Dipole-like interface states in quasi-periodic elastic waveguide based on Fibonacci sequences

Abstract

This paper investigates the dipole-like interface states in a quasi-periodic elastic waveguide structured according to Fibonacci sequences. The dipole-like distribution arises from the interaction of different transverse modes within the waveguide. Specifically, the non-Bragg bandgap resulting from the interaction between distinct transverse modes exhibits a stronger inhibitory effect compared to the traditional Bragg bandgap. Furthermore, our simulations reveal a notable sound field distribution on the surface of the waveguide, displaying two diametrically opposite regions with maximum sound pressures. This structure, characterized by a high Q factor, provides valuable insights into designing elastic wave applications such as filtering and wave enhancement.