Topological Tube Traps Vibrations
In theory, the propagation of damaging vibrations through a physical system can be mitigated using so-called topological mechanical metamaterials. In practice, these structures are typically complex, hindering them from being realized at scale and from being implemented into real systems. Now James McInerney at Wright-Patterson Air Force Base in Ohio and his colleagues have designed a comparatively simple topological mechanical metamaterial [1]. According to their analysis, this structure could prevent vibrations from spreading to delicate payloads in civil- and aerospace-engineering applications.
The researchers’ structure belongs to a class of topological mechanical metamaterials called Maxwell lattices. The topological physics of such lattices causes any low-energy vibrations to localize to part of the lattice’s boundary and thus become isolated. However, that capability requires the lattice to be right at the borderline between rigid and floppy. This stipulation meant that previously considered two-dimensional Maxwell lattices could not support their own weight and needed to be attached to impractical external mounts. By contrast, the design of the researchers’ structure allows it to be self-supporting. It is made by folding a flat Maxwell lattice known as a generalized kagome bilayer into the shape of a cylindrical tube. The tube’s radius must be precisely tuned for the structure to exhibit the required topological behavior.
Using theoretical analysis and numerical modeling, McInerney and his colleagues examined the vibrational behavior of their structure when attached to both a sensitive payload and a source of low-energy vibrations. As expected, they found that the vibrations were diverted from the payload and toward one end of the tube. The researchers also provided guidance on how their results could be verified in the lab, and they intend to perform such experiments in future work.
–Ryan Wilkinson
Ryan Wilkinson is a Corresponding Editor for Physics Magazine based in Durham, UK.
References
- J. P. McInerney et al., “Topological polarization of kagome tubes and applications toward vibration isolation,” Phys. Rev. Appl. 24, 044037 (2025).