Language：English   Publishing type：Research paper (scientific journal)   Publisher：Hindawi Limited  

DOI： 10.1155/2018/3762784

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Mechanical Engineers  

<p>In this paper author proposed a unique vibration suppression device that has variable inertia mass using continuously variable transmission (CVT) in order to obtain vibration isolation when a harmonic frequency was coincided with an anti-resonance frequency of 1DOF system. The device complies a ball screw mechanism, a flywheel, servo motors and CVT. The CVT is composed of toroidal wheels and power transmission wheels. The device has a small inertia force when an attitude angle of the power transmission is low by the servo motor as depending on a contact radius between two half toroidal wheels, on the other hand the large inertia force under high angle, so variable inertia force which acts as series inertia mass can be controlled continuously. The trial device was manufactured and the resisting force characteristics were measured. Theory of the variable inertia force was introduced, and compared with the experimental results. In order to confirm vibration control, an optimized inertia mass which always adjusts to anti-resonance frequency was determined in case of 1DOF system with the device, frequency response tests were carried out by using a shaking table, and experimental results were compared with calculated ones. Finally, the theory of resisting force and effects of vibration suppression were confirmed.</p>

DOI： 10.1299/transjsme.17-00292

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1299/mej.15-00731

Web of Science

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Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1002/stc.1770

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Authorship：Lead author,　Corresponding author   Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Mechanical Engineers  

The authors propose an absorber that generates electrical power in order to not only suppress vibration but also get electrical energy when many traffic signal poles are oscillated by wind, traffic turbulence. The absorber consists of a displacement magnifying mechanism by using levers, solenoid coils and rare-earth magnets. It is useful for small deformation between a beam and a column of the traffic pole. Vibration modes of the pole are analyzed by using FEM, and then a small scale model of the traffic pole is built up. The small scale model has 2.7 m high, consists of a steel column and a cantilever beam due to rescale about 1/3 times of a real scale model, and the natural frequency of first mode is arranged to 3.5 Hz. Trial absorber is manufactured and a damping force, which is caused by the coils crossing magnetic field, is adjusted. Dynamic characteristics of the trial absorber are measured by a shaking actuator. In order to confirm vibration reduction and energy conversion, harmonic vibration test of small scale model when the trial absorber is installed is carried out by using a shaking table. The experimental results of the harmonic responses are compared with the calculated results which are derived by FEM. Effect of vibration suppression and efficiency of generating electrical power are evaluated experimentally and numerically.

DOI： 10.1299/transjsme.14-00608

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Mechanical Engineers  

In this paper, a new type of small seismic isolation table using coil springs, which has a simple construction and the capability of vibration isolation in every horizontal direction, is proposed. A table board supported with roller bearings is pulled almost vertically toward a base board with four coil springs. The coil springs give horizontal restoring force and friction force to the table board when the table moves relatively to the base board. The trial small seismic isolation table is manufactured, and the resisting force characteristics are measured. The numerical results are derived theoretically and compared with the experimental results. Harmonic response test and seismic response tests are carried out by using a shaking table in order to confirm the effect of vibration isolating under some earthquakes that have several periodic component. The experimental and calculated results show that the maximum response accelerations of the table board with a loaded mass decreased to about 1/10 ~ 1/12 compared to those without the isolation table.

DOI： 10.1299/transjsme.14-00607

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Mechanical Engineers  

DOI： 10.1299/transjsme.2014dr0239

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Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1002/eqe.2355

Web of Science

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Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1002/stc.1581

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Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1115/1.4007033

Web of Science

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Mechanical Engineers  

DOI： 10.1299/kikaic.78.2733

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Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1002/stc.375

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Mechanical Engineers  

An integrated design method of structural and semi-active control systems for civil structures is presented. The Vibration Control Device (VCD) that has been developed by authors is used as the semi-active control device. A new semi-active control method, which is referred to as the <I>inverse Lyapunov approach</I>, is proposed. In the inverse Lyapunov approach we firstly assume a bang-bang type semi-active control law based on an unknown Lyapunov function. The Lyapunov matrix that defines the Lyapunov function is optimized so that quantitative performance measures on vibration suppression of civil structures are optimized. The control design problem of the semi-active control law in the inverse Lyapunov approach results in an optimization problem of the Lyapunov matrix to construct the Lyapunov function. In the present study, in addition to the design parameters to determine the Lyapunov matrix, structural design parameters, the stiffness between neighboring two floors of the structural system itself and the parameters of the VCD, are optimized simultaneously so that the structural responses subject to recorded and/or artificial earthquake waves are optimized in the sense of the specifications on vibration suppression of civil structures. We adopt the Genetic Algorithm (GA) to get the optimal Lyapunov matrix and the structural design parameters.

DOI： 10.1299/jsdd.5.665

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Mechanical Engineers  

DOI： 10.1299/jsdd.4.928

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Mechanical Engineers  

DOI： 10.1299/jsdd.4.928

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Mechanical Engineers  

We propose a semi-active control of civil structures based on a one-step-ahead prediction of the seismic response. The vibration control device (VCD), which has been developed by authors, generates two types of resistance forces, i.e., a damping force proportional to the relative velocity and an inertial force proportional to the relative acceleration between two stories. The damping coefficient of the VCD can be changed with a command signal to an electric circuit connected to the VCD. In the present paper the command signal for changing the damping coefficient of each VCD is assumed to take two values, i.e., the command to take the maximum or minimum damping coefficient. The optimal command signal is selected from all candidates of command signals so that the Euclidean norm of the one-step-ahead predicted seismic response, calculated by a numerical integration, is minimized. As an example a semi-active control of a fifteen-story building with three VCDs is considered. The simulation results show that the proposed semi-active control achieves superior performance on vibration suppression compared with a passive control case where the damping coefficient of each VCD is fixed at its maximum value.

DOI： 10.1299/jsdd.4.103

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Mechanical Engineers  

DOI： 10.1299/kikaic.76.1171

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Mechanical Engineers  

DOI： 10.1299/kikaic.76.1193

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Mechanical Engineers  

The authors have developed a vibration control device (VCD) using an electromagnetic damping. The device has an inertial force generated by a flywheel, and a damping force derived from an energy dissipation of a power generator. The small scale experimental model was manufactured, and the vibration tests were carried out. In this paper, for the purpose of applying the device to a large structure, new two VCDs of 30kN load range are developed, and shipped to NCREE in Taiwan. In order to investigate the dynamic properties of the VCD, performance tests are carried out, and the resisting force characteristics are measured. And vibration tests of 3-story structure with the VCDs are carried out by using a shaking table. The 3-story structure has 9m height, 3m width, and 18 tons weight. Seismic responses at each story are measured in cases of passive or semiactive type. The VCDs are controlled by Bang-Bang control which is based on minimizing the time derivative of the Lyapunov function. The effects of vibration suppression using the VCD are confirmed experimentally.

DOI： 10.1299/kikaic.75.2659

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Mechanical Engineers  

In this paper, a new type of arm-type damper consisting of two links and three joints (human type joints with friction) has been developed. The damper is able to suppress six modes of vibration of a machine, three in translational modes and three in rotational modes. The trial damper was made and its resisting force characteristics in three translational and three rotational directions were discussed theoretically and experimentally. The seismic responses of a three-degree-offreedom translational system and a two-degree-of-freedom translational-rotational system and the frequency responses of a single-degree-of-freedom translational system, which consist of a mass and four coil springs and supported by the damper, were measured using a three-dimensional permanent magnet type shaking table. The experimental results were compared with the calculated ones, and the effects of vibration suppression of the damper in three translational and rotational directions and the propriety of the calculations were confirmed.

DOI： 10.1299/jsdd.3.391

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Mechanical Engineers  

DOI： 10.1299/kikaic.75.2893

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Mechanical Engineers  

DOI： 10.1299/kikaic.73.3179

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Authorship：Lead author   Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Mechanical Engineers  

DOI： 10.1299/kikaic.73.2926

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Architectural Institute of Japan  

DOI： 10.3130/aijs.72.33_4

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Mechanical Engineers  

DOI： 10.1299/kikaic.73.479

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Authorship：Lead author   Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Mechanical Engineers  

DOI： 10.1299/kikaic.72.1056

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Mechanical Engineers  

DOI： 10.1299/kikaic.70.2822

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Mechanical Engineers  

In previous papers, the authors proposed two types of passive dampers using a lever-type displacement magnifying mechanism. One is a magnetic damper using rare-earth magnets and the other is a viscoelastic-friction damper using acrvlic viscoelastic material. In this paper, a new type of hybrid damper using a lever-type displacement magnifying mechanism, giant magnetostrictive actuators and rare-earth magnets is proposed. The hybrid damper generates controllable friction force together with magnetic damping force which acts as a fail-safe mechanism in case of control system trouble, and is suitable for vibration in the region of amplitude 0.1〜10 mm. The trial damper was made and the resisting force characteristics were measured. The seismic responses of a three-dimensional piping system supported by the damper were measured using an electrohydraulic type shaking table. The experimental results are compared with the calculated results obtained by the finite element method (ANSYS), and the effects of vibration suppression of the hybrid damper are discussed. Moreover, these experimental and calculated results are compared with those obtained for a semiactive friction damper (which is one removed the rare-earth magnets from the hybrid damper) and a passive magnetic damper (which is one removed the giant magnetostrictive actuators from the hybrid damper).

DOI： 10.1299/kikaic.69.2026

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Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Mechanical Engineers  

In this paper, a new type of arm-type friction damper with two links and three joints (two universal joints and a hinge) has been developed. The friction damper is able to suppress six modes of vibration of a machine, three in translational modes and three in rotational modes. The trial friction damper was made and the resisting force characteristics in the three translational directions were discussed theoretically and experimentally. The seismic responses of a two-degree-of-freedom system and a three-degree-of-freedom system consisting of a mass and four coil springs and supported by the friction damper were measured using a two-dimensional electrohydraulic type shaking table. The experimental results are compared with the calculated ones, and the effects of vibration suppression of the friction damper in two or three translational directions are discussed.

DOI： 10.1299/kikaic.69.335

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Authorship：Lead author   Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Japan Society of Mechanical Engineers  

DOI： 10.1299/kikaic.68.2896

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：IOS Press  

DOI： 10.3233/jae-2002-321

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Language：English   Presentation type：Oral presentation (general)  

Venue：Hawaii, USA  

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Venue：Vancouver, Canada  

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Language：English   Presentation type：Oral presentation (general)  

Venue：Vancouver, Canada  

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Venue：Boston, USA  

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Venue：Boston, USA  

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Venue：Anaheim, USA  

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Venue：Paris, France  

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Language：English   Presentation type：Oral presentation (general)  

Venue：Paris, France  

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Venue：Toronto, Canada  

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Venue：Washington DC, USA  

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Venue：Baltimore, USA  

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Venue：Bellevue, USA  

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Language：English   Presentation type：Oral presentation (general)  

Venue：Baltimore, USA  

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Language：English   Presentation type：Oral presentation (general)  

Venue：Prague, Czech Republic  

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Language：English   Presentation type：Oral presentation (general)  

Venue：Prague, Czech Republic  

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Language：English   Presentation type：Oral presentation (general)  

Venue：Chicago, USA  

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Venue：Vancouver, Canada  

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Language：English   Presentation type：Oral presentation (general)  

Venue：Vancouver, Canada  

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Language：English   Presentation type：Oral presentation (general)  

Venue：Vancouver, Canada  

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Language：English   Presentation type：Oral presentation (general)  

Venue：Vancouver, Canada  

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Language：English   Presentation type：Oral presentation (general)  

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