Application of magnetoelastic materials in spatiotemporally modulated phononic crystals for nonreciprocal wave propagation

Abstract

In this paper, a physical platform is proposed to change the properties of phononic crystals in space and time in order to achieve nonreciprocal wave transmission. The utilization of magnetoelastic materials in elastic phononic systems is studied. Material properties of magnetoelastic materials change significantly with an external magnetic field. This property is used to design systems with a desired wave propagation pattern. The properties of the magnetoelastic medium are changed in a traveling wave pattern, which changes in both space and time. A phononic crystal with such a modulation exhibits one-way wave propagation behavior. An extended transfer matrix method (TMM) is developed to model a system with time varying properties. The stop band and the pass band of a reciprocal and a nonreciprocal bar are found using this method. The TMM is used to find the transfer function of a magnetoelastic bar. The obtained results match those obtained via the theoretical Floquet-Bloch approach and numerical simulations. It is shown that the stop band in the transfer function of a system with temporal varying property for the forward wave propagation is different from the same in the backward wave propagation. The proposed configuration enables the physical realization of a class of smart structures that incorporates nonreciprocal wave propagation.

Nonreciprocal Wave Propagation in a Continuum-Based Metamaterial with Space-Time Modulated Resonators

“…Another way is to introduce an angular momentum bias, disobeying time-reversal symmetry as in media comprising gyroscopes or circulating fluids [5,11]. A third solution to achieve nonreciprocity is the use of dynamic materials with properties that are inhomogeneous in space and changing in time [7,[14][15][16][17][18][19][20][21][22][23][24].…”

Broadband nonreciprocal linear acoustics through a non-local active metamaterial

“…Other approaches to acoustic nonreciprocity rely on breaking the spatial or temporal symmetry in the governing equations by introducing nonlinear interactions [15], [16] or spatiotemporal modulation of the properties of the medium [17], [18]. Theoretical analysis has shown that spatiotemporal modulation of strongly magnetoelastic materials, like Terfenol, and piezoelectric materials, like PZT, can lead to impressive nonreciprocity, as shown in [19]. Both nonlinearity and spatiotemporal modulation introduce secondary tones that require later demodulation or signal processing to prevent signal corruption.…”

On the wave dispersion and non-reciprocal power flow in space-time traveling acoustic metamaterials

“…The latter has been recently demonstrated in elastic metamaterials using a perturbation approach [24]. Although very challenging, several efforts have recently investigated achieving material variations in time using negative capacitance piezoelectric shunting [25], inductance-based resonance control [26], and magnetoelastic materials [27]. In this work, we build on the work developed in [28] for non-resonant space-time traveling phononic lattices to develop a mathematical framework that captures and predicts non-reciprocal dispersion physics in lumped time-traveling LRAMs.…”