Journal of the Japanese Society for Experimental Mechanics
Print ISSN : 1346-4930
ISSN-L : 1346-4930
Volume 8 , Issue 4
Showing 1-16 articles out of 16 articles from the selected issue
Original articles
  • Kazuyoshi NISHIHARA, Yusuke NAKAHATA, Manabu IGUCHI
    Type: Original Article
    2008 Volume 8 Issue 4 Pages 327-332
    Published: 2008
    Released: June 25, 2009
    JOURNALS FREE ACCESS
    Cross flow fan invented by Mortier (1892) had a guide apparatus inside the impeller. After this however attention has been directed to a fan without a guide apparatus. It is attractive that inner guide apparatus can give higher values of total pressure and higher efficiency than the fan without inner apparatus. However the higher values of total pressure are restricted in narrow range of flow rate. Κορο_??_κ_??_ et al. obtained higher pressure coefficient ψt=6 at flow rate coefficientφ=1.5. Furthermore they investigated inner flow around the inner guide apparatus. In this paper two types of cross flow fan with partial inner guide blade are developed. The shape and the settling position of a guide blade are varied, while two types of tongue are used. Partial inner guide blade is shown to give higher performance inner wide range of flow rate.
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  • Satoru TOYOOKA, Hirofumi KADONO, Makoto MIWA, Anura P. RARHNAYAKE
    Type: Original Article
    2008 Volume 8 Issue 4 Pages 333-338
    Published: 2008
    Released: June 25, 2009
    JOURNALS FREE ACCESS
    Growing behavior of a plant is affected by surrounding environment to acclimate itself to environmental changes. Circumnutation accompanied by growth and nanometer-scale growing behavior of plants are investigated by optical methods: Digital Image Correlation and Statistical Interferometry, respectively. Variation of growth rate and its fluctuation in nanometer scale which affect growing condition of stem and root of plants sensitively were detected by statistical interferometry. A new indicator for environmental sensing is proposed.
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  • Tetsuo KUMAZAWA, Jianhui QIU
    Type: Original Article
    2008 Volume 8 Issue 4 Pages 339-343
    Published: 2008
    Released: June 25, 2009
    JOURNALS FREE ACCESS
    A deformation measurement with a thermocouple was intended to be applied for dynamic and impact deformation test. An electromotive force (Emf) was caused by bending vibration, which was tensioned and compressed alternatively in a steel plate. The Emf increased almost in proportion to the strain magnitude. The impact test was done using a Hopkinson bar made of several kinds of metals. The Emf and strain were measured at same position. Both the Emf and strain were agreed well with each other in timing, though they were different in the direction of increasing and decreasing. There was a linear relationship between the absolute Emf and strain for the steel, copper, aluminum and solder bars.
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  • Yuichi KUROSU, M. I. SHLIOMIS, Tetsuya YANO, Seiichi SUDO
    Type: Original Article
    2008 Volume 8 Issue 4 Pages 344-350
    Published: 2008
    Released: June 25, 2009
    JOURNALS FREE ACCESS
    This paper describes unique phenomena of magnetic fluid pendulum subject to alternating magnetic fields. Experimental study on a magnetic fluid torsional pendulum in an oscillating magnetic field was conducted. The experimental device is a thin disk-shaped container filled with a magnetic fluid and suspended in a horizontal linearly polarized alternating magnetic field. The dynamic behavior of the magnetic fluid pendulum in Helmholtz coil was measured with the optical displacement detector system. It was found that the magnetic fluid pendulum in the magnetic field exhibits a rich variety of nonlinear self-oscillatory regimes.
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  • Nao MATSUI, Seiichi SUDO
    Type: Original Article
    2008 Volume 8 Issue 4 Pages 351-358
    Published: 2008
    Released: June 25, 2009
    JOURNALS FREE ACCESS
    This paper is concerned with plant biomechanics to obtain inspiration from nature. The results of a morphological study on the seeds of Tragopogon pratensis are presented. The bloom of the dandelion, Taraxacum officinale Weber, and observation of unfolding flower bud are recorded in the flower blooming size. Since the seeds are very light in weight and they have flight organs such as pappus, some morphological parameters of the seeds are measured. The function of morphological structure of plant pappus is revealed. Descent experiments of the dry seeds of dandelion are conducted and the falling characteristics related to aerodynamics are revealed.
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  • Tetsuya YANO, Tamotsu KASHIWAGI, Seiichi SUDO
    Type: Original Article
    2008 Volume 8 Issue 4 Pages 359-365
    Published: 2008
    Released: June 25, 2009
    JOURNALS FREE ACCESS
    The driving characteristics of the swing type micro magnetic fluid actuator driven by external magnetic field were studied. The micro actuator consisted of a small permanent magnet and the magnetic fluid which was adsorbed to the magnet. The oscillator was placed on the upper side of the acrylic plate and an iron plate was placed under the acrylic plate. The magnetic fluid adsorbed to the magnet makes the magnet levitate in the magnetic fluid against the gravitational force and the magnetic force between the magnet and the iron plate. Therefore, the friction due to the contact between the magnet and the acrylic plate was reduced considerably. The actuator, which was the oscillator on the iron and acrylic plate, was put into the Helmhortz coil and the oscillator was driven by the external alternating magnetic field. The oscillator showed smooth alternating swing motion toward the direction of the external magnetic field generated by the coil. The motion of the oscillator was analyzed varying the frequency of the magnetic field using a high speed video camera system. Although the frequency of the swing motion corresponded with the frequency of the external magnetic field up to 100 Hz, the swing angle reduced gradually with increasing frequency without a certain frequency range.
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  • Koji TOMIYAMA, Yasushi IDO
    Type: Original Article
    2008 Volume 8 Issue 4 Pages 366-370
    Published: 2008
    Released: June 25, 2009
    JOURNALS FREE ACCESS
    Characteristics of polyurethane foam such as sound absorption depend on its inner porous (cell) structure. Double layered porous absorbing material from combination of different cell structure has wide band performance of sound absorption. In our study, new foaming technology for polyurethane foam was reported. It is named “Magnetic Induction Foaming (MIF)”. MIF is the method of cell control through magnetic induction. The polyurethane polymer is generated by the polyaddition reaction of polyol and polyisocyanate, and carbon dioxide gas is formed by the foam reaction of polyisocyanate and water (premixed into the polyol starting material). In this paper, we focused on catalyst effect on the inner porous structure of polyurethane foam and used water-based magnetic fluid to MIF in the purpose of making double layered functional gradient materials. Under a non-uniform field, the magnetic fluid (catalyser effect) tends to drift to one side of the structure where the field is strongest. It is found that the polyurethane foam sample made by using this method have the continuously-distributed cell structure, experimentally.
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  • Manabu CHIKAI, Kazuya KANDA, Yaoyang ZHENH, Kunio SHIMADA
    Type: Original Article
    2008 Volume 8 Issue 4 Pages 371-376
    Published: 2008
    Released: June 25, 2009
    JOURNALS FREE ACCESS
    This research reports the findings of a study investigating multiple properties of Magnetic Compound Fluid (MCF) composite materials, recently developed as MCF Rubber, which is considered to possess such properties as a feeling temperature, electro conductivity, a dynamic characteristic, and a magnetic characteristic. This study specifically focuses on electro conductivity, and the experiment of electric characteristic is conducted, in which resistance decreases because of pressure regarding electro conductivity, and the relationship between pressure and resistance is also indicated. The experiment also investigated impedance characteristic in the case of the impression A.C. voltage and pressurizing of MCF Rubber, and compared each impedance characteristic in accordance with the change of the electrode. The experiment result showed that MCF Rubber approximated to capacitance, and reacted to the frequency and the electrode change sensitively. Results also indicated that the change of electrode yielded a different component in the electric circuit at the contact area, which could be remarkable characteristic and applied to various fields. Findings also point to the need to approximate of relationship between MCF Rubber and pressure, and to examine equal circuit.
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  • Hirofumi WAKUDA, Seiichi SUDO
    Type: Original Article
    2008 Volume 8 Issue 4 Pages 377-383
    Published: 2008
    Released: June 25, 2009
    JOURNALS FREE ACCESS
    This paper describes the magnetic fluid sloshing in a longitudinally excited container. Liquid responses of magnetic fluid with a permanent magnet in a circular cylindrical container subject to vertical vibration are investigated. Experiments are performed on a vibration- testing system which provided longitudinal excitation. A cylindrical container made with the acrylic plastic is used in the experiment. A permanent magnet is in the state of floating in a magnetic fluid. The disk-shaped and ring-shaped magnets are examined. The different interfacial phenomena from the usual longitudinal liquid sloshing are observed. It is found that the wave motion frequency of magnetic fluid with a disk-shaped magnet in the container subject to vertical vibration is exactly same that of the excitation. In the case of ring-shaped magnet, the first symmetrical mode of one-half subharmonic response is dominant at lower excitation frequencies. The magnetic fluid disintegration of the free surface was also observed by a high-speed video camera system.
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  • Takashi HANAMI, Kunio SHIMADA, Yaoyang ZHENG
    Type: Original Article
    2008 Volume 8 Issue 4 Pages 384-391
    Published: 2008
    Released: June 25, 2009
    JOURNALS FREE ACCESS
    This report was described experiment by the surface treatment on an acrylic resin utilizing a float polishing by MCF. MCF is one of the magnetic responsive fluids. The acrylic resin has clear surface by polishing, therefore, it is generally used for many industrial products. And it is easy to manufacture the material under the condition of the low cost. However, it has difficult surface treatment on the polishing. When the MCF is used on the polishing, the material can have the nano-level surface roughness. Contrary to the MCF polishing, the ordinal polishing by the conventional polishing machine has impossible accuracy on the polishing surface roughness. In this reports, the MCF polishing technique was proposed on the polishing acrylic resin.
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  • Yaoyang ZHENG, Kunio SHIMADA
    Type: Original Article
    2008 Volume 8 Issue 4 Pages 392-395
    Published: 2008
    Released: June 25, 2009
    JOURNALS FREE ACCESS
    The MCF conductive rubber, combining the MCF in a silicon-oil rubber, has been developed with Shimada laboratory a few years ago. Recently, by means of the MCF electric conductive rubber, we are developing a haptic sensor for the applications to a robotic finger, artificial skin, and so on. For the purpose of the applications, it is important to understand characteristics of the MCF electric conductive rubber. In this paper, we proposed a new type MCF conductive rubber, the new type MCF rubber has high sensitivity and electivity. We made some experiments to compare older MCF rubber and improved MCF rubber's sensitivity and electivity. The results show new type MCF rubber catch a touch easily much than older MCF rubber, it can be effectively applied to robotic touch sensor.
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  • Kenji MACHIDA, Koichi HAYAFUNE, Shohei MIYAGAWA
    Type: Original Article
    2008 Volume 8 Issue 4 Pages 396-401
    Published: 2008
    Released: June 25, 2009
    JOURNALS FREE ACCESS
    Until now, the effect of the three-dimensional heat-conduction has been discussed by paying attention to the thickness change of a specimen. A temperature gradient increases by the increase in the three-dimensional stress gradient accompanying the increase in specimen thickness and a load. Therefore, it becomes impossible to ignore the effect of the heat conduction in the thickness direction, and it can be said that analytic accuracy falls. The effect of the heat conduction to the image of the sum of the principal stresses decreases with an increase in the frequency of a cyclic load. Then, the improvement in analytic accuracy was paid attention by changing the frequency of a cyclic load in this experiment. Therefore, in modification of the sum of the principal stresses by two-dimensional non-steady heat-conduction inverse analyses, a very accurate result was obtained at the frequency of 20Hz or more. Heat-conduction direct problem simulation when giving a cyclic load (20Hz and 25Hz) was carried out in two-dimensional analyses and three-dimensional analyses, and it was discussed whether it is possible to minimize the effect of three-dimensional heat conduction.
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  • Motoharu FUJIGAKI, Yoshiharu MORIMOTO
    Type: Original Article
    2008 Volume 8 Issue 4 Pages 402-408
    Published: 2008
    Released: June 25, 2009
    JOURNALS FREE ACCESS
    We propose a shape measurement method using pixel-by-pixel calibration tables produced with multiple reference planes. In this method, all the relationships between the phase of the projected grating and the spatial coordinates can be obtained for each pixel. This method excludes a lens distortion and intensity errors of the projected grating in measurement results theoretically. We call it "whole-space tabulation method". Tabulation also makes short-time measurement possible. In this paper, the principle of the shape measurement using the whole-space tabulation method and several results of shape measurements using this method are shown.
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  • Hiroyuki MAE
    Type: Original Article
    2008 Volume 8 Issue 4 Pages 409-415
    Published: 2008
    Released: June 25, 2009
    JOURNALS FREE ACCESS
    The tensile properties of PP⁄SEBS blend syntactic foams with the relative densities from 0.5 to 1.0 are characterized at the nominal strain rates of 1, 10 and 100 s-1. Then, the influences of the tensile properties of the matrix materials on the macroscopic tensile properties of the syntactic foams are studied by comparing the experimental results of PP⁄SEBS and PP⁄EPR⁄talc syntactic foams. It is found that the apparent elastic moduli of PP⁄SEBS and PP⁄EPR⁄talc foams obey the Gibson-Ashby law at the nominal strain rate of 100 s-1, which indicates that the microstructural deformation mechanisms of syntactic foams would be correlated well with the Gibson-Ashby model when the matrix materials are the glass phase. The yield stress of PP⁄SEBS foam obeys the simple rule of mixture at the relative densities larger than 0.9. However, the yield stress of PP⁄EPR⁄talc foam does not obey the simple mixing rule because the debonding of the blended inorganic talc filler against PP matrix is dominant characteristic for the yield stress. This localized microscopic damage mechanism makes the yield stress predicted by the simple mixing rule less accurate. The material ductility of PP⁄SEBS foam decreases drastically once the microballoons are blended in the matrix material.
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  • -Improvement of Pressure Sensitivity by Controlling the Real Contact Area -
    Yuichi ONO, Seiichiro KITAOKA, Takeshi MATSUSHIMA
    Type: Original Article
    2008 Volume 8 Issue 4 Pages 416-421
    Published: 2008
    Released: June 25, 2009
    JOURNALS FREE ACCESS
    An electrodeposited copper foil is used for the cyclic pressure measurement, since the grain growth occurs in the foil that is sandwiched between two bodies in contact. Improvement of the pressure sensitivity of this method is examined using nickel-phosphorus alloy foil with microprojections. Namely, if both copper foil and nickel-phosphorus alloy foil with microprojections are inserted together into two bodies, the real contact pressure between two foils becomes higher than nominal pressure, since the pressure is transmitted only at the tip of microprojections. Therefore, the relationship among grown grain density, cyclic pressure and number of cycles is investigated, and compared with conventional report. Moreover, the experimental expression is presented to measure the contact pressure amplitude using the grown grain density in copper foil.
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  • Kazuo ARAKAWA, Masaru KATO, Toshio MADA
    Type: Original Article
    2008 Volume 8 Issue 4 Pages 422-427
    Published: 2008
    Released: June 25, 2009
    JOURNALS FREE ACCESS
    The fracture behavior of a thermosetting polymer, epoxy resin, under the effect of static and impact tensile loading was studied using single-edge-cracked specimens. The static and dynamic loads were determined using a load cell and a piezo sensor, respectively, and the displacement of the specimen was measured using a high-speed extensometer. From the load-displacement diagram, the external work (Uex) applied to the specimen was used to evaluate the elastic energy (Ee) and nonelastic energy (En) due to viscoelastic and plastic deformation, and the fracture energy (Ef) for creating a new fracture surface (As). The energy release rate was then estimated using Gf = EfAs, and the values of Gf were correlated with the fracture load (Pc). The result indicated that although Gf increased with Pc for both tests, the impact test showed much lower values than the static test.
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