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Table of Content

    25 September 2017, Volume 28 Issue 18
    A Study of Fault Diagnosis Model of Rotary Kiln Based on Improved Structural Algorithm of Bayesian
    LIU Bin1;LIU Yongji1;LIU Haoran1;LI Lei2;SUN Meiting1
    2017, 28(18):  2143-2151. 
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    The improved mutual information hill climbing algorithm (MI&HC) had less accuracy and time consuming, and the simplified hill-climbing(SHC) algorithm generated lots of redundant edges. Aiming at these problems, this paper proposed a new Bayesian structure learning algorithm, improved hill-climbing(IHC).Firstly,this algorithm calculated the mutual information chains to obtain the Bayesian initial structure.Secondly, this algorithm utilized conditional independence tests and dealt with isolated nodes to supplement the initial structures to obtain the completed structure.Finally,the algorithm utilized improved search operators of HC to search for the optimal structure based on completed structure.The simulation results show that:compared with hill-climbing(HC),MI&HC and SHC algorithm, the IHC algorithm may obtain a more accurate and more rapid model, the redundant edges generated by IHC are far less than SHC.In the end,based on IHC algorithm and combined with some rotary kiln operating data, the fault diagnosis model of processing parameters may be constructed and a precise fault diagnosis of burning zone temperature in the rotary kiln is realized.
    Analysis of Motion/Force Transmission Efficiency Performance for a Parallel/Hybrid Electro-coating Conveying Mechanism of Automobile Bodies
    ZHU Mingxing1,2;GAO Guoqin1;WU Jun3;CHEN Taiping1
    2017, 28(18):  2152-2160. 
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    For motion/force transmission efficiency from the inputs to the outputs of a novel mechanism for automobile electro-coating conveying, an analysis and evaluation method was proposed. Firstly, the kinematics and dynamics of conveying mechanism were derived by screw form. According to the Klein form of the screw, namely a bilinear symmetric form of the Lie algebra e(3), the transient analysis and evaluation index of the input/output motion / force instantaneous transfer efficiency was presented ,which was based on the ratio of the instantaneous powers of the end effector of the conveying mechanism and the instantaneous input powers of the input terminal. Furthermore, on the basis of the proposed evaluation method, the time varying curve of the instantaneous transfer efficiency of mechanism motion / force were obtained, and the average transfer efficiency of the motion / force was obtained. Finally, the simulations of the mechanism were carried out by using MATLAB software. The simulation results show that the evaluation index is reasonable and effective.
    Dynamics Characteristics of Rotor System Supported by Offset Bearings under Rolling Conditions
    ZHANG Lei1;PEI Shiyuan1;XU Hua1;ZHANG Yabin2;ZHU Jie2
    2017, 28(18):  2161-2170. 
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    Based on the assumption of piecewise linearization of bearing stiffnesses and dampings, a offset rotor-bearing model with different rolling angles was established. Using DLAP software, coupled solutions of the offset rotor-bearing system dynamics model was presented. By means of eigenvalue and eigenvector, unbalance response analysis, stability analysis and transient dynamics analysis, the stability and safety of the rotor-bearing system were studied, and compared with that under normal operating conditions. The dynamics characteristics of rotor system supported by offset bearings under rolling conditions were obtained.
    Dissipated Energy Method for Fretting Wear Analysis of Involute Splines
    ZHENG Weitong;WANG Sanmin;XIE Xiaoxin;LI Hao
    2017, 28(18):  2171-2176. 
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    Aiming at involute spline pairs in aerial drive systems,with dissipated energy method,calculation formula for fretting wear amount was established. Besides, for three working conditions, the effects of working conditions on the distribution characteristics were studied. Consequently the conclusions were obtained as follows. Under ideal working conditions, the wear of each tooth is nearly the same, and root contact end on external spline tooth profile acts as the maximum wear position. When there is a lateral gap, the smaller the side gap is, the more serious the wear between the teeth is. When the axial deflection occurs, the wear is more serious in the middle part of the tooth surfaces in the axial position, and the maximum wear position moves towards the top of the tooth. In the design and installation of involute spline pair, to reduce failure caused by fretting wear, it is required to keep the tooth gap between the teeth evenly as far as possible. And the reduction is also suggested for the axis deviation of internal and external splines.
    Numerical Simulations of Piston Bowl Geometry on Marine Diesel Engines
    ZHAO Changpu;SUN Yakun;WANG Yaohui;ZHANG Zhigang;ZHU Yayong
    2017, 28(18):  2176-2182. 
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    In order to investigate the effects of piston bowl geometry on the performances and emissions for large-bore marine diesel engines, six novel combustion chambers were designed based on the combustion chamber of the prototype, and combustion chamber simulation modeling was established by using AVL five code to simulate the in-cylinder flows, air-fuel mixing and combustion processes with the flow dynamics metrics such as swirl number and uniformity index. Results show that chamber diameter and bowl depth have a great influence on in-cylinder flows. The deeper depth of the re-entrant bowl may result in enhancement of swirl motions and improve the combustions, while a deficient combustion occurs at the lower depth open chamber. Further, high turbulent kinetic energy with a large swirl is important to improve the quality of combustions. It is also found that power output of re-entrant chamber G1 is increased by 4.6% and emission is almost the same as the prototype's. NOx emission of straight chamber G4 is decreased by 43.3% at a slightly lower power output than that of the prototype. And open chamber is found to have lower engine-out power.
    Application Research of FastICA Noise Reduction Method Based on Wavelet Analysis in Fault Diagnosis of Rolling Bearing
    WU Yapeng;WANG Jifang;XU Xiaoli;JIANG Zhanglei
    2017, 28(18):  2183-2188,2197. 
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    There is a problem of depending on experience of selecting parameters when wavelet analysis method is used to make noise reductions of vibration signals. And there is a problem of undetermined parameters when ICA method is used to make noise reduction of vibration signal. In order to avoid disadvantages of wavelet denoising and ICA method when they were used respectively. A method of wavelet denoising and FastICA independent component analysis based on negative entropy was proposed to deal with the noise signal of rolling bearings. Firstly, original signals were processed by wavelet denoising. Then the processing results were combined with the original signal to form input matrix of FastICA, and the FastICA noise reduction processes were performed. Finally, the effectiveness of the method was verified by vibration signal of rolling bearings. Experimental analysises show that this method improved the kurtosis of vibration signals and the purposes of noise reductions of vibrartion signals of rolling bearings was achieved.
    Static Error Modelling and Calibration for Parallel Robots Based on Virtual Joint Pairs
    ZHAO Yanzhi1,2;SONG Xiaoxin1,2;YANG Jiangtao1,2;QI Lizhe3;HE Yong1,4;ZHAO Tieshi1,2
    2017, 28(18):  2189-2197. 
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    Based on the principles of parallel robot influence coefficient and virtual displacement, a case analysis of general space parallel robot, a new generalized method for parallel robot static error modelling was proposed by virtual joint pairs(VJP). The independent effects of each original processing assembly sources of errors for the end-pose were determined, the physical meaning of the proposed method was clear and the modelling and analysis processes were convenient. Based on this, taking 3-P (4S) parallel robot as the research object, the mapping matrix of each error sources was obtained by VJP, and the error calibrations of robots were conducted. The experimental results show that the maximal positioning error is decreased from 0.585mm to 0.142mm, accuracy of the robot outputs after calibrations is improved significantly than that without calibrations based on this method, and the effectiveness of the method was validated further.
    Experimental Investigation into Friction-induced Squeal of Rotating-sliding Friction
    MAI Yunfei1;LIU Zhiliang1;WANG Shuwen1;DONG Bingyang2
    2017, 28(18):  2198-2203,2208. 
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    For further studies of the formation mechanism of friction-induced squeal from a rotating-sliding friction system, a multifunctional friction testing machine was utilized to investigate the effects of sliding speeds, contact pressures and surface topographies on the squeal, by applying the single-factor experimental method. The experiments find that the friction-induced squeal occursed mostly at the conditions of a relatively low sliding speed, a large contact pressure and a negative coefficient- velocity slope. The relative sliding velocity, contact pressure and surface roughness might not affect the frequency of squeal, but the squeal intensity shows a significant downward trend with the increases of surface roughness. The cross-correlation analysis demonstrates a better correlation between the normal vibration acceleration signals and the squeal signals, which provides a reference for the further understanding of the formation mechanism and prediction model of friction-induced squeal.
    Torque Performance of Horizontal Axis Wind Turbines and Its Impacts of Blade Tip Losses
    JIANG Haibo;LI Yanru;ZHAO Yunpeng
    2017, 28(18):  2204-2208. 
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    This paper analyzed the mechanism of blade tip losses, and derived the blade chord formula according to PRANDTL and GLAUERT blade tip loss correction factor and blade element-momentum theory. With the blade chord formula, an analytical expression of torque coefficient associated with tip speed ratio and airfoil lift drag ratio of wind turbines was deduced by integrating along the wingspan using the blade element-momentum theory, and highest torque coefficient value of wind turbines in any steady state was obtained, which might be used for pre-estimating torque coefficient of actual wind turbines in design. The research shows, the impacts of blade tip losses to chord concentrated in the blade tip area, blade tip loss will reduce the torque coefficient about 4 to 10 percent when tip speed ratio changes from 10 to 4, and the value of the loss has minimal changes with lift drag ratio.
    Evaluation of Rolling Bearing Performance Uncertainty and Reliability
    CHANG Zhen1;XIA Xintao1,2;LI Yunfei1;LIU Hongbin1
    2017, 28(18):  2209-2216,2223. 
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    Based on the grey system theory and Poisson counting process, the performance uncertainty of rolling bearings was quantified by a parameter, and the performance reliability of the bearings under different working conditions was analyzed via setting threshold value, then the performance matching sequences of uncertainty and reliability were established to find out the internal connection between the two items in bearing service processes. According to a property time series during the bearing operations, its uncertainty was obtained by grey bootstrap processing. Referencing the setting threshold to Poisson count, the time series effective variation strength was gained, then the performance reliability was acquired. Finally, the grey relation between uncertainty and reliability was analyzed. Experimental results show that the evolution information of rolling bearing performance uncertainty and reliability may be really described, the normalization processing results of the two are very similar and presenting obvious grey relation. The experimental results of various cases keep good consistency.
    Study on Aerodynamic Characteristics of Flexible Blade Airfoils of Wind Turbines
    DENG Yong1,2;GONG Jiahui2;HE Yuhao2;CHEN Yan2;LUO Zhen1
    2017, 28(18):  2217-2223. 
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    The deformation characteristics of flexible blade sizes NPU airfoil was selected as the research object, lift and drag coefficient and pitching moment coefficient calculation of different airfoil deformations to the string were carried out by using the Xfoil software and the correction formula of lift coefficient of airfoil calculation after deformation was summarized. The results show that the greater the chord bending deformations of the flexible blades, the greater the lift coefficients of the airfoils and the drag coefficients will increase slightly, but the lift drag ratio shows an overall increasing trend, which is beneficial to enhance the aerodynamic performance. The modified formula of aerodynamic characteristics after airfoil deformations is also in good agreement with the simulation results.
    Assessment of Carbon Emissions of Remanufacturing Processes of Used CVT
    WANG Qiucheng;WEI Ruihui;ZHANG Qijiong
    2017, 28(18):  2224-2230,2267. 
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    Aiming at assessing carbon emission in waste car continuously variable transmission(CVT) remanufacturing processes, a carbon emission quantitative method was proposed which combined the hierarchical relevance analysis theory (HRA) and emission-factor approach (EFA). The characteristics of used car CVT remanufacturing processes were analyzed, the boundary of system was defined, various carbon sources of the system were classified, the correlation matrices among hierarchical essential factors of carbon emission were established, and then EFA was combined to compute the carbon emission of each carbon sources, then CVT remanufacturing process carbon emission quantitative method was proposed. Studying the assessment of carbon emissions of the CVT remanufacturing processes, and the perspective feasibility of the proposed method were verified through the example of CVT with wheel laser repairing processes. The results show that the carbon emission of the device is the major contributor of total carbon emissions, and compared with other carbon emission factors, the scanning speed has the greatest influences on the carbon emissions of the device and total carbon emissions.
    Fixture Locating Layout Optimization of Curved Thin-walled Parts Based on FDA
    WANG Zhongqi;LI Cheng;YANG Bo;YANG Yuan
    2017, 28(18):  2231-2236. 
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    Optimizing the fixture layout of the locating elements was an important means to reduce clamping deformations of thin-walled parts. The normal deformations were taken as the optimization objective in most of the previous studies, while the deformations in other directions were ignored. Based on FPA, a new method used to optimize the fixture locating layouts was proposed herein. At first, the locating model under normal constraints for curved thin-walled parts was established, the deformations in all directions were described by the strain energy. Then, this method, aimed at minimizing the overall strain energy of curved thin-walled parts, combined FPA and parametric finite element analysis based on Python language to realize the optimization of fixture locating layouts. Finally, the effectiveness of the proposed method was validated by the aircraft skin locating layout optimizations, and the comparison results with genetic algorithm(GA) show that the FPA outperforms the GA in terms of the convergence speed and robustness in the thin-walled part fixture locating layout optimization.
    Research on Tracking Control for Robot Manipulator Based on Fast Terminal Sliding Mode Method
    QIAN Donghai;HUANG Youxin;DONG Xiaokang;WU Peng
    2017, 28(18):  2237-2241. 
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    An adaptive fuzzy fast terminal sliding mode control method was proposed herein.In order to improve the the convergence speed,this method usd a multi power reaching law combind with fast terminal sliding-mode control. Adaptive fuzzy method was employed to approximate to the uncertain factor in the system of robotic manipulators. The system stability was proved by Lyapunov principle.The co-simulation of the 3R robotic maniputlators which was desined by authors was performed based on ADAMS and MATLAB. It turns out that the method has better convergence,and enhances robustness and reduces chatter.
    Precision Truing of Arc-shaped Diamond Wheel and On-line Monitoring of Truing Processes by AE Signals
    CHEN Bing1,2;WANG Ge3;LIU Jianming4;DENG Zhaohui1,2;ZHAO Qingliang5
    2017, 28(18):  2242-2249. 
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    To realize the efficient and precision truing of arc-shaped diamond wheels for ultra-precision grinding spherical, aspherical and freeform surfaces, a novel on-machine precision form truing of arc-shaped diamond wheels was proposed utilizing rotary GC rod. On-line monitoring of the truing processes by AE was studied. Based on the structural properties of arc shaped wheel, the technical solutions of truing and monitoring were formulated for D64 wheels. The run-out errors after truing are below 10μm which is reduced about 30μm before truing, the form accuracy of wheels was improved remarkably. The AE signals were processed to monitor the truing processes, and the Arms threshold for judging the finishing truing time was obtained. The monitoring technology will improve efficiency of the truing and grinding processes.
    Linear Regression Analysis of Arc Surface Cam Side Milling Tool Paths
    HU Dongfang1,2;GUO Jianwei1,2;REN Xiaozhong1,2
    2017, 28(18):  2249-2255. 
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    In order to reduce normal vector direction error exists for the arc surface cam unequal diameter machining method, according to the space linear regression algorithm NURBS (non-uniform rational B-Spline) ruled surface generation principles, a method was sought to minimize the machining errors of cutter axis vectors, and preliminary fitted. The initial cutter axis errors were reduced by iterative approximation, the cutter axis was taken as generatrix of NURBS ruled surface to restructure regression trajectory surface theoretical cutter axis. Using the least square method to further optimize, the optimization model of tool path errors for arc surface cam side milling was established, and a real coded artificial immune algorithm was proposed to solve the optimization model. The effectiveness of the proposed algorithm was verified by vector numerical calculations and simulations of the left-hand arc surface cams.
    Study on Dynamic Recovery/Recrystallization Constitutive Behaviors of Alloy IC10
    ZHANG Hongjian1;WEN Weidong1,2;CUI Haitao1;XIAO Jianfeng1
    2017, 28(18):  2256-2261. 
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    Various tensile experiments were conducted over the temperature range of 1073~1373K at different strain rates. Experimental results show: dynamic recovery is the dominate behavior at 1073K, and the dominate behavior over the temperature range of 1173~1373K is dynamic recrystallization. The behavior mechanism was studied by transmission electron microscope(TEM) tests. And the observation results show: there are both edge and screw dislocations on the cube plane, and these dislocations have a tendency to form the subgrains at the interphase boundaries of γ′, which is the dominate mechanism of recrystallization behaviors. At last, Sellars model, a most widely used macro constitutive model, was used to predict the flow behaviors of alloy IC10 over the temperature ranges from 1073 to 1373K and under different strain rates. The predicted data fits well with the experimental ones, and the average relative errors at various conditions are less than 5%.
    Effects of Sheet Blank Shapes on Axial Spinning Depths of Square Section Die-less Spinning
    JIA Zhen1; LI Yan1;HAN Zhiren1;XIAO Yong2;FAN Zuojun1
    2017, 28(18):  2262-2267. 
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    An experimental exploring method was adopted to study the effects of the circular and square blank shapes on the spinning depths of the square section die-less spinning comparatively, and the influence mechanism was analyzed theoretically. The method of initial determined step was used to derive the roller path formula which might be infinitely extended in the square section spinning firstly, and the spinning processes with circular and square blank shapes were simulated respectively. Then the experiments were carried out to verify the simulation results. The assessment method for the axial spinning depths was proposed and used as the criterion to analyze the subsequent spinnability of the circular and square blank conditions under the same axial spinning depths in contrast. It is found that the spinnability of square blank conditions is better than that of the circular blank conditions. The effect mechanism was revealed that the remaining flange shapes of the square blank conditions are uniform and in accordance with the square section roller paths. And this may promote uniformity of the radial metal flow.