Inducing Intentional Strong Nonlinearity in Acoustics

Nonlinear phenomena are ubiquitous in engineering and the sciences, and oftentimes are regarded as detrimental and unwanted by the common technical wisdom. Yet, recent work has revealed the many and important potential benefits that nonlinearities can offer in the fields of dynamics and acoustics (and not only), coming hand-in-hand of course, with certain potentially unwanted “side effects” that need to be avoided, e.g., instabilities, bifurcations, multiple co-existing responses, chaos etc. Hence, careful predictive analysis and experimental validation are required when implementing an intentional nonlinearity concept in mechanical design. In this work we focus on the beneficial effects that can be gained when inducing intentional strong nonlinearities in acoustical systems. Ranging from sonic vacua to acoustic metamaterials and phononic lattices, we aim to showcase the important advantages, added functionality, tunability with energy, and possibly transformative performance enhancement that the resulting nonlinear acoustical systems can be empowered with, which simply would not be achievable in traditional linear or weakly nonlinear settings. After providing a brief overview of some elements of strongly nonlinear acoustics we focus on case studies that extend over diverse application fields.