Wave propagation in a sandwich plate with a periodic composite core

摘要

By using the finite element method, the propagation of Lamb waves in a sandwich plate with a periodic composite core is investigated. The periodic composite core is constituted by a square array of elastic cylinders embedded in a solid matrix. The dispersion relations and transmission responses are calculated. The results show that both stop and pass bands are involved in the dispersion relations. The influences of the thickness and material properties of the facesheets and the filling fraction of the inclusions in the core on the stop band are discussed. It is noted that the thickness of either the core or the facesheets, the material properties as well as the filling fraction play key roles in tuning the dispersion relations of the sandwich plates. The analysis of the displacement fields shows that the eigenmodes located at the edges of the stop bands are influenced by the thickness of the facesheets. Besides, by removing one or an array of cylinders, a point or line defect is introduced into the sandwich plate. The dispersion relations and the displacement fields of the eigenmodes for such defected systems are calculated. The localization and/or propagation behaviors of the defect modes appearing in the frequency ranges of the stop bands are discussed in detail. The study is relevant to understanding the vibration and the wave motion of the sandwich plate with a periodic composite core and manipulating the propagation of the vibration and the wave motion in this structure.