Loading...

Table of Content

    10 July 2010, Volume 21 Issue 13
    Research on Test Method of Mistuned Bladed Disk System Vibration Based on Bond Graph
    WANG Ai-Lun, HUANG Hui-Fan
    2010, 21(13):  1513-1518. 
    Asbtract ( )   PDF (4576KB) ( )  
    References | Related Articles | Metrics
    A simulation test method which can be used to study dynamics characteristices of complex bladed disk systems was advanced based on the bond graph which is an effective tool for modeling of systems with multi-energy domains. The bond graph mode and the dynamic test model of bladed disk was established. The dynamics characteristices can be derived efficiently,conveniently and intuitional when the method was utilized to dynamics simulation test of complex mechanical systems,so new idea and methods have been provided for dynamics research of complex mechanical systems.

     

    Gear Position Layout Optimization for Decreasing Bearing Supporting Reaction of Gearbox
    ZHANG Chi-Qing, XIANG Chang-Le, LIU Hui
    2010, 21(13):  1518-1522. 
    Asbtract ( )   PDF (3485KB) ( )  
    References | Related Articles | Metrics
    In order to decrease the supporting reaction of bearing seat of certain vehicle dynamic shifting gearbox under different gears conditions, the shift transmission part of gearbox was simplified, and gear position layout optimization model was set up; considering the working period percentage of each gear condition, linear weighting method was applied to construct a synthetical objective function, which reflected gearbox’s reaction of different conditions. Based on nonlinear programming arithmetic theory of MATLAB optimization toolbox and “fmincon” function was used to solve the problem. The result displays that the layout optimization method is feasible, and can provide reference to the improvement of gearbox layout.
    Precise Control of Pre-tightening Force for Miniature Screw Thread Joints
    SONG Sha, WANG Xiao-Dong, LUO Yi
    2010, 21(13):  1523-1527. 
    Asbtract ( )   PDF (3619KB) ( )  
    References | Related Articles | Metrics
    Since the frictions in different screw threads are uncertain, and merely improving the control precision of torque can not assure the conformity of the pre-tightening force, a control method, torque/time control method, of the pre-tightening force was presented. The method was based on the relation of the pre-tightening force to torque and nut corner, and followed the slope changes of torque to time and the system stiffness of the screw thread at the same rotate speed. Offering different tightening torques to every screw thread can reduce the uncertainty influence of the friction in the assembly process and improve the conformity of the pre-tightening force. The assembly process of tightening nut was simulated, and analyzed by using torque/time control method. The results indicate when the ratio of stiffness to the slope of torque is ±0.02%, the precision of the pre-tightening force is 2.94%. The control method of torque/time has a preferable precision.
    Research on Interface Joint Performances of New Tool System for High-speed CNC Machine Tools
    ZHOU Qin-Yuan, ZHOU Zhi-Xiong, LIN Ying-Hui
    2010, 21(13):  1527-1530. 
    Asbtract ( )   PDF (3033KB) ( )  
    References | Related Articles | Metrics
    Structural characteristics of a new tool system in high-speed CNC machine tools were studied by theoretical, experimental and numerical calculation method.A finite element model was constructed based on the new tool system accurately, the parameters of the clamping force, the amount of interference and rotation speed to link performance were analyzed and researched. Results of the study can be used as basis and instruction of parameters’ selection of new tool system for high-speed CNC machine tools in practical manufacture.
    Research on Tool Wear Condition Monitoring Based on Combination of SOM and HMM
    LV Dun-Jie, WANG Jie, WANG Mei, TUN Huo
    2010, 21(13):  1531-1535. 
    Asbtract ( )   PDF (3601KB) ( )  
    References | Related Articles | Metrics
    Because of the identification problems of cutting tool wear condtition, a method based on the combination of SOM and HMM was proposed. At first, the singals of milling force were pretreated and the related features were extracted, then the feature vectors were presorted and coded into code book of integer numbers by using SOM as import vectors of HMM to build up 3-HMMs for different tool wear stages. And then the unknown state of tool wear was monitored and indentified. Finally, the experimental results indicate the method can exactly recongnize the tool wear state, has significant realistic meaning to automated production. 
    Tribological Performance of AS41 Magnesium Alloy under Different Temperatures
    HUANG Wei-Jiu, LIN Jiang, GUO Yuan-Jun, ZHANG Xiao-Ban
    2010, 21(13):  1536-1541. 
    Asbtract ( )   PDF (4209KB) ( )  
    References | Related Articles | Metrics
    The mechanical and tribological properties and wear mechanism of AS41 magnesium alloy under different experimental temperatures were investigated herein. The results show that the ultimate strength and yield strength of AS41 magnesium alloy decrease with increasing of experimental temperature, whereas the elongation increases with experimental temperature increasing. In particular, the ultimate strength and yield strength prominently decrease, when the experimental temperature exceedes 150. With increasing the load, the frictional coefficient and wear rate display the decline and uptrend respectively under different experimental temperatures, and with increasing of sliding velocity, the frictional coefficient displayes a few change, whereas the wear rate shows an ascending trend. Under the different loads and sliding velocities, the higher the experimental temperature, the lower the frictional coefficient, but the higher the wear rate. The loads, which are the transition spots from mild wear to severe wear, brought down with the increasing of experimental temperature. The wear mechanism of AS41 magnesium alloy under a load of 50N and different experimental temperatures are presented as follows, the dominant wear mechanism in room temperature is oxidation wear and abrasive wear, the delamination wear and adhesion wear are the dominant wear mechanisms for 150, whereas the melting wear is the dominant wear mechanisms for the experimental temperature of 200 respectively.

     

    A New Method for Analyzing Kinematic Feasibility of Multi-fingered Grasping
    LIU Yu-Wang, ZHOU Wei-Jia, WANG Hong-Guang
    2010, 21(13):  1541-1547. 
    Asbtract ( )   PDF (5360KB) ( )  
    References | Related Articles | Metrics
    A unified computational framework for the kinematic feasibility analysis of grasping was proposed.The kinematics of multi-fingered hand was deduced;the transition of grasping-element’s equation between different coordinate-systems was analyzed;and the detection of the relationship between two 3D outer surfaces was then analyzed in 2D space;the detecting algorithm and rules were given herein.An example was given to validate the method. 
    Surface Roughness Analysis on Milling of Molar Crown
    LEI Xiao-Bao, LIAO Wen-He, ZHANG Lin, DAI Ning
    2010, 21(13):  1548-1552. 
    Asbtract ( )   PDF (3572KB) ( )  
    References | Related Articles | Metrics
    Taking a molar crown as an example,a method was used to analyze theoretically the factors which influenced on surface quality in milling the molar crown.
    Then the appropriate processing parameters were selected considering the actual fabriction conditions.The surface roughness of workpiece was measured with 3D Profiler.The test results show that the surface roughness is consistent with design requirements.This analysis method has reference value for machining parts with complex structure.
    Straight Inverse Model Control for Nonlinear System Based on LS-SVM
    HU Liang-Mou, CAO Ke-Jiang, LI Xiao-Gang, XU Gao-Jun, DONG Xin-Min
    2010, 21(13):  1553-1556. 
    Asbtract ( )   PDF (3136KB) ( )  
    References | Related Articles | Metrics
    Aiming at the problem of hard system identification modeling for nonlinear system, a method of inverse model identification for nonlinear system based on LS-SVM was studied in detail. Then the method of straight inverse model control for nonlinear system based on LS-SVM was put forward. The simulation results show that inverse model of LS-SVM has high modeling precision and strong generalization. And the control effectiveness of straight inverse model control based on LS-SVM is good and is very easy to be actualized. Therefore the identification method and the control method mentioned above are valid and advanced.
    Research on Product’s BOM Model Construction and Solution Method Based on Dynamic Orders
    CHENG Hao-Qiu, BI Shao-Mei, ZHANG Shu-Wei
    2010, 21(13):  1556-1561. 
    Asbtract ( )   PDF (4200KB) ( )  
    References | Related Articles | Metrics
    In order to respond quickly to customer needs,this paper put forward an order-orientated BOM model. Firstly,the similarity matrix was built among customer orders and cases of parts and assemblies, and then the ideal components were obtained. Secondly, configurable products were retrieved from product database based on the main parameters. Finally, the products having maximum similarity to the demands of customers were acquired by using the utility function. The practical application of the model indicates that it can makes the BOM quickly,and benefits the efficiency and quality of product design.
    Optimal Configuration of Rapid Extended Manufacturing Resources Based on Multi-Agent
    YANG Liu, GUO Yu, AN Bei-
    2010, 21(13):  1562-1567. 
    Asbtract ( )   PDF (1277KB) ( )  
    References | Related Articles | Metrics
    In rapid extended manufacturing mode, in order to find a suitable extended manufacturing resources quickly and accurately, a Multi-Agent-based flexible structure was designed and implemented to support the proliferation of manufacturing resource discovery and selection. The proliferation of manufacturing resource optimization model, the agent agreement, as well as consultations among the information exchange agreements were also discussed. A specific system was developed on the JADE platform to validate the formal discussion.
    Automatic Recognition of Features with Variable Topology for Aircraft Structural Parts
    YAN Hai-Bing, LI Ying-Guang, HAN Xiong
    2010, 21(13):  1567-1571. 
    Asbtract ( )   PDF (2503KB) ( )  
    References | Related Articles | Metrics
    According to the difficulties in building predefined feature library because of variable topology, a layer-based recognition methodology was presented for aircraft structural parts. Analyses on features of aircraft structural parts show the characteristics of variable topology with directional characteristics and hierarchy distribution. The layer-based recognition dealt with interacting layers by adding virtual edges and extracted features by recognizing and combining layers. The method dealt with features with variable topology, recognized interacting features by combining layers and generated reasonable feature interpretations according to the association between layers. A feature recognition system based on the CATIA V5 platform was developed, which has been applied in a large aviation enterprise.
    Control Chart Pattern Recognition Based on Wavelet Analysis and SVM
    TUN Chang-Kun, DIAO Li-Ping
    2010, 21(13):  1572-1576. 
    Asbtract ( )   PDF (3540KB) ( )  
    References | Related Articles | Metrics
    Control chart pattern recognition based on wavelet analysis and SVM was presented to improve the accuracy of control chart pattern recognition, in particular the accuracy of hybrid control pattern recognition. Process quality characteristics data were decomposed in wavelet packet to extract low-frequency approximation signals and the band energy information, which were taken as the inputs of SVM classifier recognizing trends, step and periodic signals respectively, and these signals figure the final model together. The simulation experiment used for testing recognition effect shows that the method based on wavelet analysis and SVM has an advantage over traditional methods in identification accuracy.
    Size Dependent Stiffness of Eutectic Composite Ceramic with Eutectic Interphases
    NI Xin-Hua, LIU Xie-Quan, LI Bao-Feng, ZHONG Guo-Hui, DIAO Lei, SUN Chao
    2010, 21(13):  1577-1581. 
    Asbtract ( )   PDF (3708KB) ( )  
    References | Related Articles | Metrics
    First, four-phase-model method was used to determine the equivalent stress field and recessive expression for flexibility increment tensor of eutectic ceramic rod. Then, an analytical solution for elastic constants of eutectic ceramic rod was gotten by using Taylor series expansion. The eutectic ceramic rod was transverse isotropy and has five independent elastic constants. Finally, assuming the eutectic ceramic rod and matrix particle as transverse isotropy inclusion and isotropy inclusion respectively, the stiffness of eutectic composite ceramics with eutectic interphase was predicted. The results show that the elastic modulus and Poisson’s ratio of eutectic composite ceramics with eutectic interphase are dependent on the diameter of fibers.
    Development and Experimental Study of a Quartz Microfluidic Device Preparation Apparatus 
    MU Chi-Chi, LI Ya, ZHANG Wei-Yi
    2010, 21(13):  1581-1585. 
    Asbtract ( )   PDF (3602KB) ( )  
    References | Related Articles | Metrics
    To obtain transparent microfluid devices with good microflow characteristics,a multi-purpose quartz glass preparation apparatus for fabricating microfluidic device was designed accordingly.Based on the quality that the glass material can be molded when it is semi-molten,the glass capillary can be pulled,forged,holed and welded to make nanometer microfluidic devices such as microneedle,microchannel,three-way microchannel etc..The experiments on the two factors of temperature and pulling force were carried out in a prototype,and the impact of various parameters on the dimension of microfluid devices was analysised.The results of the experiments show that apparatus is characterized by simple structure, easy operation,low cost and multipurpose.
    A Novel Model-free Sampling on Probability Weighted Moments
    DIAO Xin-Pan, LV Shen-Zhou, ZHANG Feng
    2010, 21(13):  1586-1590. 
    Asbtract ( )   PDF (485KB) ( )  
    References | Related Articles | Metrics
    In order to improve the agreement of the statistical information of a target sample with that of observed original sample both globally and locally, a novel model-free sampling was developed, in which the constraints of the probability weighted moments and the empirical cumulative distribution function (CDF) were satisfied simultaneously. The probability weighted moment constraint guarantees the agreement of the local statistical information and the empirical CDF guarantees that of the global statistical information. Additionally, the selection of the initial target sample was improved for the convergence of the novel model-free sampling. The numerical examples demonstrate the advantages of the novel model-free sampling over the traditional one.
    Friction Force Analysis for Aerostatic Guideway under High Speed Conditions
    LI Feng-Fei, LIU Hong-Zhao, CHEN Hong-Bei, TU Shou-Qi
    2010, 21(13):  1590-1593. 
    Asbtract ( )   PDF (607KB) ( )  
    References | Related Articles | Metrics
    Aimed at aerostatic guideway, a two dimensional distribution of air pressure and effect factor on the friction force were analyzed under high speed working conditions. The equation of the friction force and the two dimensional air pressure distribution at the bottom of the aerostatic pad with one-hole or multi-hole were deduced based on the force analysis of air film. The relationship between the friction force and the speed of the aerostatic guideway was obtained. Under the high speed working conditions, the simulation of the friction force acting on the three-coordinate measuring machine was performed to study the effectiveness on speed precision. The results show that the influence of friction force acting on the aerostatic guideway reduces the position accuracy of the three-coordinate measuring machine, and cannot be ignored under the high speed working conditions.
    Mechanics Research and Optimal Design on Vertical Ring Rolling Mill’s Transmission System
    HONG Xiao-Kai, HUA Lin
    2010, 21(13):  1594-1597,1604. 
    Asbtract ( )   PDF (3408KB) ( )  
    References | Related Articles | Metrics
    According to actual circumstance of the vertical ring rolling mill’s transmission system, a 3D model was established, ANSYS/LS-DYNA was used to analyze transmission system’s stress-time changing situation under extreme working conditions. The result shows the stress is large at the sharp corner of fork joint, the stress of mid sphere is centrosymmetric. The input shaft was optimized by OPT and ANSYS parametric design language APDL, and its mass is reduced by 31.3%, the stress is declined by 57.9%, the stiffness is increased by 40.37%.The result provides sufficient basis for design, production and application of the vertical ring rolling mill’s transmission system.
    Analysis of Space Environment Effects and Failure Modes of Aerospace Electrical Connectors
    GAO Liang, CHEN Wen-Hua, LIU Juan, ZHOU Sheng-Dun, LEI Xian-Biao
    2010, 21(13):  1598-1604. 
    Asbtract ( )   PDF (4519KB) ( )  
    References | Related Articles | Metrics
    Based on the function of electrical connectors in a satellite and the space environment which the electrical connectors confront, a failure mode of the electrical connectors in space environment was analyzed. Firstly, the stress on electrical connectors confronted in orbit was analyzed; then, the effects of the stress on the electrical properties, the sealing properties and the electromagnetic shielding properties and the resulting failure modes were also analyzed. The results show that almost every space environment factor can affect the performance of electrical connector, which leads to electrical connector failures; and that the failure modes of the electrical connectors in space environment are very complex: some of space environment factors may cause a variety of failures, and the competing failure or relevant failure can happen.
    Trajectory Planning of Archwire Bending Robot
    DU Hai-Yan, GU Yu-Xiang, ZHANG Yong-De, LIU Yi
    2010, 21(13):  1605-1608. 
    Asbtract ( )   PDF (2811KB) ( )  
    References | Related Articles | Metrics
    Trajectory planning of an archwire bending robot based on Motoman UP6 was studied firstly herein.The main function of the archwire bending robot is to bend the archwire which is used to make orthodontic treatment of patients with deformity teeth alignment in orthodontics. Cartesian trajectory planning method was selected finally according to needs of the archwire’s shape. Then appropriate positions of the
    control nodes were calculated and the corresponding control assignment was inserted to each control node. These control nodes were directly related to the rationality of the trajectory planning and the efficiency of the robot operation.A correct algorithm was used to calculate control nodes and the C language program was prepared as well.
    Uncertain Multi-objective Optimization of Sheet Metal Forming Using Interval Method
    LI Fang-Xi, LI Guang-Yao, LI Hong-Zhou, CUI Fu-Gang
    2010, 21(13):  1609-1613. 
    Asbtract ( )   PDF (2125KB) ( )  
    References | Related Articles | Metrics
    An uncertain multi-objective optimization method was suggested to solve the optimization problem of sheet metal forming. The friction coefficient was regarded as the uncertain coefficient, which was treated as an interval. The binder force and drawbead restraining force were selected as the design variables, and the objectives were to minimize thickness non-uniform and wrinkle. Through a nonlinear interval number programming method, the uncertain optimization problem was converted into a deterministic two-objective optimization problem. The Kriging approximation model was constructed to improve the efficiency. The hybrid optimization algorithm based on multi-objective genetic algorithm and sequential quadratic programming algorithm was adopted to obtain the Pareto set. The results of the example demonstrate the efficiency of the presented method.
    Effect of Electrode Force on Spot Weld Quality of High Strength Steels with Different Thicknesses and Materials
    LIANG Cai-Beng, TIAN Gao-Ban, LIU Xiao-Hang
    2010, 21(13):  1614-1617. 
    Asbtract ( )   PDF (821KB) ( )  
    References | Related Articles | Metrics
     Due to bad welds including small button, weld expulsion, weld spatter, and weld whisker etc., it was studied that the effect of electrode force with servo gun on the weld quality of high strength steels with different thicknesses and materials. The results show that the electrode force has great influence on the weld strength and button size. But changing electrode force during welding progress has less influence relatively. The solutions can supply reference to enhance the quality of spot weld with different thicknesses and materials and to study the prospect of servo gun in the joining of high strength steels.
    Crash Accident Judgment and Control System of New Crash Energy Absorption Equipment
    CAO Li-Bei, TANG Meng-Fu, JIANG Ban-Hui, BAI Zhong-Gao, CHEN Huan, DING Hai-Jian
    2010, 21(13):  1618-1623. 
    Asbtract ( )   PDF (1652KB) ( )  
    References | Related Articles | Metrics
    It can be found from real vehicle tests that there exist obvious differences among emergency brake acceleration and the acceleration of other conditions. So, the emergency brake acceleration can be used to predict accident. Based on the emergency brake acceleration and the moving window integration algorithms, a control system of new crash energy absorption equipment which combines active and passive safety was developed. Real vehicle tests show that the emergency brake action of driver can be identified and accident can be predicted effectively by this system. The trigger signal can be sent to the energy absorption equipment on time and the system works stably. 
    Research on Automobile Network Structure Design Based on Real-time Scheduling and Graph Partitioning
    WANG Ti-Fei, HAN Jiang-Hong, ZHANG Jian-Jun, BANG Gao
    2010, 21(13):  1623-1626,1637. 
    Asbtract ( )   PDF (603KB) ( )  
    References | Related Articles | Metrics
    To meet the requirements of designing automobile network with multiple segments, a judgment condition for schedulability was deduced based on analyzing message scheduling mechanism. An optimization model under this condition constraint was presented when network structure design was described as graph partitioning. To solve the optimization problem, a niched adaptive genetic algorithm was built by introducing niche and adaptive strategy. The applications indicate that the design method can reduce loads across different network segments, and guarantee network schedulability of messages in automobile network. 
    Three-dimensional Stress and Strain Mesh Mapping Method in Fine Crash Simulation
    HU Shi-Bo, HU Beng
    2010, 21(13):  1627-1631. 
    Asbtract ( )   PDF (3469KB) ( )  
    References | Related Articles | Metrics
    A three-dimensional stress and strain mesh mapping method was proposed based on the one-step inverse FEA to import stress and strain distribution into fine crash simulation, which can present the forming effect of residual stress and strain in a crash simulation. By using LS-DYNA software,numerical simulations of side impact between mobile barrier and vehicle was carried out. As an example, the mesh mapping method was applied on the main energy absorption component B pillar, which verified the accuracy and feasibility of this method. Results demonstrate that different contributions of forming factors on crashworthiness of B pillar, and stress distribution play a relatively important role. Therefore, the forming effect of stress should be considered in fine crash simulation.
    Dual Electric Tracked Vehicle Small-radius Turning Control Strategy
    CHEN Ze-Yu, ZHANG Cheng-Ning, LI Jun-Qiu, WU Xiao-Hua
    2010, 21(13):  1632-1637. 
    Asbtract ( )   PDF (1413KB) ( )  
    References | Related Articles | Metrics
    Small radius steering theory of dual-motor drive tracked vehicle was analyzed to get the relationship between the turning radius and the force on each side track. Results illuminate that when torques of both motor are fixed, small radius steering without a muzzle velocity comprise three stages, in the first stage the radius is stable but the velocity and the turning rate are speeding up, in the second stage the radius is falling, in the third stage both the radius and the velocity are stable. Simulation also shows that the only difference between the steer with and without muzzle speed is the first part after the steering beginning. Based on theory analysis,a control strategy was designed and simulations were made in MATLAB/Simulink. Results of the simulation show that control strategy is valid.