Experimental Study in to Passive Auto-Tuning Compound Pendulum Mass Damper
No Thumbnail Available
Date
2020-02
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Addis Ababa University
Abstract
Now a days, the numbers of taller and lighter structures are continuously increasing in the
construction industries which are flexible and having a very low damping value. Those
structures can easily fail under structural vibrations induced by earthquake and wind.
Therefore several techniques are available today to minimize the vibration of the structure,
out of which concept of using Passive auto-tuning compound pendulum mass damper
(PATCPMD) is a newer one. There are in general large numbers of studies on theoretical
investigation of behaviour of buildings with tuned mass dampers under various impacts.
However, the experimental studies in this area are quite limited. In this thesis, A two-story
steel test model structure was used to carry out the experimental study. The PATCPMD was
suspended first in the upper and second in the lower story of the structure to be controlled by
a group of ropes in the manner that they form compound pendulum but not exactly a
compound pendulum and was free to move in any translational direction.
First, the PATCPMD efficiency tests was carried out, whereby the test model was subjected
to translational, torsional and coupled free vibration tests and translational forced harmonic
vibration tests, initially without the PATCPMD and then with the PATCPMD at different
story of the primary model structure, in order to determine the damping effects of the
PATCPMD and to determine the better effect of the PATCPMD with respect to location. The
results demonstrate that it is capable of providing significant control of translational, torsional
and coupled vibrations of the structure without being tuned in both cases. However, a better
effect was observed when the PATCPMD was suspended on the second story.
Secondly, Once the better effect of the PATCPMD with respect to location was determined,
a parameter study was carried out whereby the dynamic properties of the primary test model
was varied whilst the PATCPMD is left unchanged. The free and forced vibration tests
were repeated, without any tuning of the system taking place. Furthermore, the result
demonstrates the PATCPMD’s effectiveness under different conditions of the system,
without having undergone any tuning. Finally, the PATCPMD was suspended on to the test
model on three different connection patterns so as to investigate the better effect out of them.
Again a positive results were obtained with this regard. However, pattern 1 has got a better
efficiency among the others two. In general the study shows that the PATCPMD is robust,
simple and versatile making it an ideal application for engineering structures.
Description
Keywords
Auto-Tuning Compound, Mass Damper, Passive