| Author | Hoang Nam |
| Call Number | AIT Diss no.ST-04-02 |
| Subject(s) | Structural optimization
|
| Note | A di ssertation submitted in partial fulfillment of the requirements for the degree of Doctor of Engineering, School of Engineering and Technology |
| Publisher | Asian Institute of Technology |
| Series Statement | Dissertation ; no. ST-04-02 |
| Abstract | In this dissertation, a new method to design multiple tuned mass dampers (multiple
TMD's) for minimizing excessive vibration of structures was developed using a numerical
optimizer. It is a very powerful method by which a large number of design variables can
be effectively handled without imposing any restriction before the analysis. Its framework
is highly flexible and can be easily extended to general structures with different
combinations of loading conditions and target response quantities. The developed method
has been applied to searching of optimal TMD's for a wide range of structures, from simple
SDOF lumped-mass systems to continuous beams and floor structures with multi-mode
structural responses, under wide-band excitations. For SDOF structures, the optimally
designed multiple TMD's have non-uniform frequency distribution and unequal-and-low
damping ratios. This optimal configuration of TMD's was different from the earlier
analytical solutions and was proved to be the most effective. A robustness design of
multiple TMD's was also conducted where the system parameters were uncertain and
modeled as independent normal variates. For a simple beam with widely-spaced natural
frequencies, the results confirmed that multiple TMD's can be adequately designed by
treating each structural vibrat ion mode as an equivalent SDOF system. Next, for the
control of a beam structure with two closely-spaced frequencies, the results showed that
the most effective multiple TMD's have their natural frequencies distributed over a range
covering the controlled structural frequencies and have low damping ratios. Furthermore,
a single TMD can be made effective in controlling two modes with closely spaced
frequencies by a newly identified control mechanism, but the effectiveness will be greatly
impai red when the loading position changes. Finally, a rea listic design problem of I 0
TMD's for a large floor structure with 5 closely spaced frequencies was presented. The
acceleration responses at 5 positions on the floor excited by 3 wide-band forces were
simultaneously suppressed. The obtained TMD's were very effective and robust.
Extensive numerical verifications of control effectiveness of TMD's were shown, both in
time and frequency domains, which confirm advantages of the approach. |
| Year | 2004 |
| Corresponding Series Added Entry | Asian Institute of Technology. Dissertation ; no. ST-04-02 |
| Type | Dissertation |
| School | School of Engineering and Technology (SET) |
| Department | Other Field of Studies (No Department) |
| Academic Program/FoS | Space Technology Application and Research (SR) |
| Chairperson(s) | Pennung Warnitchai |
| Examination Committee(s) | Worsak Kanok-Nukulchai;
Noppadol Phien-wej;Yamaguchi, Hiraki |
| Scholarship Donor(s) | The Government of Japan |
| Degree | Thesis (Ph.D.) - Asian Institute of Technology, 2004 |