• Structural Engineering and Mechanics
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• v.82 no.3
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• pp.283-294
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• 2022

An inerter is a passive mechanical element whose inertance can be thousands of times its own physical mass. This paper discusses the application of an inerter-based passive control system, termed rotational inertial double-tuned mass damper (RIDTMD), to mitigate human-induced floor vibrations. First, the acceleration frequency response function of the floor with an RIDTMD is first derived. It is then employed to determine the optimal design parameters of the RIDTMD using the extended fixed-points technique. Based on a theoretical analysis, design-oriented empirical functions are proposed for the RIDTMD optimal parameters, whose performance for floor vibration control is evaluated by numerical examples, in which three typical human-induced load types are considered: walking, jumping, and bouncing. The results indicate that the applicability and effectiveness of the RIDTMD for human-induced floor vibration control are robust for various load types, load frequencies, and floor natural frequencies. For the same mass ratio, the RIDTMD is better than the TMD in reducing the floor vibration amplitude and improving the effective frequency suppression bandwidth, and for the same vibration suppression effect, the mass of the RIDTMD is much lighter than that of the TMD.

• Journal of the Society of Naval Architects of Korea
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• v.32 no.1
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• pp.94-102
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• 1995

The active control system of structural vibration using a hydraulic actuator is developed. The developed system consists of three parts : a hydraulic unit, an actuator unit and a control unit. Structural vibration is sensored by the accelerometer attached to the structure and reduced by the optimally controlled motion of active mass giving anti-phase inertia force to the structure. It is experimentally confirmed that the vibration level of model structure is reduced to about 1/6 by the developed active control system.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.23 no.1
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• pp.9-15
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• 2010

In this paper, dynamic modeling of hull structure including surface-bonded piezoelectric composite actuator was developed and structural vibration control performance was evaluated. Cylindrical shell structure with end-caps was considered as a host structure which could be used as a simple model of fuselage of aircraft and underwater vehicles. An advanced piezoelectric composite, macro-fiber composite(MFC), which has been developed in NASA Langley Research Center was applied for the effective structural vibration control. MFC has great flexibility by using piezoceramic fiber sheet and enhanced piezoelectric effect for in-plane motion by utilizing interdigitated electrode. Governing Equations were derived from the finite element model and modal characteristics were investigated. Modal test was conducted to verify the finite element model. Optimal controller was designed and implemented for the evaluation of vibration control performance. Structural vibration was controlled effectively by applying proper control input to the piezoelectric actuators.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.10a
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• pp.251-255
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• 2012

Structural intensity has been mainly utilized to identify vibration energy flow in a vessel. In this paper, the structural intensity of a shuttle tanker subjected to H-moment of the main engine was calculated using a finite element model. From the analysis, it was found that the top-bracing elements, which support the main engine onto the hull structure to prevent the excessive transverse vibration of the main engine, play the role of the dominant path and sink for vibration energy flow from the main engine. Therefore, the structural intensity was controlled by the modification of stiffness and damping characteristics of the top-bracing elements. As a result, it is observed that the transverse vibration level at the center of navigation bridge deck decreased after the control of structural intensity.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.13 no.8
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• pp.651-657
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• 2003

A new mechanical-electrical hybrid passive damping treatment is proposed to improve the performance of structural vibration control. The proposed hybrid passive damping system consists of a constrained layer damping treatment and a shunt circuit. In a passive mechanical constrained layer damping, a viscoelastic material damping layer is used to control the structural vibration modes in high frequency range. The passive electrical damping is designed for targeting the nitration amplitude in the low frequency range. The governing equations of motion are derived through the Hamilton's principle. The obtained mathematical model Is validated experimentally. The presented theoretical and experimental techniques provide invaluable tools for controlling the multiple modes of a vibrating structure over a wide frequency band.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.11 no.4
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• pp.37-42
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• 2001

Active vibration control of laminated composite plates has been carried out to design structure with maximum possible damping capacity, using piezoceramic sensor/actuators and passive constrained-layer damping treatment. The equations of motion are derived for symmetrical, multi-layer laminated plates. The damping ratio(ζ) and modal damping(2ζ$\omega$) of the first bending and torsional modes are calculated by means of iterative complex eigensolution method for both passive and active vibration control. This paper addresses a design strategy of laminated composite plate under structural vibrations.

• Journal of KSNVE
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• v.7 no.2
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• pp.311-317
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• 1997

In this paper the active vibration control system using a linear oscillatory actuator(LOA) is studied to suppress structural vibration. In the LOA, the AC-power-energized armature generates a shift field in an air gap, which produces a oscillating force to the mover in the magnetic field generated by high density permanent magnets. LOA has relatively simple structure with almost maintenance free, compared with a hydraulic actuator. Performance test of the active vibration control system using a LOA is carried out on a steel test structure under base excitation. From this test, it is confirmed that the acceleration level of the test structure is drastically reduced near the resonant region.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1993.10a
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• pp.232-239
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• 1993

The vibration damping of structure is increased by thermal actuator. The thermal actuator causes thermal stress across the section of structure. The several kinds of control theories are proposed and the proposed control theories are successful in increasing vibration damping. This scheme can be effectively applied to large space structure [LSS] having very low natural frequencies.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2003.04a
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• pp.348-354
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• 2003

This study outlines the analysis of toggle system and the vibration control performance when the toggle-rotational inertia damper system was applied to a structure. Numerical analysis shows that the relative displacement of the structure can be amplified by amplification mechanism of the toggle system and the capacity of the damper can be reduced without the loss of vibration control performance. It is also observed that vibration control effects is caused by the increase of equivalent mass due to the rotational inertia of damper.

• International Journal of High-Rise Buildings
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• v.8 no.3
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• pp.201-209
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• 2019

This paper presents a structural design of the "(Tentative Name) Toranomon Hills Residential Tower" which is currently under construction in Tokyo. The building is a reinforced concrete high-rise residential complex building with 54 stories above ground, 4 basement levels, and a building height of about 220 m. It is a requirement to provide the highest grade of residence in Japan, and in terms of the structural design, it is required to provide wide and comfortable spaces with high seismic performance. These requirements are satisfied by providing a total of 774 vibration control walls of two types. Also, to further improve the structural performance, steel fibers at the rate of 1.0vol% are provided in the ultra-high strength concrete used in the column members.