======================================================================                   ENGINEERING NEWS IN BRIEF                         E-Mail Newsletter                                No.40              Issued by the Asian TOP Panel, March2005            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) ======================================================================     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 KSME for the year 2005. ====================================================================== [Contents] (1) Rapid Prototyping with Point Grinding and Forming Sharpening for Drill with Non-linear Edge (Source: CMES) (2) A New 6 ?DOF Universal Hand Controller (Source: CMES) (3) The delegation of American Society of Mechanical Engineers visited Beijing (Source: CMES) (4) Development of a Canned Pump with Magnetic Self-levitation Motors (Source: JSME) (5) Shape Design That Makes Our Life Comfortable (Source: JSME) (6) Development of numerical method for damage evaluation of composite materials (Source: JSME) (7) Peristaltic PDMS Micropump (Source : KSME) ======================================================================== (1) Rapid Prototyping with Point Grinding and Forming Sharpening for Drill with Non-linear Edges (Source: CMES) Li Chao Nanjing Normal University A new principle and method of point forming grinding for rapid molding grinding is a new machining method of contour grinding which is close to CAD/CAM technology. The principle of work is similar to Rapid Prototyping. As a special case of application, the hyperboloid twist drill was rapidly contour ground. Having non-linear edges, this kind of drill could not be sharpened by general shape grinding wheel and grinding method. The final cost of making contour grinding wheel is too high, so researches and applications of the drill types are very difficult to make and were stopped for a long time. ======================================================================== (2) A New 6 ?DOF Universal Hand Controller (Source: CMES) Cui Jianwei Southeast University A New 6 ?DOF Universal heterogeneous Hand Controller was proposed. Two parallelogram linkages composed two platforms which were divided into two classes and with three motion DOF. Each of its 8 joints with 2-DOF was an universal coupling with $B!0(B+$B!1(B shape and their motion range is over $B!>(B 60 degree. $B!0(B U $B!1(B form components constructed two rotary DOF that their rotary range was adaptive to human whist. The structure has the decoupling characteristics of moving and rotation, but has no singular point in its workspace. The final DOF is the finger motion of the hand controller. DC moment motors were used to be as driving devices and to feed back the forces to the operator. ======================================================================== (3) The delegation of American Society of Mechanical Engineers visited Beijing (Source: CMES) The ten more persons delegation of American Society of Mechanical Engineer led by Harry Armen, President of ASME visited Beijing on April 19 to 24. Mr. Song Tianhu, Vice- President and General Secretary of Chinese Mechanical Engineering Society met with the ASME guests. Trusted by Mr. Lu Yongxiang, President of CMES who was on business outside Beijing Mr. Lu Yansun, Honorary President met the main members of the delegation and invited them for dinner. The main program of the delegation was presenting the Engineering Management International Forum sponsored by American Society of Mechanical Engineers, Chinese Association for International Exchange of Personnel, School of Continuing Education, Tsinghua University and supported by Chinese Mechanical Engineering Society, Chinese Academy of Engineering and other units. Beijing Mechanical Engineering Society, China National Machine Tool Corporation, China National Heavy Machinery Corporation and others have paid vigorous assistance to this forum. Mr. Lu Yansun was invited to give a splendid lecture. During their visit ASME and CMES exchanged their ideas about academic exchange, personnel certification and the issue of Beijing International Education Conference which will be held on March 31 to April 4, 2006. Both parties express that they will make further effort to build good atmosphere of exchanging and cooperation to offer better service for the engineering and technical staffs in China and America. Mr. Guo Dongming, Standing Member of CMES Governing Council, Mr. Ding Peifan, Mr. Zhang Qiang and Wang Ruigang, Deputy General Secretaries had talks about the responsible work respectively. Some relative directors of CMES joined the activities as well. ======================================================================= (4) Development of a Canned Pump with Magnetic Self-levitation Motors (Source: JSME) Tadashi SATO, Ebara Research Co., Ltd. We have designed and manufactured a prototype of a canned pump with magnetic self-levitation motors. This pump consists of two self-levitation motors, each equipped with a high efficiency rotor (IPM type) for generating magnetically radial levitation force to support the rotor and the torque in the same space. The axial position of the rotor is stabilized by the hydraulic balance structure of the pump impeller. Stationary parts of the pump are completely isolated from the fluid with thin cans, creating a pump mechanism without a seal. Conventional pumps, due to mechanical contact, produce particles from friction and wear that degrade the purity of the fluid. Furthermore, dry operation of such pumps shortens the life of their bearings. On the other hand, our innovative design is free from the above-mentioned disadvantages; it does not possess any source of friction and ware, such as bearings, seals or mechanical contacts. Adoption of magnetic levitation is generally avoided because it demands large space. However, our design can equal the size of conventional pumps because it incorporates high-speed rotation and an efficient rotor structure while avoiding the use of magnetic axial bearing. ============================================================ (5) Shape Design That Makes Our Life Comfortable (Source : JSME) Katsuhiro Maekawa, Ibaraki University It is difficult to evaluate shape design in relationship to human sensitivity. A frequency analysis is introduced to evaluate geometric features included in three-dimensional objects such as pottery. To discriminate between handmade design by a ceramist and machine-made one, the outer surface of ceramic tea bowls is measured with a CCD laser displacement sensor system. Surface topography is then analyzed by the first Fourier transform to plot a correlation between its power spectrum and the spatial frequency that is defined by the number of waves per unit distance. The power spectrum decreases with increasing spatial frequency on the double logarithmic plot, being approximated by a linear curve. Especially, the 1/f-fluctuation pattern appears on the handmade tea bowl. The frequency characteristics are then utilized to design surface texture of an artificial 3D object. A nylon tea bowl with the 1/f-fluctuation surface texture is substantiated by means of stereolithography. This approach leads to shape design that makes our life comfortable. ============================================================ (6) Development of numerical method for damage evaluation of composite materials (Source : JSME) Yuichiro Aoki, Japan Aerospace Exploration Agency (JAXA) Hiroshi Suemasu, Sophia University A numerical method to evaluate an impact damage growth in a composite laminate is developed by using a finite element method. A three-dimensional cohesive interface element is placed at an interface between ordinary 2nd order finite elements to model the propagation of delaminations and crack-like damages. The softening cohesive constitutive relation between tractions and relative displacements is derived by a specific separation energy density function which is equivalent of the interlaminar fracture toughness. A damage parameter is introduced to prevent the recovery of cohesive zone during unloading process. First, the element is applied to DCB test in order to verify its validity. The result shows good agreement with theoretical one and the convergence of the solution is smooth. Then, the element is applied to the damage growth problem in cross-ply CFRP laminates subjected to transverse concentrated load. In this analysis, both transverse cracks and delaminations are modeled by the element. The predicted delamination shape can explain a realistic one. The present method can be good tool to simulate the damage growth problem for more practical composite structures. ============================================================ (7) Peristaltic PDMS Micropump (Source : KSME) Professor Sang Sik Yang of Ajou University reported the fabrication and drive test of a peristaltic PDMS micropump actuated by the thermopneumatic force in a recent issue of Journal of Mechanical Science and Technology (Vol. 19, no, 2, pp. 649-654, 2005). The micropump consists of the three peristaltic-type actuator chambers with microheaters on the glass substrate and a microchannel connecting the chambers and the inlet/outlet port. The micropump was fabricated by the spin-coating process, the two-step curing process, the JSR (negative PR) molding process. The diameter and the thickness of the actuator diagram are 2.5 mm and 30 $B'-(B, respectively. The meniscus motion in the capillary tube was observed with a video camera and the flow rate of the micro pump was calculated through the frame analysis of the recorded video data. The maximum flow rate of the micropump was about 0.36 $B'!(B/sec at 2 Hz for the zero hydraulic pressure difference when the 3-phase input voltage was 20 V. ============================================================ Editor : Professor Mansoo Choi of Seoul National University,            Director of General Affairs, KSME            ksme@ksme.or.kr

 

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