Propagation of elastic waves in one-dimensional periodic stubbed waveguides

In this paper, the effect of side branches (or double stub) on the transmission of acoustical wave through periodic structures made of glued beads constituted of solid materials is studied. The displacement picked up at the end of the waveguide is numerically analyzed with the help of the dispersion curves. Experiments are conducted on finite one-dimensional specimens (chains) on which are grafted periodically double stubs. Two situations are investigated in which the mass of the stub beads and beads in the chain are identical or different. The experimental results are compared with numerical calculations and clearly demonstrated that the mechanical properties of the materials are of crucial importance for the width of the pass and forbidden bands (or gaps) as well as the existence of stub, evanescent, and propagating modes.