Beat phenomenon in combined structure-liquid damper systems

The classical beat phenomenon has been observed in most combined structure-liquid damper systems. The focus of this paper is to provide a better understanding of this phenomenon, which is caused by the coupling that is introduced through the mass matrix of the combined system. However, beyond a certain level of damping in the secondary system (liquid damper), the beat phenomenon ceases to exist. This is due to coalescing of the modal frequencies of the combined system to a common frequency beyond a certain level of damping in the secondary system. Numerical and experimental results are presented in this paper to elucidate the beat phenomenon in combined structure-liquid damper systems.