Vibration and Acoustics Research Journal (VARJ)

Research Article

Implementation of the KDamper as a Stiff Seismic Absorption Base: A Preliminary Assessment

Konstantinos A. Kapasakalis¹, Ioannis A. Antoniadis² and Evangelos J. Sapountzakis¹

¹Institute of Structural Analysis and Antiseismic Research, School of Civil Engineering, National Technical University of Athens, Zografou Campus GR-157 80, Athens, Greece.

²Dynamics and Structures Laboratory, Mechanical Engineering Department, National Technical University of Athens, Zografou Campus GR-157 80, Athens, Greece.

Submitted: August 2, 2019; Accepted: December 20, 2019

Abstract

This study proposes a novel base isolation approach, based on the KDamper concept. The KDamper is a passive vibration absorption concept, based essentially on the optimal combination of appropriate stiffness elements, one of which has a negative value. A spectra driven optimization of the KDamper nominal frequency for implementation in a typical 3-story concrete building structure is proposed. The effect of the KDamper nominal frequency to the system transfer functions, power spectral densities, and root mean square responses are examined. Two alternative options for the implementation of the KDamper are considered. In the first one, the nominal KDamper frequency is selected equal to the low frequency of a conventional base isolation system, resulting in a drastic improvement of the superstructure dynamic performance. The second one foresees the implementation of the KDamper with a much higher nominal frequency. This leads to a drastic reduction of the base relative displacement, in the order of a few centimeters, combined with an acceptable superstructure dynamic behavior. The results are evaluated in the time domain and indicative designs of the KDamper devices prove that the stiffness values, as well as the additional mass and the artificial damper, are within reasonable technological capabilities. Finally, it is proven that the results of the non-linear proposed configuration are in a very good agreement to that of the initial linear problem. As a consequence, the KDamper can be implemented as a “stiff seismic absorption base”, as an alternative to conventional base isolation approaches.

Keywords

Vibration Control; Negative Stiffness; Seismic Protection; KDamper.

Downlaod Full Text >>