Experimental Study of Bending Vibration Bandgaps for an Acoustic Metamaterial Beam

With the complexity of aerospace structures, the demand for vibration and noise reduction technology is increasing. It is well known that locally resonant acoustic metamaterials have significant elastic bandgap characteristics, which can effectively control the low-frequency vibration of structures. And the locally resonant structure can be formed by using the distributed dynamic vibration absorbers. For realizing the control of vibration, in this paper, a locally resonant acoustic metamaterial based on vibration absorbers is constructed on a free-free beam. The ratio of the total mass of vibration absorbers to the mass of the beam was changed to explore its ability to tune the bandgap. Furthermore, the relationship between the bandgap characteristics and the mass ratio is discussed experimentally.