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Abstract Active metamaterials are a type of metamaterial with tunable properties enabled by structural reconfigurations. Existing active metamaterials often achieve only a limited number of structural reconfigurations upon the application of an external load across the entire structure. Here, a selective actuation strategy is proposed for inhomogeneous deformations of magneto‐mechanical metamaterials, which allows for the integration of multiple elastic wave‐tuning functionalities into a single metamaterial design. Central to this actuation strategy is that a magnetic field is applied to specific unit cells instead of the entire metamaterial, and the unit cell can transform between two geometrically distinct shapes, which exhibit very different mechanical responses to elastic wave excitations. The numerical simulations and experiments demonstrate that the tunable response of the unit cell, coupled with inhomogeneous deformation achieved through selective actuation, unlocks multifunctional capabilities of magneto‐mechanical metamaterials such as tunable elastic wave transmittance, elastic waveguide, and vibration isolation. The proposed selective actuation strategy offers a simple but effective way to control the tunable properties and thus enhances the programmability of magneto‐mechanical metamaterials, which also expands the application space of magneto‐mechanical metamaterials in elastic wave manipulation.
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On-Demand Noise Mitigation With Time-Modulated Active Acoustic Metamaterials
It is generally accepted that active metamaterials could, in principle, address long-standing challenges in noise mitigation. However, the research of active structures capable to meet these challenges has been slow due to issues of stability and scalability. This work shows that 2D active metamaterials composed of arrangements of sensor- driver pairs can be configured to be excellent sound absorbers very well matched to the background fluid and thus scatter-free. The property is achieved by programming the metamaterial effective mass density and bulk modulus to be complex numbers with matching phases. Moreover, the metamaterials can be switched from being opaque absorbers to transparent media on very small time scales by time-modulating their effective material properties without adverse effects such as ensuing instability. Furthermore, the metamaterial unit cells are completely independent of each other thus promoting scalability.
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- Award ID(s):
- 1942901
- PAR ID:
- 10661181
- Publisher / Repository:
- European Acoustics Association
- Date Published:
- Page Range / eLocation ID:
- 75 to 78
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript
- Conference Paper:
- https://doi.org/10.61782/fa.2025.0655
