ON THE DYNAMIC OPTIMISATION OF SONIC COMPOSITES

Abstract

An optimization scenario for the full band-gaps size and the localised modes around interfaces in a multilayer film is presented in this paper. The film is consisted of alternating layers of material with different mechanical properties, following a triadic Cantor sequence. The Cantor structure is characterized by anharmonic coupling between the extended-mode (phonon) and the localized-mode (fracton) vibration regimes, and by extremely low thresholds for subharmonic generation of ultrasonic waves, as compared to the corresponding homogeneous and periodical ones. The dynamic optimization tracks the enhancing of full band-gaps for both Lamb and Love waves.