Vibration localization and reduction in plates via lightweight soft acoustic black hole and vibration absorbers

Abstract

A lightweight composite resonator, consisting of a soft material acoustic black hole (SABH) and multiple vibration absorbers, is embedded in a plate to achieve localization and absorption of low-frequency vibration energy. The combination of local and global admissible functions for displacement enhances the accuracy of the Ritz method in predicting vibration localization characteristics within the SABH domain. Utilizing soft materials for the SABH can reduce the mass and frequency of the composite resonator. Due to the lack of orthogonality between global vibration modes and localized modes, the low-frequency localized modes induced by the SABH are used to shape the initial global modes, thereby concentrating the global vibration of the plate in the SABH region. Consequently, the absorbers of the composite resonator only need to be a small fraction of the mass of the local SABH to achieve substantial vibration control of the host plate. This vibration localization strategy can significantly reduce the vibration amplitude of the host plate and enhance the effectiveness of lightweight absorbers in vibration reduction.