Non-Hermitian elastic waveguides with piezoelectric feedback actuation: non-reciprocal bands and skin modes
Abstract
In this work, we investigate non-Hermitian (NH) elastic waveguides with periodically applied proportional feedback efforts, implemented through piezoelectric sensors and actuators. Using one-dimensional spectral models for longitudinal motion, it is shown that dispersion diagrams of this family of structures exhibit non-reciprocal imaginary frequency components, manifesting as wave attenuation or amplification along opposite directions for all Bloch bands (BBs). The effects of positive and negative proportional feedback, as well as local and non-local actuation are investigated. Overall, switching the sign of the feedback effort inverts the amplification direction, while increasing the degree of non-locality produces splitting of the BBs into multiple bands with interchanging non-reciprocal behavior. Furthermore, skin modes localized at the boundaries of finite domains are investigated and successfully predicted by the winding number of the complex dispersion bands. These results contribute to recent efforts in designing metamaterials with novel properties associated with the physics of non-Hermitian systems, which may find fruitful technological applications relying on vibration and noise control, wave localization, filtering and multiplexing.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- May 10, 2021
- Source ID
- 10.1088/1361-6463/abf9d9
Entities
People
- Danilo Braghini
- José Roberto de França Arruda
- Luis Gustavo Villani
- Matheus I. N. Rosa
Organizations
- Army Research Office
- Office of Emerging Frontiers and Multidisciplinary Activities
- São Paulo Research Foundation