Projects

Elastoacoustic Wave Propagation in Biphasic Mechanical Metamaterial

A high contrast mechanical metamaterial made of periodic solid cells with interconnected air-filled voids presents simultaneous acoustic and elastic frequency bandgaps in its dispersion spectrum, the dispersion curves are polarized in accord with the strain energy of fluid and solid.

The sound and vibration insulation performances were verified by a finite element analysis of forced waves propagating through a finite-size metamaterial domain, which is composed by a finite array of repetitive cells and is representative of a real application.

Design of Biphasic Metamaterials

Mechanical metamaterial, characterized by a biphasic (fluid and solid) periodic cell, that exhibits acoustic as well as elastic bandgaps in the dispersion spectrum, which – in principle – could provide insulation from both sound and vibration in prescribed frequency ranges.

Through a tuning of the mechanical properties of the metamaterial, waves of given nature and frequency can be remarkably attenuated simultaneously in the two different domains.

Wave Mixing Technique

Wave mixing means when two internally resonant Lamb wave modes of different frequencies are allowed to mix within the material, which generates a third type of harmonic waves at frequencies. Finite element model was employed and showed that the amplitude of the secondary harmonics is sensitive to the state of prestress

Second harmonic generation in prestressed media

Nonlinear guided wave propagation in prestressed Aluminum plates associated with the second harmonic generation was investigated by FEM.

The model empoyed is a second-order approximation accounting for material and geometric nonlinearities.