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On the performance of gyro‐mass devices for displacement mitigation in base isolation systems
Author(s) -
Saitoh Masato
Publication year - 2012
Publication title -
structural control and health monitoring
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.587
H-Index - 62
eISSN - 1545-2263
pISSN - 1545-2255
DOI - 10.1002/stc.419
Subject(s) - displacement (psychology) , damper , base isolation , acceleration , tuned mass damper , base (topology) , engineering , structural engineering , control theory (sociology) , computer science , physics , mathematics , mechanical engineering , mathematical analysis , classical mechanics , control (management) , frame (networking) , artificial intelligence , psychotherapist , psychology
SUMMARY This study presents the performance of a so‐called ‘gyro‐mass’ provided for mitigating displacements of base isolation systems. The gyro‐mass generates a reaction force due to the relative acceleration of the nodes between which it is placed. This study assesses three types of systems incorporating a gyro‐mass, in the frequency domain and in the time domain. Numerical studies with various types of earthquake waves show that, although the systems tend to reduce the lateral displacements, they still generate large displacements when subjected to an observed earthquake wave containing long‐period components, except a system proposed in this study. The gyro‐mass device in the proposed system is composed of two units arranged in series: one unit consists of a gyro‐mass and damper arranged in parallel; and the other unit consists of a spring and damper arranged in parallel. It is found that the damper arranged in parallel with the gyro‐mass has a large effect on decreasing the lateral displacements of the system when subjected to long‐period earthquake waves. This study presents closed‐form formulae derived based on idealized simple models of the base isolation systems incorporating gyro‐masses. Moreover, matrix expressions of the models are also presented for estimating the time‐history of responses in the systems. Copyright © 2010 John Wiley & Sons, Ltd.