Elastic wave propagation in cubic non-centrosymmetric and chiral architectured materials: Insights from strain gradient elasticity

• Published in: International journal of solids and structures 2024-12, Vol.305, p.113059, Article 113059
• Main Authors: Rosi, G., Auffray, N., Combescure, C.
• Format: Article
• Language: English
• Subjects: Acoustical activity; Chirality; Elastic waves; Generalised continua; Mechanics; Physics; TMPS
• ISSN: 0020-7683
• DOI: 10.1016/j.ijsolstr.2024.113059

In this paper, we investigate wave propagation in cubic periodic architectured materials. We analyse three different types of unit cells, with distinct symmetries (centrosymmetric, non-centrosymmetric chiral and non-centrosymmetric achiral) with the aim of investigating the consequences of such symmetries on the elastodynamic behaviour of the architectured material. To this end, numerical simulations are performed on unit cells representative of the three types, to extract phase velocities and polarisations of waves along different directions. It is shown that some unconventional couplings between the different eigensolutions give rise to circular or elliptically polarised waves, associated with dispersive effects (acoustical activity). Subsequently, a theoretical analysis using a generalised equivalent continuum model (strain gradient elasticity) is performed to analyse these results and unveil the links between the symmetries of the architecture and the macroscopic elastodynamic behaviour. Indeed, it is shown that strain gradient elasticity is able to discriminate between the three symmetry classes, that are seen as equivalent by a classic continuum theory. •Acoustical activity can only be observed in chiral architectured materials.•Non-centrosymmetry is not enough to ensure acoustical activity.•Acoustical activity is captured by odd order constitutive tensors.•Strain gradient elasticity can describe acoustical activity.