title: Composite 3D-printed metastructures for low-frequency and broadband vibration absorption.
abstract: Architected materials that control elastic wave propagation are essential in vibration mitigation and sound attenuation. Phononic crystals and acoustic metamaterials use band-gap engineering to forbid certain frequencies from propagating through a material. However, existing solutions are limited in the low-frequency regimes and in their bandwidth of operation because they require impractical sizes and masses. Here, we present a class of materials (labeled elastic metastructures) that supports the formation of wide and low-frequency band gaps, while simultaneously reducing their global mass. To achieve these properties, the metastructures combine local resonances with structural modes of a periodic architected lattice. Whereas the band gaps in these metastructures are induced by Bragg scattering mechanisms, their key feature is that the band-gap size and frequency range can be controlled and broadened through local resonances, which are linked to changes in the lattice geometry. We demonstrate these principles experimentally, using advanced additive manufacturing methods, and inform our designs using finite-element simulations. This design strategy has a broad range of applications, including control of structural vibrations, noise, and shock mitigation.
authors.affiliation: Department of Mechanical and Process Engineering, ETH Zürich, 8092 Zurich, Switzerland; matlackk@ethz.ch.
authors.forename: Kathryn H
authors.identifier: 0000-0001-7387-2414
authors.initials: KH
authors.lastname: Matlack
authors.affiliation: Department of Mechanical and Process Engineering, ETH Zürich, 8092 Zurich, Switzerland;
authors.forename: Anton
authors.initials: A
authors.lastname: Bauhofer
authors.affiliation: Department of Mechanical and Process Engineering, ETH Zürich, 8092 Zurich, Switzerland;
authors.forename: Sebastian
authors.initials: S
authors.lastname: Krödel
authors.affiliation: Department of Mechanical and Process Engineering, ETH Zürich, 8092 Zurich, Switzerland; Department of Civil, Chemical, Environmental and Materials Engineering, University of Bologna, 40126 Bologna, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Palermo
authors.affiliation: Department of Mechanical and Process Engineering, ETH Zürich, 8092 Zurich, Switzerland;
authors.forename: Chiara
authors.initials: C
authors.lastname: Daraio
keywords: 3D printing; band gaps; metamaterials; phononic crystals; vibration absorption