Title

Numerical and Experimental Analyses of Actively Controlled Pendulum Tuned Mass Damper

Date of Award

1-1-2018

Degree Name

Ph.D. in Mechanical Engineering

Department

Department of Mechanical and Aerospace Engineering and Renewable and Clean Energy

Advisor/Chair

Advisor: Reza Kashani

Abstract

Modern structures such as floor systems, bridges, and high-rise buildings have become lighter in mass and more flexible with negligible damping and thus prone to vibration. Extensive studies have been carried out by various researchers to mitigate the unwanted structural vibration caused by human activities, machinery, and environmental effects (wind and seismic). Various vibration control devices and strategies have been developed and used to abate the unwanted vibration and to increase the serviceability level of such structures. In this research, semi-active control strategies have been developed to a) adjust the tuning frequency and b) introduce damping into an air-suspended pendulum tuned mass dampers (ASTMD). The system is made up of air springs, a proportional valve to control the flow of air in and out of the air springs, and a pendulum. The tuned damping system is designed, built, and evaluated numerically and experimentally. The focus of this work has been the synthesis and analysis of the control algorithms and strategies to vary the tuning accuracy, introduce damping into air suspended ASTMD, and to enable the ASTMD to self-tune itself. The acceleration of the main structure and ASTMD as well as the pressure in the air springs are used as the feedback signals in two different control strategies.The outcome of this research showed that the semi-actively controlled ASTMD dissipates the undesirable vibration, efficiently. This results showed that control strategy 1 (controlling air flow to and from the auxiliary air springs) is more effective than control strategy 2 (controlling air flow to and from the main air spring). The ASTMD's performance is improved, by feeding back the main structure's acceleration, in a cascading manner with the above-mentioned semi-active control strategies. Finally, the use of the self-tuning algorithm is shown to be a very effective techniques in improving the performance of the ASTMD. This technique allows that the ASTMD to autonomously re-tune itself and adapt to any change in the natural frequency of the main structure.

Keywords

Mechanical Engineering, Semi active tuned mass damper, structural vibration, Air spring, Pendullum

Rights Statement

Copyright 2018, author

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