JSME international journal. Ser. 3, Vibration, control engineering, engineering for industry
Print ISSN : 0914-8825
Volume 34 , Issue 4
Showing 1-16 articles out of 16 articles from the selected issue
  • Kenzo SATO
    1991 Volume 34 Issue 4 Pages 459-465
    Published: December 15, 1991
    Released: February 18, 2008
    JOURNALS FREE ACCESS
    The influence of shear deformation and rotatory inertia on the vibration and stability of a clamped-elastically restrained column subjected to a nonconservative force is studied in the present paper. The direction of an external force following the deflection of the column at its elastically restrained end is generally expressed in terms of the arbitrary angle dependent on the slope at the column end. In the analysis, the governing equations derived according to Hamilton's principle are used. The depen-dence of the eigenfrequency, and flutter and divergence loads on the slenderness ratio is numerically examined for various spring stiffnesses and follower force directions. It is shown that although the effect of shear deformation and rotatory inertia is almost to destabilize the system, there may be a case in which it is to stabilize the system in connection with the spring stiffness and follower force direction. Detailed discussion is also presented for the special case of a clamped-free column subjected to a fully tangential follower force in comparison with the other study.
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  • Hiromi DEWA
    1991 Volume 34 Issue 4 Pages 466-474
    Published: December 15, 1991
    Released: February 18, 2008
    JOURNALS FREE ACCESS
    Experimental evaluation of the torsional rigidities and loss factors of a sandwich rod and a covered rod having a viscoelastic core and viscoelastic covered layers, respectively, are carried out in order to verify the analysis results previously presented. The experimental results are discussed for typical nonsylnmetrical rods with the same total thickness of the outer layers and also symmetrical rods with the geometrically similar thicknesses. The damping characteristics of the sandwich rod and the covered one present remarkably different features. These characteristics are given by the experimental and analytical results. Furthermore, the optimal temperature showing the highest loss factor of the sandwich rod usually differs from the glass transition temperature of the viscoelastic core material. Such a difference results in less damping capacity of the rod. A strain energy analysis and the experimental results explain that the arrangement of the core layer thickness enables minimization of such a difference, if the properties of the core material are previously known.
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  • Helmut F BAUER
    1991 Volume 34 Issue 4 Pages 475-480
    Published: December 15, 1991
    Released: February 18, 2008
    JOURNALS FREE ACCESS
    A liquid is placed between two concentric parallel discs in a zero-gravity environment. Its circular cylindrical free surface is held together by surface tension, which may act in the case of a disturbance as the restoring force of the oscillation. Therefore the natural axisymmetric frequencies of a cylindrical liquid column and an annular liquid layer between two discs and anchored liquid edges (stuck-edges) have been determined. It was found that with increasing aspect ratio of the liquid system the natural frequencies decrease. If the liquid column was placed between two parallel plates with no edge effects, i.e. freely slipping liquid edges, the natural frequencies exhibit much lower values. It may also be seen, that the liquid with free edges becomes unstable for aspect ratios h/a≥π, while those with anchored edges exhibits instability for h/a≥2π, a being the radius of the column
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  • Pey-Chung CHEN, Ming-Chang SHIH
    1991 Volume 34 Issue 4 Pages 481-489
    Published: December 15, 1991
    Released: February 18, 2008
    JOURNALS FREE ACCESS
    In this paper, a fuzzy-PID controller implemented in the personal computer PC/XT is proposed and applied to control the position of a servo-hydraulic cylinder. The experimental results show that the performance of the control system with variable load is excellent. This indicates that the proposed controller is one of the possible approaches to control a nonlinear and time-varying hydraulic system.
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  • Hiroyuki KOJIMA, Kikuo NEZU, Kenji SAKAMOTO, Takashi KAWANABE, Hideo K ...
    1991 Volume 34 Issue 4 Pages 490-495
    Published: December 15, 1991
    Released: February 18, 2008
    JOURNALS FREE ACCESS
    A position control system consisting of a linear DC motor and a beam, based on inverse dynamics, is proposed. The rapid and exact control performance is confirmed experimentally and theoretically. In the experiment, the linear DC motor is made of an aluminum coil frame or an acrylic resin coil frame. It is confirmed that, by the present control method, the moving part of the linear DC motor can be controlled accurately to the position control command for an arbitrary settling time without undesirable mechanical vibrations. When the settling time is comparatively long, the wave shape of the control current of the motor is affected mainly by the bending force of the beam. Then, with a decreasing settling time, the inertial force has significant effects on the wave shape of the tontrol current. Furthermore, the numerical simulation results obtained with the finite element method agree well with the experimental results.
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  • Takefumi HAYASHI, Toshifumi OHKUBO, Kenji MOCHIZUKI, Isamu SATO
    1991 Volume 34 Issue 4 Pages 496-502
    Published: December 15, 1991
    Released: February 18, 2008
    JOURNALS FREE ACCESS
    Signal output from a piezoelectric transducer bonded to a flying head slider for magnetic disk storage is analyzed. Slider-core natural vibrations induced by contacts between the slider and the recording medium are identified with frequency peaks of the signal output. The analyses are applied to highly sensitive contact detection and evaluation of dynamic characteristics of a slider on an actual recording medium. The influence of the medium surface roughness on the dynamic behavior of the slider is presented for both the full flying state and the contact start/stop operation.
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  • Hitoshi HATTORI, Noritsugu KAWASHIMA
    1991 Volume 34 Issue 4 Pages 503-511
    Published: December 15, 1991
    Released: February 18, 2008
    JOURNALS FREE ACCESS
    A method for dynamic analysis of a rotor-journal bearing system, in which large dynamic loads act on the rotor, is introduced. The governing equations are solved by numerical calculation. The system is analyzed as a coupled problem regarding the equations of motion for a rigid rotor and the Reynolds equations for the oil film in all the bearings supporting the rotor. Then, an analysis method for when a relative misalignment exists between the bearings is also presented. A rigid rotor supported by three bearings was analyzed for use in rotary compressors. The rotor motion, the bearing load characteristics and the misalignment influence are shown as the results of the analysis.
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  • Akira ISHIBASHI, Satoru MUTA, Shigeru HOYASHITA
    1991 Volume 34 Issue 4 Pages 512-517
    Published: December 15, 1991
    Released: February 18, 2008
    JOURNALS FREE ACCESS
    The authors introduced two kinds of new pressure-release ports for improving the performance of gear pumps with involute profiles. High-pressure gear pumps as well as low-pressure ones were used for verifying the effectiveness of the new release ports. In the case of the low-pressure pumps, the total efficiency of the pump with the new release ports was higher by about lO% when compared with the one having conventional release ports. However, when the improved conventional release ports, which were found in a gear pump currently available on the market, were used, the increase reduced from l0% to about 4% at a delivery pressure of about 700 kPa. Running noise and vibration of the gear pumps with the new release ports were appreciably smaller than those of the one with the conventional release ports. In the case of the high-pressure gear pumps, the increase in the total efficiency was about 5% at a delivery pressure of about 10 MPa. The reason for the improvement in the total efficiency was clearly explained by the maximum pressure measured in the semienclosed tooth space between two mating gears of the gear pumps with different release ports.
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  • Hiroshi NAGATA, Akira ISHIBASHI, Shigeru HOYASHITA, Hidenao TAKEDOMI
    1991 Volume 34 Issue 4 Pages 518-525
    Published: December 15, 1991
    Released: February 18, 2008
    JOURNALS FREE ACCESS
    The mechanism of a continuously variable speed traction drive (CVT) with two internal spherical disks was introduced. Equations were derived for calculating changes in speed ratio and power losses caused by the spinning motion at the contact surface. The effective traction force between contact surfaces with an elliptical shape was calculated using the traction coefficient curves obtained by two roller tests and the resulting empirical equations. In this calculation, the effective pressure was utilized instead of a Hertzian mean pressure. The spinning loss was divided into torque and speed losses at the contact surface. Numerical calculations were performed to estimate the losses produced in a trial CVT with a capacity of about 5 kW at 1800 rpm. The equations developed are aplicable to any other type of CVT after certain modifications.
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  • Takashi KOBAYASHI, Tsuneo MATSUBAYASHI
    1991 Volume 34 Issue 4 Pages 526-532
    Published: December 15, 1991
    Released: February 18, 2008
    JOURNALS FREE ACCESS
    The deformation characteristics of a cantilever beam structure, in which a beam was bonded onto a base using a bonding surface parallel to the axis of the beam and which was subjected to a bending load tangential to the bonding surfaces, have been examined both theoretically and experimentally. It was shown that the deformation and rigidity of the adhesive joint could be well estimated by using the theory of bending of a beam on an elastic foundation. Effects of the length of the flange and the thickness of the adhesive layer on the rigidity were clarified, and a design criterion of adhesive joints was proposed. It was observed that the rigidity of the adhesive joint was greater than that of the bolted joint when the thickness of the adhesive layer was thin, and that greaterload could be applied to an adhesive joint than to a bolted joint.
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  • Susumu YAMASAKI, Tatsuo OZAKI
    1991 Volume 34 Issue 4 Pages 533-539
    Published: December 15, 1991
    Released: February 18, 2008
    JOURNALS FREE ACCESS
    Single-side straight cutting of aluminum sheets is performed to investigate the effects of inclination angle, tool clearance and cutting-off length on loads, sheared surface qualities and deformation behaviour of the material, where the sheet is inclined with respect to the descending direction of an upper blade. The following facts are found with an increase in the inclination angle. The height of the smooth sheared surface increases when the tool clearance is small. Roll-over depth and height of burr decrease. Shearing resistance decreases as the result of an increase in tension acting in the direction perpendicular to a cutting line. The tension acts throughout the process in shearing of inclined sheet metals, even when the cutting-off length is small compared with the sheet thickness.
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  • Mototaro SATO, Takao YAMAZAKI, Yasuo SHIMIZU, Toshihide TAKABAYASHI
    1991 Volume 34 Issue 4 Pages 540-545
    Published: December 15, 1991
    Released: February 18, 2008
    JOURNALS FREE ACCESS
    An orthogonal cutting test was conducted using a high-precision machine to study the characteristic phenomena in micromachining of aluminum single crystals. The results of the experiments and the analyses can be summarized briefly as follows : (1) A high-precison machine having a microdepth cutting apparatus was produced by way of trial. (2) The size effect appeared in the cutting force (Fh) when the depth of cut reached l.0 μm. (3) The alternation phenomenon appeared in the cutting force (Fh) and the chip length when the depth of cut reached above l.5 μm. (4) The alternation phenomena can reasonably be explained through the introduction of the cold-worked region model. (5) The roughness and flatness of the finished surface were affected by the cutting direction, and this information suggests that control of the specimen orientation is effective for improving the working accuracy.
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  • Sawai SUKVITTAYAWONG, Ichiro INASAKI
    1991 Volume 34 Issue 4 Pages 546-552
    Published: December 15, 1991
    Released: February 18, 2008
    JOURNALS FREE ACCESS
    The needs of today's complex manufacturing systems requires the use of machine tools operated by means of an adaptively controlled system. Adaptive control provides continuous monitoring of performance and adjusts the system variables in order to approach the conditions optimum for the chosen performance objectives. This investigation proposes the in-process parameter estimation method of tool life in turning, in which the force ratio of feed force to tangential force due to the tool wear is detected. The method involves the analysis of the optimum cutting conditions based on the machining cost per unit volume of metal removed under the considered cutting constraints.
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  • Sawai SUKVITTAYAWONG, Ichiro INASAKI
    1991 Volume 34 Issue 4 Pages 553-560
    Published: December 15, 1991
    Released: February 18, 2008
    JOURNALS FREE ACCESS
    The machining process can be considered as a planned interaction of workpiece, tool, and machine tool. In an unmanned situation, the results of this interaction are to be continuously monitored so that any changes in the machining environment can be sensed in order to take corrective action. In order to design the process monitoring system for unmanned manufacturing, the identification of chip form is proposed. The system proposes the method of using acoustic emission signal analysis to identify the chip form during cutting. The acoustic emission signals are analyzed using the standard deviation, the skew, and the kurtosis of the beta distribution and the counted frequency at the acoustic emission mode. The fuzzy set theory and the neural network are applied to identify the chip form. In fact, the percentage of correct recognition of the identification of thip form using both the methods is always higher than 90% in experiments.
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  • Katsumi WATANABE, Tateyoshi TAKADA, Kenichi MITOME, Masashi YANATORI
    1991 Volume 34 Issue 4 Pages 561-567
    Published: December 15, 1991
    Released: February 18, 2008
    JOURNALS FREE ACCESS
    An index of motion-transmission characteristics γ of the spatial four-link mechanism, which has two stationary turning pairs and two moving spherical pairs, is presented through investigation of the sensitivity of the angular displacement of the links to the deviation of the kinematic constants and the forces acting at the pairs due to the external forces on the links. Generally speaking, the average of the absolute values of the sensitivities S and the average of the forces acting at the pairs F decrease rapidly in the interval [0, 0.3] and slowly in [0.3, 1] as γ increases. The γ-S and γ-F relations are approximated by the regions bounded by two rectangular hyperbolas. Consequently, it is possible to estimate the values of S and F of any mechanism at the given crank angle by means of γ.
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  • Jeong Tae KIM, Byung Man KWAK
    1991 Volume 34 Issue 4 Pages 568-573
    Published: December 15, 1991
    Released: February 18, 2008
    JOURNALS FREE ACCESS
    A computer algorithm for determining the symmetry of a kinematic chain is developed. The vertex set of the graph generated from the kinematic chain is partitioned into classes of vertices according to certain structural properties in graph theory. Permutations of vertices in each class are selected if they can map the set of edges into the original set of edges corresponding to the class. They are then concatenated with those from other classes. All the permutations that remain after checking the automorphism become the vertex-induced group of the graph, which represents the symmetry of the corresponding kinematic chain.
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