Recent Advances in Phononic Crystals, Acoustic and Mechanical Metamaterials

Phononic crystals and metamaterials are artificially engineered structures with exceptional static and dynamic properties that are not usually observed in natural materials. Among the most popular manifestations of unconventional behavior in phononic crystals and metamaterials, one might point out negative Poisson’s ratio, the ability to cloak mechanical deformation, negative effective mass, and the capacity to exhibit multiple stable configurations with different properties. The extreme performance of metamaterials originates in their intricate internal architecture, and new design strategies are constantly advancing and evolving. Over the last decade, a vast variety of different designs for phononic crystals and metamaterials have been proposed, numerically assessed, fabricated, and then tested experimentally. Now the research field is not satisfied with the realization of just “frozen-in-time” materials, and it starts to look for metamaterials capable of changing their unique properties on demand via external stimuli or innate time-dependent mechanisms. The current state-of-the-art research goes beyond physical intuition and extends to mimicking living materials, drawing inspiration from the Japanese art of paper folding (origami) and cutting (kirigami), all while employing cutting-edge artificial intelligent methods and manufacturing techniques.

The scope of this Special Issue is to highlight the recent advances and latest trends in the realm of phononic crystals, acoustic and mechanical metamaterial that enable practically relevant configurations, multifunctional properties, and other fantastic characteristics. The research articles included in this special issue will cover advances from fundamental research to applications of phononic crystals, and acoustic and mechanical metamaterials in a multi-disciplinary domain.

This special issue aims to spotlight and consolidate the latest research developments in the field. It encompasses acoustic metamaterials for noise absorption, lightweight metastructures with broadband vibration mitigation, seismic metamaterials for earthquake shielding, and other manifestations of wave-related phenomena. Additionally, this special issue focuses on mechanical metamaterials with unconventional coupling between deformation modes and quasi-zero stiffness structures. Specific attention is directed towards phononic crystals, elastic and mechanical metamaterials capable of altering their internal architecture and properties on demand, including metamaterials with active stimuli-responsive components. This special issue also covers novel approaches to predicting and generating metamaterials with desired properties, including classical optimization methods as well as modern data-driven techniques.

We invited manuscripts with breakthrough research on phononic crystals, acoustic and mechanical metamaterials that cover the following topics but not are limited to:

- Phononic crystals, acoustic and mechanical metamaterials

- Novel data-driven design and optimization methods

- Active and reconfigurable phononic crystals, acoustic and mechanical metamaterials

- Elastic and seismic metamaterials

- Origami and kirigami-inspired metamaterials

- Bio-inspired metamaterials

- Topological phenomena in metamaterials

- Applications of phononic crystals, acoustic metamaterials, and mechanical metamaterials