China Mechanical Engineering

Determination of Optimum Parameters in Plane Grinding by Using Grey Relational Analysis

LI Hao-Lin, WANG Jian

2011, 22(6): 631-635.

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The grey relational analysis was used for optimizing the plane grinding process parameters for the work piece surface roughness and the flatness. Various grinding parameters, such as grinding wheel speed, mode of feeding, feeding speed, grinding depth, grinding concentration and grinding time were considered. An orthogonal array was used for the experimental design. Optimal machining parameters were determined by the grey relational grade obtained from the grey relational analysis for multi-performance characteristics (the surface roughness and the flatness). Experimental results show that the surface roughness and the flatness in plane grinding process can be improved effectively through the new approach.

Study on Continuous Measurement Method of Flow Rate Characteristics for Pneumatic Regulator

WANG Chao, TAO Heng, BANG Guang-Zheng

2011, 22(6): 636-641.

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In ISO6953 and GB/T20081, there is a disadvantage that two measuring devices must be used for determination of the flow rate characteristics of pneumatic regulators with forward flow and relief flow characteristics. A new set of measuring device and method was proposed herein, which made use of an electric regulator with large relief function as the load pressure and flow regulation device and a dual directional flow meter. With the continuous conditionings from maximum forward to maximum relief flow, pressure and flow rate, as well as flow rate characteristics can be obtained in real-time. This will simplify the measuring circuit, avoid measurement instrument exchange and the caused errors, improve the test efficiency and save the amount of used air.

Novel Inner-teeth Type Linear Oscillatory Motor with Two Divided Stators

LEI Mei-Zhen-1, DAI Wen-Zhan-1, JIA Yong-Meng-1, WANG Li-Jiang-2

2011, 22(6): 642-647.

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High magnetic flux leakage between two divided stators leads to low

utilization ratio of permanent magnet(PM) of a conventional linear oscillatory motor(LOM) with two divided stators. In order to decrease the magnetic flux leakage of a motor, a

novel inner-teeth type LOM with two divided stators was designed. Firstly, the construction and working principles of the motor were introduced, the analytical expressions of electromagnetic force were derived, and the quasi-2D parametric finite element model of the motor was built to verify the correctness of the expressions. Then, based on the finite element model, the air-gap magnetic flux distribution of the LOM was analyzed, and the electromagnetic force and flux linkage under different winding current and mover displacement were calculated precisely. Finally, the vibration characteristics of the LOM was investigated. Compared with the LOM without inner-teeth, the magnetic flux leakage between the two divided stators of inner-teeth type LOM reduces obviously, and the axial length of PM decreases about 17%. The comparison results verify the validation of inner-teeth type LOM.

Dynamics Analysis of Logarithm Curved Surface Sprag PCE Clutch

TUN Kai-1, YAN Hong-Zhi-1, HE Meng-Sheng-1, TAN Huan-Jiang-2

2011, 22(6): 647-651.

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On the basis of analysis of a clutch structure and work principles, the sprag,key element of the clutch,was designed. Meanwhile, three-dimensional models of the logarithm curved surface sprag PCE clutch and the single arc curved surface sprag PCE clutch were formed. Importing the model into ADAMS, the engagement process of the clutch was simulated. Through the analysis of the engagement time,contact forces and sliding angle, it indicates that the logarithm curved surface sprag clutch engages rapidly and both transient impact and steady contact force are lower than that of the single arc curved surface sprag clutch.

Reliability Analysis and Optimization Based on Non-probabilistic Interval Model

HAN Zhi-Jie, WANG Zhang-Ai

2011, 22(6): 652-656.

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According to the fluctuating factors of the target components’ structural parameters and the interval characterization of the material properties, this paper adopted reliability analysis and structural optimization method, and analyzed the control parameters, material strength and load distribution considering uncertainty of structural parameters of the target components.The reliability index with structural failure probability was constructed by using non-probabilistic interval reliability analysis. And combined with N-dimensional complex optimal algorithm with interval constraints, the optimal results were obtained. To billet slings clamp plate, for example, this method was proved to be practical and effective. And it is a new way of the reliability-based design.

Design for Basic Rack of Harmonic Drive with Double-circular-arc Tooth Profile

XIN Hong-Bing

2011, 22(6): 656-662.

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On the basis of research on engagement principle of harmonic drive with circular-arc tooth profile, a design method was presented for double circular-arc tooth profile of basic rack for flexspline and rigid spline of harmonic drive. The double circular-arc tooth profiles of basic rack ensured the tooth profiles of flexspline and rigid spline to keep on conjugating with each other during the meshing period, especially there existed so-called dual-conjugated meshing zones, in which the convex and concave profiles of flexspline conjugated with the concave and convex profiles of rigid spline simutaneously, this characteristics played important roles in improving the torsional stiffness and transmission accuracy of the harmonic drive. The double-circular-arc tooth profiles of basic rack of harmonic drive with elliptical wave generator were developed and applied in design and manufacture of the hobs with double-circular-arc tooth profile for flexspline, the shaping cutters with double-circular-arc tooth profile for rigid spline and the sample device for experimentation. Compared with the involute profile, the flexible strength, transmission accuracy, and torsional stiffness of the harmonic drive with double-circular-arc tooth profiles are markedly improved. 

Experimental Study on Deep-hole Drilling Gamma Titanium Aluminide

CHEN Xin, SHU Lin

2011, 22(6): 663-666.

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γ-titanium aluminide alloy has the advantages of high temperature resistance,high performance of anti-oxidation effect, low-density, high specific strength and rigidity etc. But high strength, hardness and brittleness of the material also make processing difficultly. This problem is more acute in deep hole drilling.

We analyzed the cutting performance of γ-titanium aluminide and designed a deep-hole drills with appropriate tool material and geometric parameters herein.The experimental results show:(1)YG8 cemented carbide is the appropriate tool material for drilling γ-titanium aluminide. (2)small rake angle of external edge (γ_o=-1°) and big clearance angle of external edge (α_o is about 10°～12°) should be chosen.

Kinematics Analysis and Parameter Optimization of a Hybrid Input Mechanical Press

FU Ca-An, CHEN Wen

2011, 22(6): 666-670.

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This paper established the principles of hybrid input mechanism. Kinematic analysis on the mechanism was carried out under the condition of the given law of output. The variation laws of position,speed and acceleration of auxiliary driven were obtained. The simulation analysis and parameter optimization of this mechanism were completed with the aid of ADAMS parametric module，thus the kinematic performance of this mechanism is improved，and the quality of parts and life of dies are improved too.Then a reference basis is provided for the applications in engineering project of hybrid input mechanical press.

Predictive Method of Vibration for Permanent Magnet Linear Synchronic Motor’s Mover 

NING Jian-Rong, JIA Jia-Kuan, CHEN Li, WANG Cheng-Yuan

2011, 22(6): 671-674.

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PMLSM drives the feed table of an ultra-precision CNC machine tool directly,so the vibration of PMLSM’s mover affects directly the precision of the machine tool.The method of vibration prediction in the design stage was constructed herein.Firstly,FEM was used to analyze the dynamics of the mover, and the transfer function of magnetic force and acceleration were obtained.Secondly, the connection of current and magnetic force was set up. Thirdly, the transient current was got by MATLAB while the PMLSM was running in transient. Then magnetic forces were calculated by interpolation using the relationship of current and magnetic force. Lastly, acceleration was calculated by the transfer function. It is helpful to vibration analysis and design optimization of PMLSM in the future work.

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Mechanism Design Principle and Process CAD Based on Information Processing

ZHANG Xiao-Zhong, YANG Zhe, LUO Dan

2011, 22(6): 675-680.

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Based on view of information processing, the basic ideas, methods and techniques of mechanism design process were researched.Through the analysis of representational forms, evolution and methods of information processing on mechanism design process in the brain and on the computer, the design principle and CAD technology framework of mechanism design on view of information processing were put

forward.The mechanism behavior analysis by parametric technology, and CAD methods about performance analysis based on sample and simulation were discussed. Meanwhile,the processing methods of abstract concept based on linguistic reasoning, the methods of transforming abstract expression to be visualized based on attributes matching, the agency programs and performance design methods based on auxiliary reference assembly were given. At last,an example of innovative design on link mechanism was given, which achieved the intelligent and automatic design process under human-computer interaction environment.

Nonlinear Model Predictive Control of Trajectory Tracking for Nonholonomic AGV

DIAO Han, YIN Xiao-Gong, TUN Yan-Meng

2011, 22(6): 681-686.

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Considering the kinematic model of three-wheeled AGV with non-holonomic constraint and input saturation,a nonlinear model predictive control was studied and an united control algorithm of tracking and stability was proposed. Firstly, an optimal controller was obtained based on the principles of model predictive control.Secondly, a terminal controller and an invariantterminal region were designed in order to keep the AGV system stable.Then，the noise problem of state estimation was solved by using a state observer, which improves the localization precision and enhances the control effectiveness.Finally，a module was designed to avoid obstacle. The designed control algorithm has generality for kinematic model of other wheeled mobile robots. Computer simulation results show its correctness and validness.

Research on Fault Prediction Approach for Reciprocating Machinery Based on Local Wave Method and SVM Prediction Model

BIE Feng-Feng, LIU Yang, ZHOU Guo-Jiang, LV Feng-Xia

2011, 22(6): 687-691.

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According to the real working status of running reciprocating machines,a grey prediction method of diagnosis based on local wave time-frequency spectrum and SVM was presented. By local wave time-frequency spectrum, power fluctuate of the vibration signals could be reflected on time and frequency domain. Comparing the precision of the two main analysis models in diagnosis prediction on industrial equipment, a step-changing grey prediction model was chosen, in which the local wave decomposition was set as the basic input. Application of the method in fault prediction on a reciprocating compressor system illustrates the precision improvement.

A Study of Knowledge Model Supporting Rolling Stock Rapid Design

TAO Jia, GUO Yu

2011, 22(6): 691-696.

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In order to meet the demands of rapid design,design processes using for organizing design knowledge were constructed on the basis of design knowledge analyzing. Starting from design constraints and design processes,using key words and design parameter matching,based on the relations among knowledges,engineers were obtained comprehensive,personalized design knowledge and appropriate CAD models.New design process for knowledge reusing was established based upon the

knowledge model to gear rapid design requirements. In the end, an example was given to testify the effectiveness of the knowledge model.

Type Synthesis and Analysis of Workspace of a Novel Series Chinese Medical Massage Arm

XIE Dun, KUANG Li-Hui, MA Lv-Zhong, YANG Qi-Zhi

2011, 22(6): 697-701.

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Based on the Chinese medical massage manipulation of pressing, kneading, rolling, and vibrating method, from aspects of type-synthesis and dimension-synthesis, the design rules of mechanical arm of Chinese medical massage manipulator were introduced. At the same time, the massage mechanical arm’s kinematics model was established by means of the homogeneous coordinate transformation using the Denavit-Hartenberg coordinate system. Its forward kinematics was solved. The workspace of this Chinese medical massage arm was analyzed by graphical approach. It shows that the length of upper arm and forearm of this kind of Chinese medical massage arm must be equal. The workspace of this Chinese medical massage arm was also portrayed based on the Monte Carlo principle through programming on MATLAB. It indicates that the working points in the workspace of this massage mechanical arm are distributed compactly and uniformly, which can satisfy the Chinese medical massage requirements with high efficiency.

Laser Cladding Forming of a Ramp Thin Wall with Variable Powder Feed Rate

WANG Xu-Ti, GUO Hui-Ru, XU Wen-Ji, GUO Dong-Meng, WANG Lian-Ji

2011, 22(6): 701-705,714.

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To prevent stair-step effect when layered forming parts using

2.5D slices, a geometrical model formed with variable thickness slices was developed. The research work performed with variable powder feed rate. The relationships between the geometrical precision of the parts formed by laser cladding forming (LCF) and the variable powder feed rate were investigated. While change of the powder feed rate every 2mm,the height of the cladding layer increases from 0.05mm to 0.46mm with the powder feed rate varying from 0.5g/min to 3.0g/min. The correct scanning paths were planned by simulating forming process of a ramp and a mountain shape parts through Matlab program. Using the scanning path obtained, a relatively smooth ramp of 316L stainless steel with a slope angle (3.37°) was formed through experiments. The results show the method with variable powder feed rate reduces the stair-step effect significantly and improves the geometrical precision of the ramp thin wall.

Efficient Method for Computation of Multi-parameterized Problem Based on Least Square Mapping

CHEN Pei, HAN Xu, JIANG Chao, ZHANG Zheng

2011, 22(6): 706-709.

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A new reduced-basis method based on the least square mapping was suggested to improve the efficiency of solving complex and multi-parameterized problems in mechanical engineering.In this method,sampling points were obtained from the parameter domain,and a reduced-basis space was constructed by computing responses of the problem at these points.Then the least square mapping was employed to conduct projection from original space onto the reduced-basis space.A reduced system was obtained and

can be solved efficiently.By projecting the reduced solution back into the original space,an approximate solution of the original system was obtained efficiently and accurately.Even with new variables, the solution can be obtained fastly by solving the reduced system.The numerical example demonstrates that this method is of validity and reliability.

A Numerical Method of Fatigue Life Prediction for Truss Structure Based on Grey Model

LI Yuan, HAN Xu, JIANG Chao, WANG Lin-Jun

2011, 22(6): 710-714.

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A numerical method of fatigue life prediction of statically indeterminate truss structure based on gray model was established herein. This paper analyzed principles in dealing with the order of logarithm times, and determined right order of times to predict fatigue lifetime. Then it amended the definition of the critical parameters identifying failure elements, so that the choices of bounded parameters were more accurate. Before the search of main fatigue failure modes, this paper added the critical failure internal stress criterion, reducing the calculation of recognition algorithms for identifying failure modes. Based on the improved grey model(GM), it estimated the Weibull distribution function, and calculated different safe lifetimes of truss structure system under different reliability degrees. The numerical example of 10 truss structure shows the validity of the numerical method established. 

Predicting Skid and Spin Power Loss in a High Speed Hybrid Ball Bearing

YU Wei, LIN Cheng-Jie, LIU Qing-Chao, WANG Dong-Feng

2011, 22(6): 715-719.

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The rapidly increased heat generation of high speed hybrid ball bearing draws a need of predicting skid and spin power loss of the bearing. A hybrid dynamic finite element method was proposed to simulate high speed hybrid ball bearings. The results show that when axial load varies from 16kN to 24kN and shaft speed varies in a large range, the spin-to-roll ratio and the spin power loss of outer race is close to that of inner race. It is not appropriate to ignore the spin-to-roll ratio of outer race when predicting the skid and spin power loss of the bearing. A proper preload may decrease the spin-to-roll ratio of inner race efficiently.

Binary Image Authentication Algorithm Based on Digital Watermarking

WANG Chun-Xian, LI Hui-Shan, SHU Yun-Li

2011, 22(6): 719-722.

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A novel digital watermarking technique was proposed for authenticating binary images.The pixels in binary image were divided into two categories,one was the flippable pixels and another was the unflippable pixels. In the watermark generation process, the unflippable pixels were input into a Hash function for generating the authenticating signals which depended on the content of the image, and then the authenticating signals and the image ownership information were encoded with a chaotic sequence to form the watermark. The watermarked image can be obtained by inserting the watermark into the flippable pixels. Experimental results show that the watermark can be blindly extracted, the proposed method can detect any modification to the watermarked image, and verify the ownership while the watermarked image is not manipulated.

Optimization Design of Blank Sheet in Body Panel Progressive Stamping 

NIE Cuan, CHENG Ai-Guo, SHEN Dan-Feng

2011, 22(6): 723-728.

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A front rail reinforcement panel is an example to illustrate how the process of progressive stamping was simulated by finite-element method herein,so the problems occurred in production could be predicted such as carrier distortion, inaccurate blank size, cracks, and wrinkles and so on. Besides, the method which combined manual modification and the scale factor method were supplied to optimize blank sheet. In the end, the method is proves its advantages and supplies reference for trial in practice.It can also shorten development cycle and reduce cost.

Forming Simulation of Textile Composite Stamping on Double Dome

Zia-Ur-Rehman, BANG Xiong-Ai, DAN Shao-Qing, DING Bang-Bang

2011, 22(6): 728-731.

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The paper presented a fully continuum mechanics-based approach for stamping simulation of textile fiber reinforced composites by using finite element (FE) method. A non-orthogonal constitutive model was used to represent the anisotropic mechanical behavior of textile composites under large shear deformation during stamping. Simulation was performed on a balanced plain weave composite over a benchmark double dome device. A user material subroutine UMAT for the woven composite was developed for commercial FE package ABAQUS/Standard to implement the algorithm. The main advantage of this approach lies in its ease execution whilst computationally effective. Simulation results show good agreement with experimental output in terms of a number of parameters selected for comparison.

Inverse Approach to Identification of Anisotropy Parameters Based on Flange Edge of Drawing Cup

CUI Fu-Gang, LI Guang-Yao, LIU Di-Hui, LI Fang-Xi

2011, 22(6): 732-735.

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Based on flange edge of drawing cup,an inverse approach to identify anisotropy parameters was presented.This inverse approach achieved the flange edge of drawing cup through drawing cup experiments and reverse engineering technology, and taking the coefficient of normal anisotropy as the inverse variables, the differences of flange edge between the simulation and experiment as the objective function,

numerical simulation and multi-island genetic algorithm were combined to identify the anisotropy parameters. An example was performed to demonstrate that this method can identify these parameters rapidly under simple experimental conditions. Using the parameters inversed by this method can improve the precision of sheet metal forming simulation.

Arbitrarily-shaped Contact Boundary Processing in Application of Meshless Method for the Simulation of Metal Forming Process

SONG Xiao-Wen, SU Jian-Min, WANG Yun, HU Shu-Gen

2011, 22(6): 736-743,747.

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Arbitrarily-shaped contact boundary problem is so complicated and challenging, that how to treat it accurately and efficiently is a difficult and central issue.

The authors concentrated on this issue herein. Based on the algorithm used in FEM,

the authors raised a new algorithm for contact detection by deviding the projection area of possible contact surfaces into small rectangles which were called sub-domains. Using penalty function method to calcute the contact force and then introducing its virtual power into the deformation controlling equation to satisfy the constraints on the contact surfaces. The new algorithm is high in efficiency and easy in implement, and is suitable for metal forming simulation with meshless method. Finally, a numerical example was given to illustrate its correctness and efficiency in simulation of metal forming process based on meshless method.

Comparative Research of Overflow-hole Positions on Coach Sidewall

JUE Dan, DIAO Cuan, NA Jing-Xin, WANG Qiu-Lin, GAO Jian-Feng

2011, 22(6): 744-747.

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According to integral bus body structure characteristics and production process,a method was proposed to discuss the local strength effection of overflow-hole positions on joints of a coach. Several joints on the sidewalls were selected to analyze the stress of different overflow-hole positions at cases of full-load bending, left crankling and right crankling. Then the stress influence law was found out by comprasion,which can be as a reference for further design of overflow-holes in the progress of electrophoresis.

Study on Quality Evaluation of Automobile Surfaces Based on Fuzzy Comprehensive Evaluation

WANG Zheng-Ru, LIANG Jin, WANG Li-Zhong, LIANG Xin-Ge

2011, 22(6): 748-751.

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To evaluate the quality of automobile surfaces precisely, on the basis of considering both of precision and smoothness，a factor set of evaluation was determined.Using analytic hierarchy process(AHP) to determine weights of the evaluation factors, combining with fuzzy analysis and artificial neural network, the quality evaluation model of automobile surfaces was established. After training and testing, the results prove that the model is accurate.

CST Control System Based on Combination of Automotive Collision Warning and Collision Energy Absorption Technology

DU Jing-Yun, LEI Zheng-Bao, WEI Shu-Ban

2011, 22(6): 751-755.

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