Table of Content

26 March 2012, Volume 23 Issue 6

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Anslysis on HSK Toolholder-Spindle Interface at High Rotational Speed for CNC Machine Tools

ZHANG Guo-Jun-1, CANG Yun-Feng-1, LV Feng-2, XIU Shi-Chao-1

2012, 23(6):  631-636. 

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The connection performance of HSK toolholder and spindle has great influences on machining accuracy and security of CNC machine tools. In viewing this, given the crucial fact that the HSK toolholder/spindle connection may encounter failure at high rotational speed, a contract stress model on the HSK toolholder/spindle junction surface was built at any rotational speeds. And the results of finite element analysis
have good uniformity with this model. By using this stress model, considering the influence of clamping force and magnitude of interference, the computational model of critical rotational speed based on the HSK toolholder and spindle connection and the interface reliability were established. With the computational model of critical rotational speed, an accurate calculation of the critical rotational speed was attainable. And the influence of clamping force and magnitude of interference on critical rotational speed was also discussed. The interface reliability at any rotational speed can be accurately calculated and the relationship between rotational speed and interface reliability was found according to the interface reliability mode. The establishment of the two modes is meaningful to prevent the HSK toolholder/spindle interface failure and guarantee machining accuracy and security of CNC machine tools. Meanwhile, it also provides a theoretical foundation for the reasonable utilization, optimization of parameters and reliability design of the HSK tool-holder.

Investigation on Vibration of Ball End Milling Harden Steel Assembled with Different Hardness

WANG Yang-Yu, JI Shi-Ming, WANG Hui-Jiang, WEN Dong-Hui

2012, 23(6):  636-641. 

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Aimed at identifying and isolating effects of hardness and cutting conditions on milling vibration during ball end milling harden steel assembled with different hardness steels an experimental investigation was conducted. Effects of cutting speed and feed rate on the vibration signals were studied for different hardness, characteristics and energy distribution of acceleration signals were computed by using LMS Test.Lab software. Experimental and FFT analysis results show that spectrum is consists of tooth pass frequency and its harmonics, and the maximum value can be found on the fundamental wave. Time and frequency domain analysis on single hardness and hardness transitional zones were compared to release effects of milling parameters on acceleration value, it is helpful for parameter optimization and decrease milling vibration.

Study on Nonlinear Dynamic Coefficients and Transient Vibration Response for a Non-contact Mechanical Seal

WANG Ji-De-1, ZHANG Guo-Yuan-2

2012, 23(6):  642-646. 

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Considering the tilt of a seal ring,the transient vibration response analysis model of a non-contact mechanical seal was presented.The model was consisted of  transient Reynolds equation,motion equation and equation for solving the second-order nonlinear dynamic coefficients of the seal.With Euler method,the characteristic parameters of the transient vibration response were obtained,which included the axial vibration displacements and the angle-swing of the static ring.14 nonlinear forces and 14 nonlinear overturning moment dynamic coefficients for the non-contact mechanical seal were calculated.The results show that the influences of the damping effects of the sealed fluid between the seal gaps on the axial vibration displacements and the angle-swing are linear.The film thickness distribution changes
with the axial vibration of seal,which will lead to static ring swing,and the swing can also cause the axial vibration of the seal.

Experimental Study of Effects of Work Mode on Conceptual Mechanical Design Cognition Process through Protocol Analysis

LI Fa-Quan-1, XIONG Shi-Quan-2

2012, 23(6):  646-650. 

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Three theoretical hypotheses were presented on the effects of work mode on design time, design quality, and novelty of design result. In order to test the hypotheses based on protocol analysis, a series of cognition experiments were conducted on adjustable seat conceptual design by 14 postgraduates in mechanical major. The results of Mann-Whitney nonparametric tests show: in terms of novelty of design result, there is generally no significant difference between the different work modes of the designers; but in terms of design time and design quality, the designers working in alternant mode generally perform better than those in sequential mode. It confirms that alternant mode can take the advantages of both media that traditional media is good for representing design concept and CAD media for analyzing and checking design intention, and thus alternant mode can enhance the efficiency of design.

Study on Precision Measurement of Ultrasonic Wave Transmission Time and Its Applications

ZHANG Xin-Gong, XIANG Feng-Yun, ZHANG Tian-Heng, CA Wei

2012, 23(6):  651-654. 

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In accordance to the characteristics that ultrasonic wave echo signal is a periodic signal with variational amplitude of each wave,a precision measurement of ultrasonic wave transmission time through digital subdivision method was proposed.The principles of ultrasonic transducer drive circuit as well as how to
realize this method by using high-resolution A/D and high-speed FPGA circuit to actualize high frequency data sampling from ultrasonic wave echo signal were illustrated.A ultrasonic flowmeter was designed based on these methods and circuits.It is pointed out that the measurement resolution of ultrasonic wave
transmission time depends on the frequency of ultrasonic signals and the revolution of A/D circuit.In order to improve measurement accuracy,the sampling frequency should be as high as possible. Because the measurement of ultrasonic wave transmission time is based on all ultrasonic wave echo signal sampling data, it has good reliability and strong anti-interference ability.

Multi-objective Optimization Design for Microsatellite Structure Based on Approximation Model Management

ZHENG Kan, LIAO Wen-He, ZHANG Xiang

2012, 23(6):  655-659. 

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According to the characteristics of multi-objective optimization for microsatellite structure,a new method for approximation model management was presented based on the trust region.Orthogonal and Kriging approximate method were used for the approximation model.The crowding distance in multiobjective particle swarm optimization was selected as the core algorithm.Meanwhile,the max-min distance algorithm was used for ensuring the accuracy and rationality for trust measurement.Thus the results consistent with the real model could be obtained.The optimization results from five groups indicate that the structure mass is decreased at different degrees.The maximum amplitude reduction reaches 14.1%.Meanwhile,the first three orders of natural frequencies for the microsatellite are improved obviously.The successful
applications of the approximation model management frame in multi-objective optimization for satellite structure verify the effectiveness and the rationality,which can provide application values for complex engineering multi-objective optimization.

Research on Working Characteristics about Wind Rotor Matching with Hydrodynamic Variable Speed Drive Unit

DONG Yong-1, ZHOU Xu-Jiang-2, BI Jiang-3

2012, 23(6):  660-665,687. 

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By means of analyzing characteristics of hydrodynamic variable speed unit applied in wind power system, relationship between wind rotor speed and turbine output speed of hydrodynamic torque converter was achieved comparable to the variable wind rotor speed to sustain constant generator speed. Ratio of input power of torque converter pump to wind rotor power and overall transmission efficiency of hydrodynamic variable speed drive were determined based on the power splitting fundamentals and energy balance equation.Output working characteristics of hydrodynamic torque converter was analyzed combining wind rotor characteristics.Overall evaluation  was done with major factors of influencing the transmission efficiency.System matching computation was done in the light of lower speed ratio and higher speed ratio of  two types torque converter. Model selection and design for the torque converter,determination of the key construction parameters for differential gear train and ordinary gear train,the research methods and conclusions herein are for reference. 

Simulation of Wheel Topography and Forecasting of Roughness in Cylindrical Grinding

LV Chang-Fei-1, 2, LI Hao-Lin-1

2012, 23(6):  666-671. 

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This paper provided a simulation and modeling method of wheel topography,cylindrical grinding process and workpiece topography,and forecasting of grinding roughness,the model was calibrated
 and validated based on experimental data.With both Johnson transformation method and Gabor wavelet transformation method,the inter-transformation of Gaussian field and non-Gaussian field were presented,then,the simulation of wheel topography at a random field was realized.Based on the analyses of cylindrical grinding kinematics and interaction of wheel and workpiece,the grain motion trajectory equation and workpiece topography simulation equation were gained.Considering the cutting,ploughing and rubbing action of grains,and the cylindrical grinding progress and workpiece topography were simulated,the cylindrical grinding model was established,and the workpiece surface roughness was predicted.

Research on Digital Variable Displacement Pumps Based on High-speed On/Off Valve

CEN Shun-Feng, TUN Zhang-Yong, WANG Xian, WANG Xiao-Bei, WANG Jing-Chao

2012, 23(6):  671-675. 

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A digital variable displacement pump was presented to achieve the functionality of a variable displacement pump by combining a fixed displacement pump,a high-speed on/off valve,a cartridge valve and an accumulator etc.The different parameters influenced on the performance of digital variable displacement pumps were studied.The best control performance of the digital variable displacement pump are achieved by closed-loop feedback optimal control,decreased the ripple size of output pressure and the response time.

Research on Evaluating Index and Method of Enterprise Maturity on Integration of Industrialization and Informationization

LI Gang, HU Bing

2012, 23(6):  676-680. 

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Based on the contents and methods of traditional enterprise informationization evaluation,an index system was proposed for evaluating enterprise integration level of industrialization and informationization
comprehensively.From three aspects of readiness,maturity and contribution,the composition,meaning and calculation formulas of each layer in index system of enterprise integration level were analyzed thoroughly.This paper focused on the evaluation of the maturity method,and through business surveys,the data was calculated and analyzed to demonstrate the validity of the proposed approach.

Cost Estimation Service Model of Product in Mass Customization

JI Shi-Ming-1, BAO Zhi-Tan-1, 2, XIAO Gang-1, RUAN Shu-Feng-3

2012, 23(6):  681-687. 

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Aimed to satisfy the manufactories' needs of cost estimation at different periods in mass customization,a cost estimation service model of product in mass customization was proposed.Several atomic services including dynamic weights assignment algorithm,similar instance group matching,exponential smoothing algorithm were established,and composite services like coarse cost estimation,rapid cost estimation,
real-time cost estimation,accurate cost analysis were also put forward.These services were assembled piecemeal in the application systems,such as rapid quoting for customer,final order quoting,cost control,profit calculation.Assistant decision chart for final quoting of new customization products was also presented.The proposed methodology demonstrates the effectiveness in an instance of cost estimation of an overhead traveling crane product.

Multi-plant Supply Chain Scheduling with Parallel Machines Based on Taboo Search Algorithm

JIANG Da-Kui, LI Bei

2012, 23(6):  688-693. 

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A multi-plant supply chain scheduling problem with parallel machines was proposed. Decisions of different functions including order assignment, production scheduling and batch delivery scheduling were integrated for a simultaneous optimization. A mixed integer programming model for the problem was built to minimize the production and distribution cost under the conditions that all jobs were finished before the due date. A taboo search algorithm with vector array representation was designed to solve the problem. Experiments adopting supply chain scheduling approach and decoupled approach respectively were conducted on the problem, and the results confirm the substantial advantages of the supply chain scheduling approach. Furthermore, compared with exact solutions provided by CPLEX, the results show that the designed algorithm is an efficient method for solving the problem.

Design of Multi-object Optimization Algorithm for Customized Product Development

AI Jing-Song, HU Jiang, LIU Quan

2012, 23(6):  693-698. 

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A new method of multi-objective optimization based on the customer requiremnents was designed.In order to improve the efficiency of the traditional algorithm, the concept of object focus degree was proposed,so that the evolutionary algorithm convergence was of selective.There are several limitations of the existing evolutionary algorithms, such as easily falling into local optimal solution and uneven solution distribution. According to these weaknesses,a concept of object spacing matrix was proposed.The
new method can avoid the earlier algorithm convergence and make sure
the diversity of the optimal solution.The proposed method was simulated based on
MATLAB7.0.The simulation results indicate that the proposed algorithm is feasible,
and has better reliability and superiority than other two popular evolutionary algorithms(NSGA-2 and SPEA-2). 

Research on  FlexRay Message Slot Distribution Methods Based on Bus Occupancy #br# Rate

ZHANG Li, ZHANG Ben-Hong, WANG Ti-Fei, DIAO Xin-Chao, LIU Zheng-Yu

2012, 23(6):  699-702,720. 

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Message slot distribution method is one of the key problems of design of FlexRay vehicle bus.On the basis of analyzing characteristics of FlexRay and its frame of format and physical layer transmission features,methods of calculating message frame slots and bus occupation rate were obtained,factors that
influenced on bus occupation were given herein.With the goal of minimal bus occupation rate,a message frame slot distribution method was proposed which assigned the longest static message frame to the dynamic segment.By example validation,the proposed message frame slot method is proved to be feasible,it reduces bus occupation rate effectively,and increases efficiency of the network. 

Vision Calibration for AGV Based on Static and Motion Two States

YU Dun, LOU Pei-Huang, WU Xing, WANG Long-Jun

2012, 23(6):  703-707,724. 

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A vision calibration technique based on two states of static and motion was proposed for a vision-based bidirectional AGV.First,internal parameters,radial distortion parameters and external
parameters were estimated using planar pattern in static scene,and then an union model of correcting distortions was designed for three individual image distortion models.Finally,rotation and translation parameters between corrected image and AGV coordinate system can be calibrated in two motion cases.Experimental results show that the technique has good flexibility and high precision.

Research on Dynamics of an Impact-progressive Mechanical System by Beat Frequency Excitation

GOU Xiang-Feng, LV Xiao-Gong

2012, 23(6):  708-712. 

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A mathematical model of impact-progressive mechanical system accounting for the motions of vibration and progressive was developed.That can transfer a high-frequency low-amplitude excitation into low-frequency high-amplitude response.Conditions for synchronous and non-synchronous motions of impact components immediately after the impact were studied.A special beat frequency kinematic excitation was used,which has two distinctive features:①the low-frequency modulated excitation was tuned to the natural frequency(which was the desirable low-frequency) of the vibratory system;②the excitation was asymmetric,i.e.only positive part of the modulated signals excited the mass M2.The results indicate that effective impact forces,i.e. hammer effect,are generated by the excitation.Two different ways to achieve a steady progression were explored.

Analysis of Mechanical Property of Corrugated Bellow Used for Pressure Balance for Underwater Equipment

LIU Huan-Jin, LIU Zheng-Shi, WANG Yong-；Bi-Rong, CHEN En-Wei

2012, 23(6):  712-716. 

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A large deflection deformation of U-shaped bellow under high pressure in deep sea was analyzed by means of nonlinear finite element method,and the method for calculating the volume change of bellow and related formulas were given.Based on the compressibility of liquid,the relationship among the working-depth of equipment,the volume change of the bellow and the pressure difference between inside and outside of the equipment was deduced.And the calculation process was also put forward,which can provide reference for design and calculation of bellow used for pressure balance.The relationship between the pressure balance performance of U-shaped bellow used for oil-filled deep-sea pressure sensor
and various factors was analyzed.The design principle of the structure using
bellow as pressure balance element was generalized, which can provide as guide to design underwater equipment using bellow as pressure balance element. 

Design on Flexible Honeycomb and Research on Its Equivalent Modulus

BANG Hai-Feng-1, 2, DONG Er-Bao-1, ZHANG Shi-Wu-1, YANG Jie-1

2012, 23(6):  717-720. 

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The skin of a morphing wing would be highly anisotropic with low in-plane stiffness and high out-of-plane flexural bending stiffness,having the ability to undergo large strains.The approach of mechanics of material was presented  to evaluate the elastic modulus of properties of the U-shape honeycomb. The U-shape honeycomb was proved to have low in-plane axial stiffness, which has a good flexibility and low modulus in certain direction and high load resistance.Both of finite-element modeling and experimental testing were carried out to verify the accuracy of the proposed analytical formulation. The analytical solutions developed compared well with both experimental test and FE modeling.The FE modeling of a large area was also carried out to get the Possion's ratio of the honeycomb.The simplified analyses and formulation presented for U-shape cores can be used in design and optimization of efficient cellular core structures.

Study on WPASS Based on DTFCD

LI Chun-Tian, DU Chang-Hua, HU Hui-Bin, LUO Yi

2012, 23(6):  721-724. 

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Based on differential theory and considering the full load conditions from the external circuit on the course of dynamic welding,the research object was regarded as WPASS.Some models about the WPASS were found,they can obtain the analytic expression of system stability coefficient,and a qualitative analysis of WPASS' conditions,including its basic and optimal conditions.On the basis of these, by the method of  relative conversion of current deviation,a DTFCD was obtained by analytical equation.Then,it was used to quantify stability of the system by the way of decaying time of deviation.Testing results based on experimental analysis of voltage and current waveforms,are the same to quantify WPASS based on DTFCD.

Research on Influence of Different Conduction Modes on EDM of High Resistivity Semiconductor Silicon

LIU Zhi-Dong, CAO Yin-Feng, QIU Meng-Bei, TIAN Zong-Jun, HUANG Yin-Hui

2012, 23(6):  725-728. 

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Electrical discharge milling experiments on high resistivity semiconductor silicon were conducted,and processing conditions under three kinds of conduction modes as fixed,rotating,and follow-up were compared.Results show:in fixed conduction mode,as the non-conductive passive film is gradually formed on the electrical conduction spot,contact resistance increases,total resistance in the circuit continues to rise,
discharge peak current decreases,and as a result, the machining process is unable to continue;in rotating conduction mode,as the distance between the inlet-electrode and machining area getting long,bulk resistance in the discharge circuit increases,and consequently discharge peak current gradually decreases;in follow-up moving conduction mode,the inlet-electrode in discharge circuit will continuously clear off the generated passive films and maintain the distance between electrodes,
therefore,contact resistance and bulk resistance remain steady,leading to the good stability of condition in discharge machining.

Research on Robust Control Strategy for Variable BHF of TWBs Part

WANG Chun-Yan-1, DIAO Mo-Zhong-1, SUN Pei-Kun-1, XU Xiao-Hong-1, WANG Yu-2

2012, 23(6):  729-732. 

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Because of the deficiencies of constant BHF method in the stamping process of TWBs,a mixed H₂/H_∞ control method for the variable BHF was proposed.A control model for the mixed H₂/H_∞ control was built,then its control algorithm and logic were designed. Based on the designed model,the feedback numerical simulation was used to analyze the influences of the mixed H₂/H_∞ control method on defects of TWBs.The tests were conducted on the variable BHF hydraulic press in order to verify the simulation results,and the simulation and test results show that the cowls top cover board can be stamped successfully based on the mixed H₂/H_∞ control theory for the variable BHF.Considering the stamping tip and blank holder board position, the proposed BHF determination approach can avoid wrinkling and cracking under constant BHF,which makes it a robust strategy.

Effect of Strength Mis-matching on Elastic-plastic Deformation Behaviors of Welded Joints with Cracks

XIONG Lin-Yu, ZHANG Pan-Hua

2012, 23(6):  733-738. 

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Elastic-plastic deformation behaviors of strength mis-matched welded joints with cracks were investigated using finite element method.Effects of strength mis-matching,hardening property of weld metal and crack length on plastic deformation were analyzed.The results show that strength mis-matching has significant influence on plastic deformation of welded joint.Deformation is first concentrated in weld for under-matched joint,while for over-matched joint,strength over-matching can protect weld metal to some extent.When strength mis-matching facor is constant,the plastic deformation trends for welded joints with different hardening properties of weld metals are similar,whereas local plastic deformation levels are different.Plastic deformation increases with the hardening property of weld metal decreasing.

Coordinated Control for Mode-switch of a New Parallel HEV

DU Bei-1, QIN Da-Tong-1, DUAN Zhi-Hui-2, XIE Xin-1

2012, 23(6):  739-744. 

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A new parallel HEV with planetary gear mechanism was introduced.The operation model region of the hybrid system was divided at the aim of achieving optimal system efficiency.Energy assignment management strategy was set up.A torque coordinated control algorithm was put forward to suppress the torque ripple during different mode switching processes.The simulation analysis of driving conditions was performed.The results show that energy assignment management strategy and coordinated control algorithm both optimize system efficiency and improve the vehicle drivability during mode-switch processes.

H∞ Robust Control for Twin Clutches of DCT during Vehicle's Starting and Shifting Processes

DIAO Chi-Guo, CHOU Jiang-Hai

2012, 23(6):  745-750. 

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Based on the structure and working principles of DCT, some dynamic models during the vehicle's starting and shifting processes were built. Considering the uncertain factors such as engine torque fluctuation and jitter of gas pedal during the vehicle's starting and shifting processes, a H∞ robust controller was designed based on the Riccati inequality and the LMI, the jerk and the slipping friction work which standed for the two performance indexes of clutch engaging were analyzed, the optimal pressure of twin clutches was obtained using the above H∞ robust control method. And relative simulation analyses were made comparing with linear quadratic optimal control algorithm. Simulation results indicate that the provided H∞ robust control strategy can resolve the problem of the clutch pressure control effectively during the vehicle's starting and shifting process and greatly improve the robustness of clutch control.

Study on Vehicle Stability Control Based on Distribution of Yaw Torque

ZHANG Sai-Ai, ZHANG Tian-Xia, ZHOU Chu-Wen

2012, 23(6):  751-754. 

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This paper presented a vehicle stability control strategy,which was integrated with active torque distribution and differential braking system.Differential braking system worked on high speed obstacle avoidance under emergency and active torque distribution operates on overtaking.Depending on the comparison results between the reference model and the actual vehicle,the stability control strategy choosed corresponding control method.The stability control simulation was performed on a multi-body dynamic model based on virtual prototyping.The results show that the stability control proposed herein can stabilize the vehicle on overtaking or high speed obstacle avoidance under emergency.