Table of Content

25 October 2012, Volume 23 Issue 20

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Digitization and Intellectualization for Manufacturing Industries

ZHOU Ji

2012, 23(20):  2395-2400. 

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This paper holds that,first of all,as the world economic competition framework is undergoing profound changes,major developed countries have proposed the strategy of “reindustrialization”,putting forward significant measures to revitalize manufacturing industries dependent on scientific and technological innovations.A new round of industrial revolution is deepening.The author continues to argue that,the digitalization and intellectualization of manufacturing industries can be viewed as key technologies for the new round of industrial revolution.On the one hand, they are the generic enabling technologies for the realization of mechanical products innovation,developing mechanical products towards “NC generation” and “intelligent generation”,boosting the functions,overall performance as well as market competitiveness of them fundamentally.On the other hand,they are the generic enabling technologies for the manufacturing technology innovation,developing manufacturing industries towards integrated manufacturing system featuring digitization and intellectualization, promoting the products design,manufacturing as well as management levels comprehensively,with the manufacturing service industry being developed at the same time,thus reforming the production mode and industrial pattern & structure of manufacturing industries greatly.Last but not least,the author believes that,the next twenty years can be regarded as a period characterized by precious opportunities of strategic importance,for China to transform from being a “big nation in manufacturing” to a “powerful nation in manufacturing”.China's manufacturing industries should and are most likely to make leaping progress during this time span,especially to make strategic breakthroughs in “digitization and intellectualization of manufacturing industries”,thus making historical contributions for the modernization of China.

Uncertainty Evaluation of CMM for End Distance Measurement

LI Gong-Chi, CHEN Xiao-Fu, WANG Hong-Chao

2012, 23(20):  2401-2404. 

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A complete uncertainty evaluation process of end distance measurement by CMM was presented.To begin with,the major sources of uncertainty,which would influence measurement results,were found out after analyzing,then, a general mathematic model of end distance measurement was established.Furthermore,Monte Carlo method(MCM) was used,and the uncertainty of the measured quantity was obtained.The complete results were given out,so the application value of CMM was enhanced.Moreover,seen from the evaluation example,the results of uncertainty evaluation obtained from MCM method and from the method provided by Guide to the Expression of Uncertainty in Measurement(GUM) method were compared,the comparison result indicates that the mathematic model is feasible,and MCM method to evaluate uncertainty is easy and efficient.

Reverse Design and Kinematic Analysis of Non-circular Planetary Gear Trains Weft Insertion Mechanism

CHEN Jian-Nai, WANG Yang, LIN Gen-Yong, DIAO Xiong, LEI Chang-Yi

2012, 23(20):  2405-2409. 

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In order to analyze the kinematic characteristics of non-circular planetary gear trains weft insertion mechanism and then obtain a group of preferable parameters, a kinematic model of this mechanism was established. Besides, the aided analytical and kinematic simulation software was compiled based on Visual Basic 6.0. The influences of several important parameters on the shape of pitch curves of the non-circular gears in this mechanism were analyzed, and a group of preferable structural parameters were obtained. The movement simulation analysis was conducted under this group of parameters. Under the condition of same reed width and rotary speed of loom spindle, this novel mechanism was compared with the weft insertion mechanism applied on the TT96 rapier loom. The conclusion shows that non-circular planetary gear trains weft insertion mechanism has smaller maximum value of velocity and acceleration, and it can meet the requirments of weft insertion.

Study on Rapid Design of Key Parts for TBM

TUN En-Qi-1, WANG Rui-1, MIN Dui-2, SUN An-Bei-1, DU Bao-Jiang-1

2012, 23(20):  2410-2413. 

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A rapid virtual design system for key parts of TBM was developed.Based on the experience of design and construction for TBM and the correlative experimental data,an expert database was constructed.Firstly,more than two virtual prototypes were built by interactive design in real time.Secondly,the key parts and assembly were optimized by FEA.Through this method,human experience factor is decreased.The TBM development time is saved more than 30%.

Research on Product Robust Design Model Based on Quality Structure

FANG Zhi-Geng, LI E-Beng, LIU Yuan, XU,LAN,YANG Bao-Hua

2012, 23(20):  2413-2419. 

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Parts as basic elements of a product,constituted a whole as a result of their hierarchies and cross-relationships.Nevertheless,classical thrice design was just based on simple quality structure and designed single parts only,ignoring hierarchies and cross-relationships.For this reason,we proposed a new top-down model based on quality structure for product robust design.On the basis of customer's demands for product quality,the framework of product quality structure according to relationships of its function structure(chart) was established.Then we considered the chart as the design path and decomposed quality objective top-down,making each part having its own objectives.Next we carried on parameter design and tolerance design on the basis of quality indexes of each part.At the same time,hierarchies and their cross-relationships of quality factors should be considered.Finally,a case was used to prove the feasibility and effectiveness of new model and algorithm.

Regulating Method on Deflection of Comma Blade

WANG Yong, TUN Chang-Qiang, LIU Zheng-Shi, LIU Huan-Jin

2012, 23(20):  2420-2423. 

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In the working process of a coating machine,the regulation of comma blade has an important influence on the quality of the products.Nowadays,the problems of low precision and efficiency of regulating deflection were caused by manual manipulation.Based on coupling of deflection regulation theory and nonlinear control theory,a linear regulating method based on the balance position was proposed,and the formula of regulate deflection was deduced.In the regulating experiments of comma blade,the defomation figures of blade in different loads and different positons were obtained,the principle of regulating deflection was tested.Results show that the formula of regulatinge deflection can improve the blade deflection substantially.

Numerical Simulation and Experimental Verification on Magnetic Fluid-based Level Sensor

CUI Hai-Rong, ZHENG Jin-Jie, YANG Chao-Zhen, WANG Hua-Feng

2012, 23(20):  2424-2429. 

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This paper deduced detection principles of one kind of inductive level sensor based on magnetic fluid.An approach of numerical simulation for simulating output characteristics of this kind sensor was proposed.The results of the simulation were verified by an experimental test and there is a good correlation between the two results.It shows that,after structural parameters are decided,the output voltage and sensitivity of this level sensor are all linear with magnetic susceptibility,with the peak value of driving current,and with pumping frequency whose appropriate span is  as 500～2000Hz.Meanwhile,output voltage signal is linear with level tilt angle while the sensitivity is independent with it.

Design Method of NC-EDM Electrode for Components with Closed Complex Flow Channel

TUN Pan-Nong-1, DIAO Jian-She-1, TANG Lan-Jian-1, LIU Chen-2

2012, 23(20):  2430-2433. 

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Taking the flow channel in a closed integral impeller processing by numerically controlled electrical discharge machining (NC-EDM) for instance, by analyzing manufacturability of the flow passage among the impeller and machining areas partition, a method of electrode design was presented based on equal discharging gap hypothesis as well as its machining moving path with method for reducing the processing errors caused by electrode orbiting discussed. This method for designing electrodes was proposed by employing CAD/CAM module of Unigraphics redevelopment, whose feasibility was verified on a four-axis NC-EDM machine by trial-manufacturing a closed integral impeller with complex flow passage.

Analysis of Structural-acoustic Coupling of a Panel in a Rectangular Enclosure

TAO Hao-Ping, ZHANG Jing

2012, 23(20):  2434-2437. 

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A model of sound field of a rectangular enclosure with a middle flexible panel was deduced. By means of continuous distributions of artifical springs along boundary of flexible panel, this model allowed the consideration of a wide variety of boundary conditions. A general formulation considering the full coupling between the two cavities and the panel with different boundary conditions was developed. Two main issues were reached herein with the cavity 1 was excitied by internal sound source. One is that the translational stiffness has more influences on the structural-acoustic coupling of the model and the panel velocity than the rotational stiffness has，the other is that the sound response of cavity 2 caused by panel increases with the increase of the translational stiffness. The paper provides some supporting in engineering theoretically.

Gaussian Curvature of Micro-WEDM Surface Convex Peak

ZHANG Zhi-Hang, GUO Li-Bin, CUI Hai, ZHANG Ban

2012, 23(20):  2438-2442. 

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Micro-WEDM surface of microscopic three-dimensional morphology with the traditional cutting of the surface is completely different; the surface morphology with a single mechanical cutting surface is entirely different. It belongs to isotropy surface, the measurement directions have great effects on hybrid parameter when it carries on the 3D assessment of surface roughness. The improper choice of measurement directions will make the hybrid parameter with a lower calculation precision, or even the calculation opposes the actual observation for measured surface. This paper used Gaussian curvature characterization concave-convex quality of micro-WEDM surface convex peak
according to the characteristics of micro-WEDM surface convex peak, and eliminated the interference of measurement directions on calculation results. The experimental results indicate that Gaussian curvature characterization concave-convex quality of micro-WEDM surface convex peak achieves high computational precision, and the results are reliable accurately.

Motion Analysis of a Spatial RSSR Mechanism of Joints Laminated Coupling

SHEN Tu-Liu-Fang-1, YANG Beng-1, ZHANG Yu-Lou-1, SUN Cheng-Long-1, 2

2012, 23(20):  2442-2444,2452. 

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Joints laminated coupling can be simplified into a spatial RSSR mechanism.The paper obtained the coordinates of both ends of coupler of RSSR mechanism by means of the method of matrix transformation,derived the input and output equations according to the invariance of length of coupler;at the same time,
obtained three relative corners of coupler relative to the output shaft according to the direction cosine matrix.The paper also obtained the corresponding position equation by projecting the closed vector on the axis;and derived the relative angular velocity and angular acceleration by asking the first derivative and the second time derivative of three corners.At last,on the basis of these,the absolute angular velocity and absolute angular acceleration of the output shaft were abtained.

Research on Modeling Technology of 3D Statistical Model for Gingival Contours

TUN Ting-1, 2, LIAO Wen-He-1, DAI Ning-1

2012, 23(20):  2445-2452. 

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A novel and automatic shape modeling methodology for gingival contours from dental triangle meshes was proposed to build a 3D statistical model.The gingival feature lines were first obtained from the 3D dental model through a discrete curvature analysis and shortest path searching algorithm.Based on the gingival line differential characteristics, the feature lines were partitioned to demarcate the gingival line of each individual tooth.Through B-spline curve approximation to form the closed and smooth gingival contour of each tooth,the shape vector for training the model was then achieved using the control points of the B-spline curves.Finally,the statistical shape model was constructed through principle component analysis on the training set of the gingival shape vector.Experimental results demonstrate that this method can detect the gingival contours automatically and fastly,and the statistical model can capture the important variations effectively in arch and gingival morphology.

Point Cloud Based Dynamic Representation for Heterogeneous Objects

YANG Ji-Quan-1, SHU Yu-Fang-1, 2, LI Jing-Bei-1, SHI Jian-Beng-1

2012, 23(20):  2453-2458. 

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An approach of point cloud based dynamic representation for  heterogeneous objects(HEO) was proposed to describe those HEO,whose materials distribution was ununiformed or irregular.Mesh refined STL model and micro-tetrahedral cell were employed to rebuild HEO geometry.Meanwhile,distribution property,volume fraction and distribution vector were used to represent material features of HEO nodes within each material layer.HEO geometry and material composition representation can be defined after the above interrogation process was implemented layer by layer.The approach is effective and practicable through some numerical examples demonstrated based on developed HEO fabrication system. 

Design Method of Marine Cable Twisting Machine Based on Case-based Reasoning

CHEN Qing-Lin-1, LIN Shao-Fen-1, ZHANG Jun-2

2012, 23(20):  2459-2465. 

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Based on the principles of CBR,the characteristic parameters and their degree of association of a cable twisting machine were analyzed and calculated to set up the case library.The designed reasoning algorithm can retrieve each characteristic parameters and their correlation degrees in the design process.CBR was an artificial intelligence methodology that used past design solutions and adapted them to solve current problems,allowing reuse and modification of previously successful designs to accelerate the design process.The prototype of  cable twisting machine was established by adding constraints with dynamics software to the 3D model.The load of axle was calculated with different cable velocities,and the control precision of the converter was figured out when simulation computation on the constant tension control was processed with the test data of tension.In addition,FEA of the reel was carried out in order to check the structure strength. 

Analysis of DEM Numerical Simulation of Media Movement for a Stirred Mill

MU Fu-Sheng, YANG Feng

2012, 23(20):  2465-2468. 

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A vertical stirred mill was used widely and its internal media campaign was understood poorly,so a stirred mill of a company was studied.Media particles in the mill were tracked using three-dimensional discrete method,a mathematical model of stirred mill system was established to simulate the whole process of the complex motion of particles considering their gravity,friction and impact force.The results show that the speed of the media in the vicinity of the screw stirred is large,grinding efficiency is high,the mill system achieves a state of equilibrium in operation approximately,friction work increases linely with time but the total kinetic energy is at a fixed value with upper and lower fluctuation.

Study on Automatic Generation Method of BOM of Bolts and Parts of Steel Bridge Based on Coordinates rojection

CHEN Lei, DENG Meng-Ran, JIANG Zheng-Feng, LUO E-Bei

2012, 23(20):  2469-2476. 

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Main structure of a steel bridge is mainly composed of plates and angle steels,which possesses ten thousands of high strength bolts and parts.Bolts information obtained through artificial estimation or shaft and hole assembly feature number is not accurate and BOM of parts and bolts can not be automatically generated.Focusing on this problem,an automatic generation method of BOM of bolts and parts based on three-dimension CAD system was proposed.Firstly,the structural relation of parts was obtained from the relation of components of assembly model and geometry informations of parts were obtained from solid features,so the minimum containment size can be computed by coordinate projection.Meanwhile,part sets connected by bolts were filtered from assembly features of the assembly model,then numbers,diameter and coordinates of bolt holes were obtained from solid features of the model.Secondly,coordinates of bolt holes and coordinate of the fitting point were projected to the minimum contain region of the fitting face.According to the projection relation,the parts penetrated by the bolt holes were determined.Finally,the number and size of the bolts can be obtained based on geometric information of the bolt holes and geometric information of parts.The BOM of bolts and parts can be generated by the information.This method has been applied successfully to bridge and tower design.

Calculation of  Upper Iimit Load for Assembled Frame Hydraulic Press under Given Pre-tightened Force

JIN Miao-1, DONG Xiao-Chuan-1, JU Zong-Wan-1, SUN Jian-Xin-2

2012, 23(20):  2476-2480. 

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Aiming at the defects of traditional calculation model of the pre-tightened assembled structure,a critical criterion was proposed that the stress of inside corner at the top of upright column was equal to zero.Then a calculation model considering bending,tension and compression deformation was established under the given pre-tightened force.Combining with the force balance and deformation coordination conditions,
the formula of upper limit load was derived,when the typical pre-tightened assembled structure hydraulic press was under the center load.Taking a 120MN heavy free forging hydraulic press as the prototype,
a metal model press  by the ratio of 1∶15 was made to verify the proposed model.The experimental results demonstrate that the model established  herein is accurate and reliable,there is a substantial increase in the accuracy than that by the traditional one.

Motion Control Strategy Simulation of a Lunar Rover for Slope Travel

HUANG Wei-Dong-1, 2, BAO Jin-Song-2, XU Wei-Sheng-3, DIAO Hai-Liang-3

2012, 23(20):  2481-2487. 

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The slopes are a typical terrain of the rugged lunar surface.Based on the analysis and improvement of the wheel-terrain interaction model,a lunar rover terramechanics model for climbing-up-slope was established.Taking into account the deformation of the front wheels on the lunar soil,the calculation of the front and rear wheels sinkages were proposed.Finally,with the analysis of the course of the lunar rover climbing up the slope,it can be concluded that when the slope angle exceeds 21.8°,the motion control strategy aimed at obstacle avoidance should be adopted.When the wheels have enough traction,the wheel's rotating speed can be controlled,so as to carry out the motion control strategy,which can enable the lunar rover to run at the optimal slip rate with the maximum driving efficiency.And the motion control strategy was simulated in a 3D visualization simulation platform of lunar rove and verified by experiments.

Joining Strength Comparison among Self-piercing Riveting,Clinching and Resistance Spot Welding

HUANG Zhi-Chao, LIU Xiao-Kun, JIA Lian-Jun, TIE Jin-Jing

2012, 23(20):  2487-2491. 

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Self-piercing riveting,clinching and resistance spot welding were described by joining Q195 steel sheets and 5A05-O aluminum sheets respectively.The tensile tests and failure modes were also analyzed.The results show that the joint of resistance spot welding have higher static strength than the other two joints when steel sheets are joined;while the joint by self-piercing riveting have the best strength when aluminum sheets are joined.The joining strength of steel sheets is about 2~4 times larger than that of aluminum sheets for the same jointing technology. 

Calculation of Steady-State Equilibrium Position of Tilting Pad Journal Bearing in Motorized Spindle

XU Shen-Bei, CHEN Shi-Ban

2012, 23(20):  2492-2496. 

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A novel search method was presented to calculate the steady-state equilibrium position of a tilting pad journal bearing in motorized spindle for solving the problem of difficult search of equilibrium position from the nonlinear hydrodynamic force.It is found that the slight variations in fulcrum position of pads will have a great influence on the 8 hydrodynamic coefficients during the calculation.With the proposed methods,the steady-state equilibrium position can be calculated in multiple directions search in motion  polar coordinate system. The calculated results show that the stability is improved by increasing the difference between outside diameter of pad and inner diameter of bearing bracket.Never-ending loop in process of search is avoided effectively by using of the novel search method. The method can also be applied to other forms of hydrodynamic bearings.

Flight Data Visualization System Based on Testing Data

MENG Qiang-Rui, YAN Chu-Liang, TIAN Zhao-Feng, LI Wu-Yi

2012, 23(20):  2496-2500. 

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According to the demands of flight testing data visualization,a method of flight visualization  was proposed based on the flight testing data.A general data optimization layer was established by data pretreatment technology.Modelling and control of aircraft were carried out by the technology of OpenGL,and the plane flight attitude visualization module was completed.Through KML and Bursa-Wolf method the aircraft flight track visualization module was designed.Each module is versatile and ductility,multiple types of flight visualization function were finished through this method,and was used in flight measured data management platform ultimately successfully.

Impacts of  Press Amount on Forming Property of Micro Fuel Cell Bipolar Plate

WANG Jun, DING Cheng, HU Zhen-Yang, ZHANG Wan-Wan, YIN Bi-Feng

2012, 23(20):  2501-2503,2508. 

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The bipolar plate is a key component of micro fuel cell.It is difficult to form the high precision flow channel of bipolar plate under the micro scale.Herein,an accumulative forming method for the characteristics of bipolar plate was presented.On the basis of introducing the principles of micro-accumulation forming,we set up the corresponding experimental apparatus,selecting 9mm×9mm×0.165mm and 9mm×9mm×0.27mm aluminum plate as the bipolar plate blanks to do the accumulated forming test.We analyzed the shaping law and the influence of different amount of underdraught on the forming force,comparing the maximum forming force under different amount of underdraught.The results show that the plates with different thickness present the same law of forming force,the forming force reaches maximum at the starting point as increasing the amount of underdraught,then the forming force decreases firstly and then increases,at last reaches the vicinity of the maximum forming force at the end of flow channel.The bigger the amount of underdraught and the thickness of plates,the greater the maximum forming force.The maximum forming force of 0.27mm sheet plate with the underdraught of 0.5 times thickness is greater than that of 0.165mm sheet plate with the underdraught of 2 times thickness.

Investigation on Improving Accuracy of  Bending Workpiece with Crowning Compensation Method

LI Heng-1, LIU Quan-Kun-1, CHEN Chen-1, XU Zheng-2

2012, 23(20):  2504-2508. 

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In order to solve the problem of inconsistent angle in the length direction of the bending pieces due to structural deformation in the loading process of C-type bending machine,Timoshenko beam theory was applied to establish a analytical model of crowning,and the influence of some factors such as shape,size and inertia on the accuracy of bending were considered.Then,the deformation mechanism of bender slider and table stand plate was deduced,and general laws of deformation as follows were obtained.It is concluded that the superimposed deformation curve of the slider and table stand plate can  be expressed by a quartic equation,and the deflection of the fixed point is in proportion to the load.Based on the analysis of commonly used deflection compensation methods,a wedge-type crowning compensation method was proposed.For one style of bending machines,the results of theoretical analysis and wedge compensation method were utilized together to design a kind of deflection compensation device.Through the trial comparison,it is found that the angle deviation of the bent piece was controlled in the range of  ±25′  by using this new device and exceeded I grade accuracy provided in the China national standard,while the deviation  is ±1° without compensation.This design method can be used commonly to different types of  C-type bending machines.

Simulation on Vehicle Semi-active Suspension Decoupling Control Algorithm Based on Differential Geometry

CHEN Jian-Guo-1, 2, CHENG Jun-Ku-1, NIE Yong-Gong-1, CHEN Yo-Rong-2

2012, 23(20):  2509-2514. 

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Since each tire of a vehicle undergoes excitation from road,the sprung mass vibration couples the vibration of the tires.In order to attenuate the vibration of the vehicle effectively,a nonlinear 1/2 vehicle model was created.Considering the realization of a magnetorheological damper control,a hysteretic polynomial model was adopted.A differential geometry method was used to decouple the nonlinear model and the
nonlinear system was separated into several independent linear subsystems,and the vibration of  the vehicle was not influenced by road excitation.An attenuation control rule was designed,according to which the control current acted on a magnetorheological damper was calculated,to attenuate the vibration of the decoupled subsystems.The simulation results show that the acceleration of the sprung mass is attenuated greatly,which indicates that the control algorithm is effective and the hysteretic polynomial model is practicable.

Structure Strength Analysis and Optimal Design for Automotive Gearbox Housing

MIN Hai-Chao, GAO Juan, MA Tian-Fei

2012, 23(20):  2514-2519. 

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In order to realize the lightweight of the gearbox housing,the finite element analysis was used to build the gearbox housing model of a light-duty trucks,which was analyzed and vertified by modal test,including structural strength analysis under statics and dynamics conditions.Based on the analysis results,a topological optimization design for the gearbox housing was carried out.The optimization results show that the mass of the improved gearbox housing has reduced 8% which is reduced from 30kg to 27.6kg,on the premise of the box's stiffness staying the same and the strength and vibration performance of the box basically unchanged.