A panorama of dispersion curves for the weighted isotropic relaxed micromorphic model

TL;DR

This paper provides a comprehensive analysis of dispersion curves in the weighted isotropic relaxed micromorphic model, highlighting how parameter variations influence wave propagation and band-gap properties.

Contribution

It introduces a generalized micromorphic model with tensor decompositions, enabling independent control of dispersion cut-offs and offering detailed parametric insights.

Findings

Split of micro-inertia controls optic band cut-offs.

Tensor Curl P decomposition affects dispersion curves.

Complete parametric panorama of dispersion behaviors.

Abstract

We consider the weighted isotropic relaxed micromorphic model and provide an in depth investigation of the characteristic dispersion curves when the constitutive parameters of the model are varied. The weighted relaxed micromorphic model generalizes the classical relaxed micromorphic model previously introduced by the authors, since it features the Cartan-Lie decomposition of the tensors $P_{,t}$ and Curl $P$ in their dev, dev sym, skew and spheric part. It is shown that the split of the tensor $P_{,t}$ in the micro-inertia provide an independent control of the cut-offs of the optic benches. This is crucial for the future calibration of the relaxed micromorphic model on real band-gap metamaterials. Even if the physical interest of the introduction of the split of the tensor Curl $P$ is less evident than in the previous case, we discuss in detail which is its effect on the dispersion curves. Finally, we also provide a complete parametric study involving all the constitutive parameters of the introduced model, so giving rise to an exhaustive panorama of dispersion curves for the relaxed micromorphic model.