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Table of Content

    25 June 2016, Volume 27 Issue 12
    Analysis for Fracture of Oring in Hang Hydraulic Cylinder of TBM Based on Fracture Mechanics
    Li Lin, Zhang Fengrong, Tao Jianfeng, Liu Chengliang
    2016, 27(12):  1563-1567. 
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    To study the causes for the fracture of the Oring in the hang hydraulic cylinder of a TBM, the maximum stress which Oring might withstand was analyzed with fracture mechanics under different Poisson's ratios and the initial cracks. Stress distribution of the Oring was simulated under the actual working conditions of TBM using ANSYS. The analysis results show that in the process of practical work of the TBM, due to the complicated working conditions, the local stress of Oring will beyond the maximum stress that may sustain before the crack rapidly propagates and it will result in the fracture of Oring. It indicates that a larger Poisson's ratio of Oring of hang hydraulic cylinder may be chosen in order to avoid the fracture based on the theoretical analyses and simulation results and the initial crack must be carefully controlled.
    Efficiency Analysis of Main Hydraulic Transmission System in a 30kV·A Hydraulic Wind Turbine Simulation Experimental Platform
    Ai Chao, Chen Lijuan, Kong Xiangdong, Li Hao, Ye Zhuangzhuang,
    2016, 27(12):  1568-1572. 
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    Taking 30kV·A hydraulic wind turbine simulation experimental platform as the research object, the basic structure, composition and working principles of the experimental platform were briefly introduced herein. To further understand the efficiency of this simulation experimental platform, the efficiency formula for the closed hydraulic transmission system was derived, and based on the key control technology of wind turbine—maximum power point tracking control technology, the experimental study on the efficiency of the experimental system was conducted. Finally, the accuracy of theoretical calculation formula was verified.
    Optimal Configuration of the Storage Capacity in Hybrid Excavator Motoring System
    Guo Hao, Wang Hui, Wu Xuan, Chen Jianwen
    2016, 27(12):  1572-1578. 
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    In order to solve the problems of large storage capacity, high cost, and improve the performances of the whole drive system, a power matching strategy was proposed based on super capacitor energy storage system applied to hybrid excavator rotary system. And then the performance price ratio of the super capacitor energy storage system was used as the optimal target of the storage capacity. The genetic algorithm was used to optimize the mathematics model established and simulation validation was made in the MATLAB model of the hybrid electric drive system, the parameters were compared before and after optimization. The results show that the optimized model may improve the performance price ratio of the hybrid excavator rotary drive system, the optimization of the storage capacity in hybrid excavator motoring system has some theoretical and practical guidances.
    Experimental Study on Surface Layer Quality of Prestressed Grindhardening Parts
    Bai Bin, , Xiu Shichao , Zhang Xiuming
    2016, 27(12):  1579-1584,1590. 
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    Starting from the antifatigue manufacturing and green manufacturing concepts, fusing the principles of prestressed grinding and grindhardening technology, an prestressed grindhardening approach integrated with residual stress control, surface quenching and grinding was presented. Based on the prestressed grindhardening test of 45 steel, the residual stress, hardness and roughness of the workpiece grindhardening layer surface were studied and analyzed. Comparing with the results for the grindhardening process under the same conditions. the results are as follows: the residual stress status of the prestressed grindhardening workpieces are better than that of grindhardening specimens, revealing that prestressed grindhardening process has significant effects on the drop of residual stretch stress and increase of residual press stress; the surface hardness of prestressed grindhardening workpiece is almost three times of original hardness, meanwhile, prestressed grindhardening workpieces can achieve lower roughness than that of grindhardening workpieces. Therefore, the fatigue resistance, corrosion resistance and surface integrity of prestressed grindhardening workpieces are better than that of the grinding hardening workpieces.
    Frequency Conversion Beam Pumping System Dynamic Simulation and Real Time Frequency Optimization
    Dong Shimin, Li Weicheng, Zhao Xiaofang, Zhao Ran
    2016, 27(12):  1585-1590. 
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    A dynamic parameter simulation model of beam pumping system with frequency conversion control was established, considering effects of real time frequency variation on motion law of suspension points, longitudinal vibrations of sucker rod, polished rod loads, ground device node torques and powers. By transforming the real time frequency function into the Fourier series, and taking the Fourier coefficients as design variables, an optimization mathematical models of the real time frequency function was setup, where the minimum root mean square of motor output power was taken as optimization objective function, and some constraints were considered, including constant strokes per minute, the ratio between the upstroke time and down stroke time, and real time frequency varies within the given bounds. Simulation and optimization results show that: simulation accuracy is high and can meet the demands of project applications; dynamics performance of beam pumping unit is improved significantly after real time frequency optimization, suspension point load fluctuation is reduced, maximum torque of crank shaft and torque fluctuation amplitudes are reduced significantly, motor output power amplitudes and fluctuation are reduced significantly and power utilization is improved, active power saving rate is as 25.8%.
    Study on Contact Model and Influencing Factors of Multiplanar Pyramid Needle
    Li Chenggang, Lin Jiaqing, Shen Jingjin, Xie Zhihong, Cui Wen, Hou Xiaolei
    2016, 27(12):  1591-1597. 
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    Considering the difficulties in analyzing multiplanar pyramid needle's force at the tissue's contact stage, a multiplanar pyramid needle's contact model was derived, which was based on the deformation between needle and tissue, and the problems of contact force and the puncturing performance was emphatically discussed. The model indicated that the contact force of the multiplanar pyramid needle was influenced by three factors, tissue's shear modulus, needle's halfapex angle and the number of needle's surfaces. The contact model was validated by the experiments and the experimental curves are in good agreement with theoretical data, which indicates the model is accurate and effective. According to the research results, in order to reduce the contact force and improve the puncturing performance of needle during the contact stage, it is a wise choice to select smaller tissue shear modulus, decrease needle's halfapex angle or the number of needle's surfaces.
    Modification Design and Contact Property Analysis for Profiles of Archimedes Type Sprag Clutch
    Yan Hongzhi, Zhao Cong, Liu Zhihui, Zhang Shiying, Wang Yiwei
    2016, 27(12):  1598-1602,1608. 
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    Contact properties of Archimedes type sprag clutch (including Hertz stress, circumferential stress and total deformation) were analyzed and compared with threearc type sprag clutch on the basis of different initial inner wedge angle models. To improve the bearing capacity of Archimedes type sprag clutch, modification on sprag profile of Archimedes was conducted by increasing the initial inner wedge angle, and contact properties of clutch were analyzed after modification; The results show that contact stress is reduced and the critical torque is improved when increasing modification coefficient. Moreover, the maximum modification coefficient μ is obtained from selflocking condition analysis.
    Detecting Outliers in Complex Profiles with ISOMAP
    Nie Bin, Li Jingya, Yao Xuehai
    2016, 27(12):  1603-1608. 
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    Researches of outlierdetection methods for the highdimensional complex profiles are as an important branch of profile monitoring. Considering the complexity of some highdimensional profiles, a matrix model for nonparametric profile was set up. Based on this model, a combined method was proposed, where ISOMAP could reduce the dimensionality based on geodesic distance and χ2 control chart could identify profile outliers. The proposed method shows good performance in the accuracy of outlier detection by both simulation studies and real case studies.
    Breakout Prediction Classifier for Continuous Casting Based on Active Learning GASVM
    Fang Yiming, Hu Chunyang, Liu Le, Zhang Xingming
    2016, 27(12):  1609-1614. 
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    Aiming at the problem that was difficult to obtain a high accurate breakout prediction model of continuous casting in the case of small sample data, a breakout prediction algorithm was proposed based on active learning GASVM classifier. Firstly, the algorithm preprocessed temperature data of continuous casting mold and labels valid data. Secondly, SVM model was obtained after SVM empirical parameters were optimized using labeled small sample data and GA. Finally, the optimized SVM model was tested using the historical data of a steel plant. The results show that in the case of small sample data for training model, the breakout prediction algorithm based on active learning GASVM classifier can obtain higher breakout prediction accuracy and 100% reported ratio. The presented breakout steel prediction algorithm was validated.
    Visualization of Hole Series Drilling Vibration Signal Feature Fluctuation and Its Applications
    Zhou Youhang, Yang Wenjia, Xie Saiyuan, Zhang Qiao, Zhang Benyi
    2016, 27(12):  1615-1620. 
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    To analyse the consistency evaluation of hole series part drilling quality, a clustering analysis method was presented based on fluctuation of vibration signal features. A vibration sensor was used to monitor the drilling process, and the vibration signal wavelet packet energy spectrum and higherorder statistics features of each hole in drilling process were extracted to construct the monitoring signal characteristic matrix. Then radar chart was used to reconstruct the distribution graphs of wavelet packet energy spectrum features and highorder statistics features, and the center of gravity features were extracted from these radar charts. Finally, fuzzy Cmeans(FCM) algorithm was used to complete the clustering analyses of these center of gravity features points. By comparison, it shows that hole drilling quality distribution can be visually presented and hole drilling quality consistency evaluation can be realized simply and reliably by clustering analysis based on radar chart.
    Grey Comprehensive Evaluation of Cutting Tool Performance for Aeroengine Blisk
    Jia Yupei, Zhao Wei, Li Liang
    2016, 27(12):  1621-1625. 
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    A grey comprehensive evaluation method of CNC milling tool performance was proposed for an aeroengine titanium alloy blisk with the CNC milling of a type of aeroengine blisk as the research object. In this method, a benchmark with some typical difficulttomachine features extracted from aeroengine blisk was designed, and the processing route was developed. In addition, grey comprehensive evaluation models of cutting tool performance were established for roughing and finishing tools respectively. Finally, experiments of CNC milling the benchmark were carried out, and then the grey comprehensive evaluation models were used to evaluate the cutting tools. The results show that the method is convenient and effective to evaluate the cutting tool performance for aeroengine blisks.
    A Method for CMM Inspection Path Planning Based on GA
    Zhou Kaijun, Xiao Yi, Zhou Xiaoqing
    2016, 27(12):  1626-1631. 
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    In order to improve the defects in present methods of CMM inspection path planning, a part measuring feature group model and solution processes were proposed. Then according to the characteristics of the mathematical model, a fitness function module was constructed based on the changing times of working planes, inspection angles, checking probe and the distance of detection paths. From macro and micro angles, the matrix crossover GA and sequence planning optimization GA were applied for solving optimization of inspection path planning. Finally, taking testing part of Hexagon Company for an example, the part initial checking data was acquired as well as the optimization algorithm for solving process was described. Practice proved that this method is fast and effective with good engineering application values.
    Stability and Control for Cutting Chatter Based on Active Magnetic Bearings
    Qiao Xiaoli , Zhu Changsheng, Zhong Zhixian
    2016, 27(12):  1632-1637. 
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    An active control technology for milling chatter was proposed based on AMBs. The effects of the AMB equivalent stiffness and equivalent damping on the milling stability were analyzed by finite element, and the milling chatter was controlled actively. The results show that the equivalent stiffness of AMBs may change the critical speed of electric spindle, and has little effect on critical milling width. On the contrary, the equivalent damping of AMBs can increase the critical milling width dramatically, and has little effect on the spindle critical speed. In addition, the chatter control effects show that the milling chatter can be suppressed by adjusting the equivalent stiffness of AMBs effectively.
    Experimental Investigation on Characteristics of a Novel Hydraulic Shock Pulse Generator
    Hu Yong, Ji Huanyu, Wang Gongxian
    2016, 27(12):  1638-1642. 
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    A novel structure of shock pulse generator with combination of throttling by coneshape spool and orifice was presented herein. Its mechanical dynamic properties were demonstrated experimentally such as: being able to selfadapt to the external loads applied to it; with high efficient dissipation of kinetic energy instantly; prompt and easy adjustment of the widths and amplitudes of shock pulses by changing the equivalent flow area of the damping orifices and the gap between the cone and inter wall of the cylinder. The experimental results indicate the feasibility of the openloop control approach by changing the equivalent flow area to control the pulse waveform and the shock pulse generator can meet the requirements of various impact tests.
    Research and Development of an Offline Dynamic Secondary Cooling Control Model for Beam Blank Continuous Casting
    Huang Wen, Lian Tianlong, Zhang Xingzhong, Yang Ladao, Gao Qi
    2016, 27(12):  1643-1647. 
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    A 2D solidification and heat transfer model for the secondary cooling process of beam blank continuous casting was established based on the solidification and heat transfer theory. The 2D space region of the beam blank section was discretized by using the nonequidistant grid, and the heat transfer equations was discretized based on the algorithm of explicit finite difference. The PID control model was established to control beam blank temperature. A dynamic distribution of water control software was developed for secondary cooling process in beam blank continuous casting with Visual Basic 6.0.When the casting speed, pouring temperature and casting steel grade changed, this software might track, record and display the informations of the beam blank in secondary cooling section and dynamically distribute water flow rate for different sections of secondary cooling to maintain the stability of the temperature distribution of the casting blank. This software is of very userfriendly, versatile and the simulation results prove that the control effects are desirable. This software lays the foundations for the development of dynamic secondary cooling control system for beam blank.
    Active Suppression for Terminal Residual Vibration of a 3DOF Parallel Robot with Limbs of Embedding Structures
    Ke Hui, Wang Xiaohui, Zhang Jianjun, Li Weimin
    2016, 27(12):  1648-1655. 
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    Aiming at the problems of terminal residual vibration suppression of a 3DOF parallel manipulator with limbs of embedding structures,an active suppression method was proposed based on the classical positive impulse input shaping combined with the optimal Scurve profile. Firstly,using the Lagrange method a rigidflexible coupling dynamics model was built for the parallel manipulator with limbs of embedding structures,which consisted of the rigid rod and the flexible components, and then through the dynamic characteristic analyses, it was confirmed that the influences on the residual vibration most were the low order modal. After that, resonant frequency and damping ratio were obtained through experimental analyses and simulations, and based on the residual attenuation vibration model of the linear secondorder owed damping system that affected by impulse sequence, changing the input signals of the drive through feedforward positive impulse input shape combined with the optimal Scurve profile,so as to achieve active suppression of the terminal residual vibration of the parallel manipulator with limbs of embedding structures. The experimental results show that the chain nested residual vibration attenuation time of the end of the parallel robot is reduced by 14%, the maximum amplitude is reduced by 22%,the positioning accuracy and trajectory precision are improved in the process of high speed and high precision wafer handling.
    Degradation Trend Prediction of Rolling Bearings Based on Fuzzy Information Granulation and Wavelet Support Vector Machine
    Chen Fafa, Yang Yong, Chen Baojia, Chen Congping
    2016, 27(12):  1655-1661. 
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    Aiming at the problems where the performance degradation index and its fluctuation ranges of the roller bearings were difficult to forecast effectively, a method was proposed herein based on fuzzy information granulation and WSVM for roller bearing performance degradation trend prediction. Firstly, the vibration signal sequences of rolling bearings in the operation process were acquired at a certain time interval, then, those feature indexes were extracted from those vibration signals. In order to acquire the effective component information, the process of the fuzzy information granulation for those feature indexes might be performed. Subsequently, a prediction model was established for each feature index by constructing the WSVM, and the degradation trend and the fluctuation ranges of the performance feature indexes of the rolling bearings were predicted. The experimental results show that the proposed method can track the change tendency of the rolling bearing performance effectively, and the degradation trend and the fluctuation ranges of the performance feature indexes may be predicted effectively.
    Study on Self Defense Delay Valve of High Voltage Circuit Breaker
    Zhang Jianzhuo, Du Zhichun, Wang Jie, Sui Xin
    2016, 27(12):  1662-1666. 
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    In order to ensure the safety and stable operation of high voltage transmission network, the high voltage circuit breaker needed to have the function of self defense delay. The existing high voltage circuit breakers realized this function by the auxiliary switch, time relay and other ways, but it resulted in the problems of structural complexity and low reliability. A new type of self defense delay structure was proposed herein based on the hydraulic system of the operating mechanism, which might adjust the time delay steplessly by adjusting the displacement of the self defense delay valve spool. The optimized design and orthogonal experiments were used to optimize the parameters of the structure. According to the optimized results, two experimental prototypes were processed and the experimental study was carried out. The measured results are in the range of 41.6~59ms, which can meet the requirements of the safe operation of power grid.
    Multiobjective Flexible Job Shops Robust Scheduling Problem under Stochastic Processing Times
    Zhu Chuanjun, Qiu Wen, Zhu Mengzhou, Chen Guang, Zhang Chaoyong
    2016, 27(12):  1667-1672,1678. 
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    Multiobjective flexible job shop schedule problem with uncertain processing time was studied. Two uncertain parameters were adopted to describe the degree of disturbance volatility and allowable constraints violence respectively. A robust optimization approach to translate multiobjective flexible job shop scheduling problem into deterministic robust counterpart problem was proposed. A set of global nondominated solution was adopted to preserve the best solutions in every generation, and the solution which in the set was selected to participate in the mutation operation. After crossover and mutation, a local search strategy was proposed based on neighborhood structure. Several benchmark problems were handled by the algorithm, the results indicate that it is effective for such problem.
    Effects of Different Die Sets on Forming Quality of 0Cr21Ni6Mn9NStainless Steel Tube during NC Bending
    Lu Shiqiang, Fang Jun, Tang Jinxing, Wang Kelu
    2016, 27(12):  1673-1678. 
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    The laws of stress/strain distribution, wall thickness variation and cross section deformation of 0Cr21Ni6Mn9N stainless steel tube during NC bending under different die sets were studied by using the finite element method. The results show that adding a wiper die to the base die set including bending die, clamp die and pressure die increases the effective stress, tangential tensile stress and tangential tensile strain, but decreases tangential compressive stress, effective strain and tangential compressive strain; adding a mandrel to the base die set decreases the tangential stress and effective strain, but increases effective stress and tangential strain; adding the wiper die and mandrel simultaneously to the base die set increases effective stress, tangential stress and tangential strain, while decreases the effective strain. Adding the wiper die increases the cross section deformation ratio, but has no obvious effects on wall thickness variation ratio; adding the mandrel can restrain cross section deformation effectively, and the wall thinning ratio is far less than 15% of the aviation standard, which is only 9.0%~9.15%. Considering the forming quality and cost of 0Cr21Ni6Mn9N stainless steel tube during NC bending, the optimal die sets are bending die, pressure die, clamp die and mandrel.
    Optimization of Load Distribution for Lead with Rolling Processes Based on Intelligent Algorithm
    Jiang Chengcan, Rui Yannian, Liao Lili, Guan Miao, Shen Ming
    2016, 27(12):  1679-1682. 
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    Aiming at equilibrium and based on genetic algorithm and BFGS algorithm, the new optimization method was called mutative scale hybrid genetic algorithm(MSHGA), which was used for load distribution of lead with rolling processes and was verified the feasibility through the simulation experiments. The experimental results show that the optimized total rolling force is down 10.7% from empirical load algorithm under the conditions of invariable parameters in rolling strip shape of lead, thickness, precision and performance indicators. The research lays a theoretical basis on save power of lead with rolling.
    Strategies for Chinese Automotive Companies Going Abroad
    Zhao Fuquan, Liu Zongwei, Wang Yue
    2016, 27(12):  1683-1688. 
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    Chinese automotive industry has entered into the peak period of overseas development with no smooth growth. A clear and appropriate goingabroad strategy is of vital importance for both enterprises and the nation. Strategic necessity was analyzed based on the law of business development stages. The relevant factors were classified by thinking block diagram and round intersection method. The framework of strategic thinking for overseas development was put forward. Several specific recommendations were given and it was proposed that entering the US market is of great value, with the aim of strengthening Chinese automotive industry.
    Automobile Bellows Fatigue Analysis under Influences of Temperature
    Huang Zehao, Jiang Guangzhi, Zheng Fengyun, Yuan Guangliang
    2016, 27(12):  1689-1693. 
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    Started from the working environment of the bellows, this paper analyzed the fatigue life of automobile bellows with fully considerations of material nonlinearity properties under the temperature. First, according to the requests of bellows fatigue test the boundary conditions of the model were set. Then, the stress of the dangerous position of the bellows was studied from two conditions of yield strength changes and without yield strength changes to find out the influence characteristics of temperature variation on the stress of the bellows. Finally, on the basis of the stress analysis results, the fatigue life of bellows under different temperatures was evaluated by using the local stressstrain method,and the influences of temperature variation on the fatigue characteristics of bellows were obtained.
    Advances on Dynamics Modeling and Experimental Studies for Flexible Manipulators
    Gu Yongxia, Zhang Yuling, Zhao Jieliang, Yan Shaoze
    2016, 27(12):  1694-1703. 
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    This paper summarized the latest advances on the flexible manipulator modeling theories and relevant experiments of scholars at home and abroad, systematically expounded the study status of the methods to describe the flexible manipulator deformations, the joint dynamics modeling, the dynamic modeling methods of flexible manipulator systems, the stiffening and softening effects of the arms and the experimental methods. Then this paper proposed the present problems and shortcomings of manipulator dynamics theory and experimental study, predicted the main direction and core technology of the flexible manipulator dynamics research and analyzed key technical problems about the optimal mode order selection of flexible manipulators in detail. The system parameter optimization based on the dynamic characteristics of flexible manipulators, the determination of joint driving laws, the stiffening and softening effects of manipulator arms under high speed, the fine modeling of flexible manipulator joints and the crawling phenomenon in the super low speed of space flexible manipulators were presented.