Simulation and Analysis of the Launching Process of Air-turbine Pump Launch System

LIAN Yong-qing, TIAN Bing, WANG Shu-zong, WU Zhao-hui

2011, 32(2):  155-162.  doi:10.3969/j.issn.1000-1093.2011.02.005

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In order to study the air-turbine pump(ATP) launching system, the mathematical models are established for its main components, such as air-bottle, launching valve, air-turbine, rotary pump and so on. The simulation of the launching process is realized by the use of the simulation program based on the mathematical models. The simulation result shows that the mathematical models are correct. These models can be used to analyze the performance characteristics of ATP launch system，and be used in the design of this launching system.

Trajectory Design and Simulation of Flank Array Self-Guidance Torpedo

GAO Li-e , LIU Duo, LIU Wei-dong, YU Li₁

2011, 32(2):  163-168.  doi:10.3969/j.issn.1000-1093.2011.02.006

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Flank array self-guidance torpedo has changed the operating frequency, array aperture, self-guidance detection distance and restriction in target identification means of old forward-looking self-guidance system. The flank array self-guidance torpedo possesses some features, such as long detection distance and strong detecting capability. The detection range of flank array self-guidance torpedo system is the sectors in two sides of torpedo, and the front sector of torpedo exists a detecting blind area. The mathematical models of searching, tracking and attacking a target are presented for the trajectory of flank array self-guidance torpedo. For this features, the searching and tracking trajectory design of flank array self-guidance torpedo system is made. It is shown from the simulation of flank array self-guidance torpedo system that the system can use a particular trajectory to improve the target detection probability and tracking accuracy. Meanwhile, the system also has an ability to reduce the voyage consumption.

Research on Time Delay Difference Estimation Techniques for Passive Location of Signal Impulses

XU Fu， HE Wen-xiang， HUI Jun-ying， YU Yun

2011, 32(2):  169-175.  doi:10.3969/j.issn.1000-1093.2011.02.007

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A reformed amplitude gated estimation method of time delay difference of signal impulses, i.e. an amendment method for short, is developed by introducing a channel equalization technique to its conventional version, which is called a direct method in this paper, so as to improve the stability of the estimation based on the analysis of error relativity between time delay difference and time delay estimation according to the principle of three-point location. After the inherent relationship between time delay and phase shift of a signal is analyzed, the multi period compensation method of estimation error is proposed by using the contribution of estimation error of concerned parameters to the estimation error of time delay difference and its different contribution modes under the condition of high precision phase estimation on the basis of the error theory. The amendment method and the direct method are combined into a cooperative multi amplitude gated estimation method which can process the signal impulses with three amplitude gates to reduce the estimation error of time delay difference of signal impulses. Experimental measurements are carried out to verify theoretical predictions.

Improved Bartlett Beam forming for Vector Sensor Array

YAO Zhi-xiang, YU Gui-shui, HE Fu-qiang

2011, 32(2):  176-180.  doi:10.3969/j.issn.1000-1093.2011.02.008

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The traditional Bartlett beamforming based on an acoustic vector sensor array(AVSA) cann’t demonstrate the anti-interference capability of AVSA. To improve its performance, a modified Bartlett direction estimation algorithm based on the AVSA is put forward. The pressure and velocity output of AVSA are processed using the modified method. The calculation process of this algorithm is given. A gain of suppressing left-right ambiguity is defined to analyze the single side directivity of two Bartlett azimuth spectra. The improved algorithm has lower side and better performance of left-right ambiguity suppressing for the combined processing which can suppress a noise more sufficiently. The results of computer simulation and sea experiment show that the improved algorithm is feasible.

A Fusion Approach to Target Recognition of Multiple Unmanned Underwater Vehicles

WU Ze-wei, WU Xiao-feng

2011, 32(2):  181-185.  doi:10.3969/j.issn.1000-1093.2011.02.009

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A new approach for fusing the results of target recognition from the multiple unmanned underwater vehicles is proposed to achieve their consentaneous judgment on target status based on the theory of distributed information consistence. A network model is built for the formation of the multiple unmanned underwater vehicles, and a consistence judgment algorithm for ensuring the formation to consentaneously recognize the target is designed. The sufficient condition of the consistence is proven and finally verified in the numerical examples.

Development of a Wheel for Dry Grinding of CFRP Parts and Investigation on Its Machining Performance

GAO Hang, YUAN He-ping

2011, 32(2):  186-191.  doi:10.3969/j.issn.1000-1093.2011.02.010

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The carbon fiber reinforced plastics (CFRP) is a typical difficult cut material since it has high hardness, anisotropy and non-homogeneity. It is easily delaminated and the wheel is loaded during grinding. An electroplated grinding wheel with controlled abrasive clusters is developed to meet the requirement of dry grinding of carbon fiber/epoxy resin composite parts. And the dry grinding experiments of carbon fiber/epoxy composites are conducted with reference to a conventional electroplated grinding wheel. The experimental results show that the steady axial force and good surface integrity are obtained by using the new grinding wheel with controlled abrasive clusters, and the surface roughness R_a of the workpiece is kept in a range from 0.8 μm to 1.3 μm. The spaces among the abrasive clusters serve as the rooms and accesses for accommodating and removing the grinding chips, which are beneficial to avoid wheel loading effectively. The new grinding wheel with controlled abrasive cluster can be used for dry grinding of large carbon fiber composites parts.

Research on Friction and Wear Property of (WTi)C/Graphite/Ni-Base Alloy Composite Coatings

CAI Bin， TAN Ye-fa， JIANG Guo-liang，XU Ting， TAN Hua， ZHOU Chun-hua

2011, 32(2):  192-198.  doi:10.3969/j.issn.1000-1093.2011.02.011

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In order to obtain the self-lubrication and anti-wear metal surfaces and improve the service life and reliability of metal friction couples under condition of high contact stress, the composite coatings composed of Ni-base alloy, (W,Ti)C and graphite particles are prepared on the surface of No. 45 steel by plasma spraying process. The friction and wear properties of the coatings are investigated under the conditions of dry friction conditions at room temperature, and the worn surfaces of the composite coatings are analyzed by SEM and EDX. The results show that the friction coefficients of the composite coating are 35％ and 38％ lower than those of the Ni-base alloy coatings when it rubs againdt Si₃N₄ and GCr15, and the wear resistance of the former is 3 and 3.5 times

Monitoring Methods and Relationship Between Piezoelectric Transducer Electrical Characteristics andVibration Cutting Force

LI Wen， ZHANG Wen-quan， ZHANG De-yuan

2011, 32(2):  199-203.  doi:10.3969/j.issn.1000-1093.2011.02.012

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The monitoring of cutting force has a great significance in promotion and processing of ultrasonic vibration cutting technology in vibration cutting process. On the basis of the research on the relationship among cutting force, transducer electrical impedance and load, a new monitoring method which uses the transducer electrical properties to reflect the cutting force of ultrasonic elliptic vibration cutting is proposed, and a transducer electrical properties measurement system is designed.The feasibility of cutting force monitoring based on piezoelectric transducer electrical properties is proved by the cutting experiments.

Copula-Based Reliability Modeling for Structural Systems Composed of Identical Components

ZHOU Jin-yu, XIE Li-yang, HAN Wen-qin, SUN Kui-zhou

2011, 32(2):  204-209.  doi:10.3969/j.issn.1000-1093.2011.02.013

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Copula is a new tool of statistical analysis, by which the probabilistic models for the multiple random vector can be built in terms of flexible expression, and by which the complex feature of statistcal dependence of random variables can be depicted. Copula is introduced in the reliability analysis of structural system. Copula-based method is put forward for the reliability modeling of structural systems composed of identical components. According to the failure-dependence mechanism of components, the modeling steps based on Gauss Copula and Archimedean Copulas are discussed by taking the twin stress and components strength as the basic variables and the safety margins as the analytic variables. Compared with Gauss Copula, Archimedean Copulas has a powerful capability to describe the failure-dependence mechanism since it can determine the adjustable parameters from the rank correlation coefficient and the information about the critical failure point. Archimedean Copula-based reliability models are applicable to non-normal situations. A numerical example shows that the new method is reasonable and feasible. Copula-based reliability model provides a new way for reliability assessment and reliability-based design of complex electromechanical equipment systems with failure-dependence.

Target Scale Adaptive Mean Shift Tracking Algorithm

KANG Yi-mei, XIE Wan-dong, HU Jiang, HUANG Qi

2011, 32(2):  210-216.  doi:10.3969/j.issn.1000-1093.2011.02.014

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The traditional Mean-Shift tracking algorithm is not applied to track a size-changing target effectively due to the fixed band-width of its kernel function. For this reason, a new algorithm is proposed. In each frame, Mean Shift tracking algorithm is employed to get the target location, and then the affine structure between frames is calculated to re-correct the position and size of the target. Different experiments prove that the present method has better stability and robustness than the traditional algorithm.

Research on Risk Correlation Based on the Module Coupling

MENG Jin， JIANG Li-ming， LI Qian-mu， ZHANG Hong

2011, 32(2):  217-224.  doi:10.3969/j.issn.1000-1093.2011.02.015

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The existing software risk management mainly focuses on all modules of the whole system. To narrow the scope of risk management, the concept of module risk correlation set is proposed to reduce the risk management to the management of related modules. To reduce the system risk analysis to the risk analysis of the module and the correlative module, the module risk correlation is defined and analyzed based on the theory and methods of module coupling, the concept of module risk correlation measure and module risk correlation set is proposed, and the module coupling measure is given. On the basis of this, the solution algorithm model of module risk correlation measure and module risk correlation set is established——the reformative multi-Dijkstra algorithm, the module risk correlation measure is measured, and the module risk correlation set is obtained. Finally, the correctness of the algorithm and effectiveness of the research of related risk module is verified through the experimental results.

Research on Performance of U-figure Inertia Separator in Sand and Dust Test System

LI Hong-wei, HAN Hai-bo, WANG Jun, ZHANG Hua

2011, 32(2):  225-229.  doi:10.3969/j.issn.1000-1093.2011.02.016

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Sand/dust test is one of the key projects to examine the environmental adaptability of weapon and equipment. In order to decrease the abrasion of test facility caused by the sand/dust particles, the high efficacious callback of particles contained in the airflow is needed. A mathematical model of U-figure inertia separator is established, the flow field and the trajectories of particles in the separator are obtained by using a numerical simulation method, and the separation efficiency and pressure drop of separator with different rows of separate components are obtained at various flow velocities. The simulation results indicate that the efficiency of U-figure inertia separator is affected by the flow velocity evidently, and a reasonably designed separator can meet the requirement of the separation efficiency in a particular situation. All the results provide reference for the design and test of sand/dust separate systems.

Research on Combustion Characteristics of Methane-Hydrogen-Air Mixture

ZHANG Hong-guang, BAI Xiao-lei, HAN Xue-jiao, SUN Na

2011, 32(2):  230-235.  doi:10.3969/j.issn.1000-1093.2011.02.017

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The combustion characteristics of methane-hydrogen-air mixture in constant volume combustion chamber are studied in the case of different initial temperatures, initial pressure, equivalent ratio and hydrogen blend ratios. The effects of the above conditions on maximum combustion pressure, rate of maximum pressure rise, flame development time, combustion duration, and cyclic variation of maximum combustion pressure are obtained. The results show that the higher temperature and the lower pressure are helpful to achieve the higher flame propagation velocity while other initial conditions keep stable; as the hydrogen fraction increases, both the combustion velocity and combustion peak pressure gradually rise, the appearance time of combustion peak pressure is moved up, and the variation coefficient is obviously lower.

Effect on Heat Dissipation Structure Parameters of Tunnel for Rotor Plate of Eddy Current Retarder

LIU Cheng-ye, SHEN Jian-ming₂, HE Ren, JIANG Ke-jun

2011, 32(2):  236-241.  doi:10.3969/j.issn.1000-1093.2011.02.018

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Kinetic energy of automobile could be transformed into heat energy when an eddy current retarder (ECR) starts braking. The temperature on the rotor plate rises rapidly to result in instable braking performance because of heat energy. For the above question, a cylindrical disturbance setup with forced heat dissipation is proposed to be installed in the rotor plate. To select the reasonable cylinder dimensions, the physical models of single tunnel are established. Heat exchange mechanism and performance of every model are analyzed using K-ε standard double equations and energy equation on condition that inlet airflow velocity is variable, and compared to the original model without disturbance components. The results show that the pressure drop increases with increase in cylinder diameter, the average convective heat transfer coefficient of former row is higher than that of next one, and the higher strengthening heat transfer coefficients on work plane and back plane of the blade are achieved after the disturbance components are installed, furthermore their effect on former is greater than on latter.

Research Notes

Adaptive Predictive Control of Vehicle Semi-Active Suspension

WU Yun-peng, GUAN Ji-fu, GU Liang

2011, 32(2):  242-246.  doi:10.3969/j.issn.1000-1093.2011.02.019

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The ride comfort and road holding of vehicle can be obviously improved by using the semi-active suspension. With the constraint of suspension travel and damping coefficient variance, a control algorithm is used to dynamically optimize the vibration acceleration and wheel dynamic load according to the variance of road irregularity and vehicle velocity. The optimal control law is adaptive to the model error caused by the vehicle load variance, variance of suspension component, etc. The generalized predictive control (GPC) is used for vehicle semi-active suspension, which utilized model prediction, rolling optimization, and feedback compensation to optimize the objective function. Simulation results show that the resulting system can provide better control performance.

The Nonlinear Model and Control of Magnetic Suspension Bearing Flexible Rotor

YUAN Hui-qun, LI Ying₂, LI Dong₂, WU Wen-bo₁

2011, 32(2):  247-251.  doi:10.3969/j.issn.1000-1093.2011.02.020

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Considering gyroscopic effect, flexibility of shaft and nonlinear electro-magnetic force, a nonlinear magnetic suspension bearing rotor model is established. An exact nonlinear feedback method is used to realize the effective control of nonlinear magnetic suspension bearing rotor model. The differences of controlled parameters are compared between the nonlinear and linear models of magnetic suspension rotor system , and the flexible and rigid magnetic suspension rotor systems. The simulated results show that the difference of controlled parameters is obvious for different model. Since the nonlinearity of electromagnetic force and the flexibility of bearing has a great influence on the magnetic suspension rotor system, they can not be ignored. The result above may be helpful for the engineering practice.

Research on Integrated Navigation for Autonomous Underwater Vehicle Based on an Improved Unscented Kalman Filter

LIU Ming-yong， HU Jun-wei， LI Wen-bai

2011, 32(2):  252-256.  doi:10.3969/j.issn.1000-1093.2011.02.021

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To meet the stability, precision and real-time performance of navigation system for autonomous underwater vehicle (AUV), a novel SINS/DVL integrated navigation method based on improved unscented Kalman filter (UKF) algorithm is presented. By analyzing the characteristics and error model of the low-precision integrated navigation system, a simplified UKF integrated navigation algorithm based on spherical simplex sampling transformation is designed for the additive and complex noise model of the system. Simulation results show that this algorithm can effectively reduce the computational complexity and improve the efficiency of the navigation system without loss of filtering accuracy compared with the traditional UKF algorithm using scaled symmetric sampling.