Decoupling Nonclassical Nonlinear Behavior of Elastic Wave Types
Résumé
In this Letter, the tensorial nature of the nonequilibrium dynamics in nonlinear mesoscopic elastic
materials is evidenced via multimode resonance experiments. In these experiments the dynamic response,
including the spatial variations of velocities and strains, is carefully monitored while the sample is vibrated
in a purely longitudinal or a purely torsional mode. By analogy with the fact that such experiments can
decouple the elements of the linear elastic tensor, we demonstrate that the parameters quantifying the
nonequilibrium dynamics of the material differ substantially for a compressional wave and for a shear
wave. This result could lead to further understanding of the nonlinear mechanical phenomena that arise in
natural systems as well as to the design and engineering of nonlinear acoustic metamaterials.