＜正＞Passive periodic structures exhibit unique dynamic characteristics that make the passive periodic structures act as mechanical filters for wave propagation.As a result,wave can propagate along the periodic structures only within specific frequency bands called the pass bands and wave propagation is completely blocked within other frequency bands called the"stop bands".A theoretical method based on the transfer matrix formulation is developed in order to effectively investigate the influence of periodicity,variable geometry and material properties on the wave propagation characteristics of one-dimensional periodic rod.Several numerical examples are presented in order to illustrate their unique tunable filtering and localization characteristics.The experiments are conducted to verify the numerical predictions and to demonstrate the capability of the wavelet transform as a very powerful tool to uniquely identify and compare the energy distribution both in the time and frequency domain.The flexibility that the spectral width and location of the pass and stop bands can be tuned by introducing intentional variation in geometric and material properties for the individual substructure or cell is identified completely by both numerical predictions and experimental results. The results demonstrate the potential of such one-dimensional periodic structure in controlling the dynamics of wave propagation as a mechanical filter such as engine mount,gearbox support strut and other applications.
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