Table of Content

10 June 2015, Volume 26 Issue 11

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Research on Dynamic Stiffness of Ball Bearings Considering Ferrule Deformation and  Elastohydrodynamic  Lubrication

Xiong Wanli, Zhao Zisheng, Zhou Yang, Lü Lang, Hou Zhiquan

2015, 26(11):  1421-1428. 

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Aiming at the shortage of traditional quasi-static analytical method which   did  not consider the changes in geometrical positions of bearing inner raceway curvature center and the rolling body center caused by bearing thermal deformation,the centrifugal force deformation and the elastohydrodynamic lubrication effect,a   bearing quasi-static modified model  was established considering the effects of ferrule deformation and elastohydrodynamic  lubrication.The effects of thermal deformation, the centrifugal force deformation and the lubricating oil film on bearing dynamic stiffness were  studied by established model  under conditions of different rotational speeds  and bearing preloads.The validity of the established model was verified by comparison with the Gupta typical examples and experiments.

Experimental Research on Electrochemical Machining of Lightweight Stepped Hole Structure

Liu Yujie, Zhao Jianshe, Gan Weimin, Qi Lu

2015, 26(11):  1429-1433,1515. 

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For the structure characteristics and machining difficulties of lightweight stepped hole with big inside and small outside, a fixed cathode electrochemical machining method was proposed to realize the inner hole machining. Taking the center stepped hole on rotation shaft of an airplane landing gear for example，in order to improve the machining quality and efficiency, the cathode structure was optimized firstly based on numerical analysis and experimental verification. Stepped variable voltage machining method was proposed which met the actual production needs. Based on the above, taper of cathode was modified and experiments were conducted. Finally, passable products were manufactured and the process is stable, which can meet the requirements of mass process.

Modeling, Simulation and Experiment of a Pneumatic Line-thrower

Wang Zhiwen, Xiong Wei, Wang Haitao, Wang Zuwen

2015, 26(11):  1434-1437. 

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The structure and the working principles of a line-thrower were introduced,which was controlled by pneumatic valve herein. A model of the line-thrower was developed in AMESim software. The dynamic behaviors of main components were obtained by simulation. The results of the simulation and the experiments are consistent with each other and testify the reliability of the model, thus providing reference for further optimization of a line-thrower.

Analysis on Three-dimensional Temperature Field of Permanent Magnet Synchronous Motor in Vehicles

Liu Lei, Liu Guangfu, Liu Malin, Zhu Biaolong

2015, 26(11):  1438-1444. 

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In order to study temperature field of PMSM used in vehicles, a rated power of 25kW PMSM in vehicles was taken as the research object, and its three-dimensional solution domain model was built based on the basic theory ofheat transfer. The motor's steady state condition temperature field and the temperature rise changes were derived through simulation analysis. Also, the simulation analysis on temperature rise of the key parts in the motor was carried out under continuous variable power working conditions, for the sake of studying the changes in motor temperature field under actual driving conditions of the vehicle. By building an experimental platform, the effective tests of motor's temperature rise were carried out under rated operating conditions and continuous variable working conditions. By contrast and analysis, experimental data are close to simulation data, which verifies the accuracy of the simulation.

Analysis and Optimization of Ride Comfort for a Wheel-tracked Rescue Robot

Li Hao, Shi Caihong, Kang Shaohua, Zhang Xizheng

2015, 26(11):  1444-1449. 

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This paper presented a new kind of wheel-tracked rescue robot,which could efficiently search and transport the wounded in the disaster sites and other complex environments by converting the structure between wheel and track. Considering the safety and comfort of the wounded,this paper focused on the vibration analysis during the transporting of the wounded, and used the multi-body dynamics software ADAMS to establish the rescue robot's dynamics model.This model was about the simulation analysis of the operation in the actual road conditions. Considering different parts of the human body have different frequency weighting functions in different directions, the simulation curve should be processed by the corresponding filter designed by MATLAB to calculate the robot's ride comfort. Target to better ride comfort, the suspension parameters should be redesigned by the MATLAB optimization toolboxes.And the further simulation outcomes demonstrate the rationality of the optimization results.

Diagnosis Method for Rolling Bearing Incipient Faults Based on Sparsity of Envelope Spectrum and Maximum Correlated Kurtosis Deconvolution

Tang Guiji, Wang Xiaolong

2015, 26(11):  1450-1456. 

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Early fault  features of rolling  bearings  are   very weak and are  affected by environment  noise  seriously,so it  is difficult to draw fault features.Aiming at solving this problem,MCKD  was tried to diagnose faults  for bearings,and sparsity of envelope spectrum was used to select the optimal deconvolution period parameter,then incipient  fault diagnosis method for  rolling bearings was proposed  based on sparsity of envelope spectrum and MCKD.MCKD  method corresponding to  the optimal parameter was used to process the original signals  and the envelope spectrum of deconvolution signals was obtained,the bearing faults were  judged by analyzing the envelope spectrum.Simulated incipient fault signals and full lifetime datasets of  rolling bearings  were used  to  examine  the  feasibility  of this method and the results show  the new method can  be  applied  to  diagnose the incipient fault effectively. 

Knitting Motion Analysis and Mechanism Design for Multi-bar Warp Knitting Machine

Shen Huiping, Li Mi, Wang Minqi, Wang Shui, Yin Hongbo, Zuo Shuangshuang

2015, 26(11):  1457-1463,1470. 

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On the basis of understanding basic principles for mechanism design of foreign warp knitting machines, knitting motion and the mechanism for performing the motion were studied systematically. Firstly, knitting mechanism,knitting processes and its working principles were introduced and Stephenson 6-link transmission mechanism with intermittent function was designed.By sharing a three-thrown crank shaft,three 6-link transmission mechanisms and 3-DOF plane 8-link knitting sub-mechanism were concatenated. A 3-DOF plane 22-link knitting main mechanism with single driving axis was designed and its kinematics property   was also analyzed.Secondly,the key feature points of knitting action were planned based on  the configuration of  guide needles and knitting processes and the polynomial function of each trajectory was obtained by least square method. Further,the whole physical model of the 3-DOF plane 22-link  knitting main mechanism was analyzed and optimum design of mechanism  parameters was conducted based on the knitting action trajectory approaching using genetic algorithm.

Method of Autonomous Compact Local Characteristic-scale Decomposition and Its Applications

Wu Zhantao, Cheng Junsheng, Li Baoqing, Zheng Jinde

2015, 26(11):  1464-1470. 

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The least extrema scale was defined to measure other signal scales for restraining the mode mixing problem of LCD, and by adding pseudo-extrema autonomously to homogenize the signal scales. Based on this, a novel method of ACLCD was proposed. Compact coefficient was introduced, and the optimal evaluation criteria of compact coefficient was given. The paper firstly studied the theory of ACLCD, then simulation experiments were used to compare the performance of ACLCD with LCD and empirical mode decomposition(EMD). The results indicate that ACLCD is more efficient in improving the veracity, orthogonality in components and inhibiting the mode mixing than that of LCD and EMD. Finally, the proposed method was applied to diagnose the rotor with rub-impact fault successfully which indicates the effectiveness of ACLCD.

Dynamic Coordination among Manufacturing Resources and Tasks Based on Endocrine Regulation Principle

Gu Wenbin, Tang Dunbing, Zheng Kun

2015, 26(11):  1471-1477. 

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For solving the coordination problems of tasks and resources in dynamic manufacturing environments, the optimization process of the coordination problems among tasks and resources was analyzed, and a mathematical model was established. Inspired by the endocrine regulation principle, two kinds of hormone（task hormone and resource hormone）were designed. Considering the influences of the emergency in manufacturing system, a novel dynamic coordination approach was proposed based on the hormone regulation principle. This proposed approach was characterized by higher efficiency, lower communication, and better robustness. A prototype system was developed, and experimental results confirm that the approach has excellent stability and optimization ability for task allocation problems in a static environment, and it also has excellent control performance and adaptability to disturbances in shop floor.

Integrated Optimization of Equipment Maintenance and Shop Scheduling Problem Based on Multi-objective Hybrid Imperialist Competitive Algorithm

Song Wenjia, Zhang Chaoyong, Ying Yong, Shao Xinyu

2015, 26(11):  1478-1487. 

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In order to improve equipment utilization rate and maximize the efficiency of assets, preventive maintenance should be considered in production plan.A mathematical model to optimize the integrated flexible job shop equipment preventive maintenance and scheduling problem was established based on the real environment of the manufacturing shop with three objectives, including minimizing makespan, production cost, and average maintenance cost. An improved algorithm, which was referred to MOHICA, was proposed to solve the problem. This paper designed the process of encoding, decoding and empire assimilation as well as the procedure of MOHICA.An improved weighted TOPSIS (technique for order preference by similarity to an ideal solution) method was employed to choose the most satisfactory solution in the Pareto-optimal solutions to achieve the purposes of improving the reliability of the equipment, in-time delivery and saving cost. To validate the proposed strategy, an experimental test on a real-world instance was conducted. The computational results indicate that the proposed model is feasible and the algorithm is effective.

Optimization Method of Remanufacturing Assembly Shop Scheduling Based on Fuzzy Chance-constrained Programming

Zhang Mingxin, Ge Maogen, Zhang Xi, Liu Chonghu, Ling Lin, Hu Jing

2015, 26(11):  1488-1493. 

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The quality uncertainty during the process of parts reassembling caused the big range of the fluctuation of the assembly time and difficult description of scheduling mode. Aiming at this problem, the assembly time of the reassembled parts was represented by the fuzzy variable based on credibility measure to establish the scheduling model with the fuzzy chance-constraints based on the confidence level. Then, a hybrid intelligent optimization algorithm was proposed combined with a neural network and genetic algorithm, where the neural network based on back propagation algorithms was to approximate the undetermined relation function between the input and output data generated by using the fuzzy simulation technique and the genetic algorithm embedded the trained neural network was to solve the scheduling model. Finally, a study case was given to prove the feasibility of the proposed model and algorithm.

Dynamic Facility Layout Method under Uncertain Product Demands

Ma Shumei;Cai Huisen;Zhang Yifan;Li Aiping

2015, 26(11):  1494-1502. 

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The dynamic facility layout method combined with fuzzy set theory and improved genetic algorithm was brought out on the basis of considering the influences of uncertain product demands, aiming at the deficiency of the present dynamic facility layout method. The characteristics of product demand uncertainty change over time were analyzed, and the uncertain demands were described by the triangular fuzzy numbers. The dynamic layout was transformed into several static layouts through analyzed facility relocation process between each period so as to establish a dynamic facility layout model under uncertain demands based on flexible bays structure. An improved genetic algorithm was proposed by combined triangular fuzzy number operation and adaptive local search with genetic algorithm, and then solved dynamic facility layout problems with uncertain product demands and unequal area constraints; the target of the problem was minimum the total cost of material handling and facility relocation. At last，the examples were illustrated to verify the practicability and effectiveness of the given method．

Thermal-mechanical Coupled Modelling and Numerical Simulation for Twin-roller Casting Process with Technique of Deactivate and Reactivate Element

Huang Huagui, Liu Wenwen, Wang Wei, Du Fengshan,

2015, 26(11):  1503-1508. 

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Aiming at the 160mm×150mm vertical type experimental twin-rollers continuous caster, a thermal-mechanical coupled FEM model of twin-roller casting process was established with MSC.Marc and its' secondary development interface based on the solid-liquid two phases constitutive model of pure aluminum and the thermal resistance model considering the contact pressure. The technique of deactivate and reactivate element method was used to simulate the continuous casting of aluminums liquid, and the problem of coupled heat transmission between the cast roll shell and aluminum strip in the cast rolling area was therefore resolved. From the simulation results, the influences of casting speed, casting temperature, the height of cast rolling area on the position of KISS point and the time history of temperature on the roll surface were presented. An twin-roller casting experiment was carried out, and the numerical simulation results are in good agreements with the experimental data.

DOF Representation and Operation of Geometric Feature and Its Applications for Tolerance Technology

Wu Yuguang, Liu Yusheng

2015, 26(11):  1509-1515. 

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The intrinsic direction of geometric feature, the representation method and calculation rules of DOF of geometric feature were proposed. The intrinsic direction of geometric feature was determined based on the geometric characteristics and position relations among toleranced geometry feature and datum geometry feature. According to the geometric measurement principles, the computation method of constraint capability of datum feature to the DOF of target feature was proposed,and the calculation rules of constrained DOF of toleranced features were proposed by datum reference frames. The tolerance specification validation method were proposed according to the relationship among tolerance type and geometry of the datum and target entity, and the correctness and completeness validation rules were discussed against the dimensioning and tolerancing standards and against good practice rules in industries. 

Application of Lanczos-based Modal Reanalysis Algorithm in Topological Optimization

Liu Dan, Wang Hu

2015, 26(11):  1516-1520,1526. 

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In topological optimization,the structures were often required to make some modifications,and it was very important for improving the effciency of optimization that the low-order eigenvalues could be calculated accurately and quickly. The Lanczos-based modal reanalysis method was applied to topological modification.The presented method which combined Lanczos  algorithm and projection techniques,solved the natural frequency and mode shapes for the modified structures utilizing the already obtained eigenvectors with reduced-basis algorithm.The major advantages laid that the fast convergence of Lanczos vector and high-accuracy of reduced-basis method based on global approximations.A stiff frame example was demonstrated the high accuracy of the reanalysis method.The optimization results of the clamped square plate and vehicle frame indicate that the method can also ensure the calculation accuracy and optimization iteration speed to a certain extent.

Reliability Allocation Based  on Interval Analysis and  Grey System Theory

Liu Ying, Yu Wu, Li Yue, Wang Yang

2015, 26(11):  1521-1526. 

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Aiming at the factors influenced reliability allocation with uncertainty and  the problems  of lacking data during the early product design,a comprehensive reliability allocation method was proposed to allot the reliability index of a  series of horizontal machining center based on the interval analysis and grey system theory.Considering  five factors such as the complexity,failure frequency,technical level,harmfulness and maintainability that influenced allocation, combining with the expert experiences and some known informations,and  using interval analysis,grey correlation analysis and entropy weight method their weights were determined.Finally,the reliability  index of each subsystem was allocated according to the grey comprehensive evaluation value, and compared with the actual fault statistics results,therefore,the feasibility and accuracy of the method were  verified.

Characteristics Simulation for Hydraulic Wind Turbine

Ai Chao, Chen Lijuan, Kong Xiangdong, Yan Guishan

2015, 26(11):  1527-1531. 

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Aimed at the simulation problems of the wind turbine characteristics in hydraulic wind turbine without wind field environment, a mathematical model of the wind turbine output characteristics was established on the basis of the actual data. According to the similar simulation principles and the use of direct speed control compensation method,the experiments of wind turbine characteristics were conducted. Finally, the results of the equivalent power experimental data multiplied by the conversion coefficient，the simulation results and the actual data of 850kW wind turbine provided by the related cooperation company were compared, and the results show that the system can accurately simulate the output power and output torque of wind turbine in the range of allowable errors.

Gearbox Fault Feature Fusion Based on Principal Component Analysis

Gu Yingkui, Yang Zixi, Zhu Fanlong

2015, 26(11):  1532-1537. 

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To effectively reduce the dimension of gearbox fault feature and improve the accuracy of diagnosis, a fault signal feature fusion method of gearbox was proposed based on principal component analysis, and the support vector machine and BP neural network were used to analyze the diagnosis accuracy. The 36 features with different crack gears in gearbox were selected based on time-domain, frequency-domain and Hilbert transform, which could be used to characterize the fault states of gearbox. The principal components which had more than 95% cumulative contribution rate were extracted and input into support vector machine classifier for identification. BP neural network classifier was used for comparative analysis of the results. Results show that a combination of principal component analysis and support vector machine method can reduce the feature dimension and computational complexity, characterize the gearbox running status effectively, and identify the different levels of gear crack. The diagnosis accuracy is higher and the training time is shorter than that of individual support vector machine classifiers.

Finite Element Simulation and Experiments for Repetitive Deep Drawing of Spherical Parts

Luo Junting, Tian Baorui, Chen Yimin, Zhang Chunxiang

2015, 26(11):  1538-1541,1549. 

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A new repetitive deep drawing forming of spherical parts was presented and finite element simulation and experiments were carried out. The stress state and values were almost equal in the flange area and in the circle-corners compared with once deep drawing forming, but in the ball bottom area the radial stresses and circumferential stresses were pressure stresses or small tensile stresses, which were much less than that in once deep drawing. The thinning strain of parts is reduced evidently in the ball bottom area for repetitive deep drawing. The thinning rate of forming parts in thinnest point for once deep drawing, 2-time deep drawing and 3-time deep drawing are as 0.189, 0.122, 0.049 respectively.The thinning strain is very small in the 3-time repetitive deep drawing, which realizes near equal-thickness wall forming. Combined with the bottom cold sizing technology, the technology can realize the forming of deep cup with uniform thickness.

Research on Robustness of Sheet Metal Deformation Using Response Window

Duan Libin, Chen Zhuo, Song Kai, Zeng Siqin, Zhang Hongmin, Liu Jiuwu

2015, 26(11):  1542-1549. 

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Based on uncertain deformation and low robustness of sheet metal deformation, considering noise factors, the influences of random variations were studied. The control factors were as the numbers and positions of the locating points, the sizes and areas of the extend forces. The noise factors were as fixture variations and material variations. Descriptive sampling was applied to random noise factors. Through DOE and finite element simulation, the effective deformations and response windows in all levels were obtained. The goal control strategy might be obtained by analyzing the above data. The examples indicate that the analysis method can successfully analyze and solve the problem of the robustness of sheet metal deformation when considering noise factors. So, the method provides an important and significant idea to reduce the deformation and improves the robustness of sheet metal.

Research on Dynamic Control Strategy of a HEV Based on Drivability Optimization

Zhang Donghao, Xiang Changle, Han Lijin, Zheng Hailiang

2015, 26(11):  1550-1555. 

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To solve the optimal control problem of HEVs during the dynamic process, a dynamic control strategy was proposed based on drivability optimization. A control-oriented dynamic power distribution model was established according to the characteristics of the power-split hybrid electric system. Based on the driver's expected status and the vehicle's actual status, the index function of the drivability was come up with. A control strategy satisfying the drivability was presented firstly. The dynamic characteristics of the different components and the speed tracing requirements of the engine were fully considered in the optimization model. Additionally, a real-time optimization algorithm of the drivability was proposed. It can be seen from the simulation results that this control method improves the drivability dramatically without scarifying the fuel economy.

Accurate Simulation and Investigation on Valve Performance of Shock Absorber Based on Large Deflection Theory

Wei Yong, Zhao Liang, Kang Yu

2015, 26(11):  1556-1561. 

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To get the expression of large deflection for telescopic shock absorber annular throttle-slice with its radius , based on the large deflection theory of circular plate, a intrinsic unified expression of thin plate deflection was put forward. Meanwhile, combined the large deflection's analytic expression of the annular plate's edge and the mature equation of small deflection, the mix analytical formula of large deflection for annular throttle-slices and its deformation correction factor related with radius were deduced. Moreover, the deformation of annular throttle-slice was simulated by finite element analysis software ABAQUS and the accuracy was verified. The analysis formula of superposition throttle-slices was established according to mix method. The equivalent thickness and stiffness of superposition throttle-slices were studied. The analysis formula and the conclusions can provide helpful reference for the future design and analysis of shock absorber throttle-slices.