VIBRATION CONTROL OF VARIABLE THICKNESS PLATES WITH EMBEDDED ACOUSTIC BLACK HOLES AND DYNAMIC VIBRATION ABSORBERS

摘要

In the past decade, plate-like structures embedded with one or more acoustic black hole (ABH) features have been developed as a promising passive approach for structural sound and vibration control. In this study, the concept of combining dynamic vibration absorbers (DVAs) and the ABH effect is proposed to further improve the vibration control effectiveness of a variable thickness plate. A finite element (FE) model is developed to analyze the vibration response of a plate embedded with both ABHs and DVAs under point force excitations. To demonstrate the effectiveness of different vibration control approaches, the vibration responses of plates of uniform thickness, variable thickness embedded with ABH features, variable thickness embedded with both ABH features and damping layers, and variable thickness embedded with both ABH features and DVAs are compared experimentally. It is shown that, in the frequency range considered in the current study which is up to 6.4 kHz, the uniform plate presents high average velocity response level. On the other hand, although 11.5% lighter, the variable thickness plate integrated with both ABH and DVA features results in the lowest response level. Results in this study demonstrate the potential of combing DVAs and ABHs together as an effective lightweight noise and vibration control approach.