Table of Content

25 April 2011, Volume 22 Issue 8

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Experimental Study on Drilling Glass Fiber Reinforced Plastics

SONG Zhong-Quan, CHENG Yu, GAO Chao, JIN Gao

2011, 22(8):  883-886. 

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Drilling trials were carried out on glass fiber reinforced plastics with twist drill which had S shaped drill tip coated by TIN and the ground surfaces of drilled holes were observed by using scanning electron microscope(SEM),the fracture mechanism of glass fiber and the microscopic characteristics of ground surfaces were analyzed.The experimental results show that twist drill with S shaped drill tip offers less drilling thrust force and delamination fracture campared with conventional twist drills.Therefore,

twist drill with S shaped drill tip is suitable for drilling glass fiber reinforced plastics and has a wide application prospect.

Study on Thermal Field and Cooling Method of Electromagnetic Continuously Variable Transmission

TUN Jian-Yu, LUO Yu-Chao, HUANG Xiang-Dong

2011, 22(8):  887-891. 

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The basic structure and working principles of an EMCVT were introduced.To solve the temperature rise problem of EMCVT, a cooling method named soak-splash was presented. The mathematical model of 2D steady thermal field was established. The stator and rotor thermal field was calculated using finite element method. Simulation results show that the designed cooling system is feasible, which provides some references for EMCVT practical applications.

Dynamics Performance Optimization of Cylindrical Shell with Constrained Damping Layer Using Homogenization Approach

WANG Meng-Xu, CHEN Guo-Beng

2011, 22(8):  892-897. 

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To improve the dynamics performance of a constrained damping cylindrical shell, topology optimization of the constrained damping cylindrical shell for the maximized modal damping coefficient was studied. According to the first 3 orders modes,a novel topological optimization model was proposed and analyzed,where the volume was taken as the constraint function and the function of the modal damping coefficient as the target function.The reasonable topology configuration was obtained for the damping structure.The results show that this method can be applied to solve the optimization

problem of a constrained damping cylindrical shell with the damping materials volume constrained.Numerical simulations were performed to verify the effectiveness of the presented method.

Structure of Gecko Inspired Flexible Foot and Control System

LI Bing, HONG Xiao-Hua, XU Shu-Lin, SUN Shao-Meng, MEI Chao

2011, 22(8):  897-900. 

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A compliant outward bend foot was designed, drawing inspiration from geckos, which used adhesion array to absorb. Mechanical analysis and computation were developed on the structure of this foot. The bionic flexible soles inspired foot’s motion was controlled by using servo motor actuators. Controlling the servo motor by using single chip microcomputer,thus the bend and flat of foot were controlled.Through experiments by physical platform, the validity and feasibility of design were verified.

Instantaneous Frequency Identification of a Time-varying Structure Using Wavelet-based State Space Method

HU Xin, SHI Chi-Yu, LONG Shuang-Li

2011, 22(8):  901-904,925. 

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A method for identifying the instantaneous frequency of a linear time-varying structure was proposed. Firstly, the second-order vibration equations can be rewritten one order state-space equations. Secondly, free response signals were decomposed using the Daubechies wavelet scaling functions. Based on the orthogonality of the scaling functions, the state-space equations of the time-varying system were transformed into simple linear equations. Lastly, the varying equivalent state-space system matrices of structures at each moment were determined by solving the linear equations and the instantaneous frequency can be extracted though eigenvalue decomposition of the state space system matrices. A continuous cantilever beam model and a three degrees-of-freedom close modal structure with three kinds of time-varying cases (abruptly, smoothly and periodically) were investigated. Numerical results show that the proposed method is accurate and effective to determine instantaneous frequency of a time-varying structure.

An Experimental Study of Effects of Cognitive Failure on Mechanical Design Process under CAD Environments

LI Fa-Quan

2011, 22(8):  905-908. 

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Two theoretical hypotheses for the effects of cognitive failure on design time and design quality were presented. A series of design cognition experiments about improvement design of a high-level gear pair of spiral conveyer reducer were conducted to test the hypotheses. The results of statistical analysis through Mann-Whitney non-parametric tests indicate:in terms of design time, the designers with fewer cognitive failures, as a whole, perform better than those with more; but in terms of design quality, there is generally no significant difference between the two groups of designers. So enhancing human design capability and rationally distributing CAD functions contribute to the improvement of design cognition process.

Research on Compound PID Control Strategy of Energy Regulation Based Variable-speed Electrohydraulic Drive

HU Meng, CHEN Guo-Jin, NI Jing

2011, 22(8):  909-913. 

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The energy regulation based variable-speed electrohydraulic drive is a good solution to improve the response and low-speed performance of variable-speed electrohydraulic drive.However,it is a multiple-input multiple-output control system,

coupled with strong nonlinearity and some parameters of volatility and uncertainty, which make the control strategy complicated.A multiple-compound PID control strategy, as well as the parameter tuning rules, were proposed based on energy regulation principles.

The proposed control strategy and the parameter tuning rules were verified by experiments.They can promote the applications of energy drive.

Research on Failure Mechanism of Super-high Pressure Crystal Vessel

LIU Kang-Lin, ZHANG Jing-Wei, GONG Chao

2011, 22(8):  914-916. 

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Though material tensile test,fracture and fatigue tests, hardness test and microstructure analysis for deactivated crystal reactor vessel,the maximum stress and deformation were obtained in danger zone at the bottom crystal vessel by finite

element method and the rupture strength and fatigue life of crystal vessel were also analyzed and calculated.Combining the analyses about stress corrosion, corrosion fatigue and creep deformation,it is pointed out that the failure of crystal vessel is a brittle fracture under the co-activation between corrosion fatigue and creep.

A Multi-objective Model on Product Planning Based on Theory of Design Domains

LI Bai-Shu, LUO Xin-Gang, TANG Jia-Fu

2011, 22(8):  917-921. 

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The method and model of product planning were studied based

on the theory of design domains herein.The method was started from the

customers’ requirements for the product quality and developed upon a benchmarking product which was selected according to the product positioning. It was explored based on quantifying the cascading mappings among four design domains’ representative parameters, i.e. customers’ requirements, functional requirements, design parameters and process variables. By integrating the analysis results,a goal programming model was set up to achieve the design solution which involves customer’s satisfaction,production cost and investment. By way of illustration, a medium sedan was designed and its results demonstrate the effectiveness and practical value of the method.

Control of Torch’s Pose for 5-axis Flame NC Pipe Cutting Machines 

QIN Yuan-Fei, LI Quan-Cai, XIAO Ju-Liang, WANG Guo-Dong, WANG Gang

2011, 22(8):  922-925. 

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In light of problems in conventional flame pipe cutting

machines, such as low processing precision and efficiency, complex process, and not capable of machining two cuts of a pipe in one time process, the motion control of a 5-axis

 NC pipe cutting machine was studied. The machining of intersecting curves

 was disassembled into the travel of torch assembly along the pipe’s axis and the pipe’s

rotation.The machining of welding groove was divided into the rotation of torch plane,the tilt of torch in normal section and compensation motion. The mathematical models of intersecting curves with welding groove were established based on the motion types of each axis. By virtue of these mathematical models, NC software was developed to realize real-time control for the 5-axis NC pipe cutting machine. 

An Approach of Agile Customization Design Integrated Rough Set and Multi-ANN Models

YUAN Chang-Feng, WANG Mo-Lei, LI Jian-Feng, CHEN Yan

2011, 22(8):  926-931. 

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Customer requirements are divided into two types. One is ordinary requirements and the other is customized requirements. They play different roles for determining product structure in custom design. According to their different roles, as well as integrating the respective advantages of RS theory and ANN,a novel approach of agile customization design based on rough set and multi-ANN (MANN) models was proposed.In this method, RS was applied to reduce and extract the effective customer

requirements;ANN was applied to establish the matching relation between reduced customer requirements and corresponding product structure.The renewable MANN models

were formed from which a appropriate network could be selected according to different customer requirements. Consequently,the perfect design scheme could be obtained

quickly. Finally, a roll plate machine’s customization design was taken as an example to validate the validity of the proposed approach. 

Rapid Simulation of Elastic Problems Based on GPU

WANG Jian-Hua, LI Guang-Yao, LI Qing, ZHANG Yong

2011, 22(8):  932-937. 

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In order to eliminate the lasting calculation bottleneck on

applications of finite element,a new method was proposed to accelerate the computing of FEM by using the existing modern GPU and programmable shading tool.Under the FEM theory, this paper analyized the pros and cons of using GPU parallel process,

coordinated the task assignment and data exchange between GPU and CPU and designs a new FEM processing architecture by using the computational resources of GPU.

The GPU parallel simulation calculation rate is 22 times faster than that by using CPU’s,as well as it has useful and practical value in solving the project problems.

A Study of Rolling Stock Assembly Simulation Based on Quest

GUO Yu, TAO Jia, XU Ti-Bin, FAN Guo-Hai

2011, 22(8):  937-942. 

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Problems such as unbalanced working status, inconvenient in adjusting and acquiring parameters, were encountered when using flexible equipment in rolling stock assembly. To solve these difficulties, simulation tool Quest and Quest-based secondary developing were used to simulate rolling stock chassis assembly procedure.

By defining a simulation model with collision detection function, the simulation

reaches the goal that obtaining, coordinating the parameters to support enhance assembly

efficiency, and the technology worked well in practice.

Process Control and CAD Software Development for Continuous Flexible Forming

CA Zhong-Xi, LIU Lin, WANG Shao-Hui, LI Meng-Zhe, CAO Jun-Hui

2011, 22(8):  943-947. 

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A control method was presented about the process of continuous flexible forming.Firstly,the target surface was discretized to triangular mesh and extracted a series of equidistant lines from it.Computing the coordinate values of the control points,a lateral control model in the forming process was established based on the cubic B-spline curves.For the part of ideal elastoplastic material,the relationship between the longitudinal curvature of target surface and the downward displacement of top flexible roll was

established.Using these mathematical descriptions,the software development and the

simulation of continuous flexible forming process were finished from the view of geometry.

Research on Reliability Enhancement Testing Method of NC Rotary Table

ZHANG Gen-Bao, HU Zhi, HE Wen-Hui, CHU Lin

2011, 22(8):  948-951. 

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The failure data of NC rotary table were analyzed statistically and it is found that the leak of hydraulic system and components damage caused by cutting fluid infiltrated through shield are the main failure models affected reliability of NC rotary

table seriously.Reliability enhancement testing plan was proposed based on the analysis of the failure mechanism. Several kinds of environmental stresses were adopted in testing profile in order to stimulate the failure of NC rotary table.The measures to enhance the reliability were suggested.The testing results demonstrate the testing profile is reasonable and the testing plan can achieve the purpose of reliability of enhancement testing.

Motion Analysis of Abrasive Particle in Near Wall Region of Rectangular Channel

HU Jing-Lei, JI Shi-Ming, TAN Da-Feng

2011, 22(8):  952-956. 

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Based on the fluid motion equation, abrasive particle kinetic equation and numerical simulation method, motion rules of abrasive particle in near wall region of rectangular channel were analyzed in detail. The parameters of abrasive particle pump were given according to fluid viscosity and turbulent flow conditions. Abrasive particle motion traces were determined by applying particles of different diameters. The greater viscosity and velocity can cause greater wall pressure and shear stress, which is helpful to make material removal on work piece surface. Abrasive particles mainly move along the flow direction, among which the bigger are suited for rough machining, the smaller for fine finishing. The distribution of pressure and velocity has a strong significance on surface finishing.

Characteristics of Electro-hydraulic Servovalve with an Asymmetric Nozzle Flapper

YIN Yao-Bao, MENG Wei

2011, 22(8):  957-960,970. 

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The structure and characteristics of an electro hydraulic servovalve with an asymmetric nozzle flapper which has a pair of hydraulic resistances in

the nozzle chambers were analyzed. The load pressure characteristics, nozzle chamber

pressure characteristics and the pressure characteristics at zero point were obtained. The design method of force and rigidity of the torque motor were discussed. The theoretical results are in good agreement with the experimental ones.The load pressure of electro hydraulic servovalve with an asymmetric nozzle flapper at zero point is bigger than 50% of supply pressure, but the nozzle chamber pressure is less than 50% of supply pressure. The load pressure characteristics are asymmetric, and the cross point of the two load pressure curves deviates the neutral point.The coefficient of hydraulic resistance is suggested to be

1.5 to 2.5 in order to get good linearity of load pressure.

Study on Precision Cutting of n-WC/12Co Coatings Using PDC Fiber Cutter

ZHANG Gao-Feng, ZHANG Bi, DENG Chao-Hui, HU Zhong-Wei, TAN Huan-Jiang

2011, 22(8):  961-966. 

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This study is to investigate precision milling of nanostructured WC/12Co (n-WC/12Co) coatings experimentally by using PDC fiber of sectional size 10mm×0.6mm×0.3mm, which were prepared by cutting PDC with YAG laser.The depth of cut of per fiber was smaller than that in the conventional milling but larger than the individual grit depth of cut in grinding, and the rake angle of fiber milling was -30° and 0° respectively. During cutting experiments, a piezoelectric force transducer (Kistler model 9257BA) was used to measure cutting forces on line, and a scanning electron microscopy (SEM) was utilized for observing the machined surfaces. Moreover,

n-WC/12Co coating was ground by using SD80N100B and SD600N100V, and the ground surface was compared with that milled by PDC fiber.The study verifies that a

diamond fiber cutter with zero rake angle results in better surface finish than the 600# diamond wheel. On the other hand, the diamond fiber cutter with -30° rake angle results in large ratio of normal to tangential forces and the resulting machined workpiece shows a surface with granular surface roughness and also obvious microcracks at an increased depth of cut. Finally, the material removal mechanism of n-WC/12Co coating cutted by PDC fiber was discussed herein.

Influences of Axial Force on Axial Deformation of Circular Saws

FANG Fu-Yang, LI Yuan, XU Xi-Feng

2011, 22(8):  966-970. 

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Some factors influencing axial deformation of circular saws

were analyzed. Considering sawing parameters and axial forces acting on the saws,axial deformations of either moving or static circular saws were studied.It is shown that axial deformation shapes of the circular saw in the above mentioned states are similar.In the stone sawing process, axial deformation of the circular saw is governed mainly by the static axial force.The influences of sawing parameters are relatively small. And axial deformation has an obvious periodical feature. 

Study on Parameter Design Based on Orthogonal Test and Support Vector Machine

SUN Lin, YANG Shi-Yuan

2011, 22(8):  971-975. 

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In response to the defects of traditional parameter design method,the paper put forward an optimization design based on SVM and orthogonal

test.SVM intelligent model was established and the limited orthogonal test swatches

 were studied, the precise relationship among each parameter and quality features of products as well as signal-to-noise ratio can be obtained,so as to guide the optimization design of technological parameter.

Deformation Behavior of Equal Channel Angular Pressing and Torsion with Retained Sample

WANG Xiao-Xi, XUE Ke-Min, LI Ping, ZHANG Xiang, WANG Cheng

2011, 22(8):  976-979. 

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Considering the real deformation process, numerical simulation on the single pass of ECAPT was investigated by DEFORM-3D program.By comparing and analyzing the results, it is indicated that the existence of retained sample increases the initial and maximum extrusion load of the next sample,raises the hydrostatic stress and effective strain of the deformed sample,and improves its deformation uniformity as well.In addition,the results of coordinate grid method have good consistency with numerical simulation ones which shows the reliability of established finite element model.

Phase Transformation Stress and Its Influence for Arresting Crack Propagation Using Electro-heating Effect

WANG Beng, BAI Xiang-Zhong

2011, 22(8):  980-984. 

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An experimental investigation of arresting crack propagation

by pulse discharging to a 45# steel plate with crack was shown herein. Through the microstructure analysis near crack tip after crack prevention by using electromagnetic heating effect, it is found that the phase transformation has been occurred. Also, the residual strain of phase transformation near crack tip has gotten by X-ray diffusion method.

The theoretical calculation of the phase transformation stress was finished by Eshelby’s model of imaginary cutting method.The affection of the residual stress on the crack propagation was discussed. It is found that the residual stress will have a long term effect for crack prevention. The results obtained show that the technique of arresting crack propagation by

using electric magnetic heat effect has both academic feasibility and practicability. 

Research on Drive Train Matching for a Series-parallel Hybrid Electric City Bus and Its Control Strategy

LEI Liang-Yo, ZHANG Pei-Pei, DIAO Da-Xu, LIU Jian-Jun

2011, 22(8):  984-988,993. 

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Based on the drive train for series-parallel hybrid electric vehicle that can make more combination between engines, generators, motors and so

on,and the system can be ensured to work under the better conditions from the

structure.By matching and analyzing on the drive train for series-parallel hybrid electric

city bus,it is advanced that matching scheme and control strategy were proposed on drive train for series-parallel hybrid electric city bus,also,a sample bus was developed successfully.By the demonstration,it is indicated that the vehicle performance of drive and economy meets the design demands.The sample vehicle has better result in saving oil and can provide the reference for the scale demonstration.

Transitional Amphibious Vehicle Shape-designing and Numerical Analysis of Its Water Performance

CUI Jin-Yi, DIAO You-Qun, RUAN Mi-Qiang

2011, 22(8):  989-993. 

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A new type of amphibious vehicle body with fast features and a fresh style of wash plate were designed herein by using CATIA shape-design module. Numerical analysis for waterborne performance was carried out for two amphibious vehicle models:one with wash plate and the other without, using the VOF method,the standard turbulence models, open channel flow and the theory of high speed boat dynamics in Fluent. The results show that the model with wash plate is better in waterborne

performance and these methods can be applied effectively to high-speed transitional amphibious vehicle waterborne performance research.

State-of-the-art of Machining Dust Researches and Their Framework 

LIN Fan, LIU Fei, LI Cong-Bei, ZHANG Wen-Yuan

2011, 22(8):  994-1001. 

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A study of environmental impacts in widely-used machining is important in green manufacturing research.The studies about the machining

dust were reviewed herein.Firstly,the attributes like chemical composition,particle size,particle size distribution and concentration, and the harms of machining dust were introduced.Then the formation mechanism,influence factors and their effects and controlling

methods were summarized.Finally,based on the above analyses,the framework and the  trends of research on machining dust were proposed.

Current Researches on Integrated Process Planning and Scheduling

GAO Liang, LI Xin-Yu

2011, 22(8):  1001-1007. 

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Firstly,the necessity of IPPS was analyzed. And then, the current researches about the IPPS were reviewed,including integration models and algorithms

which were two aspects of IPPS. Based on the analyses of various research methods about IPPS, some existing issues, possible approaches and development trends of IPPS

were pointed out. Finally, some useful research directions were proposed.