Acoustic methods for metamaterials

Metamaterials are materials whose properties depend not only on the material but also on an internal architecture. Due to the often complex geometry, it is essential to further develop conventional characterization methods in order to be able to comprehensively characterize these materials. To this end, a measurement methodology is being developed based on a classic acoustic impedance tube, which allows the reflection, absorption and transmission properties of metamaterials to be determined over a wide frequency range. In particular, the focus is on extending the measurement range to low frequencies below 400 Hz. A modular design of the measurement system also makes it possible to test materials with variable acoustic properties by applying external triggers.