Beyond Band Gaps: Modeling Mechanical Metamaterials for Engineering Applications by Svenja Hermann, Dec. 17, 2024

Beyond Band Gaps: Modeling Mechanical Metamaterials for Engineering Applications

Svenja Hermann

TU Dortmund

December 17, 2024

Abstract:

Mechanical metamaterials offer unique capabilities for wave control and vibration mitigation. For these materials, there are certain frequency ranges in which waves cannot freely propagate in space—so-called band gaps. The unusual behavior of metamaterials stems from their specially designed microstructure. The metamaterial is composed of repeating geometric elements, called unit cells, which form the periodically arranged microstructure. Conceptually, a metamaterial consists of an array in which the unit cells are repeated to an infinitely large extent.

Modeling techniques involve periodicity theorems that enable the representation of a metamaterial of an infinitely large extent by a single unit cell. Therefore, it has become a well-established practice in the engineering community to optimize vibration mitigation in a mechanical metamaterial based on modifying the underlying unit cell during the last few years. Meanwhile, the performance of metamaterials in finite-sized structures, in which they are integrated with and connected to commonly used materials, has been much less explored. For practical engineering design tasks, however, dealing with finite-sized structures is essential.

This talk will begin with a short review of established practices in modeling infinite metamaterials. We will then shift focus to the challenges of modeling and experimental testing finite-size metamaterial structures, such as boundary conditions and the modeling of large-scale structures. Following this topic, a continuum modeling approach for metamaterials will be introduced. We will discuss briefly how using the so-called relaxed micromorphic model allows us to represent the dynamic behavior of structures in which metamaterials and classical materials of finite size are combined while keeping the computational effort comparatively low. Finally, we will examine several remaining challenges and perspectives for the work with finite-sized metamaterial structures.

Biography:

Svenja Hermann is a Postdoctoral Researcher at the chair of Continuum Mechanics of the Institute of Structural Mechanics, Statics and Dynamics at TU Dortmund, which is led by Prof. A. Madeo. She received her PhD from the Université Bourgogne-Franche-Comté in 2021, where her research focused on the modeling and experimental testing of magnetoactive elastomers, taking into account the magneto-mechanical coupling in the composite. Her current research at TU Dortmund involves the modeling and testing of mechanical metamaterials at finite scales and is being carried out as part of the ERC-funded research project META-LEGO.