Sweeping tunable vibration absorbers for structural vibration control

Abstract

Tuneable vibration absorbers (TVAs) have been successfully implemented in distributed thin structures (e.g., panels shells) to control either tonal vibration, produced, for example, by unbalanced machinery, or low-frequencies broadband vibration, generated, for example, by stochastic pressure distributions due to diffuse sound fields or turbulent boundary layer fluid flows. This study is focused on the broadband control of structural vibration where often multiple TVAs are used to control the response of the natural modes that resonate in the controlled frequency band. Normally, each TVA is tuned to minimize the resonant response of a specific natural mode of the hosting structure by tuning the TVA natural frequency to the resonance frequency of the mode and setting the TVA damping ratio to properly dissipate energy. The proposed sweeping tuneable vibration absorbers (STVAs) have been conceived to operate on the multiple natural modes of the hosting structure where they are mounted by sweeping the TVA tuning frequency over the frequency band of control and simultaneously varying the TVA damping ratio to effectively dissipate energy over the desired frequency range. The operation principle of a single STVA is first discussed and demonstrated experimentally. The implementation of multiple STVAs is then examined.