Table of Content

    16 October 2011
    Volume 41 Issue 5
    A study on high speed cutting database of die steel for automobile covering panels
    HUANG Chuan-zhen1,2, ZHUANG Xin-qiang1,2, ZOU Bin1,2, LIU Zi-ye1,2
    Abstract ( 355 )   PDF (1358KB) ( 1514 )   Save
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    A B/S(browser/server) structurebased high speed cutting database system of die steel for automobile covering panel has been established, which contains five functional modules such as case library, tool library, processing technology library, material library and intelligent optimization library. The customers can select the function modules to query detailed information of the tools, cutting processes, workpiece materials and processing cases. The tool wear in finish machining of die steel can be predicted online by means of the MATLAB neural network model.

    Model and key technologies of cloud manufacturing
    Meng Xiang-xu, Liu Shi-jun, Wu Lei, Pan Li
    Abstract ( 403 )   PDF (2626KB) ( 1307 )   Save
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    Cloud computing has been providing a new promising paradigm and changes the way of design and build of information systems and service provisions. With the more and more fierce competition in the global market, there are also increasing demands for individual manufacturing enterprises to collaborate with each other in a flexible, on demand, and selforganized way. As a new manufacturing model, cloud manufacturing is borrowed from the concept of cloud computing and integrates the key technologies of cloud computing, Internet of things, service computing and some others. In the cloud manufacturing environment, manufacturing resources are encapsulated as manufacturing services by using virtualization technology, and the resources and services are then provided to enterprises on demand. In this paper, the characteristics of cloud manufacturing model were briefly described, and the key technologies such as resource virtualization, resource integration, cloud manufacturing platform and trading technologies for cloud service were also discussed. Finally, the preliminary research results were introduced and several applications of cloud manufacturing were presented.

    Experimental research on heat transfer enhancement characteristics of  a new type of flow-induced elastic tube bundle
    TIAN Mao-cheng1, JIANG Bo2, LENG Xue-li1, CHENG lin1
    Abstract ( 358 )   PDF (918KB) ( 1165 )   Save
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    Comprehensive heat transfer experimental platform was set up to investigate the heat transfer characteristics of a new type elastic tube bundle under different experimental conditions. In the experiment, variations of the external, internal and overall heat transfer coefficients with Reynolds number were obtained. The experimental results show that the average convective heat transfer coefficient outside the tube for the new type elastic tube bundle is 3 times more than that of the stationary tube bundle at the same Reynolds numbers, which indicates a significant heat transfer enhancement. From the comparison of experimental results under different conditions, it can be conclude that the best heat transfer performance can be obtained for the steamwater heat transfer, which is better than that of the waterwater heat transfer, and the constant heat flux heat transfer exhibits the poorest performance. The reason is that the fluid medium inside the tube has great influence on vibration characteristics of the new type elastic tube bundle and the intensification of the tube bundle vibration leads to the enhancement of heat transfer performance. 

    An RFID tag localization method for object localization
    TIAN Guo-hui, SONG Bao-ye
    Abstract ( 345 )   PDF (1590KB) ( 2009 )   Save
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    To overcome the difficulty of relative position estimation between RFID tag and RFID antenna, an RFID tag localization method was proposed for RFID based object localization in intelligent space. A kind of multipower RFID tag recognition rate model was established and the upper and lower bounds of statistical multipower RFID tag recognition rate were obtained. Then the RFID tag localization problem with multipower RFID information was converted into uncertain information fusion problem. Bayesian estimation was used to construct basic belief assignment function, and DSmT generalized fusion machine was used for multi-power RFID tag localization information fusion. The random particles in the identifiable area, which indicated the position of RFID tag, were weighted with the information fusion to estimate the position of RFID tag. The experimental results demonstrated that the RFID tag localization errors could be less than 025m, and efficienty of object searching was increased by 60% comparing with conventional methods, which met the demand of object localization.

    Mechanical design and gait planning of a hydraulically actuated quadruped bionic robot
    LI Yi-bin1, LI Bin1,2, RONG Xue-wen1, MENG Jian1
    Abstract ( 798 )   PDF (1531KB) ( 6264 )   Save
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    A hydraulically actuated quadruped bionic robot has been developed by Center for Robotics at Shandong University is described in this paper. The objective is to design a highly dynamic and high load quadruped robot that enables the adaptation to complex terrain. Based on mule/horse creature bionics, the leg configuration with passive structure and hydraulic actuation are met the needs of stability control and high load capacity. And the stability dynamic trotting gait of the quadruped robot is planned based on the forward kinematics and inverse kinematics. Experiments of the developed quadruped bionic robot platform show the rationality of mechanical design and the effectiveness of gait planning.

    Tri-axial compression test study on mechanical characteristics of the oil shale under the water
    LIANG Bing, LAN Bo, WANG Jun-guang
    Abstract ( 275 )   PDF (1485KB) ( 1658 )   Save
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     For researching mechanical Properties of the oilshale, it was got the sample form Yedian Jilin Province was studied by using the  hydraulic testing enginery of YE-200A and home-made triaxial stress room to make triaxial compression experiment to the oilshale. By triaxial compression tests under the conditions of different confining Pressure and different hydration time, the evolution laws was revealed  for  all stress-strain, Peak strength, elastic modulus and poisson′s ratio with different confining Pressure and hydration time and the destructive forms of oil shale. At last,the results showed that the hydration taked prominent influence on mechanical properties of oil shale,which made the peak intensity and elastic modulus of oil-shale reduced. At the same time, owing to hydration, oil shale had obvious ductility. In addition,  the comparative  analysis of confining pressure and hydration showed  that the strength of oil shale influenced by hydration was smaller than natural state under certain confining pressure. Because of different fracture development in oil shale in-situe, oil-shale after hydration presented different destructive forms.

    Numerical simulation of single particle acceleration process by  SPH coupled FEM for abrasive water-jet cutting
    WANG Jian-ming, YU Feng, LIU Fei-hong, ZHANG Gang
    Abstract ( 422 )   PDF (1731KB) ( 1586 )   Save
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    The existing eulerian and arbitrary lagrange eulerian (ALE) grid-based algorithms were limited to study the hydrodynamic characteristics of pre-mixed abrasive waterjet (AWJ) in a cutting head. Smooth particle hydrodynamics (SPH) coupled finite element method (FEM) algorithm was adopted to establish a new AWJ model, by which the abrasive particle could enter into the mixing chamber in a low velocity and chould be accelerated in the focus tube by a high-speed waterjet from the orifice. SPH particles were used to model the high-speed waterjet and the FEM was applied to model the discrete abrasive particle, cutting head and workpiece. Consequently, the evolution of abrasive and waterjet velocities along focus tube was analyzed and the trajectory of single abrasive particle in focus tube was sighted. The relationships between abrasive particle velocities and different water pressures were studied and the rule of outlet velocities of abrasive particle vs. dimensionless ratio of diameter were conducted. The penetration depth caused by single abrasive particle impact was obtained. This model was validated by the existing theoretical and experimental data.

    Research on control system and test of full-scale highway accelerated loading testing
    GUAN Zhi-guang1,2, LIN Ming-xing1*, WANG Xu-guang2, ZHANG Ji-wei2
    Abstract ( 347 )   PDF (1812KB) ( 1445 )   Save
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    The facility of the full-scale highway accelerated loading testing(ALT) was developed, which has self-owned intellectual property. The control system was studied and designed for the full-scale ALT facility, and  the pavement experiment was analyzed. The ALT control system adopted CAN bus, which can improve reliability. The circulating-type and single direction loading can be realized by vectorcontrol of the inverter. The tested pavement can produce rutting and mild fatigue in a compressed time period, which can help analysis the failure mechanism of the life cycle and can also offer reference for the road design, construction and acceptance. The relationship of dynamic pavement response with load, speed and tire pressure was  researched using the facility. The results showed that there was not only tensile strain but also compressive strain at the bottom of the asphalt layer; furthermore, the variation of tensile strain was bigger than compressive strain, while the change trend reduced with the speed increasing.

    DSC analysis for latent heat of aluminum-silicon alloy
    SUN Yu-cheng1, ZHENG Hong-liang1, WU Shu-xia2, TIAN Xue-lei1*
    Abstract ( 451 )   PDF (1675KB) ( 2238 )   Save
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    The latent heat of Al-Si alloy, prepared by vacuum arc furnace and with different Si content, was studied by differential scanning calorimeter (DSC). The results indicate that the latent heat of the primary phase and the eutectic phase should be computed independently, the latent heat of the alloy increased  with the mass fraction of Si increasing from 4.16% to  21.4%, and the linear relationship of the latent heat of the hypoeutectic alloy and the hypereutectic alloy was  different, which were  Lhypo=353.4+12X and Lhyper=409.6+7.54X. It was also  found that it was  the different forms of Si in Al-Si melt and the pure Si melt that caused the different latent heat of the Si phase in different melt.