Table of Content

25 July 2015, Volume 26 Issue 14

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Calculation  of  Misjudgment Probability  in  Product  Tests  Based  on  Measurement  Uncertainty

Chen Xiaohuai, Wang Hanbin, Cheng Yinbao, Jiang Rui

2015, 26(14):  1847-1850,1856. 

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According to ISO14253-1, the principles and methods of conformity assessment were studied based on measurement uncertainty. The effects of measurement uncertainty on  conformity assessment in product tests were analyzed, and based on the distribution function of measurement uncertainty,formula  of misjudgment probability in batch product quality tests  was derived; situations for a single product were then discussed when measurement results were in different sections. Software for conformity assessment was designed based on  LabVIEW,from which the conformity assessment results and the misjudgment probability could be acquired simply by inputting related parameters.An actual experiment shows that measurement uncertainty may cause misjudgment in product test. Software for conformity assessment can effectively improve the operability of applying uncertainty theory in product tests,and calculation of misjudgment probability based on measurement uncertainty can provide reliable basis for consumer and producer to reach an agreement on the conformity of products.

Simulation and Experiments on Stress Characteristics of Arc Binding Interface for Oil-film Bearings

Wang Yao, Wang Jianmei, Xiang Dan,

2015, 26(14):  1851-1856. 

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The mathematical models to calculate the resultant stress in transition area and the peak of interfacial stress were established based on the thick-cylinder theory and Hertz contact theory. And the analytical expression was derived. Simulation results reveal  the stress characteristics of arc binding interface.It is concluded that the axial stress  presents the U-distribution, both ends of the stress are large, the middle stress is relatively stable. Obvious stress mutations of the circumferential stress appear in the junction of bearing and non-bearing area. Comparing the calculated and simulated methods, the mean error of stress in arc binding interface is less than that in transition area, and both of them is less than 5%. Experiments show all errors of experimental values and simulated values are less than 2%. Experimental results are consistent with simulation ones. It suggests that analytic solution and simulation are relatively effective. This work can provide references for the theoretical calculation and experimental verification of interfacial binding strength, and give out some improvement recommendations for oil-film bearing maintenance.

Test Device  Design and  Experimental Verification of Deployable Mechanism of Folding-wing

Hu Ming, Zhang Bin, Chen Wenhua, Tian Fangfei, Zhang Hong, Zhou Xiaohong

2015, 26(14):  1857-1861. 

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Based on working principles and functional requirements of folding-wing deployable mechanism,the performance parameter measurement method of a folding-wing deployable mechanism was determined,the test device design and development of principle prototype  was completed.Using the developed test device of the deployable mechanism of folding-wing,spread experiments were  carried out and the various performance indicators were obtained.According to multiple spreading experiments in different torques,performance parameters the regulations were researched.The group test data show that the folding-wing can unfurl to the appointed place quickly,can be located accurately and locked reliably,and there is no interference between each part during the deployment process.

A Pattern Recognition Method Based on Fusion of Time Series Analysis with VPMCD and Its Application in Machinery Fault Diagnosis

Jia Minping, Han Bing

2015, 26(14):  1861-1865. 

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A pattern recognition method was proposed herein based on fusion of time series analysis AR model with VPMCD for fault  diagnosis. AR model of fault signals was established by using time series analysis,taking its autoregressive parameters that contain the fault features as the fault characteristic values, fusing VPMCD training to get the prediction models of fault characteristic values,and by using these predictive models to classify and recognize the faults  of sample types and working states.Analyses of rolling bearings  and gear vibration signals show the effectiveness of this method, comparison of the diagnosis method based on fusion of empirical mode decomposition(EMD) with VPMCD shows the superiority of this method.

Composite  Curve  Spiral  Tool-Path  Generation Method  for  High-Speed  Machining

Zhao Donghong, Lu Zhangping, Wang Tingjun, Yang Lian

2015, 26(14):  1866-1870. 

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Existing spiral cutting methods are only suitable for circular and quasi-circular boundaries.Herein,a kind of composite curve spiral cutting method was proposed.Lines and arcs were used to construct regular-shaped auxiliary boundaries to contain irregular original boundaries of the surface.Smooth mesh surfaces were built  as  the  projecting surface of the helixes.Finally,the project curves and the planar helixes were bridged and used as the drive curves to produce composite spiral tool paths.In addition to avoid the influences of boundary corners,the advantage of tool path continuity was remained.It was fit for kinds of flat surfaces with irregular boundaries.The software simulations and the practical processing  results show that the composite curve spiral cutting method effectively solves the problem of continuity and vector sudden change of tool-path,particularly  for  high-speed  machining of composite surfaces.

Chaotic  Characteristics  of  Nonlinear  Metal  Rubber  Vibration  Isolation  System

Li Yulong, Bai Hongbai, He Zhongbo, Cao Fengli, Lu Chunhong

2015, 26(14):  1871-1876. 

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The  chaotic  characteristic of nonlinear metal rubber vibration isolation system  was studied  herein.The system state equation was derived,the Lyapunov exponent  was calculated,the displacement  time history diagram and the phase track diagram were draw out,it proved that the system was  in the chaotic  state under the conditions  of the given parameters. Through the analysis of the system response spectrum diagram,the metal rubber nonlinear vibration isolation system chaos  was  illustrated in the important role of line-spectrum  control.The parameters  of the excitation and the vibration isolator's  impacts  on system dynamics  characteristic  were analyzed by using numerical methods.The parameter scopes in the chaotic state were confirmed  based on the bifurcation diagram changed with the parameters of the excitation and the vibration isolator.The general selection method of  the parameter was got,which could make the system be in the chaotic state,and it  lays  a  foundation for the applications  of  the nonlinear metal rubber chaotic vibration.

Experiments  of  Parameter Optimization  of EDM Titanium Alloy  Based  on  Gray Relation Theory

Zhao Jianshe, Yu Zixin, Zhou Xujiao, Yu Ze, Dou Haifeng,

2015, 26(14):  1877-1882. 

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Material  removal rate,electrode wear ratio and surface roughness were chosen as the performance characteristics.To comprehensively evaluate the performance characteristics above, adjustable process parameters such as peak current, pulse duration, duty factor and tool jump cycle were studied in orthogonal experiments,which tested titanium alloy using commercially mature EDM equipment.Test process was simplified and optimized process parameter combination was achieved based on gray relation analysis,which converted  multiple performances objectives into a single index(gray relation grade).Based  on  the  confirmation experiments,the parameter  combination  can  achieve a higher material removal rate and lower electrode wear ratio simultaneously and meet the requirements of surface roughness.

Method of Testability Dynamic Evaluation for Military Engineering Machinery

Wang Haitao, Zhang Qi, Zhu Chunsheng, Zhao Hongfei, Li Huanliang

2015, 26(14):  1882-1887. 

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In order to achieve the accurate and scientific evaluation of  the testability index requirements, based on the dynamic characteristics of the testability evaluation indexes, the time series were introduced to build three-dimensional evaluation model which consisted of evaluation object, evaluation index, and evaluation time. The dimension reduction algorithm which combined the subjective weight determination method and the objective weight function was used to solve the dynamic three-dimensional appraisal matrix. And the dynamic evaluation of testability design process for military engineering machinery was realized. The application instance shows that the dynamic evaluation method can provide effective evaluation for testability design process of military engineering machinery.

Global Optimization with Multi-targets for Rough  and  Finish  End-milling Parameters Based  on Minimum Energy Performance

Li Aiping, Bao Jin, Li Cong, Liu Xuemei , Xie Nan

2015, 26(14):  1888-1894. 

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With the  research of surface end-milling for both of rough and finish processes, a piecewise function concerned with CNC idle energy consumption was built considering the characteristics of variable volocity variable frequency(VVVF) machine tool. Mathematical models of energy consumption for rough and finish milling processes and processing efficiency were established. Related experiments were performed to test the models and the related constraints on rough and finish milling processes. Global optimization searching for the best combination of milling parameters were achieved using GA, moreover, the results were compared with that of the local optimization.The verified experiments show that the local optimization method can reduce 12.51% of the total energy consumption,and the reduction for global method is 15.04%. Meanwhile, the local optimization method can also cut 18.48% of the processing time and the reduction for global method is as 21.26%.

Design and Parameter Analysis of Soft-start Permanent Magnet Eddy Current Coupling

Li Yanmin, Li Shen, Tai Zhiheng

2015, 26(14):  1894-1899. 

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This paper introduced the working principles and the advantages of the permanent magnet eddy current coupling systematically. The torque of permanent magnet coupling was calculated by the equivalent model using Faraday's law of  electromagnetic induction.According to lots of ANSYS Maxwell 3D simulations, the relationships among key parameters of permanent magnet coupling (the size of magnet, the number of magnet, the copper plate thickness and the air gap, etc.) and the torque characteristics were analyzed,which provided a strong support for the design.Applying the above analysis results, a coupling with 7.5kW,1500r/min was designed which had a new type of structure and the function of soft-start and the experimental results of the prototype met  the design requirements. The calculation and simulation method herein will be as references for the design of permanent magnetic coupling.

Simulation-based  Ship Block Building Dynamic Spatial Scheduling

Wang Jinjian, Du Jiwang, Fan Xiumin, He Qichang,

2015, 26(14):  1900-1907. 

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To reduce the difference among ship block spatial scheduling results and actual working assignments,a simulation-based dynamic spatial scheduling method was proposed.According to different stages of ship-block  building and analyzing the influence forms of affecting factors,three dynamic adjustment strategies were put forward,including positioning delay strategy, progress control strategy and swing waiting strategy.With these strategies,the ship-block building processes could   be adjusted so as to adapt to affecting factors.A ship block building simulation model was  developed to realize the dynamic spatial scheduling simulation under the influence of affecting factors.The simulation results indicate that the proposed method can reduce the difference between the scheduling plan and actual working ones,and  can provide guidance to optimize ship-block building production plan.

Study  on  Production  Efficiency of  U-Shaped   Assembly  Line  Based  on  Assembly  Line  Balancing

Cao Yanghua1;Kong Fansen2

2015, 26(14):  1908-1915. 

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The  purpose of  this paper is  to  improve the production efficiency of   human-oriented   U-shaped  mixed  model  assembly lines.The cooperation based task assignment  strategy  within workstation was proposed;the influences  of workers movement on  balance were considered.The basic task division was decided by forced rhythm assembly line balancing  model.The line was changed to free rhythm line by setting up reasonable buffer and changing the work  order;a fixed source send rhythm was set up to  maintain the production pressure.The task balance rate was improved by cooperation.Simulation results show the following conclusions:changing forced rhythm to free rhythm is effective enough to improve the production efficiency of U shaped line when there is lower production pressure;changing forced rhythm to free rhythm and cooperation can  all  improve the production efficiency effectively when there is higher production pressure,cooperation can improve the task balance rate as well.

A  Method  for Generating Robot Spraying Paths on Complex  Surfaces with Islands

Wang Jintao1;Xu Jinting2

2015, 26(14):  1916-1919. 

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A method  for generating robot spraying paths on complex surface with islands was proposed  by using the coordinate mapping theory which  was  used to flatten the sprayed  surface  onto  a plane.On  this plane,the spray points were calculated  by iteratively offsetting the  inner and outer boundaries of the planar surface.Then,using the mapping from the sprayed surface  to the planar region as a guide,the planar offset curves without self-intersections  were  mapped onto the sprayed surface inversely,thus forming the resulting contour-parallel  spraying paths.Benefiting the mapping of  the sprayed surface to the planar region,the task  of  generating the spaying paths was simplified  from is reduced from 3D surface to 2D plane,geometric computations related to spraying  path generation were  considerably  reduced,especially for self-intersection elimination of offset path. Finally, the proposed method was tested on several sample surfaces and is shown that it can generate contour-parallel spraying paths for complex surfaces nicely,especially for those with holes or islands.

Restraining Method of End Effect  for  EDM  Based on Error Calibration by HMM and Neural Network

Meng Zong, Yan Xiaoli, Wang Sai

2015, 26(14):  1920-1925. 

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End effects reduced the precision of EMD greatly, and neural network extension was used to restrain the end effects. However, there were forecast errors in the data forecasted by neural network. Here, a new method, error calibration by HMM was proposed to solve the problem. The radial basis function(RBF) neural network was firstly used to forecast outboard of both ends and estimation part of original signals. Then HMM was used to analyze the forecasting errors and to find the regularity of forecast errors of neural network. According to the analysis, the forecasting errors in next step were analyzed and forecasted to adjust neural network's forecasting results. Simulation and experiments prove that the method can solve the end effects effectively.

3D Model Retrieval of Mechanical Parts Based on Skeleton and Grey Correlation Analysis

Zhu Wenbo, Qi Lijie, Chen Long

2015, 26(14):  1926-1931,1937. 

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A 3D model retrieval method of mechanical parts was proposed combined skeleton and grey correlation analysis.Firstly,3D model of mechanical parts  was simplified to get a coherence model without hollow structure by ignoring additional features of model, such as  fillet,chamfer and hole etc.Then the skeleton was extracted,which expressed shape and topology features of the parts model from simplified  3D  model of mechanical parts based on the electric field method;and the skeleton was  converted into characteristic curve.Finally,calculating the similarity degrees among characteristic curves and grey correlation analysis method  was used  to  obtain similarity degrees of parts.Through the example verification and experimental analyses, the method can accurately retrieve the similar 3D model of mechanical parts.

Automatic Verification  System  for Time Grating Angular Displacement Sensors

Yang Jisen, Zhang Jing

2015, 26(14):  1932-1937. 

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In order to resolve the problem of low efficiency and verification quality in the procedure of time grating angular displacement sensor quality verification due to manual reading mode,an automatic verification system for time grating angular displacement sensor was proposed.In the automatic verification system, the PMAC was selected as motion control unit and the direct driving motor was used as the driving equipment to reduce the ransmission errors.The  electronic autocollimators  ELCOMAT3000  with errors less than  ±0.25″  acts as the precision measuring instrument in the system. A  programmable linear trapezoidal acceleration motion model was presented in the motion control and one product quality verification algorithm was proposed to improve the quality verification. The experimental results show that the steps of product quality certification all are completed automatically and the accurate results of quality verification is obtained.The work efficiency is improved greatly and product quality of time grating angular displacement sensor is assured further.

Multi-objective Genetic Optimization of Impeller of Rail Axial Fan Based on Kriging Model

Qu Xiaozhang, Han Xu, Bi Rengui, Tan Yan

2015, 26(14):  1938-1943. 

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In order to reduce the weight of impeller, a multi-objective genetic optimization method and process of the impeller of rail axial fan was established by analyzing the impeller of the numerical calculation method and constructing Kriging model. The numerical calculation method was established by the reverse analysis model and mesh density accuracy. The sampling space of impeller was obtained by Latin hypercube experimental design model. Kriging model of impeller with sufficient accuracy could replace the numerical analysis. The sensitivity of the main technical parameters of the force on the impeller structure was analyzed by the method and the most influential parameters on the impeller structural stress were identified. The weight of impeller is reduced by 31.7% by optimization and save the cost of materials. The maximum stress value is also changed from the initial 21.5MPa to 16.5MPa, which effectively improve the mechanical performance of the impeller. After optimization, dynamic and static experiments were used to the impeller by the slip ring electric and dynamic and static strain testing system, and the impeller rotating machinery equipment and the technology of testing plan was designed. Experimental results and calculation results are very close and the dynamic stress is relatively small, so the impeller has a good mechanics and vibration performance, and has high value in engineering applications.

Reliability Test and Evaluation for Hydraulic Hose Assembly

Chen Dongning, Li Shuo, Yao Chengyu, Xu Haitao,

2015, 26(14):  1944-1952. 

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Aiming at the faults/failure problems of hydraulic hose assembly such as leakage,joint pull-out,wire fracture and hose burst,in consideration of  the life influence factors such as hydraulic impact,temperature,pressure and bending radius,the reliability  test rigs for hydraulic hose assembly were designed:including a 12-channel  pulse test rig based on electro-hydraulic  servo technology and a pressure-proof and burst test rig based on double pneumatic-hydraulic pumps hybrid pressurization technology.Then the test data were dealt with through failure distribution goodness-of-fit  test and distribution identification,and it  is confirmed that the pulse and burst test data  are  following lognormal distribution and Weibull distribution respectively.Finally,the point estimate and confidence lower limit of mean life,reliability life and reliability for hydraulic hose assembly under the conditions  of pulse and burst  tests  were acquired from reliability evaluation.

Experimental Research on Combined Particle Impact Damper

Du Yanchen, Zhang Hong

2015, 26(14):  1953-1958. 

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A new kind of combined particle impact damper was proposed, in which two kinds of damping forms-via springs outside and via particle plastic deformation inside. The response of various damper components was obtained from experiments, by varying the particle packing ratio, the container clearance, the stiffness of spring, and the particle materials. The experimental results show that the combined particle impact damper has excellent damping performance, and is better than the traditional particle impact damper. The damper has the best performance when the volume ratio between the steel ball and particles is about 1∶2 and the spring stiffness is about 10% of the main system stiffness. Changing particle materials has little influence on the damping performance.

Fabrication  and  Characteristics  of  Thermocouple Temperature Measuring  Cutter  for  Cutting  Zone

Liu Zhijun, Lin Xingui, Quan Yanming

2015, 26(14):  1959-1963. 

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Cutting  temperature measurement sensor could not directly  contact the cutting zone, for resolving this problem,a heat-resistant insulation layer was sprayed on the surface of platinum rhodium wire so as to form the heat-resistant  thermocouple initially, and then,the thermocouple covered by a  heat  insulation layer was embedded into the cemented  carbide powder,and pressed and sintered to form a thermocouple temperature measuring blade.Temperature measuring performance of thermocouple was judged by the temperature measurement experiments  in  thermostat,and the  normal  thermocouple temperature measuring cutter was used in the experiments of cutting temperature measurement. The   experiments show that the thermocouple temperature measuring cutter can take the temperature measurement of the cutting zone directly and reliably,but the life of cutter is short.Experiments also show that the larger the diameter of platinum rhodium wire,the higher yield of the thermocouple temperature measuring cutter,but accordingly,the life of cutter  is shorter.Experiments further reveal that the temperature differences among each points in the cutting zone are bigger,but the temperature of cutting measure point is stable when the temperature field of the cutting zone is in a steady state,the change of the temperature field in steady state cutting temperature can quickly response the change of the tool wear state.

Orthogonal Experiments on Recycling Radial Tires Using High Pressure Water Jet Techniques

Liu Ping, Zhang Ke

2015, 26(14):  1964-1968. 

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Air  pollution,high  energy  consuming,complex  equipment,etc. occured when waste  tires were pulverized  with  traditional methods.To  solve  these problems,an  equipment of  recycling waste radial  tires was designed by the high  pressure  water jet.Moreover,this paper introduced some  experiments of orthogonal array  L25(53).The  three factors including  the  jet's driving pressure,target distance and movement velocity were investigated in  5  levels.The results of these  experiments  show that the optimal jet parameter  is  A3B3C3  for obtaining the finest rubber powder.The factors affecting the rubber powder particle size were listed  as  follows:the movement  velocity is the biggest effect factor while target distance is the smallest effect factor.

Fault Diagnosis Based on Rough Set Attribute Reduction and Bayesian Classifier

Yao Chengyu, Li Nan, Feng Zhongkui, Chen Dongning,

2015, 26(14):  1969-1977. 

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An improved  wavelet  package  was  used  to extract  feature  of  collected  signals  and  to  solve the wavelet packet aliasing problem.Considering redundant  attributes  in  fault informations,rough set attribute reduction algorithm was proposed based on  class  discernibility matrix  and improved attribute significance,new attribute significance was defined according to the frequency of each condition  attribute  equal to  1  in the class discernibility matrix,which  improved the efficiency of  attribute reduction. Considering the relativity  among  different  condition attributes  and  class  attributes,the  entropy  weight  method-based attribute  weighted  naive Bayesian classifier  algorithm  was  proposed,which  improved the fault classification accuracy.By comparative analysis of  rolling bearing failure data,it shows that the proposed  hybrid method herein has  certain  advantages  in  fault  diagnosis  accuracy  and  rapidity.

A Modified Norton-Hoff Constitutive Model and Experimental Verification

Wang Qiaoling, Tang Bingtao, Zheng Wei

2015, 26(14):  1978-1982. 

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In  order  to  establish  constitutive descriptions for B1500HS  boron steel,it  was subjected  to isothermal uniaxial tensile testing on a Gleeble 1500  thermomechanical simulator at  temperatures  ranging  from  550℃ to  850℃ and  strain  rates  ranging  from 0.1s-1  to 10s-1.According to the characteristics of the flow  stress  curve of boron steel,Norton-Hoff  model was modified.The  predicted flow stresses using the modified model were compared with Tong-Wahlen  model,Norton-Hoff  model  proposed  by  Brosius,and
 evaluated  by the degree of the predicted value  deviation from the experimental values.By comparison with the experimental results,it shows that the modified Norton-Hoff  model  is  better  to  predict  the  flow stress of B1500HS boron steel.

Experiments of Pulsed  Magnetic  Treatment  for  Diamond Segments  and  Numerical Simulation of  Magnetic  Field

Fu Yuming, Liu Ming, Guo Jianlong, Zheng Lijuan

2015, 26(14):  1983-1986. 

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Diamond segments were made by hot-pressed sintering technology and treated by alternating magnetic field.The impact energy of diamond  segments were investigated by impact toughness test,which were treated with  pulsed magnetic  treatment  and  not  treated.And the numerical simulation  was made for the transient magnetic field.The microstructures of diamond segments both before and after the magnetic experiment were  observed.The experimental results indicate that  the impact toughness of diamond segments is  improved  on  average about 35.4% and the crystalline grain gap become more uniformity  after  magnetized.The  numerical analysis  results reveal that the intensity of  magnetic  field and the magnetic force in the edge of diamond segment  is  concentrated,the magnetic vibration  due  to alternating magnetic force is in favor of magnetic shock effect.It provides  intuitionistic evidences for that the alternating magnetic treatment can be used as one  kind of effective technique to improve the material performance of diamond segments.