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Analogous electrical networks were previously derived from the Euler–Bernoulli and Kirchhoff–Love theories to represent beams and plates, respectively, for use in multimodal structural vibration damping. However, these networks do not account for shear deformations or rotary inertia, which can result in suboptimal vibration damping performance when used on moderately thick beams and plates. In this paper, we investigate the incorporation of shear deformation and rotary inertia using Timoshenko–Ehrenfest beam theory and Mindlin–Reissner plate theory to develop improved electrical networks that can more accurately represent thick beams and plates. Our findings suggest that the inclusion of shear deformation and rotary inertia can significantly improve the frequency coherence of the electrical networks and multimodal vibration damping for thicker structures. The electrical analogs presented here are of use for various applications, especially to conveniently design complex circuit topologies in fields spanning from vibration attenuation to energy harvesting. [ABSTRACT FROM AUTHOR]

Rainbow trapping is a phenomenon that enables vibration confinement due to the gradual variation of the wave velocity in space, which is typically achieved by means of locally resonant unit cells. In the context of electromechanical metastructures for energy harvesting, this strategy is employed to improve mechanical-to-electrical energy conversion and thereby to maximize the harvested power. In contrast to structures endowed with either mechanical or electromechanical resonators, we investigate a hybrid configuration that leverages the synergistic interplay between them. We compare numerical results for different grading laws in comparison to prior efforts on the topic, demonstrating enhanced energy harvesting and wideband vibration attenuation capabilities of the hybrid metastructure. We also discuss the formation of grading-induced localized modes and we shed light on the role of the motion of individual resonators on the overall power output increase. [ABSTRACT FROM AUTHOR]

This Letter presents an experimental demonstration of tunable exceptional points (EPs) in an electromechanical waveguide. EPs are non-Hermitian singularities typically found in parity-time (PT) symmetric systems with balanced gain and loss. Here, piezoelectric transducers on an aluminum beam (waveguide) are shunted to synthetic impedance circuits that emulate negative and positive resistors (responsible for gain and loss) and inductors (for resonant tunability), whose properties can be programmed digitally. Specifically, an electrical mode is introduced via inductive shunts to electromechanically interact with target structural mode(s) to create degeneracy. While the internal structural damping of the waveguide has the effect of breaking PT symmetry inherently, we show that EPs can still be created by using non-trivial gain and loss combinations. The results in this Letter pave the way for practical realization of EPs in elastic media toward their application in enhanced sensing and asymmetric wave control, among others. [ABSTRACT FROM AUTHOR]