GREENS-FUNCTION OF SUPPORT-EXCITED STRUCTURES WITH TUNED-MASS DAMPERSDERIVED BY A PERTURBATION METHOD

A tuned-mass damper is a small damped spring-mass system which vibrate s in resonance with the main structure to which it is attached so as t o be able to dissipate vibration energy and reduce the structural resp onse. In this paper, explicit forms of Green's function for the transi ent response of main structures equipped with the tuned-mass damper an d subjected to support excitation are derived by perturbation techniqu es and provide an insight into the characteristics of the damper. It i s found that there exists a critical damping level for the tuned-mass damper. If the damper damping is higher than this critical damping lev el, increasing the damper damping will enhance the structural response . When the damper damping is below this critical value, something call ed 'beat phenomenon' occurs where the structure will have a smaller re sponse in the first beat cycle, but have a higher rebound in the follo wing beat cycles.