Table of Content

25 April 2008, Volume 19 Issue 8

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Improvement of Friction Characteristics of Paper-based
Wet Clutches by Laser-texturing of Separator Plates

Meng Yonggang;Wang Donghua

2008, 19(8):  0-885,. 

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Steel separator plate surfaces were treated with a Nd:YAG laser,and then tested on a Falex friction test machine to measure their friction versus sliding speed curves when rubbing against a paper-based friction plate.The effects of the depth,diameter and distribution patterns of the laser dimples were investigated,and the best laser texture among the 21 different patterns has been found. 

A Most Probable Point Perturbation Method for Reliability Analysis

Zhang Yimin;Wang Shipeng;Xie Yancai

2008, 19(8):  0-1007. 

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To improve the efficiency of locating the most probable point(MPP),a novel MPP search algorithm was presented that employed a new search strategy.Techniques from the perturbation method and the reliability theory were employed to present a most probable point perturbation method
(MPPPM) for reliability analysis and the proposed method is a practical and effective for searching MPP.The method was compared with the Monte Carlo simulation(MCS) method to verify the effectiveness.Two numerical examples are given to illustrate the application of the presented method.

Modal Truncation Method and Its Application in Vibration Analysis of Complex Structures

Ren Huili;Wang Xuelin;Hu Yujin;Li Chenggang

2008, 19(8):  0-885,. 

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In order to avoid time consuming solution of equations in complex structure dynamics analysis,modal truncation method was studied herein.DC gains of the individual modes of vibration were used as the criterion of modal truncation,the relative importance of the contributions of each of the individual modes was obtained and a small state space model was defined.The reduced model can accurately describe the pertinent dynamics of original system.A tower crane was used as an example to demonstrate both the theories and the methods.The results show that it is a feasible method to establish theoretic models of complex structures which can then be used in frequency and transient analysis.

Research on Uniform Design Theory for Dynamic Measurement Systems

Cheng Zhenying;Fei Yetai;Chen Xiaohuai

2008, 19(8):  0-1007. 

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Based on “whitening” error model of the total system,a uniform design method for dynamic measurement systems was put forward according to the tracing results of dynamic errors.By applying neural network method to error separation,accuracy loss function of every element can be first obtained according to that of the total system.Then,after analyzing the unbalance of the accuracy loss of every element,the authors set up uniform accuracy loss models for weaker elements by equal life design principle and present some approaches to improve system life.Finally,the method is proved to be true and effective by simulation.

An Adaptive Optimizing Tool Orientation Method for 5-axis Toroidal-end Milling of Free-form Surfaces 

Zhang Ying;Zhang Dinghua;Wu Baohai;Li Shan;Luo Ming

2008, 19(8):  0-885,. 

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This paper focused on the 5-axis milling of free-form surfaces with the toroidal-end cutter.First,the function between the machined strip width based on second order approximations and the tool orientation was constructed and analyzed.Second,according to the principle that the cutting shape of the cutter matches the designed surface at the cutter contact point,the inclination angle which satisfied the local millable condition was calculated automatically.Finally,the optimal tilt angle was determined by maximizing the machined strip width.Examples show that the algorithm presented herein is feasible and the results are with shorter tool path and efficiency.

Study on 3D-Coordinate Measurement Technology Using Light-pen 
Based on Binocular Stereoscopic Vision System

Xie Zexiao;Jin Ming; Xin Yuexiang

2008, 19(8):  0-1007. 

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A novel 3D-coordinate measurement system using light-pen based on binocular stereoscopic vision system was presented.Based on contact measurement mode the system used light-pen with light sources as a contact measurement tool.Firstly,the cameras were calibrated high accurately,and the stereoscopic vision system model was established.Secondly,the 3D coordinates of the center of LED on the light-pen were achieved through matching the 2D images grabbed by the two cameras.Then,a series of the 3D coordinates of the center of LED were used for fitting straight line,and the 3D coordinates of the pen-points can be obtained from the line. The test results show that this system realizes contact measurement on objects, with virtues such as simple configuration and low cost,and possesses high accuracy.

Applied Research of Reproducing Kernel Particle Methods to 
Structural Dynamics Response Analysis

Zhang Jianping;Gong Shuguang;Huang Yunqing; Chen Renke;Nie Songhui

2008, 19(8):  0-885,. 

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According to the basic theory of meshless method and
structural dynamics,dynamics equations based on
Reproducing Kernel Particle Methods for beam and plate were deduced,and the correlative programs were written.The displacement response of damped beam and plate under different boundaries and types of load was computed.The effects of penalty factor and time step on the calculation accuracy and efficiency were discussed,
and then these results were compared with finite element analysis results. It shows that this method has a good convergence and accuracy,and a new numerical computation
method is presented for structural dynamics response analysis.

3D Reconstruction Technology of the MFL Inspection Data

Song Xiaochun,;Zhao Daxing，; Zhong Yuning,

2008, 19(8):  0-1007. 

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According to the difficulty in the visualization for magnetic flux leakage (MFL) inspection data, an effective method was proposed to reconstruct the 3D defects profiles from the measured MFL data. Firstly, the iterative algorithm,based on the 3D finite element neural network (FENN), was used to solve the MFL inverse problem and generate 2D slice image series of the defect, and each slice image had its corresponding sensor.In order to reduce the effects of the deficient-sensors on the reconstruction accuracy,the matching points for interpolation were determined in accordance with the contour features of the defect on the ferromagnetic objects, and the linear method was then used to realize the interpolation between the adjacent contours of the slice images.Finally,some triangle meshes were used to join the two adjacent contours,and the 3D surface model of the defect was reconstructed from the slice image series.

On Density Evolution Analysis for Dynamic Behaviors of Maintenance System

Yin Xiaohu;Qian Yanling;Yang Yongmin;Wen Xisen

2008, 19(8):  0-885,. 

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The dynamic behaviors of equipment maintenance system,which was under multiphase mission and was subjected to more than one maintenance strategies,were discussed.With analyzing the state evolution,the partial differential equations of state probability density were built up with supplementary variable method,which can be used to portray the dynamic behaviors of maintenance system.The performance indexes of maintenance system,including equipment availability and maintenance frequency,were calculated,and the optimal minimal repair numbers were determined.Dealing with the two levels,micro and macro,of maintenance system,the method can be used to model and analyze the operation process of maintenance system.The information about the system state probability density can be used to explain the mechanism of maintenance system, which is critical to the optimization and control of maintenance system.

A Contact Stylus Profilometer with Large Range

Yun Jianping;Yang Xudong;Xie Tiebang;Zhang Lingling

2008, 19(8):  0-1007. 

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It is important to precisely measure surface topography for studying surface properties and monitoring the technological process.A novel contact stylus profilometer had been constructed,which was a combination of a lever mechanism,an x-y scanning stage and a Linnik microscope interferometer with a spatially and temporally incoherent light source.Incorporating a vertical scanning stage,the profilometer has large measurement range,high precision and small touch force.Its vertical measuring range is 5mm with a resolution of 1nm;and the horizontal measuring range is ±25mm in x-and y-range with a resolution of 1.25μm. 

Research on Evaluation Method of Modularization Grade of Products

Liu Fuyun;Qi Guoning

2008, 19(8):  0-885,. 

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Applying complex network to product modularization field,a module disassembling method of products was proposed.A coding method of dimensions of product was proposed.A method of how to construct dimension correlative relation network was presented,and a network of dimension correlative relation based on main model and main structure of product was constructed.A method of how to calculate the modularization coefficient of product was proposed,and an evaluation method of modularization grade of product was
obtained.As an example,all methods were applied to gear-box product, and the methods were verified.

A Partner Selection Algorithm Based on Immunity for Agile Virtual Enterprises

Su Zhaopin;Jiang Jianguo;Xia Na;Zhang Guofu 

2008, 19(8):  0-1007. 

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Optimizing the math model by introducing multi-objective constraint conditions,an immunity based partner selection algorithm was proposed for agile virtual enterprises,moreover adaptive vaccine obtaining strategy
and 2-dimensional and binary coding manner were presented.Finally a typical simulation study was carried out to illustrate the validity and practicability of the algorithm. 

An Improved Algorithm for Single Machine Scheduling with Release Dates

Li Kai,;Ma Huawei,;Yang Shanlin, 

2008, 19(8):  0-885,. 

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This paper considered the single machine scheduling problem with unequal release dates so as to minimize total completion times.This problem was proved to be as an NP-hard problem.Traditional heuristics for the problem were analyzed,and then we presented an improved algorithm.A numerical example and its computational result were given.The performance of the algorithm was also analyzed by experiments and the experimental results show that the algorithm is more effective than the existing heuristics.

Project Control for Virtual Enterprise Collaborative Manufacturing
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Li Yingjie;Chen Qingxin;Chen Xindu;Chen Xin

2008, 19(8):  0-1007. 

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The project schedule control problem for virtual enterprise was investigated.And analyzing the uncertain factors of the project control in virtual enterprise,two kinds of stochastic models were first put forward,which can describe the uncertainties of the durations and the costs of the activities in the project.Based upon these models,the method of estimating crash project was brought out.And the negotiation mechanism which synthesizes duration’s safety and costs validity in the project rescheduling procedure was presented.Next,the implementation of such an mechanism was explained with a simple example.As for the characteristics of the mould and die manufacturing,the negotiation mechanism was carried out on a manufacturing project of the industry.The simulation result shows that the model was applicable,and the negotiation mechanism is reliable and effective as well.

Research on Process Modeling of Product Structural Design Based on Knowledge Driven and Its Applications

Zou Chunwen;Zhang Shuyou;Lai Jianliang

2008, 19(8):  0-885,. 

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Genetic code of knowledge unit was defined.Correlation matrices of function-structure and knowledge-structure of products were introduced.Process models of product design were established according to correlation matrix.By operating on genetic codes,process modeling of product design based on knowledge driven was implemented.The approach proposed was proved in the design of a hot runner with 32 cavities,and it lays the foundation for the realization of the knowledge-based product design.

Research on Smooth Filling Algorithm of Large Holes in Triangular Mesh Model

Wei Zhengliang;Zhong Yuexian;Yuan Chaolong;Li Renju

2008, 19(8):  0-1007. 

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To large holes on the area where curvature variation is complex,this paper presented a smooth holes filling algorithm based on surface fitting.First the basic feature information of hole was achieved and hole was directly filled according to its boundary;then new sample points were acquired inside hole by mesh sub-division and optimization;finally the position of every sample point was adjusted by its weighed surface fitting.Application examples prove that excellent repair mesh can be achieved by this algorithm.It well approximates the original surface and smoothly transits to the original neighbor mesh.

The Thermal Dynamic Characteristic of Ball-screw under the Variational Multi-thermal Source
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Xia Junyong;Wu Bo;Hu Youmin;Shi Tielin

2008, 19(8):  0-885,. 

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On the basis of theory of heat transfer, temperature response and variational characteristic of ball-screw brought by periodic endmost heat source
was researched. Temperature response of ball-screw produced by random heat source signal was discussed. And, the function of temperature field induced by variational multi-thermal source was brought out with overlap technique.By finite element simulating,the validity of academic result was verified,and the dynamic graph of thermal error in track of ball-screw was gained.

Movement Reliability Analysis of Joints in Deployable Truss Antenna

Hou Guoyong;Guan Fuling;Zhao Mengliang

2008, 19(8):  0-1007. 

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Aiming at the deployable joints in truss antenna,considering them as separate rockers,breaking up the function,its movement reliability was found to have two parallel performance functions:the performance function according to deploying work and that according to deploying moment.Corresponding to the decomposed phase in deploying process,the expressions of two performance functions were established.Then two-kind reliabilities can be calculated from the two performance functions by means of the random functional moment method and the second moment method for reliability analysis.The movement reliability of one deployable joint can be got from two parallel reliability models.Finally,the movement reliability of deployable joint was analyzed with an example. 

Analysis on Jet Stability of Magnetorheological Jet Polishing

Zhang Xuecheng;Dai Yifan;Li Shenyi;Peng Xiaoqiang

2008, 19(8):  0-888,. 

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In magnetorheological jet polishing(MJP),the stable and collimated jet of magnetorheological(MR) fluid magnetized by a local axial magnetic field near the exit of the nozzle was used to polish the remote surface in a deterministic precision process. But the theoretical considerations on the mechanism of jet stabilization were required for optimization of the technology.Therefore,the stabilization of MR jet under the external axial magnetic field was analyzed.Firstly,a kinematic model was developed to analyze the MR effects on the jet flow.Secondly,the stabilization of MR effect was numerically simulated by finite element methods based on the Maxwell equations and the kinematic equation of MR jet.Thirdly,experiments were conducted to observe the jet structure of the MR jet under the external magnetic filed.Finally,the stabilization of axial magnetic field on MR jet was analyzed based on the knowledge of continuous medium.And the results are consistent with the experimental ones.The longitudinal chain-like fibrillation and subsequently high apparent viscosity within the MR jet induced by a local axial magnetic field can suppress jet breakup in the stage of initial dynamic disturbances and result in a stable and collimated jet remaining for a relatively long distance.Due to the insensitivity to the offset distance MJP has potential advantages in deterministic precision polishing of complex shapes of steep concave optics and cavities.

Research on Roll Contour Optimization in Solving Defect of Local Convexity of Steel Coil

Yu Bin;Yue Xiaoli;She Guangfu;Yang Xiuliang;Lian Jiachuang;Liu Hongmin

2008, 19(8):  0-1007. 

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To solve defect of local convexity of steel coil caused by bad profile of cold-rolled strip,which was inherited from bad profile of hot-rolled strip,an optimization way of work roll contour was presented based on the objective functions of strip profile and proportion crown for repairing bad profile of hot-rolled strip.The optimization model was established based on the research of practical production conditions and shape flatness theory,then roll contour and calculation analysis were developed.Production experiments show that strip profile is obviously improved,and defect rate is greatly reduced by the technique of contour optimization,which brings enormously economic benefits for corporations.

Sample Approach for Fatigue Life Prediction of Structures under Random Vibration

Wang Mingzhu;Yao Weixing;Sun Wei

2008, 19(8):  0-888,. 

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A sample approach was proposed herein,which was for fatigue life prediction.The approach can estimate the lifetime of structures under broad band random vibration loading in the frequency domain described by power spectral density.Firstly,random vibration loading in the frequency domain was converted to the repeated loading in the time domain.Secondly,the stress-time history at the damage location of the structure was obtained by FEM analysis and the stress spectrum of random vibration was formed by range counting method.Consequently,the structural fatigue life is estimated by the traditional method.Its expectation and variance at damage location is gained.An example was employed to demonstrate the suitability of the approach.The predicted results show a good agreement with the experimental data.

Product Interface Shape Design Method Based on Energy Optimization Theory

Liu Xiaojian;Sun Shouqian

2008, 19(8):  0-1007. 

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For the purpose of getting high ergonomics quality shape of complex human-product contacting surface, human body shape and interface pressure need to be considered.The distributive feature and interface pressure of product interface were analyzed,and an energy optimization design method based on interface pressure was proposed.The energy functions and the solving equations were given, with a design procedure model based on energy optimization theory,considering the load, pressure distribution,
surface material property setting and smoothness.The basic mechanism is built to realize the mapping from experimental data to product interface shape.The design method was used to design the seat surface for result evaluation.The mapping rules from interface pressure to product shape were discussed,with a comparison of the result interface shapes.

Experimental Investigation of Grinding Temperature and Its Effects on Surface Quality in Surface Grinding 

Zhou Zhixiong ;Mao Cong;Zhou Dewang;Ren Yinghui

2008, 19(8):  0-888,. 

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The grinding temperature distribution and the grinding forces within the contact zone were measured by using a thermocouple and a 3-axis piezoelectric dynamometer,respectively.The morphologies of the ground workpiece surfaces were observed by a scanning electron microscope(SEM).A Talysurf was used to measure the surface roughness of the ground surface.It is found that the grinding parameters have serious effects on the grinding temperature, and the grinding temperature significantly interacts with the contact length.From the viewpoint of the generating mechanism and deformation state of chips,it is analyzed that the temperature of down grinding is higher than that of up grinding. The relation between the grinding temperature and the morphology of the ground surface was discussed,as well as the relation between the grinding temperature and the surface roughness of the ground surface.The grinding temperature has little effect on the surface roughness of the ground surface,provides that the grinding temperature is not high enough to cause an evident burnout on the ground surface.

Research on Rotor Dynamics with Sudden Change Frequency
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Wang Zongyong;Gong Bin;Wen Bangchun

2008, 19(8):  0-1007. 

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Dynamical model and equation of Jeffcott rotor system with sudden change frequency were established based on rotor dynamics.Vibration expression of rotor system with sudden change frequency was obtained through analytical method.Relationship between the steady-state amplitudes fore and after frequency suddenly changed was analyzed,and the influence of sudden change frequency on maximal axis displacement was also studied.Transient time after frequency suddenly changed was defined and rubbing parameters region was determined.The conclusion indicates that sudden change frequency can cause the magnification of rotor amplitude;rigid rotors system with sudden increased frequency and flex rotors system with sudden reduced frequency have huge influence on steady-state amplitude; transient time is related with system damp, operating frequency,and axis azimuth when frequency suddenly changed;rubbing parameters region will increase with mass eccentricity enhancing.

Study on the Influence of Single Wheel Sprung 
Weight on Valves Design Parameters of Hydro-Pneumatic Spring

Zhou Changcheng,;Jiao Xuejian

2008, 19(8):  0-888,. 

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With the computation formula of opening valve pressure and throttle slice deformation, the design analytic formula of single throttle valve slice thickness was established.Through the relation of pressure with the flux,and the continuum theorem of liquid,the design formula of throttle aperture of hydro-pneumatic spring was established.Based on this,the influence of sprung weight on valves design parameters was analyzed,the influence coefficients were found.Using practical example of hydro-pneumatic spring,the valve parameters were designed with the methods of analytical design and influence coefficients,the equivalent thickness of superposition slices,opening valve characteristic and stress intensity were validated, and the performance test was conducted for the designed hydro-pneumatic spring.The experimental and design results show that the sprung weight has influence on the valves design parameters,the analytic design method of valves parameters of hydro-pneumatic spring is accurate,and the sprung weight influence coefficients is reliable.

Development of the Control System for 16MN Fast Forging Hydraulic Press

Chen Baijin;Huang Shuhuai;Jin Long;Gao Junfeng

2008, 19(8):  0-1007. 

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A control system consisting of a computer and PLC was developed for 16MN forging hydraulic press.In this system,the software was utilized to carry out the performances of control,adjusting and monitor,i.e.,software instead of hardware.Multi-mode fuzzy prediction technology was used to realize the smooth,steady,no vibrating and precise position control.The actual application demonstrates that the developed system has advantages of low cost,low complexity and high reliability.Furthermore,the frequency and precision are also improved .

Study on Aluminum Anticorrosion Protective Coating on Magnesium Alloy by Magnetron Sputtering

Wang Zhenlin;Yang Hui;Yang Donghua

2008, 19(8):  0-1007. 

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Aluminum protective coating was deposited on AZ31 magnesium alloy by magnetron sputtering.The composition profile,morphology,micromechanical properties,anticorrosion performance and influence of processing conditions on the coating were investigated.The results show that fine crystals sized 1~2μm deposited uniformly to form dense coating on the surface of magnesium alloy substrate with a diffusion intermediate layer between them;the coating has elevated hardness,elastic modulus relative to substrate with surface roughness lower than 2μm and adhere well to the substrate being characterized by somewhat toughness;the coating quality can be improved by reducing Argon pressure and increasing sputtering current.The corrosion potential of magnesium alloy is increased and the corrosion current reduced by depositing the coating and the corrosion tendency is restrained accordingly,although the corrosion potential is lower than that of hot spray aluminum and current higher than that of macroarc oxidation.

Fuzzy Distribution of Braking Forces in United Braking System of Downhill Automobile at Constant Speed

Zhao Yingsheng;He Ren;Wang Yongtao 

2008, 19(8):  0-1007. 

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The conception of automobile united braking system was brought forward,and the dynamics model of downhill automobile and thermodynamics model of eddy-current retarder and primary brakes were established.Based on these models,a fuzzy distributor of braking forces of the united braking system was designed,which dynamically distributed braking forces between the eddy-current retarder and the primary brakes according to the temperature of the retarder rotor plate and the primary brakes.The simulation calculation results of an actual vehicle at different initial running situations show the united braking system，comparing to the retarder only or the primary brakes only,can effectively alleviate the temperature burden of the retarder rotor plate and the primary brakes,and prove that the fuzzy distributor designed can control the brake arrangements temperature to guaranty the braking efficiency.