Table of Content

10 September 2013, Volume 24 Issue 17

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Rapid Design System of Non-backlash Double-Roller Enveloping Hourglass Worm

Li Yang;Zhong Liangwei;Li Haiyuan;Zhang Xin

2013, 24(17):  2273-2279. 

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 In order to improve the efficiency and precision of the solid modeling of a new worm which is called non-backlash double roller enveloping hourglass worm, after the in-depth analysis on the mathematical models of worm gearing and the helixes' equations of tooth surface, a rapid design method of product was put forward, which was based on case-based reasoning and SML(Sach merkleisten). Firstly, the secondary development was carried out on a three-dimensional CAD platform using high-level language and tabular layouts of article characteristics which was established by SQL Server database technology. Secondly, the rapid design system of non-backlash double roller enveloping hourglass worm was established by both integrated. Finally, the system was demonstrated to be correctness and reliability with specific design examples.

Near Field Acoustic Levitation and Rotating Actuation of Spherical Objects in Micromanipulation

Hua Shunming1;Sun Xuguang2;Liu Jianfang2;Wang Xiaojun1;Wang Yiqiang1

2013, 24(17):  2280-2284. 

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To realize levitation and actuation of solid sphere objects in micromanipulation process, we deduced the formula describing levitation height of near field acoustic levitation. The main influence factors on levitation height were proclaimed. Then, specialized transducer with concave spherical tool attached were designed and manufactured. The near field acoustic levitation was proved through a series of experiments. At last, an eccentric pneumatic drive system was established to study manipulative performance of the solid sphere. The influences of air pressure, offset, levitation height and disturbance on rotational speed were all tested. The experimental results show that air pressure is the major impact factor for rotating speed, while the offset distance is the minor one. As speed increases, the levitation height decreases and perturbation intensifies.

Building Silicon Crystal Dislocation Models for Molecular Dynamics Simulation

Guo Xiaoguang;Zhang Liang;Jin Zhuji;Guo Dongming

2013, 24(17):  2285-2289. 

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According to the dislocation formation mechanism and the silicon crystal structure,the silicon crystal dislocations were analyzed.The slip dislocation and
spiral dislocation models of  the silicon crystal were built based on the dipole model
which ensured that the dislocation models satisfied the periodic boundary conditions.
And the silicon spiral dislocation model was introduced into the MD simulation of  the silicon grinding.From the MD simulation results, the basic properties and grinding mechanism are obtained.

Research on Parametric Modeling and Strength Analysis of Strand Loose Tube Composite Cable

Zhang Zhenzhou;Zhong Liangwei

2013, 24(17):  2289-2284. 

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In order to improve the efficiency and accuracy of strand loose tube composite cable and research its strength analysis method, after the analysis on the equation of circular helix, the methods of parametric modeling and static strength analysis using ANSYS were used, which were based on the mathematical model of tensile strength. The system was combined strength design and finite element analysis which was based on knowledge engineering achieved rapid modeling and strength analysis. The way is demonstrated to be correctness and reliability with the results.

Identification Analysis and Improvement on Abnormal Noise Source for Front Gear Chamber Assembly of Diesel Engine

Meng Haodong1;Li Shunming1;Lü Zhixiang2;Li Dianrong3;Xu Yi4;Miu Yuechuan4

2013, 24(17):  2295-2300. 

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In the light of the abnormal noise problem occurred in the commonly used speed for front gear chamber assembly of diesel engine, wavelet time-frequency analysis method based on EEMD(ensemble empirical mode decomposition) was applied to identify abnormal noise source. The time-frequency characteristics of abnormal noise source were extracted by the analysis of vehicle set-test and chassis dynamometer test; the natural frequencies and modal shapes of constrained mode of gear chamber assembly were calculated by the simulation analysis of its finite element model. The reason led to abnormal noise was discovered by comprehensive analysis results. It is found that the low local stiffness of its shell structure results in system resonance. The inherent frequency of gear chamber assembly is improved by the way of improving its shell structure, the abnormal noise was removed finally.

Design of a Novel Servo Synchronizer

Li Bo;Chang Siqin;Lin Shusen

2013, 24(17):  2301-2305. 

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In order to reduce the shift force needed in synchronization phase during the process of shifting, a novel design of synchronizer was developed. Design program used the difference of tangential force affected on synchronizer ring to increase the shift force applied on shifting mechanism in synchronization phase. The analytical models for servo synchronizer were established. On the basis of that, the influence of main design parameters on the servo synchronizer performance was discussed. The simulation results show that the shift force and energy loss are reduced by nearly 40% and 66% separately in synchronization phase when the servo synchronizer is used to 5-gear transmission.

Error Modeling and Error Compensation Decoupling of CNC Gear Shaper

Xia Lian;Wang Sheng;Han Jiang; Zhang Kuibang;Tian Xiaoqing

2013, 24(17):  2306-2310. 

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In order to improve the machining accuracy of a CNC gear shaper,the errors should be compensated. The motion characteristics of the CNC gear shaper were analyzed and a motion model was created. The error model of tool related to the part was established with the homogeneous transformation matrix. Couples effects exited between the joint variables and position/orientation of the cutting points. Adjusting one joint usually resulted in changes in multiple components in the tool-part relation. A volumetric error compensation model was created by coupling the error compensation motions based on the rigid body kinematics with small error assumption and coordinate transformation method. Finally,the position and orientation compensation values of the joint variables can be obtained with the model, which gives the theoretical basis of the error compensation for the machine.

Analysis on Exact Shape Surface and Its Grinding of Guid Roller for Superfinishing of Tapered Rollers

Gao Zuobin1;Ma Wei2;Deng Xiaozhong2;Chen Shiyou2

2013, 24(17):  2310-2316. 

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Expressions for exact shape surface of a guid roller for superfinishing of tapered roller were fixed on and analysised numerically,and some conclusions are drawn as follows: among the two feature parameters proposed herein,the incline angle of the shape surface is most sensitive to the roller's cone angle,and is more sensitive to the cantact angle,but it is not sensitive to the roller's diameter;the concavity of the shape surface is more sensitive to the roller's cone angle,and is not sensitive to the cantact angle as well as the roller's diameter. Expressions for the ground shape surface of the guid roller were proposed and analysised numerically, and some conclusions are drawn as follows: cone angle of the grinding wheel and vertical angle of the wheel head are two key parameters,and the exact shape surface can be obtained by gringding when the key parameter values are appropriatly selected.In the examples provided, the error of the ground shape surface is the same as that of exact shape surface and is in 0.1μm.

Stiffness and Dynamics Analysis of a Novel 3-RPC Compliant Precision Stage

Li Shihua;Gong Wen;Li Fujuan;Jiang Shan

2013, 24(17):  2317-2323. 

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A novel type of space flexible parallel precision platform driven by PZT was designed, and flexure hinge with circular notches and one rotational degree of freedom was utilized to realize the passive adjustment of the three translation movement of the platform. Stiffness model of the stage was established by computing method for flexibility matrix, validated by finite element method. Then, the influence of geometrical parameters on the stiffness of the stage were discussed analytically. Dynamics equation of the stage was established by Lagrange equation, the model analysis of the stage was carried out by means of ANSYS, then, the influence of geometrical parameters of R flexure hinge on the natural frequencies of the stage were discussed analytically.

Influence of Phase Angle between Flange Yokes on Transmission Characteristics of a Double Hooke Universal Joint

2013, 24(17):  2323-2327. 

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The motion equations were established by means of spatial geometric projection method.The equation for relationship between phase angular of flange yokes on two ends of jackshaft and transmission ratio was deduced.Hereafter,the influence of true joint angles and phase angle in a  double cardan universal joint on the instantaneous transmission ratio and the rotation angle difference was analyzed,besides the influence of the initial angle on the rotation angle difference.The results indicate that the rotation angle difference and the rotation speed difference are periodic functions of rotation angle about input angle.The amplitude of rotation angle difference and the amplitude of the rotation speed difference increase with the phase angle.The amplitude of rotation angle difference and the amplitude of rotation speed difference increase with the true joint angles.

Experimental Study on Modal Parameter Identification for Large Wind Turbine Blade

Zhang Leian;Huang Xuemei

2013, 24(17):  2328-2331. 

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First,damping ratio identification formula was derivate by the wind turbine blade attenuation vibration equivalent to the cantilever vibration in order to identify the modal parameters of wind turbine blade.Then,a test platform for large wind turbine blade modal parameter identification was built.The aeroblade 3.6-56.4 wind turbine blade free decay test was finished using rapid unloading device for rapid release of large force.By the damper identification,a law of damping variation was obtained under different initial amplitudes.At the same time,the low-frequency of wind turbine blade was gotten by FFT using the accelerator signals.

Dimensional Error Modeling Analysis and Simulation of Sheet Metal MultiStage Assemblies

Yu Dezhong;Xu Xianghong

2013, 24(17):  2331-2336. 

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The dimensional precision of SMS, which was usually assemblied in the multistage process, determined its appearance, airproof and fatigue performance. Based on the multistage transmitting model of dimensional errors of SMS, this paper detailedly analyzed the dimensional errors of SMS in locating phase,over-locating phase and springback phase, and a state space model of dimensional errors of multistage assemblies about SMS was erected. Finally, this paper simulated their dimensional errors of aeroplane wainscot subassembly sample by MATLAB and FEM, and furthermore analyzed transmitting law of assembly dimensional errors.It is of vital help to reduce dimensional errors of SMS.

Prediction of Residual Life of Pre-corrosion Aluminum Alloy with Fractal Dimension

Zhang Chuan1;Yao Weixing2

2013, 24(17):  2337-2340. 

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Several smooth specimens of aluminum alloy LC4CS soaked in EXCO solution for different time were measured to obtain corrosion surface profiles and then tested to obtain residual life. The relationship between pre-corrosion residual life and fractal dimension of profile near fracture for different pre-corrosion time were discussed. Fractal dimension was selected as pre-corrosion damage parameter on residual life. The results show that fractal dimension of corrosion surface profile near fracture is influenced little by dispersion of corrosion surface, and there is a linear relationship between fractal dimension and residual life, which is not related with loading. The residual lives calculated by fractal dimensions are in twice scatter band.

Research on Active Isolation Feedforward Control for Magnetic Suspension Floating Raft Based on Notch Filter

Zhang Jinguang1;Hu Yefa1;Song Chunsheng1;Chen Yong2;Wang Qilin1

2013, 24(17):  2341-2345. 

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The reference signal in magnetic suspension floating raft feedforward control system contained multi-frequency components with difference in energy. The reference signal was also affected by the superposition of the secondary vibration and the output of control channels. It became unstable and time-varying, resulting in the failure of the whole control system. A FXLMS control algorithm based on notch filter was proposed. By block processing of a plurality of adaptive filter system, the influence of instability of the reference signal can be reduced and the convergence speed of the system can be improved as well. The simulation analysis was carried out by using several sinusoidal disturbance signals with different frequencies, different amplitudes and different phases as the reference signals. The simulation results show that the control algorithm can offset multi-harmonic disturbances effectively. The algorithm has much better performance in vibration isolation than that of traditional FXLMS algorithm.

Mapping Model of Design Parameters in Product Customization Driven by Uncertain Users

2013, 24(17):  2346-2351. 

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Information driven by uncertain user requirements usually has semantic, missing and redundant information. It can reduce accuracy of the mapping model from user requirements to product design parameters. In response to these problems, a fusion mapping model of fuzzy rough set+SVM was established. Fuzzy rough set was used to do granulation for quantified user data to fill missing information. The attribute reduction of rough set was used to eliminate redundant information and reduce space dimensions of input information. Then, SVM was used to construct the mapping model from user requirements to design parameters. Finally, the fusion model was applied to injection molding machine to verify its applicability.

Study on Matrix-based Material Information Integration Model for Aircraft Tooling

2013, 24(17):  2352-2357. 

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Current bill of material(BOM) model lacks of comprehensive expression of product material change information for aircraft tooling. To solve this problem, a BOMII model based on matrix tuple was proposed. BOMII model construction method, the change information expression method using matrix tuple, and recording method for the change history information using validity matrix were studied. The results show that BOMII realizes the effective integration of multidimensional information of product materials based on single model, and it can fully describe the current and change historical information of product materials.

Flow Field Simulation and Structure Optimal Design for Passage in Swash Plate Axial Piston Pump of Pressure Washer

2013, 24(17):  2358-2361. 

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A flow field model of inside pump head was setup herein. Inlet integrated passage and outlet integrated passage could be simplified as the Venturi passage structure. Optimal design was applied for inside passage structure of pump head, the simulation and testing results show that the optimization achieves the pressure loss reduction of the Venturi passage and the unloading balance pressure decrease of the bypass.

Mechanism Design and Kinematics Simulation of Load Port Based on Linkage's Theory

2013, 24(17):  2362-2367. 

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According to theory of type synthesis of mechanism,
a series of parallel four-bar linkages and slider-crank mechanisms were put forward as the drive mechanism of a loading port open box device and a mapping system. A new kinematics simulation models of traditional institutions and new mechanisms were established in MATLAB simulation components,the rational design of new institutions was verified by analyzing the motion characteristics of both.

Study on Coupling Faults of Rotary Machinery Diagnosis Method Based on Improved EMD

2013, 24(17):  2367-2372. 

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 A method of coupling faults diagnosis on rotary machinery based on improved EMD was proposed. The method which combined advantages of similar extrema extension and cosine window function, solved the problems that continuation parts were not accurate and the original signal changed because of adding window function, and improved the operation precision of EMD method. Vibrating signal feature extraction and fault diagnosis were studied on rotor-bearing system with coupling faults of crack and rub-impact by the method. The vibrating signals from rotor disk of fault system were diagnosed with both high-frequency components due to crack and low-frequency components due to rub-impact, and the coupling fault features were acquired.It is proved the method is effective.

Research on Driving Characteristics of Airscrew Maglev

2013, 24(17):  2373-2376. 

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Airscrew maglev used magnetic levitation technology to levitate the railway carriage and used airscrew to drive the railway carriage. To enhance the driving force of the airscrew airflow thrust and improve the driving efficiency, windshields were laid on the overhead rail of the airscrew maglev. The influence of the angle of windshield on the driving force was analyzed when airscrew maglev running at low speed by experimental and theoretical methods. Then the influence of equivalent friction of the magnetic levitation on the driving force was studied at the same time. Finally, the feasibility of practical application of airscrew maglev was discussed.

Research on Uniform Processing Method of Complex-shaped Surface in Abrasive Flow Machining

2013, 24(17):  2377-2382. 

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In order to improve the consistency of a complex-shaped
surface by AFM,a method of processing the complex-shaped surface uniformly was
put forward.In the processing of the complex-shaped surface,the uniformity of the shear force distribution was improved and the consistency of
the surface roughness was enhanced by setting up a mold core.At first,according to the properties of  the abrasive medium and the relational algebra between the shear rate and viscosity,a power law model was established.Then,the distribution of the velocities,shear rate and shear forces of the abrasive flow on the surface was obtained by CFD module of the COMSOL Multiphysics software.The simulation results show that the relatively uniform runner is formed and shear stress on every part of the abnormity bent surface is more uniform
when the similar shape of the mold core is inserted into the complex hole.The experimental results demonstrate that the surface roughness Ra is reduced from 0.376μm to 0.017μm through adopting the mold core.

Damage Detection Based on Transmissibility and Singular Value Entropy

2013, 24(17):  2382-2385. 

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A damage detection method based on transmissibility and
singular value entropy was proposed to detect damage in structures without acquiring
the exciting force and the damage features were extracted directly from the vibration response.Transmissibility was obtained by taking the ratio of two response spectra,and
then the singular spectrum value was acquired by singular value decomposition of the
transmissibility matrix after phase space reconstruction,which can be used as an
indicator for damage detection.Experimental tests undertaken on a three story
structure validate the proposed method.

Development and Research of Sonic Drilling Rig Driven by Dual-eccentric Shaft

2013, 24(17):  2386-2390. 

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A kind of sonic driller virtual prototype driven by dual-eccentric shaft was developed based on virtual prototype technology herein. The structure and working principle of the sonic driller were analyzed in detail. The physical prototype of the sonic driller was manufactured in factory based on the virtual prototype, and the operating characteristics of the sonic drilling method were research by the in-situ test. The results of practical applications show that the sonic driller driven by the dual-eccentric shaft has the simple structure, stable performances and high output energy density. The soil sample took by the sonic driller has merits of highly fidelity and pollution-free. It also proves that the design scheme of the sonic driller is feasibale.

Multi-granularity and Hierarchy Low-carbon Efficiency Analysis Method for Products

2013, 24(17):  2390-2397. 

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Multi-granularity and hierarchy low-carbon efficiency analysis
for products was proposed to support product low-carbon design.A multi-granularity and hierarchy low-carbon efficiency analysis model was established.The quantitative model of product carbon footprint was put forward,product utility was analyzed by the application of quality function deployment for environment and technique for order preference by similarity to ideal solution(TOPSIS),the low-carbon efficiency of product was computed.Carbon footprint of module unit was calculated and allocated,the utility of module unit was analyzed by a  configuration model for parts,the low-carbon efficiency of module unit  was assessed and analyzed.The application of  this method in design improvement was discussed.Finally a case study of refrigerator  was done to illustrate the feasibility and applicability of this method.

Carbon Emission Model and Parameter Optimization of CO2 Shielded Welding Based on GRNN

2013, 24(17):  2398-2403. 

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The carbon emission function of CO2 shielded welding was proposed based on the analysis of its carbon emissions behavior by synthesizing the material carbon emission,energy carbon emission and process carbon emission.In order to optimize its carbon emissions while guaranteeing its cost and quality,a comprehensive evaluation model of carbon emission performance was then established by taking advantage of the GRNN to approximate the relationship between welding parameters and the carbon emission,quality and cost.Furthermore,genetic algorithm was applied to resolve this model.Finally,the model was validated by the investigation of welding process of loader fuel tank and the results show that the model can reduce the carbon emissions while guaranteeing the quality and cost welding.

Simulation Test and Performance Improvement Strategy of Vehicle Diesel Engine at Plateau Area

2013, 24(17):  2403-2407. 

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The performance of diesel engine working in different altitude regions were studied by simulation test. The influence of the altitude on engine performance, such as power, economic, cold starting and thermal balance were verified,and some measures were put forward to improve diesel engine performance at plateau, such as boosting technology, fuel system improvement, cold starting, heat balance control, calibration for electronic controlled diesel engine. The purpose was to provide reference for improving plateau environmental worthiness of diesel engine.

Research on Torque Distribution of a Complex Hybrid Drive Train System Based on Optimal Overall Efficiency

2013, 24(17):  2408-2413. 

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This paper focused on the torque distribution of a complex hybrid electric vehicle.With the intention of getting an optimal efficiency of the overall hybrid system,the equivalent BSFC method was employed to distribute the working torque of the engine and electric machines.The torque split maps of engine and electric machines were obtained.The simulation model was built in MATLAB/Simulink and the simulation was carried out.The control strategy was loaded into the control unit for real car tests.Both the results of simulation and tests indicate the control strategy meets  the requirements of the driver quite well and can reduce fuel consumption.