THE OPTIMIZATION OF FULL BAND-GAPS IN MULTILAYER FILMS
Journal Title: ROMANIAN JOURNAL OF TECHNICAL SCIENCES - APPLIED MECHANICS - Year 2016, Vol 61, Issue 2
Abstract
The multilayer films are consisted of alternating layers of material with different mechanical properties, following a triadic Cantor sequence. The extremely low thresholds for subharmonic generation of ultrasonic waves has a significant importance in the generation of the full band-gaps due to the nonlinear coupling between the extended-mode (phonon) and the localized-mode (fracton) vibration regimes. In this paper, the optimization is performed with respect to most important features of sonic composites, such as the localized modes around interfaces and the size of the full band-gaps. The case of a relevant uncertainty of the design parameters which may change over frequency is taken into consideration. Uncertain parameters are related to the local band-gaps and boundary conditions where the displacement and the traction vectors can be discontinuous. Maximizing the full band-gaps is taken as the objective function, while the constant volume of the structure is taken as the constraint. The results show an unexpected influence of discontinuities upon the generation of the full band-gaps.
Authors and Affiliations
VETURIA CHIROIU, LIGIA MUNTEANU, CRISTIAN RUGINA, DAN DUMITRIU, PIER PAOLO DELSANTO
Keywords
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