Vibration attenuation in pipes: design and experimental validation of a resonant metamaterial solution

© 2017 National Technical University of Athens. All rights reserved. In recent years, locally resonant metamaterials have shown great potential in efficiently attenuating mechanical vibrations and providing noise insulation in various applications. Given the wide application range of lightweight pipes and considering that such structures can serve as excellent waveguides as they are often quite long, a locally resonant metamaterial pipe is presented in this paper. This metamaterial solution is chosen to investigate whether it is possible to use the metamaterial concept on pipe-like structures. Resonators are added to the pipe on a subwavelength scale in order to create a stopband zone in the propagation of flexural waves. Utilizing the Bloch-Floquet theorem and considering a periodic distribution of the local resonators, unit cell modelling is adopted to design the metamaterial pipe with a stopband zone in the frequency range of interest. Only a limited number of resonators are added to the original pipe in order to keep the added mass ratio due to these resonators below 10%. The results obtained from Bloch-Floquet theorem hold for an infinite metamaterial pipe with a periodic distribution of local resonators, but previous studies have shown that they provide a reliable prediction of the zone of highly attenuated response of the finite structure as well. Finally, the metamaterial pipe is manufactured to experimentally validate the results provided by the numerical prediction of the stopband zone. The metamaterial structure is composed of an Aluminum pipe as the host structure with added local resonators which are produced from Plexiglas using a laser cutting technique. The experimental results prove the existence of the stopband zone as predicted by the unit cell analysis of the infinite metamaterial pipe. The proposed concept provides an easy-to-apply metamaterial solution which can provide the stopband behavior while meeting the lightweight criterion.

ISBN:9786188284425

Publication year:2017