Topological Flexural Modes in Polarized Bilayer Lattices

Mohammad Charara, Kai Sun, Xiaoming Mao, Stefano Gonella

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


Topological lattices have recently generated a great deal of interest based on the unique mechanical properties rooted in their topological polarization, including the ability to support localized modes at certain floppy edges. The study of these systems has been predominantly restricted to the realm of in-plane mechanics, to which many topological effects are germane. In this study, we stretch this paradigm by exploring the possibility to export certain topological attributes to the flexural wave behavior of thin lattice sheets. To couple the topological modes to the out-of-plane response, we assemble a bilayer lattice by stacking a thick topological kagome layer onto a thin twisted kagome lattice. The band diagram reveals the existence of modes whose out-of-plane character is controlled by the edge modes of the topological layer, a behavior elucidated via simulations and confirmed via laser vibrometer experiments on a bilayer prototype specimen. These results open an alternative direction for topological mechanics whereby flexural waves are controlled by the in-plane topology, leading to potential applications for flexural wave devices with engineered polarized response.

Original languageEnglish (US)
Article number064011
JournalPhysical Review Applied
Issue number6
StatePublished - Dec 2021

Bibliographical note

Funding Information:
This work is supported by the National Science Foundation (NSF Grant No. EFRI-1741618). We acknowledge the help of Peter Ness at the UMN CSE shop for his expert assistance with the specimen fabrication.

Publisher Copyright:
© 2021 American Physical Society.


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