Experimental research on vibration reduction characteristics of adhesively bonded beam structures with acoustic black hole geometry

Beam structures are widely used in industrial applications such as automobiles, aircraft, naval architecture, trains, and buildings. The vibration characteristics of beams are inherent phenomenon and directly affect usage comfort and service life, but more dangerously may damage the structure due to excessive vibrations that are transmitted through the surrounding structure of the system. Vibration reduction of beam structures is a continuous challenge for industrial applications. It is important to reduce vibrations of the beam structures for stability. In this study, experimental research on vibration reduction characteristics of adhesively bonded beam structures with Acoustic Black Hole technique is presented. The Acoustic Black Hole, which is a geometry, tapered with a power-law profile enables vibration reduction by decreasing the velocity and the wavelength of vibration. The inherent natural vibration properties called modal parameters such as the natural frequencies, damping, and mode shapes of the beam structure with and without damping layer using power-law profile having various the Acoustic Black Hole length and exponent values were investigated and evaluated with experimental modal analysis. For validation, natural frequencies are determined numerically by the finite element method, and then compared with results obtained by the experimental modal analysis. The overall results indicated that the Acoustic Black Hole has ability to significantly suppress the vibration level and showed the capability of enhancing the damping efficiency when using the damping layer attached to the Acoustic Black Hole length of the beam structure.