Intelligent seismic isolation system using air bearings and earthquake early warning

Fujita, Satoshi; Minagawa, Keiji; Tanaka, Go; Shimosaka, Haruo

doi:10.1016/j.soildyn.2010.06.006

Cited by 25 publications

(8 citation statements)

References 3 publications

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“…Another type of hybrid device is the intelligent hybrid multidimensional mitigation and isolation device. Fujita et al (2011) studied the basic property and performance of an intelligent three-dimensional isolation system encompassing air bearings and an earthquake early warning system, which indicates that this system is suitable for earthquakes in multiple directions and complex situations, even against near-field earthquakes. MR damper is also considered to be an effective intelligent control method.…”

Section: Hybrid Multi-dimensional Mitigation and Isolation Devicementioning

confidence: 99%

Recent Advances in Multi-Dimensional Vibration Mitigation Materials and Devices

Chen

Zhou

et al. 2019

Front. Mater.

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Harmful vibrations can cause many engineering problems, such as disasters of civil engineering structures, failure of precision equipment, and the disruption of some spacecraft components. In most situations, the vibrations are usually three-dimensional excitations. Therefore, research on multi-dimensional vibration control has become a worldwide hotspot in engineering. This article presents a comprehensive assessment of recent developments of multi-dimensional vibration mitigation devices and the material applied in such devices. The vibration mitigation materials mainly include the passive vibration mitigation materials and smart vibration mitigation materials. Subsequently, the vibration mitigation devices in civil engineering, mechanical engineering, and aerospace engineering are reviewed and commented, respectively. Above all, the multi-dimensional vibration mitigation devices and materials are found to be effective for reducing multi-dimensional vibrations. However, enhancing the mitigation performance of the devices in each direction, including improving the mitigation capability of materials, is still a challenging issue.

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Section: Hybrid Multi-dimensional Mitigation and Isolation Devicementioning

confidence: 99%

Recent Advances in Multi-Dimensional Vibration Mitigation Materials and Devices

Chen

Zhou

et al. 2019

Front. Mater.

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“…Using eigenvector fU i g, the displacement vector fUg of the whole structure of n-degrees-of-freedom can be expressed as Eq. 11 (Chopra 1995):…”

Section: Recurrence Relations Applied To Active Controlmentioning

confidence: 99%

“…Concerning point (2), whenever an earthquake occurs in Japan, the Earthquake Early Warning System provides advance warning of estimated seismic intensities and the time when the principal motion is expected to arrive. This system has been in operation around the country since 2007 (Megro and Fujinawa 2007;Fujita et al 2011). These estimations are based on the prompt analyses using wave-form data observed by seismographs near the epicenter.…”

Section: Introductionmentioning

confidence: 99%

Improving Active Preview Control System of Structures Using Online Prediction of Seismic Waves

Tsuji

Nakamura

2016

J. Eng. Mech.

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This paper presents a study on the applicability of the preview control method for improving the performance of active seismic control systems. The active preview control method is examined as described for its ability to improve vibration suppression as follows: (1) the relation between the number of preview steps and the degree of improvement in control performance is clarified by analysis using predicted earthquake waves, and (2) to evaluate the applicability to an actual structure, predicted surface seismic waves are calculated by an autoregressive model from observed KiK-net data on 100-200-m-deep underground seismic waves and the applicability of the method is confirmed.

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“…(2006), Xu et al. (2006), Nagarajaiah and Sahasrabudhe (2006), Pnevmatikos and Gantes (2010), Kim (2011), Fujita et al. (2011), Lu et al.…”

Section: Numerical Illustrationmentioning

confidence: 99%

Frequency-dependent optimal control in independent modal space for seismic response control of structures

Chakraborty

Ray-Chaudhuri

2014

Journal of Vibration and Control

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In this study, a frequency-dependent algorithm is proposed in independent modal space as an improvement to the linear quadratic Gaussian (LQG) control algorithm. The passive control parameters such as mass, stiffness and damping of a dynamic system are sensitive to different frequency ratios when subjected to external excitation. Depending upon the sensitivity of these parameters, the algorithm is developed in such a way that a response reduction similar to that of an LQG algorithm can be achieved with a significantly smaller control force. An effective gain is obtained by optimizing the H2 norm of the transfer function. It is observed from the results that the algorithm works well for high frequency ratio and near resonance regimes. Thus, a combination of the LQG and the proposed algorithms is considered as a modified LQG control algorithm, where the effectiveness of both algorithms is utilized. The efficiency of the modified LQG control algorithm is demonstrated by considering a base-isolated structure when subjected to earthquake base excitations. By comparing with the results it is observed that the modified LQG control algorithm is more efficient in terms of response reduction with a much lower control force as compared to the LQG control algorithm. It is envisioned that the modified LQG control algorithm will be highly useful for response control of base-isolated structures.

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Intelligent seismic isolation system using air bearings and earthquake early warning

Cited by 25 publications

References 3 publications

Recent Advances in Multi-Dimensional Vibration Mitigation Materials and Devices

Recent Advances in Multi-Dimensional Vibration Mitigation Materials and Devices

Improving Active Preview Control System of Structures Using Online Prediction of Seismic Waves

Frequency-dependent optimal control in independent modal space for seismic response control of structures

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