Seminar Fallah

How Magnetic Fields Whisper to Acoustic Waves?

Arash Soleiman Fallah

OsloMet, Norway

30th September 2025, 15:30-16:30 CEST, Room B-366 @ Thákurova 7, 166 29 Prague 6

Abstract: The design of smart acoustic metamaterials relies heavily on the ability to precisely control parameters that define their band structure and dispersion surface morphology. This talk is a journey to examine how 3D metamaterials made from elements embedded in magneto-elastomers can be dynamically tuned by adjusting the stiffness of the substratum and surrounding shells, both of which depend on the external magnetic field induction. Changes in stiffness affect the wavelength of surface waves at characteristic core vibration frequencies, altering the coupling between shell and core modes. This leads to shifts in the dispersion surfaces along the frequency axis—either forming new band gaps or converting existing ones into pass bands—with varying degrees of responsiveness. Depending on the magnetic field some dispersion surfaces may even flatten. In anisotropic systems, this approach also allows for the creation of directional band gaps with tunable frequency and angular widths. The results, derived from an idealised mass-spring model, offer a framework for designing acoustic systems with tailored, real-time tunable properties.