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Vertical vibration isolator having piecewise‐constant restoring force
Author(s) -
Araki Yoshikazu,
Asai Takehiko,
Masui Takeshi
Publication year - 2009
Publication title -
earthquake engineering and structural dynamics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.218
H-Index - 127
eISSN - 1096-9845
pISSN - 0098-8847
DOI - 10.1002/eqe.915
Subject(s) - isolator , restoring force , piecewise , constant (computer programming) , earthquake shaking table , vibration isolation , vibration , stiffness , structural engineering , acceleration , engineering , control theory (sociology) , physics , computer science , classical mechanics , mathematics , mathematical analysis , acoustics , electrical engineering , control (management) , artificial intelligence , programming language
We present a vertical vibration isolator having a piecewise‐constant restoring force, which belongs to a class of passive and nonlinear vibration isolators. In vertical vibration isolation, direct use of low‐stiffness elements leads to unacceptably large deformations due to self‐weight. To overcome the difficulty, we apply a combination of constant‐force springs, each of which sustains a constant load regardless of its stretch. By arranging the constant‐force springs, so that the isolator has a piecewise‐constant restoring force, we alleviate the problem of the excessive deformation caused by self‐weight, provide stability at the static equilibrium state along with the self‐centering capability, and realize a large stroke while keeping the mechanism simple and compact. Further, we attempt to limit the response acceleration within a tolerance regardless of the frequency spectrum and the magnitude of earthquake ground motions. We demonstrate the effectiveness of the present isolator through shaking table tests and numerical simulations. Copyright © 2009 John Wiley & Sons, Ltd.