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Table of Content

    10 October 2012, Volume 23 Issue 19
    Extension Configuration Model of Product Scheme Design Based on Axiomatic Design
    WANG Ben-Chun-1, CHEN Bing-Fa-1, BO Liang-Feng-2
    2012, 23(19):  2269-2275. 
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    Due to the complicated, multi-hierarchy, multi-attribute and creative process of a mechanism scheme design configuration, an extension configuration model of the mechanism scheme design was proposed based on axiomatic design and the extension theory. By reusing the design cases, the axiomatic design frame of complex mechanism scheme design was developed. In the developed axiomatic design frame, the design object could be processed with extension transformation, extension data mining and dependent function foundation. Based on these, the volatilization extension design method and the implication extension design method were put forward. And then, the extension configuration model and the corresponding algorithm were presented. Finally, an example was provided to the examine the model and algorithm.

    Effects of Fixed Orifice Length on Null Position Characteristics of Double Nozzle Flapper Valve under Low Temperature
    YIN Yao-Bao, ZHANG Xi
    2012, 23(19):  2275-2279. 
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    The length of a fixed orifice may affect the null position characteristics of double nozzle flapper valve obviously under low temperature.The formulae between the null position characteristics and the hydraulic conductance ratio of the fixed orifice and the flapper-nozzle orifice were derived. The effects of fixed orifice length on null position characteristics of double nozzle flapper valve under low temperature were analyzed by theoretical analysis and numerical simulation. Analysis results show that an proper orifice length of fixed orifice can improve the null position characteristics and their stability while working temperature changes from -40℃ to 0℃.

    #br# Milling Parameter Optimization Based on Tool Life and Material Removal Rate for AerMet100 Steel
    YANG Hou-Chuan-1, 2, YUAN Shu-1, CUI Ji-1, TANG Xiao-Liang-1
    2012, 23(19):  2280-2285. 
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    For milling high-strength steel tool life and material removal rate,the milling parameter control was investigated.  By the orthogonal experiment of milling, a Taylor mathematical model of the tool life was built. According to analysis of the milling parameter interval sensitivity based on milling parameter sensitivity and relative sensitivity model, and using the extreme difference analysis facing the orthogonal experiment, the optimization flow process for the tool life and material removal rate were proposed. then milling parameter interval and milling parameters were optimized. The results show that the optimum milling speed ranges from 100m/min to 105m/min, the optimum feed per tooth ranges from 0.11mm to 0.12mm, and the optimum milling depth ranges from 2.1mm to 2.5mm. Thus the optimum milling parameters are selected as vc=100m/min, fz=0.11mm, ap=2.5mm. The theoretical analysis and test data presented herein can be used for optimizing milling parameters of high-strength steels to control tool life and material removal rate.

    Study on Steering Wheel Shimmy with Clearance of Kingpin
    ZHOU Bing-1, SUN Le-2, ZUO Long-1, ZHANG Nong-1
    2012, 23(19):  2286-2289,2296. 
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    The tire magic formula and kingpin clearance were considered herein. A non-linear mathematical model of steering wheel shimmy with non-independent suspension was established by the Lagrange equation method. And the influences of kingpin's clearance and different parameters were analyzed. The simulation results indicate that the clearance of kingpin makes amplitude of steering wheel shimmy system increase, the speed range becomes larger, and the non-sensitive parameters may have an impact on the steering wheel shimmy.

    #br# Study on Dynamic Behavior and Stability of an Eccentric Pretightened Cushion Structure
    XIAO Shi-Fu, CHEN Zhan-Feng, CHEN Hua-Jian, LIU Shen-En
    2012, 23(19):  2290-2296. 
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    For investigating the dynamic behavior and the slip mechanism of an eccentric pre-tightened cushion structure,a dynamic model with relatively rotary vibration and rotary slip DOFs of the system was established.The dynamic behavior of the system was analyzed numerically on the assumption that the system did not rotary slip.Then the critical slip load was studied as the system undergoing stead-state vibration.The sensitivity of rotary slip to the initial conditions subjecting to uniform distribution in an interval was anatomized and its probability distribution was calculated for the system with different eccentric properties.At the present work,some dynamic phenomena were founded or confirmed.The dynamic behavior and the slip mechanism,founded by this work,can guideline the slip-forbade design of the eccentric pre-tightened cushion structure.

    Pratical Stable Control for Flexible-joint Robots Based on Adaptive Fuzzy Dynamic Surface Scheme
    TUN Zhong-Jiang-1, ZHANG Xiao-Xia-1, SHU Jie-2
    2012, 23(19):  2297-2301. 
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    Practical stable control based on adaptive fuzzy dynamic surface scheme was presented for single-link flexible robots. The unknown and time-varying functions were compensated by adaptive fuzzy approximators. By using DSC design technique, the proposed control system can overcome the problem of “explosion of complexity” inherent in the Backstepping design methods. Thus, the structure of the controller was simplified. The proposed controller guarantees the practical stability of the closed-loop system. Finally, simulation results show the effectiveness of the proposed controller.

    #br# Coupling Analysis of Vibration Fatigue Crack Growth for a Cracked Plate
    LIU Wen-Guang, HE Gong-Lin
    2012, 23(19):  2301-2305. 
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    A coupling analytical method for vibration fatigue crack growth of a cracked plate was proposed for the sake of improving the analytical precision of vibration fatigue life. Firstly, the crack was replaced by an additional external force and the vibration equation of the cracked plate was derived in view of mechanics balance principle, and the crack terms were obtained by using stress relational expression introduced by Rice and Levy. Then, crack propagation was simulated by Paris equation and a coupling relation was considered through vibration analysis and the crack growth calculation was carried out simutaneously. Influence factors of vibration fatigue crack growth for the cracked plate were discussed in the end. Results indicate that the crack length and the thickness of the plate are very important to natural frequency and impacts of damping and exciting force on the rate of crack growth are obviously.

    #br# Robot Accuracy Compensation Method of Spatial Grid for Aircraft Automatic Assembly
    ZHOU Wei-1, LIAO Wen-He-1, TIAN Wei-1, LI Dong-Meng-2, LIU Yong-2
    2012, 23(19):  2306-2311. 
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    This paper studied a positioning accuracy compensation method of 6-DOF KUKA robot. Through the establishment of conversion relationship between the robot and laser tracker coordinate system, the absolute positioning errors were obtained by comparing the actual positioning coordinates measured by laser tracker with the corresponding theoretical coordinates. Firstly, the robot's work space was divided into many three-dimensional grids with a certain step, then for any point within the workspace, its absolute positioning error can be estimated by the absolute positioning errors of eight vertices of the three-dimensional grid which contained it in. Finally, the robot's absolute positioning accuracy was improved by inverse compensation of estimated positioning errors to the theoretical coordinates. The results show that the maximum value of the robot positioning accuracy is as 0.386mm, and the mean value is as 0.156mm, which are much more better than the previous values 1~3mm. The robot can satisfy the requirements of aircraft automatic assembly.

    Control Process for Drilling Burr Growth of Aerospace Thin-walled Workpiece
    HONG Hua-Zhou-1, HUI Gong-Tu-1, CHEN Wen-Liang-1, JIN Xia-1, JIANG Gong-Yu-2, WANG Yu-Bei-2, TU Lu-2
    2012, 23(19):  2312-2316. 
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    The drilling burr formation mechanism of a typical aluminum alloy thin-walled workpiece in aero industries was studied.It is shown that the thrust force of drilling process is the most influential factor of the burr formation.Based on this,in order to optimal control drilling burr shapes and sizes,the drilling area was subdivided,and then a layered feed drilling process was advanced.The test drilling process was designed,and the results prove that the layered feed drilling process can inhibit the burr formation effectively,control the burr growth and improve the hole quality significantly.

    #br# Revised Contact Model among Three Dimensional Fractal Rough Surfaces
    JIN Shou-Feng-1, QI Ru-Wen-2, GUO Cai-Xia-2
    2012, 23(19):  2316-2319. 
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    A new contact model among rough surfaces was presented based on fractal theory. Y-K fractal model was revised to include all of the elastic, elastic-plastic, and fully plastic deformation regimes for asperity of the fractal surfaces. The two dimensional Y-K model was extended to a new one for three dimensional fractal contact. It is shown that simulation results from revised fractal contact agree with test one better than Y-K contact model, especially under large load. Thus the presented revised fractal contact model can provide more reasonable method for the prediction of contact behaviors among rough surfaces with more accurate than that of Y-K model relatively.

    #br# SOA-based Remote Intelligent Prognosis Maintenance System of Engineering Machineries
    LIU Mei-Fang, YIN Ji-Ting, TU Jian-Bei
    2012, 23(19):  2320-2326. 
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     Due to structural complexity, distributed tasks and difficult maintenance and management of engineering machineries, an intelligent prognosis maintenance system based on SOA was proposed herein. An equipment intelligent prognosis algorithm toolbox (SmartAgent) was developed and used as the core module in this prognostics system. This system implemented the remote distributed prognosis maintenance of engineering machineries based on SOA that performed heterogeneous resource sharing. Taking bearing as an example, self-organizing map-based performance degradation assessment model and Weibull failure function-based remaining life prediction model from SmartAgent were applied to implement bearing health prognostics. This paper described the application procedure of the proposed remote prognosis system systematically, where the methods for prognosis service establishment,publish and invoking based on SOA were presented. The experimental results demonstrate the effectiveness and engineering applicability of the proposed system.

    Application of  an Improved Ant Colony Optimization Algorithm for Solving Single-level Multi-period Capacitated Dynamic Lot-sizing Problem
    LI Yang-Dun, CHEN Zhi-Xiang
    2012, 23(19):  2326-2331. 
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    One algorithm structure of an ant colony optimization(ACO) for solving multi-periods continuous and mixed integer programming problem was first designed herein and then its application in the single-level multi-period capacitated dynamic lot-sizing problem(CLSP) was introduced.The algorithm was based on the model characteristics of CLSP and improvements of  traditional ant colony algorithm.Compared with other algorithms of other literature,the algorithm presented herein performs better than that the traditional genetic algorithm and the hybrid of simulated annealing penalty and genetic algorithm do;it has higher ability of obtaining optimal value.The application results show the method is feasible and effective for solving this kind problem.

    #br# Numerical Simulation of Flow and Spray Characteristics for a Direct Injection Engine with Variable Tumble Intake Port
    YIN Cong-Bo-1, ZHANG Zhen-Dong-1, GUO Hui-2, CHENG Jiang-1
    2012, 23(19):  2332-2336,2342. 
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    A three-dimensional moving mesh with variable tumble intake ports used for a gasoline direct injection(GDI) engine was established. With numerical simulation, the processes of intake, spray, mixture formation at the speed of 2000r/min full load were simulated and analyzed at two cases of opening and closing the tumble control valve(TCV). The simulation results show that: under low speed conditions, the flow rate around the intake valves at two cases is greatly different; tumble intensity in-cylinder is changed. When TCV is closed, tumble intensity in-cylinder is greatly enhanced, the tumble ratio is 4~6 times that when TCV is open. The effects of increased tumble intensity due to TCV close were considerable in promoting the evaporation of the droplets, and homogeneous charge mixture was achieved at start of ignition.

    #br# Research on Smooth Interpolation Algorithm for Five-axis CNC Machining
    DIAO Shi-Jiang-1, 2, XU Dong-2, ZHANG Xiao-Hui-1, 2, GENG Cong-1, 2
    2012, 23(19):  2337-2342. 
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    For the traditional five-axis NC machining methods in the processing of the part free-form curves which had large radius but little change in curvature will result in grooves,a smooth interpolation algorithm was proposed for five-axis CNC system.This algorithm used least square method of numerical calculation and applied it to the five-axis CNC system for machining trajectory finishing.Finally,by making the five-axis CNC machining path smooth,and restoring the original outline of smooth curves,it achieves completing interpolation curve on the smooth curve.The process simulation of round table was presented to validate the efficiency of the algorithm by VERICUT. 

    #br# Research on Electrochemical Dressing of Intersection Line of Fuel Injection
    LIU Ze-Xiang, KANG Min, YANG Yong, FU Xiu-Qing
    2012, 23(19):  2343-2347. 
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    A two-dimensional model of the electric field of three sorts of cathodes built in ANSYS software based on FEM was solved herein. The processing course was computed cumulatively by these several periods dividing the processing course of three sorts of cathodes. The distribution of the electric field of the processing region and the density of the nodes on the surface of the work piece model were obtained and the contour curves of simulation processing at different time were obtained by the position coordination of each node. The experiments were carried out to verify the electrochemical machining parameters based on the simulation. It is showed that with the amended parameters of the simulation it can meet the machining requirements of the fuel injection, which is the basis for electrochemical dressing of the intersection line of the fuel injection. 

    #br# Parameter Identification of Dynamics Model for Excavator Arm and Friction Model for Cylinder
    LI Bei, YAN Jun, GUO Gang, JIAN Hai-Bei, ZHANG Mei-Jun
    2012, 23(19):  2347-2350. 
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    Dynamics model for a single excavator arm and a driving-force model for cylinder were established, unknown parameters for the dynamics and nonlinear friction were described by linear-in-parameter models. Based on the acquired pressure and angular data, forgetting factor recursive least square method and recursive extended least square method were adopted to identify the unknown parameters. Comparison results demonstrate that both identified models approximate to the actual system well. Comparing with the forgetting factor recursive least square method, the error of the recursive extended least square method is reduced by 28%, it is more robust to the system noise.

    #br# Diffusion Transport Modeling and Numerical Analysis of Micro-elecforming under Supercritical CO2 Fluid
    LEI Wei-Ning-1, WANG Xing-Xing-2, LIU Wei-Qiao-1, CHEN Guo-Tan-1, JIANG Bo-3
    2012, 23(19):  2351-2356. 
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    Diffusion transport mathematics models of nickel ions and multi-species ions were established according to the micro-structure feature in supercritical CO2 fluid,which was simulated by MATLAB software.And the software was applied to analyse the effects of aspect ratio and current density on species ions concentration inside the micro-structure.The surface morphology and microhardness of nickel films were mainly discussed.The results indicate that the transport process of nickel ions approaches a steady state with the time increasing.From the top of micro-structure to the bottom,hydroxyl ions and nickel hydroxide ions concentration are increasing,but hydrogen ions concentration decreases gradually,the variation of nickel ions and sulfuric acid root ions concentration are not obvious.Compared to the conventional electroforming method,a higher uniformity surface of the nickel film is obtained under supercritical CO2 fluid at 10MPa and 323K,the microhardness of nickel films are as 701.2HV with current density of 5A/dm2.

    Influence of Coating Flow Field on Working Precision of Comma Blade
    LIU Zheng-Shi, YAN Ke, WANG Yong, LIU Huan-Jin
    2012, 23(19):  2357-2361. 
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    Based on the lubrication theory and using Reynolds equation, a calculation formula of the applied force of comma blade in the flow field was deduced herein. The pressure distribution graph and force variation graph of comma blade were also obtained. The effects of blade radius and minimum clearance on the scraping flow field were investigated: the applied force on the blade increases with the increase of the blade radius and decrease of minimum clearance. The direction of the resulting force is close to the direction of line of centers. Then, the deformation of comma blade under the effect of flow field was calculated. The results provide theoretical basis for the adjustment of comma blade straightness and structure design of coating equipment.

    Optimal Structural Design of 4-Roller Rolling Mill Frame Based on an IPSO Algorithm
    WEI Feng-Chao, SONG Li, LI Yan, LIU Feng
    2012, 23(19):  2361-2365. 
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    In order to get some reasonable parameters and best performance of a structure,taking the minimum bounce value of frame as an objective,a mathematical model for optimal design of the 4-roller rolling mill frame was established under the conditions that the frame met the requirements for structure,strength, stiffness and others.Considering the defects existed in the conventional optimal algorithm and standard particle swarm optimization algorithm used for dealing with complex mechanical systems,an IPSO algorithm was proposed which included three kinds of strategies,Logistic map initiating
    the population chaotically,nonlinear dynamic improving inertial weights and adjusting accelerated factor.The structural parameters of a 4-roller rolling mill frame was designed optimally by using an improved penalty function method and an IPSO algorithm.The results
     verify that the improved algorithm proposed  is correct and effective.

    #br# Mechanical Analysis of Pressure Grinding Wheel with Soft Abrasive Consolidation
    JI Shi-Ming, HU E-Min, JIN Meng-Sheng, ZHANG Li, CENG Xi, LI Xiao
    2012, 23(19):  2366-2372. 
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    A new model of pressure grinding wheel with soft abrasive consolidation was proposed herein for free-form mould with high hardness and wear resistance.First of all,based on the material properties,three materials consisting of the model were determined.The elastic modulus of two-phase model and ultimate strength were calculated.Secondly,the finite element analysis of this model was discussed to analyse the stress changed by layer thickness.Finally,the abrasive fixed gasbags were used to polish the
    free-form surfaces.The simulation results show that the thickness of dual elasmoter is in
     inverse proportion to the stress value while the abrasive player stress is opposite.After optimizing model,then the force of abrasive player increases obviously,that is finishing force increases significantly,the fore transmission is better and the optimum thickness of bonding layer is of 0.5 millimeters.The experimental results show that the processing results are the best when the thickness of bonding layer is as 0.5 millimeters. 

    #br# A Rolling Bearing Fault Diagnosis Method Based on Improved ITD and Fuzzy Entropy
    ZHENG Jin-De, CHENG Jun-Ku, YANG Yu
    2012, 23(19):  2372-2377. 
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    An improved ITD method was proposed. Meanwhile, for the difficulty that extracting fault features from the nonlinear and non-stationary vibration signals of rolling bearing, combined with the concept of fuzzy entropy, a new rolling bearing fault diagnosis method was put forward. Namely, decomposing the vibration signals of rolling bearing using the improved ITD method firstly, and calculating fuzzy entropies of the first few proper rotation components,then the entropy values as feature vectors were input to a SVM-based classifier to distinguish the rolling bearing fault types. By analysing the experimental data, the results show that the proposed method herein can diagnose the fault categories effectively.

    #br# Molecular Dynamics Simulation of  Friction Behavior on Nanoscale Textured Surfaces
    NA Jiang-Gong, LIU Geng, TONG Rui-Ting, LIU Lan
    2012, 23(19):  2378-2383. 
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    The nanoscale friction process of a rigid hemispherical tip sliding on a single crystal copper substrate was studied by using molecular dynamics simulations.Different surface textures were designed and used.The effects of the direction and the density of surface textures on the sliding friction were analyzed.Comparisons of the sliding friction with different texture direction show that the amplitude of the sliding friction is lower at 0° and  90° texture direction when the surface texture density is less than 50%.The phenomenon of slip deformation is discovered when the texture direction is as 45°.For 0°and 90° texture direction,the sliding friction increases with the increase of the surface texture density when the texture density has great difference.Compared with the smooth surface,the textured surface can reduce friction at 0° and 90° texture direction for lower texture density effectively.Employment of nanoscale surface texture has significant influence on the sliding friction,but it does not change the period of the sliding friction.

    An Experimental Evaluation of Four Multiaxial Fatigue Criteria
    JIN Dan, WANG Wei, SUN Dan, LIN Wei
    2012, 23(19):  2384-2388. 
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    Rainflow cycle counting and linear damage rule were used to calculate fatigue damage for SWT, KBM, FS and LKN criteria by previous test results. The effects of the maximum damage plane, which was as the critical plane on previous criteria were discussed. It is shown that comparing with the maximum shear/normal strain approach, the predictions are improved by using the maximum damage plane approach, part nonproportional paths for SWT, AV and part nonproportional paths for KBM, TV paths for FS. But for LKN, the predictions are nonconservative for some paths by this approach than that of the maximum shear/normal strain approach. The critical plane was chosen according to the weight function approach. For KBM and FS criteria, the better predictions were gained. While for SWT and LKN criteria, the unconservative predictions were gained for some paths. The quantity evaluation of different criteria was done by using several statistic parameters.

    #br# Comparative Study of Spot Weld Simulation Method between Beam and Solid
    CHEN Jun, CHENG Ai-Guo, CHEN Chao, DIAO Min
    2012, 23(19):  2388-2392. 
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    In the process of finite element analysis of automobile, spot modeling exerted a great influence on simulation accuracy. Authors used a single spot weld Lap-shear and dual spot weld Lap-shear model, when the position of spot weld in the grid and integral way of shell element of the welding base metal were changed, the stability of the mechanical properties of Lap-shear model was analyzed while the spot weld was simulated with Beam element or Solid element, and the conclusion drawn before was applied to validate 100% frontal crash of the vehicle. The results show while spot weld is simulated with Solid element, it is demonstrated that the stability of the mechanical properties of Lap-shear model is relatively high, and when considering welding failure, the better choice is to use Solid element to simulate the spot weld.