Towards the conception of complex engineering meta-structures: relaxed-micromorphic modelling of low-frequency mechanical diodes/high-frequency screens

TL;DR

This paper demonstrates that the Relaxed Micromorphic Model effectively designs meta-structures that function as mechanical diodes at low frequencies and screens at high frequencies, enabling optimized wave control.

Contribution

It introduces a simplified micromorphic modeling approach for designing meta-structures with tailored low- and high-frequency wave filtering capabilities.

Findings

The model accurately predicts metamaterials' responses for meta-structural design.

Meta-structures can be optimized for enhanced diode behavior across wave types and angles.

The approach facilitates testing various material combinations efficiently.

Abstract

In this paper we show that an enriched continuum model of the micromorphic type (Relaxed Micromorphic Model) can be used to model metamaterials' response in view of their use for meta-structural design. We focus on the fact that the reduced model's structure, coupled with the introduction of well-posed interface conditions, allows us to easily test different combinations of metamaterials' and classical-materials bricks, so that we can eventually end-up with the conception of a meta-structure acting as a mechanical diode for low/medium frequencies and as a total screen for higher frequencies. Thanks to the reduced model's structure, we are also able to optimize this meta-structure so that the diode-behaviour is enhanced for both "pressure" and "shear" incident waves and for all possible angles of incidence.