Suppression of closely-spaced modes galloping with Tuned Mass Damper (TMD) | |
| Author | Salas, Franklin Medalla |
| Call Number | AIT Thesis no. ST-91-22 |
| Subject(s) | Structural dynamics Damping (Mechanics) |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Engineering and Technology |
| Publisher | Asian Institute of Technology |
| Abstract | Some structures have vibration modes with closely-spaced natural frequencies. An example of such structures is a pylon or tower of a cable-stayed bridge. The feasibility of tuned mass damper in suppressing the closely-spaced modes galloping of this tower is studied. Beforehand, the equations of motion applicable to structure with closely-spaced natural frequencies and attached TMD are formulated. The structure is modeled as a linear two-degree of freedom system with proportional damping. The bridge tower of Higashi-Kobe cable-stayed bridge whose natural frequency of the in-plane second mode is close to that of the first mode is used as the case study. The applicability of tuned mass damper (TMD) in suppressing the galloping behavior is studied based on the analytical results obtained in order to investigate the aeroelastic instability phenomena. A nonlinear quasi-steady wind force is assumed and asymptotic analysis is made to solve the nonlinear and coupling equations of motions. The results showed that the galloping of this tower is a steady-state motion in either one of the modes in galloping, depending upon the initial disturbances. The effectiveness of TMD at various wind velocities is examined. It was found that the TMD can effectively reduce the response as well as increase the onset wind velocity of galloping. On the other hand, for structures with certain properties, e.g. non-uniformly distributed mass, galloping is a steady-state motion in two modes. The effectiveness of TMD for this type of structure was also examined. It was shown that the effectiveness of TMD depends on the initial phase lag. |
| Year | 1991 |
| Type | Thesis |
| School | School of Engineering and Technology (SET) |
| Department | Other Field of Studies (No Department) |
| Academic Program/FoS | Structural Engineering (STE) /Former Name = Structural Engineering and Construction (ST) |
| Chairperson(s) | Yamaguchi, Hiroki |
| Examination Committee(s) | Worsak Kanok-Nukulchai ;Karasudhi, Pisidhi |
| Scholarship Donor(s) | Keidanren Foundation, Japan |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 1991 |