Nonlinear Metamaterials: Amplitude-Dependent Dispersion, Group Velocity, Bandgaps, and Device Implications
Michael Leamy (Georgia Institute of Technolog)
Mechanics and Dynamics of Periodic Structures
Wed 9:00 - 10:30
Salomon 101
This talk will discuss recent progress made by the author and his co-workers on analytical, computational, and experimental analysis of nonlinear acoustic metamaterials. The inclusion of nonlinear elements in periodic unit cells allows for amplitude-dependent tuning of acoustic band structure. This enables, for example, tunable bandgaps, waveguides, filters, resonators, and logic elements (diodes, multiplexors, etc.). Many of these functionalities may be implemented by exploiting amplitude dependence in group velocity and spatial deadbands. In order to elucidate this advantageous behavior, a series of perturbation techniques [1,2] have been developed for predicting amplitude-dependent dispersion and group velocity characteristics in weakly-nonlinear discrete and continuous systems. The perturbation techniques are capable of analyzing plane waves at a single frequency, or interactions of multiple plane waves at differing frequencies. Analysis of wave-wave interactions reveals, for example, the manner in which a ‘control wave’ can alter the dispersion of a ‘primary wave,’ modifying its group velocity and spatial beaming behavior. This and other novel nonlinear behavior will be discussed using results from analytical, computational, and experimental studies. References 1 R.K. Narisetti, M. Ruzzene, and M.J. Leamy, J. Vib. Acoust. 132, 031001 (2010). 2 K. Manktelow, M.J. Leamy, and M. Ruzzene, Nonlinear Dynam. 63, 193-203 (2011).