Author(s): Melnikov Anton, Maeder Marcus, Scheffler Michael, Marburg Steffen
Metamaterials are engineered materials, which can provide properties not common in nature. Applied to acoustic wave propagation, the properties of the wave transmission can be designed according to a certain desired behavior. One of the biggest challenges to overcome was the production of the specific metamaterial structures – however, since the last decade, additive manufacturing capabilities developed and particularly 3d-printing enabled scientist to create such structures efficiently at the appropriate scales for metamaterials. Nowadays, tuned metamaterial lightweight structures with increased transmission loss for distinct frequency bands can be manufactured within an acceptable budget. On the one hand such structures can help to reduce the noise emission and on the other hand the production of these metamaterials can economically be better as common sound capsules. To design a metamaterial sound capsule for isolating a machinery, spectral information about the sound emission of the machinery must be available. It can be obtained by measurements or simulation. Numerical models of the metamaterial are required to adjust the transmission loss effect to the appropriate frequency range. Models of the unit cells can be realized by finite elements codes introducing the Floquet-Bloch approach revealing the bandgaps for free wave propagation. The tuned metamaterial design can be extended to a complete sound capsule including carrier structures. The noise reduction effectiveness of the capsule can be simulated numerically and validated experimentally.
Name: Mr Anton Melnikov