A Method for Designing and Fabricating Broadband Vibration Absorbers for Structural Noise Control

In this paper, a method for designing and fabricating broadband vibration absorbers (BBVAs) for structural noise control is described. The BBVA’s consist of a series of cantilevered masses, closely spaced in frequency and sharing a common hub that attaches to the host structure. To accommodate applications involving shell structures, both translational and rotational degrees of freedom are considered in the analysis. The BBVA is modeled with a simple, three-by-three impedance matrix to facilitate its subsequent incorporation into a larger structural optimization study. In order to validate this modeling method, an experimental impedance identification method was developed. This method was applied to a physical BBVA consisting of 12, cantilevered masses emanating from a common hub and attached to a solid base plate that simulates the degrees of freedom of a shell structure. Analytical and experimental results are in excellent agreement, demonstrating the efficacy of the approach. The proposed modeling and fabrication method provides a simple and straightforward way to incorporate BBVAs in optimization studies applied to the design of quiet structures.