Effect of tuned dampers on vibrations of simple structures.

The application of a tuned viscoelastic vibration absorber to undamped cantilever and clamped-clamped beams is discussed analytically. The cantilever beam is excited by a harmonically varying force at the free end, at which point the absorber also is attached. The clamped-clamped beam is excited by a harmonically varying displacement of the clamped ends, of constant amplitude, and the absorber is attached at the center. The absorbers are tuned to suppress only the fundamental mode, and effective loss factors are denned for the beam-damper systems, based on the computed transmissibility spectra. The effects of systematic variations of the absorber mass, stiffness, and loss factor on the effective loss factor are discussed. Experimental investigations of shaker excited cantilever and clamped-clamped beams, with tuned dampers placed at the end or the center, respectively, are described, and it is shown that the main conclusions of the analysis are verified.