Abstract
In this chapter, we consider the design of 1D amplitude-dependent acoustic absorber, i.e., acoustic metamaterial composed of an air-filled waveguide periodically side-loaded by holes. Firstly we present experimental results about high-amplitude sound wave propagation in the structure. We find that there is not only the linear viscothermal and radiation losses, but also the nonlinear losses. High-amplitude sound waves at the locations of the side holes could introduce nonlinear losses, which is due to the geometrical discontinuity. This phenomenon could be found in experiments about amplitude-dependent reflection, transmission, and absorption coefficients. The experimental results show the possibility to use the system as a nonlinear absorber, that is, nonlinear losses change the nature of the device from a reflective to an absorbing one. Our results reveal the role of nonlinear losses in the proposed device and also provide a quite accurate analytical model to capture the effect of such losses. In the end, we analytically tune the parameters of the device and design 1D amplitude-dependent acoustic absorber.