Experimental validation of band gaps and localization in a one-dimensional diatomic phononic crystal.
The propagation of compressional ultrasonic pulses through a finite one-dimensional chain of various unit cells is investigated experimentally. The chain, initially compressed by an axially applied constant force, is excited by a periodic force, which acts in line with axis of bead chain. The experimental measurements giving the eigenfrequencies of the specimen are based on a Fourier analysis of the transmitted acoustic pulse. The results are compared with the numerical calculations and it is shown that the two approaches are well correlated. A phononic band structure is observed and under certain conditions, depending on the parity of the number and on the masses of the beads in the chain, it is shown that localized modes propagating in the forbidden band are exhibited. Much attention is devoted to the existence of these localized modes according to the mass ratio between two adjacent beads constituting the unit cell.
Hladky-Hennion
Anne-Christine
AC
Institut d'Electronique, de Microélectronique et de Nanotechnologie, UMR 8520 CNRS, Department ISEN, 41 Boulevard Vauban, 59046 Lille Cedex, France.
de Billy
Michel
M