Table of Content

01 July 2012, Volume 33 Issue 7

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Paper

State-Space Model for Dynamic Heat Transfer in the Cooling System of an Electric-Drive Tracked Vehicle

WANG Fa-cheng, WANG Yi-chun, ZHANG Cheng-ning, SUN Xiao-xia, XIANG Long-yun

2012, 33(7):  769-775.  doi:10.3969/j.issn.1000-1093.2012.07.001

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Heat transfer is very important for military vehicle, and especially for an electric drive tracked vehicle. Three closed recycling waterways were designed for the cooling system of an electric-drive tracked vehicle. Based on common points of components in waterways, a heat capacity and thermal resistance model was built for dynamic heat transfer in these components. According to the heat capacity and thermal resistance model, three waterways were simplified, so that a state space model was built for dynamic heat transfer in the cooling system. Experimental study was analyzed for dynamic heat transfer in an actual cooling system. The conclusion is that heat coupling relationship among cooling system components in the electric drive tracked vehicle can be analyzed roundly and visually by that state space model, and that the state space model can be used to find the heat transfer principle of cooling system components, as well as to diagnose fault and improve the design of cooling system.

Experimental Study on the Factors Affecting Lean Combustion Limit of S.I. Hydrogen-Natural Gas Engine

WANG Xin, ZHANG Hong-guang, YAO Bao-feng, SUN Xiao-na, LEI Yan,

2012, 33(7):  776-781.  doi:10.3969/j.issn.1000-1093.2012.07.002

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An experimental study was conducted on a spark ignition engine to investigate the factors that affect the lean combustion limit of hydrogen- natural gas engine. The effects of ignition timing, hydrogen mixing ratio, engine speed, throttle opening, lubricant oil and coolant temperature were examined. The engine speed was 1 500-3 000 r/min, the throttle opening was 10%-40%, the lubricant temperature was 75 ℃-95 ℃,and the coolant temperature was 65 ℃-85 ℃ during experience. The hydrogen mixing ratio varied from 0 to 40%, and the lean-combustion limit ignition timing was defined and adopted. The result shows that both over-retarded and over-advanced ignition timing would baffle the extension of lean-combustion limit. The lean-combustion limit increases with hydrogen mixing ratio, slightly increases with throttle opening, and decreases when the engine speed is raised. Besides, it decreases with the increase in lubricant temperature. Warming-up coolant is positively related to enlarge the lean-combustion limit.

Optimal Design of Vanes in Hydrodynamic Torque Converter Based on Orthogonal DOE

LUO Hong, LI Ying-qiang, LI Xing-quan, WANG Teng-teng, SUN Xing-long

2012, 33(7):  782-787.  doi:10.3969/j.issn.1000-1093.2012.07.003

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To improve the performance of torque converter, some blade parameters were selected as variables and then optimized by orthogonal DOE (design of experiment) which based on the three dimensional flow simulation. The variables were selected through theory of hydrodynamic torque converter design and the analyzing of flow field in it. Firstly, optimal models respectively taking the stall torque ratio and top efficiency as target function were set up to get two optimal target values. Then, these two values were used to form a new function as target for next optimization. The result indicates that the stall torque ratio and top efficiency increase by 7.3% and 1.5%, respectively after the optimization proves the efficiency of this approach and its value to engineering.

Design and Optimization of Structure Parameters of Control Plunger Couple in Electronically Controlled Injector

WANG Jun₁， ZHANG You-tong₂， JIN Yi₁， XIONG Qing-hui₂

2012, 33(7):  788-792.  doi:10.3969/j.issn.1000-1093.2012.07.004

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The structure parameters of control plunger in an electronically controlled injector were designed and optimized to increase the hydraulic response speed of electronically controlled injector. Based on the analysis of work principle and function of control plunger, a design method of control plunger in the electronically controlled injector was presented. The structure parameters were calculated according to a certain diesel engine. Genetic algorithm was applied to optimize the multi-parameters, an optimum model which uses the injector hydraulic response time as an objective function was presented, and the optimization result was achieved. The performance of injector with optimum structure parameters was approved using the simulation model of electronically controlled injector.

Research on the Influence Factors about the Pressure Transformation Ratio of Angle Type Hydraulic Transformer

LI Xue-yuan， YUAN Shi-hua， HU Ji-bin， WEI Chao

2012, 33(7):  793-798.  doi:10.3969/j.issn.1000-1093.2012.07.005

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The mathematic models of displacement, angular torque and pressure transformation ratio about angle type hydraulic transformer were built. The derivative relationship between pressure transformation ratio and pressure of feed circuit, flow of load circuit and viscosity were deduced respectively. Based on it, the influence characteristics of the three factors on pressure transformation ratio were got. The result of analysis and test shows that rotations of valve plate influence the role of pressure of feed circuit on pressure transformation ratio, the increment of pressure of feed circuit may bring increment, decrease, or nothing to pressure transformation ratio with different rotation of valve plate. The increment in flow of load circuit results to decrease the pressure transformation ratio, while the decrease in viscosity results to decrease pressure transformation ratio. And there is one maximum point in the process of increasing pressure transformation ratio, and more flow of load circuit can make the time of maximal point of pressure transformation ratio appear more early.

Design of Integrated Vehicular Turbocharger and Turbine Generator System

ZHANG Qiang, MA Chao-chen， QU Xun-zhi

2012, 33(7):  799-803.  doi:10.3969/j.issn.1000-1093.2012.07.006

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In order to develop the technology of auxiliary power unit for military and civil vihicles, the design scheme based on a certain type of vehicle turbocharger was promoted. Thermodynamic parmeters analysis of simple gas turbine cycle were conducted in detail, and the influence laws of key components parameters on system performance were obtained. The research results demonstrate the feasibility of the design scheme，and the system performance is strongly effected by the efficiency of turbocharger turbine. These can provide a foundation for future development work.

Performance Analysis of Permanent Magnet Motors with Winding Switching and Switching Circuit Research

LUO Hong-hao, WANG Fu-xing

2012, 33(7):  804-809.  doi:10.3969/j.issn.1000-1093.2012.07.007

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Under the circumstances that volume and power are being limited in armored vehicles, large torque and wide flux-weakening range become conflict inevitably in permanent magnet motors. The motor winding switching method is adopted to resolve this problem. The motor performance of torque and flux-weakening was analyzed by finite element method (FEM) which windings are connected in parallel and series respectively. The results show that the output torque of the motor in series-wound mode is twice as much as that in parallel-wound mode, while the speed range of the motor in series-wound mode is half as much as that in parallel-wound mode. Thus, both of torque and speed range can be satisfied utilizing the winding switching method. The series-wound mode can be used in low speed to increase output torque of the motor, while the parallel-wound mode can be used in high speed to widen the speed range of the motor. What’s more, a switching circuit is constructed based on zero current switching to fulfill the winding switching. The experimental results show that the switching is very rapid and the impulsion is small during the switching process.

Study on the Asymmetry Characteristics of Piston Motion of the Hydraulic Free Piston Engine

WU Wei， YUAN Shi-hua， HU Ji-bin， JING Chong-bo

2012, 33(7):  810-815.  doi:10.3969/j.issn.1000-1093.2012.07.008

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Based on the hydraulic free piston engine fundamental theory, the analytical model of the system was built. The asymmetry of the piston motion and the influencing factors were investigated by simulation and prototype tests. The results indicate that the piston motion around top dead center of the single piston hydraulic free piston engine appears asymmetry. The energy transfer characteristics and the forces on the piston around top dead center determined that the asymmetry characteristic is inherent. The piston motion around top dead center is mainly determined by the cylinder gas pressure. The faster the compression procession is, the faster the expansion process is. The responses of the distributing valves affect the piston motion around top dead center little. The operation position of the load pressure mainly affects the end of the expansion process.

Improved SVPWM of AC Electrical Tank Gun Control System

YAN Zhi-feng₁， MA Xiao-jun₁， WEI Shu-guang₁， WANG Jing₂， YUAN Dong₁

2012, 33(7):  816-821.  doi:10.3969/j.issn.1000-1093.2012.07.009

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A kind of soft three-phase inverter, the auxiliary resonant commutated pole inverter (ARCPI) was designed in an researching all AC electric tank gun control system. But when the traditional SVPWM was used in the ARCPI, the main switches of ARCPI couldn’t realize soft switching condition wholly. To solve the limitation, an improved SVPWM method was proposed. It can decrease the no-ZVS’s times of the main switches maximumly and the switching times in one space vector period. Meanwhile, the efficiency of tank gun control system is enhanced and the electromagnetic environment was purified. Theoretical analyzing and experiments waves show that the improved SVPWM method is feasible and superior.

A Multifractal Spectrum Algorithm Based on 1-Norm Minkowski Measure

ZHANG Sheng, FANG Xiang, ZHANG Wei-ping

2012, 33(7):  822-825.  doi:10.3969/j.issn.1000-1093.2012.07.010

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A generalized multifractal spectrum algorithm based on 1-norm Minkowski measure was proposed to resolve the problem that present multifractal spectrum algorithm was too complicated to be applied in identification for early alarming, the experiment was implemented to prove the validity of the algorithm for tank-radiated noise identification as well. This algorithm reduced the numeration of the generalized multi-fractal spectrum by simplifies the measure according to the definition of generalized dimension. The experiment demonstrates that under low SNR the ability of early alarming identification by this method is higher than zero-pass analyzing method we use today.

Coning Error Compensation Algorithm of SINS Self-Alignment on Swaying Base

WANG Li-dong, LIU Jun, LU Jun

2012, 33(7):  826-830.  doi:10.3969/j.issn.1000-1093.2012.07.011

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Coning error compensation algorithm in the process of self-alignment is put forward in light of the strapdown intertial navigation system (SINS) self-alignment error on swaying base. It reduces coning error and increases the self-alignment accuracy. The quaternion fourth-order Runge-Kutta algorithm and two-sample and three-sample and other error compensation algorithm of equivalent rotation vector and their theoretical compensation effect are analyzed and compared in theory; through simulation and experiments, it is obtained that the self-alignment error decreases along with increasing of the number of sample. When the number of sample increases 1, the self-alignment error of north-angle is reduced nearly 1 time and the dispersibility of attitude angle is reduced; with the increasing of the swaying amplitude and frequency, the self-alignment accuracy of three-sample compensation algorithm is close to stability . Considering the sampling frequency and the number of sample and calculation and alignment accuracy, the three-sample coning error compensation algorithm should be selected and it can satisfy the self-alignment requirements of SINS on swaying base.

Movement of Air Backed Plane Plates Subjected to Shock Wave of Underwater Explosion

TANG Ting， ZHU Xi₂， WEI Zhuo-bin₁， HOU Hai-liang₂

2012, 33(7):  831-835.  doi:10.3969/j.issn.1000-1093.2012.07.012

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The wave theoretical formulae about the response of air backed plane plate to the shock wave of underwater explosion were got by applying one dimension plane wave theory. By comparing the wave theory formulae with the Taylor formula, it shows that two results are coincident when the impedance of plate is far higher than that of water. As the elastic modulus and density of plate decrease, the error of Taylor formula increases, but the wave theoretical formulas are still accurate. If the mass of plate and the shock wave of underwater explosion are fixed, the maximum velocity of plate is inversely proportional to the elastic modulus and density of plate. By comparing the responses of plates with different thicknesses to the same shock wave of underwater explosion, it is shown that the maximum velocity of plate is inversely proportional to the thickness of plate, but a good vibration isolation effect can be reached by increasing the thickness of plate.

Study on Heat Transfer in Aqueous Camouflage Foam

ZHANG Yong， MA Yu-zhong， JIANG Xiao-jun， YU Kun， YANG Li-jun

2012, 33(7):  836-839.  doi:10.3969/j.issn.1000-1093.2012.07.013

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The thermal camouflage effect of aqueous camouflage foam is good. For even aperture and close hole of aqueous camouflage foam, a cell model and a heat transfer model were established using an effective thermal resistance method. Then the rationality of heat transfer model was verified by the experimental samples of aqueous camouflage foam. At last, the relations among effective thermal conductivity, frothing time and structural factor were analyzed, and the good ideas about the foam machine and frothing liquid were put forward. The heat transfer model based on effective thermal resistance method provides a theoretical basis of th research on the relations among heat transfer, interior structure and preparation technique of aqueous camouflage foam, which is very important for the latter.

Effect of Laser Heating Temperature on Coating Characteristics of Stellite 6 Deposited by Cold Spray

LUO Fang, KONG Fan-zhi₃, William O’NEIL₂, YAO Jian-hua₃, CHAI Guo-zhong₃

2012, 33(7):  840-846.  doi:10.3969/j.issn.1000-1093.2012.07.014

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Laser-assisted cold spray (LCS) is a new coating and fabrication process which combines some advantages of CS: solid-state deposition, retain their initial composition and high build rate with the ability to deposit materials which are either difficult or impossible to deposit using cold spray alone. Stellite 6 powder is deposited on medium carbon steels by LCS using N₂ as carrier gas pressure. The topography, cross section thickness, structure of the coatings is examined by SEM, optical microscopy, EDX. The results show that thickness and fluctuation of coating are improved with increased deposition site temperature. Porosity of coating is affected by N₂ and deposition site temperature. In this paper, it presents optimal coating using N₂ at a pressure of 3 MPa and temperature of 450 ℃ and deposition site temperature of 1 100 ℃.

Research on the Cutting Stability of Thin Cylindrical Shell of Aluminum Alloy

LIN Bin, CHEN Dong, HAN Zhi-lin, ZHANG Bao-xing, ZHANG Lei

2012, 33(7):  847-851.  doi:10.3969/j.issn.1000-1093.2012.07.015

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The thin cylindrical shell has a relatively low stiffness and poor processing, and is easy of deforming and vibrating during processing because of its material properties and structural characteristics. Regenerative chatter is a main vibration reason of cutting machine tools. The law of limit cutting width of regenerative chatter varying with the speed of spindle was researched. The kinetic parameters of cutting system were identified through the dynamic test, model experiment and dynamic cutting forces. Finally, the diagram of cutting stability of thin cylindrical shell was obtained. Furthermore, the area of strict stability was proposed compared with traditional stability.

A Deterministic Algorithm for Acitve Region of Clamping Force of a Complex Workpiece

QIN Guo-hua, GUO Xi-yuan, YE Hai-chao, LU Yu-ming

2012, 33(7):  852-856.  doi:10.3969/j.issn.1000-1093.2012.07.016

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A workpiece is subjected to the cutting force and torques during machining. These external loads may result in the production accidents as well as the variation of workpiece position. The feasible clamping forces must be planned to stabilize the workpiece in the entire machining process. Therefore, a deterministic algorithm for the active region of clamping force of complex workpiece was proposed by taking the workpiece stability as a core. Firstly, according to the virtual work principle and the linear programming technology, a judgment algorithm was suggested for the stability analysis of workpiece. Secondly, on the basis of the surface mesh discretization method, a deterministic algorithm was further established to plan the active region of clamping force by analyzing the workpiece stability at all nodes in sequence. The proposed method can not only be utilized to verify the feasibility of the magnitude of clamping forces, but also determine the active region of clamping force.

Design of a New Ducted Fan Aircraft and Its Aerodynamic Characteristic Research

CAI Hong-ming, ANG Hai-song, DUAN Wen-bo

2012, 33(7):  857-863.  doi:10.3969/j.issn.1000-1093.2012.07.017

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Ducted fan aircraft can hover, take off and land vertically, and fly forward, which has high safety, compact structure and low noise. However, they generally can only fly forward slowly in helicopter mode. A new tilt-body ducted fan micro air vehicle (MAV) with wings which is capable of high-speed forward flight in wing-borne mode was designed. Pairs of wings were designed, and the geometry design reflects a compromise between low and high speed performance requirements. Numerical simulation and wind tunnel testing were used to study the aerodynamic characteristics of ducted fan MAV in various modes. The results indicate that the novel ducted fan MAV can hover, take off and land vertically, fly slowly in helicopter mode, and fly rapidly in wing-borne mode, and shows the good aerodynamic performances throughout the whole flight envelope.

Analysis on the Process Capability of Gearbox Item Repair Based on Bayesian Theory

CHEN Chun-liang, SHI Wen-hua, LU Hui-qiang, YE Hong-bing

2012, 33(7):  864-869.  doi:10.3969/j.issn.1000-1093.2012.07.018

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Comparing the Bayesian theory method and the traditional means, the different results validate the rationality and practicability of applying of the bayesian means to the item repair. Based on analysis on the process of replace repair of gearbox, concentrative item repair is confirmed as the key process. According to the fact of replace repair, i.e., the mean value and standard deviation is changeable with the environment, the Bayesian theory is adopted, in which the mean value and standard deviation is deemed as stochastic. The Bayesian estimate of posterior distribution is obtained from the history data and prior distribution, furthermore, the key process capability is analyzed by using SPC technology with the 97.5% one-sided confidence lower limit of process capacity index given with comparison with classical theory. The comparing result indicates that the applying of Bayesian means to the item repair is more rational and practical than the traditional method.

Research Notes

Optimal Current Phase Curve Fitting of IPM Motors in Flux-Weakening Region Based on Neural Network

LUO Hong-hao, LIAO Zi-li

2012, 33(7):  870-874.  doi:10.3969/j.issn.1000-1093.2012.07.019

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To take the nonlinear effect of interior permanent magnet (IPM) motors into account, a method of fitting the optimal phase curve in flux-weakening region by BP neural network is presented. The theory of maximum torque per ampere (MTPA) control is analyzed. Considering the voltage and current limits of power inverter, the condition for IPM motors to output maximum torque in flux-weakening region is derived. A BP neural network is constructed to map the motor speed and current amplitude to optimal phase angel in flux-weakening region. Computation and simulation results show that the maximum error between the fitting result of the constructed BP neural network and the result of finite element method (FEM) is less than 1°.

Research on Dynamic Evaluation Method for Process-oriented Virtual Training

JIAO Yu-min₁， WANG Qiang₁， SU Fan-tun₁， XU Ting₁， SU Jing₂

2012, 33(7):  875-880.  doi:10.3969/j.issn.1000-1093.2012.07.020

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Existing methods are difficult to solve dynamic evaluation problems in the process of virtual training. Based on existing methods, time serial factor is introduced to present dynamic evaluation model. In this model, time-step method and event-step method are combining to establish three-dimentional sequencing evalution matrix (evaluation object,evaluation time, evaluation index). To solve this matrix,this paper extends the ordered weighted averaging(OWA) operator to weighted evaluation function and presents time ordered weighted averaging function for process-oriented virtual training. In this way, dynamic evalution problems for training process are solved satisfactorily. Finally, the mothed is applied to virtual training system of certain machinery and realizes dynamic evaluation and visualization of the evaluation process.

Development of X-Ray Digital Radiography Automatic Inspection System for Testing the InteriorStructure of Complex Product

HAN Yue-ping， HAN Yan， WANG Li-ming， PAN Jin-xiao

2012, 33(7):  881-885.  doi:10.3969/j.issn.1000-1093.2012.07.021

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The X-ray digital radiography automatic inspection system with single camera has been developed and successfully applied to the online automated test of some products containing complicated assembly structures by comprehensively considering multiple visual inspection technique and CT in order to solve the issue of nondestructive test of interior structures. First, a method, which uses the 3-point location of hardware and the integral projection of local area to find out a backward differential extremum, locates the product quickly. Second, the principal component entropy of the whole-orientation hierarchical hybrid projection of the ordered image set was extracted as the recognition feature basis. Finally, a BP neural network system was used to speed up the recognition process with parallel operations. The test process was automatically controlled by computer except loading and unloading. The experimental results show that wrong inspection ratio is less than 4.5% without missing inspection, and the average recognition takes less than 5s in test progress.

The Exploitation Flat for Virtual Maintenance Training by Multi-users and Single User

XU Xiao-gang, OU Li-ming, SHAO Cheng-yong

2012, 33(7):  886-891.  doi:10.3969/j.issn.1000-1093.2012.07.022

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At present， the sailorman have a little measure and time to do maintains training in real equipment and its failure effect is not very good. In allusion to this problem, this text has founded virtual maintenance exploitation flat for sailormen based on the need of maintenance training. The bounding-box and geometrical restriction method was adopted to solve the problems of collision detection. The key frame technology was adopted to simulate the motion of virtual human. The network communications mechanism based on Agent was founded to set up a collaborative virtual environment. The multi-roles collaborative model for virtual maintenance was presented to harmonize users how to collaborate. The mechanism that controls the concurrent conflict from the point of view of avoidance, detection and solution was proposed to clear up conflicts between the collaborative maintenance. In this flat, the computation is realtime, the developing work is simple while designing the scene, maintenance procedure, maintenance action, and operation instruction. Some different applications proved the exploitation flat had a good currency and can adapt to set up different virtual maintenance training systems easily.

Test Periodicity Optimization of Equipment Health Management Information under Availability Constraints

YANG Shu-ming, QIU Jing, LIU Guan-jun, YANG Peng

2012, 33(7):  892-896.  doi:10.3969/j.issn.1000-1093.2012.07.023

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For a problem of that the traditional test periodicity design does not take the impact of equipment health state and availability constraints on periodicity decision into account, a test periodicity optimization model for equipment health management was presented. Control limit maintenance policy was provided based on an equipment health state degradation model. Then, a nonlinear tradeoff optimization model was established, which takes cost per unit time in renewal cycle as optimization object, equipment operational availability as constraint and test periodicity as decision variable. The test periodicity was optimized based on renewal process. The simulation results show that the proposed model can be used to guide the test periodicity optimization design and is of certain engineering application value.