JSME international journal. Ser. 3, Vibration, control engineering, engineering for industry
Print ISSN : 0914-8825
Volume 33 , Issue 3
Showing 1-23 articles out of 23 articles from the selected issue
  • Yoshihiro NARITA
    1990 Volume 33 Issue 3 Pages 291-296
    Published: September 15, 1990
    Released: February 18, 2008
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    The free vibration problem of cantilevered composite plates of arbitrary planform is solved by an extension of the Ritz method. The lamination of fibrous composite material is included in the analysis by obtaining the equivalent bending rigidities. The cantilever plate is assumed to have a straight clamped edge and free edges along an arbitrary boundary, and the boundary conditions are accommodated by use of double power series for assumed deflections. In the numerical study, four typical plate planforms are considered, and the natural frequencies are calculated for plates made of boron-epoxy material. The dependence of the free vibration characteristics on the lamination parameters, e.g., fiber orientation and number of layers, is discussed.
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  • Toshiyuki SAKATA, Kenji HOSOKAWA
    1990 Volume 33 Issue 3 Pages 297-303
    Published: September 15, 1990
    Released: February 18, 2008
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    Free, forced and transient vibrations of simply supported orthotropic rectangular plates are numerically studied. The plate is supported by a beam parallel to the side of the plate through a damping material, whose properties are modeled by the finite number of discrete springs and dashpots. The effect of the number of supporting points and the flexural rigidity of the beam on the dynamic behavior of the plate is clarified. Furthermore, the possibility of the reduction of vibrating plate deflections is discussed.
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  • Osamu ICHINOMIYA, Yoshihiro NARITA, Kouichi MARUYAMA
    1990 Volume 33 Issue 3 Pages 304-309
    Published: September 15, 1990
    Released: February 18, 2008
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    This paper presents an analytical method for determining the steady-state response of a laminated composite fectangular plate resting on some elastic point supports. The bending rigidities are assumed to be complex quantities considering material damping. The Ritz approach is used to yield a governing equation of motion for the plate, and the steady-state response solution to a sinusoidally varying point force is derived. The method is applied to a laminated square plate elastically supported at four points symmetrically located at the corners or on the diagonals. The mechanical impedance of the plate is calculated for three types of FRP (fiber-reinforced plastic) materials, and the effects of the point supports and the lamination properties upon the response characteristics are studied.
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  • Kohei SUZUKI, Kin'ya MATSUMOTO
    1990 Volume 33 Issue 3 Pages 310-314
    Published: September 15, 1990
    Released: February 18, 2008
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    This paper presents eigenvalue, eigenvector and frequency response analysis techniques based on FEM for symmetrically laminated composite plates by using stand-alone desktop microcomputers. In order to realize these dynamic analyses on a microcomputer, a technique has been proposed to substitute a symmetrically laminated orthotropic plate in a single anisotropic plate model. By using this technique, 12 d.o.f. rectangular and 9 d.o.f. triangular finite elements have been formulated. A subspace iteration algorithm is used for the eigenvalue and eigenvector analyses. A modal analysis effective for this particular problem has been developed to calculate frequency response functions using the results of the eigenvalue analysis. Furthermore, pre- and postprocessor for eigenvalue analyses have been conducted. A vibration test using CFRP (carbon fiber-reinforced plastics) symmetrically laminated composite plates as test pieces is performed to prove the effectiveness of the method. Study shows that this dynamic analysis technique could be of practical use and the proposed eigenvalue analysis technique could be effective for the plates whereby not only a wide range of fiber angles but aldo a dynamic coupling effect between bending and torsion forces are taken into consideration.
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  • Hirofumi KONDO, Setsuo YAMAMOTO, Yukio SASAKI
    1990 Volume 33 Issue 3 Pages 315-322
    Published: September 15, 1990
    Released: February 18, 2008
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    This paper presents an elementary version of a fluid-structure interaction analysis program which has been developed for vibration analysis and seismic response analysis for pool type LMFBR's. This program is based on a finite-element method combined with a boundary element method for axisymmetric structures, in which structures are mainly treated by the finite-element method and fluid regions by the boundary element method. The formulation of the present method is described, and the numerical examples are compared with analytical solutions and experimental data. Good agreements between them were obtained.
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  • Yuzuru EGUCHI, Nobukazu TANAKA
    1990 Volume 33 Issue 3 Pages 323-329
    Published: September 15, 1990
    Released: February 18, 2008
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    The present paper describes the fundamental feature of the fluid-elastic vibration of flexible overflow weir, as observed in the French demonstration fast breeder reactor, Super Phenix-1. In the experimental study, the instability criterion of the fluid-elastic vibration was investigated using a simple experimental apparatus of a rectangular tank separated by a flexible weir. A spring-mass model for sloshing motion of liquid contained in the tank was developed to clarify the mechanism of the instability. The instability condition was analytically derived from the equations of the spring-mass model. The equations of the spring-mass model were also computationally integrated in time to simulate the timewise evolution of the fluid-elastic vibration. The comparison between the experimental and theoretical results indicate that the present theoretical model is capable of predicting the general characteristics of the vibration observed in the experiment. The present study revealed that the lag-time of the water fall at the weir is the most influential parameter on the fluid-elastic instability of a flexible overflow weir.
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  • Fumio HARA
    1990 Volume 33 Issue 3 Pages 330-338
    Published: September 15, 1990
    Released: February 18, 2008
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    A small rectangular tank, 600 mm long, 100 mm wide and 800 mm high, was equipped with two vertical pipes (65 mm in outer diameter) at both sides of the tank and filled with water up to 600 mm high. The water in the tank was circulated to produce a flow in water by suction and ejection through holes in the two pipes. The tank was sinusoidally excited to generate sloshing oscillation in the flowing water. The frequency response characteristics of the sloshing amplitude were experimentally obtained for five flow-circulation patterns, and the natural frequencies and modal dampings of the first, second and third sloshing modes were estimated using a conventional modal analysis technique. The results showed that sloshing natural frequency decreased with flow velocity at the water surface and damping increased with it, and the sloshing oscillation disappeared at the critical speed of surface water flow. Approximate analysis of sloshing natural frequency based on potential flow theory gave us the formula f=√<gk tanh kh - U2k2>/2π, k = mπ/1 where 1 = tank width and h = water depth, which off ered a good agreement of the analytical and experimental natural frequencies of sloshing. The mechanism of sloshing wave disappearance at the critical value of surface-flow velocity was discussed.
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  • Shinji HAYAMAH, Yoshiki INOUE, Tatsuo WATANABE
    1990 Volume 33 Issue 3 Pages 339-345
    Published: September 15, 1990
    Released: February 18, 2008
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    As an effective antisloshing device, a reversed U-tube was investigated as a dynamic damper and its suppression characteristics were studied for a cylindrical tank theoretically and experimentally. As a result, it is confirmed that the reverded U-tube works as a dynamic damper to suppress the resonant amplitude of sloshing to less than 1/1O of the undamped amplitudes, when the ratio of the natural frequency of sloshing to that of liquid columns in the U-tube is set nearly equal to unity. When two U-tubes are set symmetrically in a cylindrical tank in a cross configuration they can suppress resonant sloshing against the excitations in any direction. The frequency response of the surface elevation calculated by the Boundary Element Method shows a good agreement with those obtained by the experiments.
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  • Masahiko UTSUMI
    1990 Volume 33 Issue 3 Pages 346-356
    Published: September 15, 1990
    Released: February 18, 2008
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    The equilibrium and dynamic behavior of a liquid in an axisymmetric container at low gravity are investigated. Partial spherical coordinate systems are introduced 1) to express the liquid surface as a single-valued function and 2) to satisfy the compatibility of the liquid surface displacement at the container wall. The former 1) is convenient for the mathematical formulation while the latter 2) is essential to the precise evaluation of the gravity and surface tension potential. The spherical coordinates, moreover, present an analytical method for solving the sloshing problem in various axisymmetric containers, for which it has been customary to resort to numerical methods such as FEM and BEM. The basic equations are obtained from variational principles, by which the surface tension potential can be calculated more efficiently than by using Laplace's law. Numerical results are shown for the equilibrium liquid surface configurations, slosh frequencies and slosh forces.
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  • Nobuyuki OGAWA, Chikahiro MINOWA, Toshio CHIBA, Hiroe KOBAYASHI, Heki ...
    1990 Volume 33 Issue 3 Pages 357-365
    Published: September 15, 1990
    Released: February 18, 2008
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    In order to study piping dynamic response related to internal liquid behaviour and liquid boundary conditions during earthquakes, a large-scale seismic test has been conducted using a 15 m x 15 m shaking table. A test piping system which is 40 m in length and 254 mm in inner diameter was supported by two main and some auxiliary frame structures on the shaking table. A long straight part of the piping system was extended outside of the shaking table and supported by uniaxial smooth-sliding supports. In the vibration test, some conditions of the internal liquid and their effects were investigated. The experimental results showed that the internal liquid behaved dynamically, not as a simple lumped mass, especially under a pressurized condition, and the liquid boundary conditions influenced on the system behaviour during strong excitations.
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  • Takuzo IWATSUBO, Shozo KAWAMURA, Hiroyuki MORI
    1990 Volume 33 Issue 3 Pages 366-370
    Published: September 15, 1990
    Released: February 18, 2008
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    This paper deals with the problem of the design of the piping system. Especially when the statistical properties of uncertainties of the system and those of an earthquake (i.e., its period, magnitude and statistical characteristics of the wave) are known, the statistical properties of the piping vibration can be obtained by using the hierarchy method, which is first applied to the reliability problem by one of the authors. Next a period of the first-passage failure of the piping system is calculated in a statistical sense. It is concluded that the statistical property of the seismic wave has more influence on the reliability than does the damping coefficient or other factors in the piping system.
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  • Katsuaki SUNAKODA, Kohichi AKIMOTO, Toshiyasu UCHI
    1990 Volume 33 Issue 3 Pages 371-375
    Published: September 15, 1990
    Released: February 18, 2008
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    Solid lubricant MoS2 films deposited by radio-frequency sputtering and a new physical process were applied to bearings and ball screws used in seismic support mechanical snubbers. The lubricity of MoS2 films was maintained throughout 720 hours of exposure at a temperature of 200 °C. The endurance life of MoS2 fi1ms using both radio-frequency sputtering and a new physical process was investigated by subjecting the mechanical snubber to a drag force test. Cumulative drag length reached lOO meters and 400 meters, respectively, for the two methods. The dynamic characteristics and durability of mechanical snubbers in an abnormal environment were also investigated.
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  • Eiichi NISHIDA, Kohei SUZUKI, Akira SONE, Masakatsu IMAMURA
    1990 Volume 33 Issue 3 Pages 376-383
    Published: September 15, 1990
    Released: February 18, 2008
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    This paper deals with a modal identification method for large-scale structures such as boiler plants in thermal power stations. Practical and accurate modal identification has been carried out using seismic and microtremor records observed in boiler plants in operation. Based on the multi-input/output identification method, 3-D mode shapes were identified from the microtremor records. They are in good agreement with the results of the FEM simulation. Identification using seismic records was then executed by the following two stages in order to evaluate the amplitude dependence of modal damping ratios : ( 1 ) processing frequency transfer functions by the autoregressive (AR) spectral analysis, and ( 2 ) an extraction of modal parameters by a curve-fitting technique. Introduction of two techniques, namely, decimation of time data and FPE criterion to optimize the order of AR models, have realized effective and accurate identification. As a result of this study, our modal identitication method has proven to be effective for seismic modeling of large scale structures.
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  • Heki SHIBATA
    1990 Volume 33 Issue 3 Pages 384-393
    Published: September 15, 1990
    Released: February 18, 2008
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    This paper deals with the operability of a nuclear power plant under a strong earthquake condition, and also with the necessity of a seismic trigger system for a NPP in relation to human operability under such a condition. There has been discussion on the necessity of a seismic trigger system for a NPP between the U.S. and Japan since the early 1960's. The author has been studying and surveying the operability of operators under seismic conditions by using a shaking table for the last several years. The result of testing indicates that the upper bound of the peak floor acceleration to maintain normal operability is 0.6∼0.7 G. The time sequential analysis of the TMI accident clearly shows that the operator should operate the plant several steps with some judgement for the first thirteen seconds, which is shorter than the duration of average ground shakings. These two facts may lead to the conclusion for the necessity of the seismic trigger system in principle. It is necessary to consider combining the seismic trigger signal and the confirmation signal of the starting-up of the emergency power supply to avoid complete power loss for core cooling. The author considers that the probability of the loss of all power supplies for the residual heat removal system under a destructive earthquake condition is not so low if the seismic trigger system and its logic are not adequately designed.
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  • Takafumi FUJITA, Satoshi FUJITA, Sadanori TAZAKI, Toshikazu YOSHIZAWA, ...
    1990 Volume 33 Issue 3 Pages 394-403
    Published: September 15, 1990
    Released: February 18, 2008
    JOURNALS FREE ACCESS
    This paper summarizes the results of research and development of rubber bearings for seismic isolation carried out by the Institute of Industrial Science, University of Tokyo and Bridgestone Corporation. A series of static tests has been carried out for normal types of rubber bearings of rated loads of 98 kN, 490 kN, 980 kN and 2450 kN. Fundamental characteristics of the rubber bearings such as horizontal and vertical stiffness and capacities of deformations have been clarified by the tests. The same types of rubber bearing have already been implemented in seven base-isolated buildings in Japan. This paper describes the static tests including the breaking tests for the rubber bearings of the 980 kN-rated load. Furthermore, this paper refers to the durability and cluality control of the natural rubber bearings, and the examples of practical implementation in buildings.
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  • Masaki KURIHARA, Kazuyo NISHIMOTO, Masayuki SHIGETA, Yasuo TACHI
    1990 Volume 33 Issue 3 Pages 404-411
    Published: September 15, 1990
    Released: February 18, 2008
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    This paper presents the effects of nonlinear behavior in horizontal stiffness and the decrease in vertical stiffness of rubber bearings on seismic response during large deformation in a horizontal isolation system of nuclear island buildings. This investigation is performed analytically. In order to examine the horizontal and vertical stiffness of full-scale bearings, rubber bearings of 4900 kN (500-ton) rated load are tested within the allowed range of horizontal deformation. To investigate the effect of nonlinear behavior in horizontal stiffness during large deformation, test results of small-scale models which have already been reported are used. Moreover, this paper comments on the design of rubber bearings taking into consideration nonlinear behavior during large deformation and the increase in stiffness due to aging.
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  • Kaoru MIZUKOSHI, Yasuaki FUKUSHIMA, Yasuo TAKENAKA, Masafumi NARIKAWA, ...
    1990 Volume 33 Issue 3 Pages 412-418
    Published: September 15, 1990
    Released: February 18, 2008
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    This paper describes an analytical evaluation of the effect of torsional motion on seismic responses of base-isolated FBR buildings which were designed conceptually in an applicability study of base isolation systems. Dynamic response coupling with torsional motion induced by obliquely incident earthquake input and by eccentricity in the structure was evaluated by response analyses, taking the biaxial nonlinearity of base isolation devices into account. As a result, it is shown that the effect of the torsional motion on the response of the building, devices, and the floor response spectra is not so large from a seismic design standpoint.
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  • Katsuhisa FUJITA, Mamoru TANAKA, Masaaki NAKAMURA, Yonezo TSUJIKURA
    1990 Volume 33 Issue 3 Pages 419-426
    Published: September 15, 1990
    Released: February 18, 2008
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    The present paper aims to verify the seismic safety of the base-isolated spent-fuel storage rack. A series of seismic tests has been conducted using a three-dimensional shaking table. A sliding-type base-isolation system was employed for the prototype rack considering environmental conditions in an actual plant. A non linear seismic response analysis was also performed, and it is verified that the prototype of a base-isolated spent-fuel storage rack has a sufticient seismic safety margin for design seismic conditions from the viewpoint of seismic response.
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  • Takafumi FUJITA, Yukio SASAKI, Shigeru FUJIMOTO, Chiaki TSURUYA
    1990 Volume 33 Issue 3 Pages 427-434
    Published: September 15, 1990
    Released: February 18, 2008
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    This paper presents results obtained from experimental and analytical studies to evaluate isolation performances of a lead rubber bearing as a hysteretic damper. In the experiment, vibration tests were first carried out using a 0.3 scale model (5840 kg mass and 2.2 m x 2.2 m x 1.8 m size) for a base-isolated building which was supported by 2 lead rubber bearings and 2 rubber bearings, in order to investigate the isolation performances of the lead rubber bearings in actual seismic wave excitations. Second, static loading tests were implemented in order to examine restoring force characteristics for the lead rubber bearing. In the analysis, seismic response analyses for the scale model, regarding the vibration tests using the actual seismic waves, were carried out to evaluate the response analytical method for the base-isolated system using the lead rubber bearings. From these results, the following is claritied. ( 1 ) Analytical results for the isolated-building model agree well with experimental results. ( 2 ) The lead rubber bearing reduces the responses sufticiently for the isolated building, and controls the responses well for installed equipment in a practical frequency range.
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  • Yohji OKADA, Ryuichi OKASHITA
    1990 Volume 33 Issue 3 Pages 435-440
    Published: September 15, 1990
    Released: February 18, 2008
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    An actively controlled vibration damper is introduced to increase the damping and robustness of the damper. Its main defect is its poor reliability under extended operation time. This paper introduces a moving coil type active damper. The state feedback is used to damp the system the most efficiently, while the band-pass feedback compensates for certain frequency excitations; simultaneously, time-domain identification is applied to evaluate the dynamic property of the actively controlled structure. The identified characteristics are used to tune the damping controller and, also, to determine the emergency stopping point of the active damper when the control algorithm fails to reduce the vibration. The proposed system is applied to a simple experimental structure and its capability is tested.
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  • Shinya KIJIMOTO, Akio NAGAMATSU, Kazuto SETO, Youichi KANEMITSU
    1990 Volume 33 Issue 3 Pages 441-445
    Published: September 15, 1990
    Released: February 18, 2008
    JOURNALS FREE ACCESS
    In order to control vibration, many mechanical structures have recently begun using active elements. Up to now, in cases of designing such structures, structural analysis and design of the controller were carried out separately, and a controller was apt to become too complex. This paper investigates a design method that can use both vibration analysis and the controller design. This method is to design a controller by using both the transfer functions of the controller and whole structure.
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  • Yuichi SATO
    1990 Volume 33 Issue 3 Pages 446-452
    Published: September 15, 1990
    Released: February 18, 2008
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    This paper describes a technique to suppress vibrations of a structure under excitation by attaching a hollow rotor partially filled with liquid. The rotor rotates about an axis parallel to the direction of vibration. Assuming the fluid motion is axially symmetric, we analyze the motion of the fluid and structure. The influence of the shape of a chamber of the rotor, the amount of liquid and the ratio of rotor speed to exciting frequency on vibration control is lnvestigated. The condition in which the hollow rotor acts as an dynamic absorber is clarified. The effectiveness of the proposed dynamic absorber is demonstrated experimentally. The theoretical results agree with the experlmental ones.
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  • Kazuto SETO, Katsumi SAWATARI
    1990 Volume 33 Issue 3 Pages 453-459
    Published: September 15, 1990
    Released: February 18, 2008
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    This paper proposes a method of noise reduction by controlling the vibration of a wall between two rooms by an active control device. This is done by using an additional sensor to measure the wall vibration and feed it back to the controller. The board speaker is used primarily to generate sound by exciting the board. However, in this study, it is used as an active vibration control device. The performance of the device is tested on a panel made from a veneer board 1200 x 900 x 5 mm in size which is exposed to sound vibration from the other speaker. The evaluation of this method is performed experimentally by comparison of the dynamic deflection of the panel with and without the device. The experimental results show a significant reduction level to 1/10 of the panel dynamic deflection at frequencies below 100 Hz. The effectiveness of the method is confirmed theofetically by simulation studies. Also, the stability of the control system using the active control device is examined through the root locus method.
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