| Author | Nakhorn Poovarodom |
| Call Number | AIT Thesis no. ST-93-19 |
| Subject(s) | Vibration--Mathematical models
|
| Note | A thesis submitted in partial fulfillment of the requirement for the degree of Master of
Engineering, School of Engineering and Technology |
| Publisher | Asian Institute of Technology |
| Abstract | Most of the optimal design of passive vibration control employ several assumptions and
simplifications, and they are usually limited to the case of simple control system which governed
by few parameters. One example is the optimal design of Tuned Mass Damper ; its mass,
stiffness and damping are the only parameters to be optimized. On the contrary, in this study,
a new approach in the optimal design, which can handle complex passive control system having
large numbers of parameters, is proposed. In this approach, the second order governing
differential equations of motion of structure-control system are transfo1med into a first order
state equations in modal coordinates. Then, the average response of system in free vibration
state or in random excited state is represented by a performance index, and it is obtained by
solving Lyapunov matrix equation. The partial derivative of the index with respect to each
design parameters is derived from various mathematical theories such as Bellman expansion,
Klienman lemma and Eigendeiivative theory. The performance index and its gradient can be
easily evaluated so that it is suitable for adapting general numerical optimizer. The optimizer
employed is Davidon-Fletcher-Powell nonlinear programming algorithm which can
automatically search for optimal parameters of passive vibration control system.
An application to the optimal design of MTMD is selected as example to illustrate the
possibility and effectiveness of this approach. The two cases of vibration, free vibration and
white noise excitation, are considered. Moreover, for the latter case, the optimal design is also
consider the uncertainties in structural prope1ties or robustness design. The robust performances
in this case are investigated in details. It is found that the new optimal design approach can
successfully give the optimal parameters of MTMD in all cases. The optimal results indicate
clearly that, in case of free vibration, high damped-single tuned frequency for MTMD is suitable,
and in case of white noise excitation, low damped-distributed tuned frequency strategy for
MTMD yields more effective and robust vibration control pe1formance. |
| Year | 1993 |
| Type | Thesis |
| School | School of Engineering and Technology (SET) |
| Department | Department of Civil and Infrastucture Engineering (DCIE) |
| Academic Program/FoS | Structural Engineering (STE) /Former Name = Structural Engineering and Construction (ST) |
| Chairperson(s) | Pennung Warnitchai; |
| Examination Committee(s) | Worsak Kanok-Nukulchai ;Sugiyama, Toshiyuki |
| Scholarship Donor(s) | King's scholarship; |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 1993 |