ENGINEERING NEWS IN BRIEF

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                  ENGINEERING NEWS IN BRIEF
                        E-Mail Newsletter

                               No.58
             Issued by the Asian TOP Panel, October 2006

           The Chinese Mechanical Engineering Society (CMES)
           The Institution of Engineers, Indonesia (PII)
           The Japan Society of Mechanical Engineers (JSME)
           The Korean Society of Mechanical Engineers (KSME)

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    According to the agreement made in the 2nd Asian TOP Panel Meeting,
the ENGINEERING NEWS IN BRIEF (E-mail newsletter) has now been edited
by the CMES for the year 2006.

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[Contents]

(1) Circular Arc Forming in Tube Expansion Forming (Source: CMES)
(2) Key Technique of RP&M Networked Service System (Source: CMES)
(3) Experiment and Numerical Simulation of 40Cr Steel in Grind-Hardening (CMES)
(4) Shock Absorbing Design For Portable PCs (Source: JSME)
(5) Project of a Development of New Hip Disarticulation Prostheses That Improve Gait      Pattern (Source: JSME)
(6) A Study on Levitation Mechanism Based on Electrodynamic Force for a Maglev Planar      Transportation System (Source: KSME)
(7) Evaluation of a Wafer Transportation Speed for Propulsion Nozzle Array on Air      Levitation System (KSME)
(8) Structural Design of a Cathod-Ray Tube(CRT) to Improve Its Mechanical Shockproof      Character (Source : KSME)

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(1) Circular Arc Forming in Tube Expansion Forming

    ZHAO Changcai XIAO Hong ZHANG Qing College of Mechanical Engineering,
    Yanshan University

A mechanical model considering sliding friction between the tube and die is proposed to explore the plastic deformation behavior of the tubes during a expansion process in a square cross-sectional die. That the radius of the circular arc with the minimum limit value is firstly proved, and the calculational formulas are given, based on researching on the no friction slipping model. The minimum radius of the circular arc which is defined can decide the workpiece's shape and forming pressure. At last, experiments of tube expansion in a square die using a self-designed apparatus are also conducted. The experimentation results are between no friction slipping model and friction slipping model. The correctness of no friction slipping model and friction slipping model is also verified by contrast with experiments and calculation results.
ly which attached or exceeded its melting point, thereby, the material of the contact zone between the bullet and the steel plate becomes mobile phase and the flow material leaves the matrix and becomes abrasive dust under the action of the grain and shock wave. The phenomenon on chip formation due to shock of ultra-high speed grinding is found, so the chip formation mechanism due to shock of ultra-high speed grinding is studied and disclosed from the deeper level, and the accuracy of "the model of mechanism of chip-formation due to shock in quasi-fluid phase on super-high speed grinding" is verified.

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(2) Key Technique of RP&M Networked Service System

     WU Ling HONG Jun LEI Xiaojun LU Bingheng
     State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong      University,

The structure of the networked integrated service system established on the basis of distributed component structure is expounded, and corresponding functional modules are designed according to each component feature. An index system of RP&M process decision including goal layer, criterion layer and scheme layer is proposed. A new method for RP&M process selection based on expert system and fuzzy synthesis evaluation is presented and the support system for RP&M manufacture process selection is set up. Based on the analysis of process planning of RP&M collaborative manufacture, different types of RP&M process monitoring points are determined according to the time scale principle ,which provides the theoretical basis for the process management and monitoring. The implementation of the networked service system verifies its capacity of supporting enterprises with the convenient and rapid remote development of new products.

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(3) Experiment and Numerical Simulation of 40Cr Steel in Grind-Hardening

     ZHANG Lei GE Peiqi ZHANG Jianhua College of Mechanical Engineering,
     Shandong University

The dissipated heat in grinding is utilized to induce martensitic phase transformation and strengthen the surface layer of 40Cr steel by raising surface temperature higher than austenic temperature and cooling quickly. The experiment of grinding 40Cr steel is taken in grinding machine. The metallurgical microstructure, depth and hardness of transect phase transformation layer are analyzed and surface roughness is measured. Temperature field and temperature history are simulated based on finite element method. The simulated hardness penetration depth is deduced from every place temperature history of work piece and martensitic phase transformation conditions. The experiment result shows that martensitic phase transformation takes place on the 40Cr steel surface layer in grinding, the hardness of surface layer is improved highly and surface roughness accords with the roughness of traditional grinding. So, it is possible for grind-hardening to take place of induction hardening. The temperature field and history can be simulated based on finite element method to predict the hardness penetration depth and optimize the grinding parameters. Thus the experiment cost and time can be reduced.

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(4) Shock Absorbing Design For Portable PCs

     Minoru MUKAI, Noriyasu KAWAMURA, Koji NAKAMURA Toshiba Corporation

With the increasingly widespread use of portable PCs, demand has arisen for the protection of PCs against mechanical shock. In response to this demand, shock-absorbing technologies have been developed. Since a period of reliability design of portable PCs is becoming shorter, the impact simulation method is important. Transfer paths of shock power in the PCs are complicated because of high-density assembly of components. Constructing a suitable finite element model of the structures with a lot of contacting parts was carried out, and a simple modeling method based on the equivalent mass and equivalent stiffness was also proposed for early stage design. Consequently, the new simulation method had been successfully adopted in the development of the shock protector of the chassis. Vital components, such as hard disk drives (HDDs), were supported to the chassis using rubber tabs to shield them from shock and vibration. These shock-absorbing structures for each component were adjusted and designed based on the results of drop impact tests. In addition, an HDD protection system with a built-in three-axis acceleration sensor was also developed. This system detects free falls in all directions and rapidly moves the HDD head in preparation for impact.
Last year, the new portable PCs by these technologies were put on the market.

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(5) Project of A Development of New Hip Disarticulation Prostheses That Improve Gait Pattern-Development of Rehabilitation Devices Using Forward Dynamics Simulation of Human Motion -

    Hisashi NAITO, Osaka University

This article describes an outline of a project of development of new hip disarticulation prostheses (HDPs). This project consists of three research tasks: a survey on mechanical properties of conventional HDPs and difficulties that users have, a development of forward dynamics simulator of human-walking using HDPs and design tools of new HDPs, and making and evaluating prototypes. Particularly, developed simulator succeeded in generating suitable gait pattern using conventional HDPs, and in addition, it could estimate performances of new HDPs, that is, calculate interactions between human motion and a HDPs motion. This result proved that the simulator will become a core technology of effective tools for designing new HDPs. Such a designing tool potentially changes the field of design of the man-machine systems, for example, HDPs and other assistive devices. It is expected that an integrated approach, which includes survey, simulation and prototyping, like this project, advances the simulation-based-design of the man-machine systems.

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(6) A Study on Levitation Mechanism Based on Electrodynamic Force for a Maglev Planar Transportation System

     Joon Hyuk Park KRRI (Korea Railroad Research Institute)
     Yoon Su Baek Yonsei University

This study describes the levitation mechanism using magnetic wheel for a maglev planar transportation system. Rotation of the magnetic wheel where the permanent magnet array is embedded produces the time varying traveling magnetic flux density and the generated magnetic flux density creates the induced levitation force and drag force with the conductor. Because the net drag force is zero, magnetic wheel can only generate the levitation force. Thus, it always guarantees the stability in levitation direction and it does not disturb other directional motion. In this paper, levitation principle of the magnetic wheel is analyzed using distributed field approach and dynamic characteristics of the levitation in the magnetic wheel system are estimated. The feasibility of the proposed levitation mechanism is verified through the several experimental works.

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(7) Evaluation of a Wafer Transportation Speed for Propulsion Nozzle Array on Air      Levitation System

     In-Ho Moon, Young-Kyu Hwang Sungkyunkwan University

A transportation system of single wafer has been developed to be applied to semiconductor manufacturing process of the next generation. In this study, the experimental apparatus consists of two kinds of track, one is for propelling a wafer, so called control track, the other is for generating an air film to transfer a wafer, so called transfer track. The wafer transportation speed has been evaluated by the numerical and the experimental methods for three types of nozzle position array (i.e., the front-, face- and rear-array) in an air levitation system. Test facility for 300 mm wafer has been equipped with two control tracks and one transfer track of 1500 mm length from the starting point to the stopping point. From the present results, it is found that the experimental values of the wafer transportation speed are well in agreement with the computed ones. Namely, the computed values of the maximum wafer transportation speed Vmax are slightly higher than the experimental ones by about 15~20%. The disparities in Vmax between the numerical and the experimental results become smaller as the air velocity increases. Also, at the same air flow rate, the order of wafer transportation speeds is: Vmax for the front-array ＞ Vmax for the face-array ＞Vmax for the rear-array. However, the face-array is rather more stable than any other type of nozzle array to ensure safe transportation of a wafer.

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(8) Structural Design of a Cathod-Ray Tube(CRT) to Improve Its Mechanical Shockproof Character

    Sang Hu Park KAIST (Korea Advanced Institute of Science and Technology)
    Won Jin Kim Keimyung University

An electronic beam mis-landing phenomenon on the ROB (red/green/ blue)-fluorescent surface has been considered as one of serious problems to be solved in cathode-ray tube (CRT), which is generally caused by mechanical shock and vibration. In this work, structural design concepts on the major parts of the CRT, such as a frame, a shadow mask, and a spring, are studied to improve the mechanical shockproof character of a CRT by FEM-analyses and experimental approaches; a frame is newly designed to have strength employing the double-corner-beads which reduces considerably the distortion of the frame and the shadow mask; the edge of a shadow-mask is redesigned to maintain the wide curved surface of a shadow-mask after mechanical shock; finally, a spring supporting the frame and the shadow-mask is designed to have enough flexibility along drop-direction. As an example, a conventional type of a l5inch CRT was utilized to demonstrate the feasibility and usefulness of this work. Overall, some favorable information on the structural design of the CRT is achieved, and the mechanical shockproof character of a IS-inch CRT is improved in the degree of 3G (1G=9.8l m/s2) as an average-value.

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Editor : Tian Ruizhu
           The Dept. of Internationa Affairs
           Chinese Mechanical Engineering Society