- Natural frequency range: 0.17 – 2.5 Hz
- Vertical Motion Isolation:
It uses a conventional spring connected to a Negative Stiffness Isolator (NSI) consisting of two bars hinged at the center. The stiffness of the isolator is K=KS-KN where KS is the spring stiffness and KN is the magnitude of a negative-stiffness which is a function of the length of the bars and the load P.
Image reproduced from [1]
- Horizontal Motion Isolation:
The beam-columns have horizontal stiffness Ks with the weight load applied laterally. Due to this the lateral bending stiffness is reduced by the "beam-column" effect. This behavior is equivalent to a horizontal spring combined with an NSI so that the horizontal stiffness is K=Ks-Kn, and Kn is the magnitude of the beam-column effect.
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