Free vibration analysis of sandwich beams with honeycomb-corrugation hybrid cores

The vibration performance of sandwich beams with honeycomb-corrugation hybrid cores was investigated in this paper. The method of homogenization was employed to obtain the equivalent macroscopic stiffness of honeycomb-corrugation hybrid cores. Finite element methods and modal analysis techniques have been used to predict their vibration characteristics (i.e. their natural frequencies and mode shapes). It is shown that in most cases the predictions by using the equivalent homogenization model (2D model) agree well with the experimental and three-dimensional finite element calculated results. For sandwich beams with corrugated cores, the filling honeycomb not only enhances their flexural rigidity and increases their natural frequency of higher orders, but also more or less eliminates the anisotropy of the structural stiffness and suppresses the local modes of vibration. In addition, considering mass efficiency, a dimensionless frequency parameter was proposed. It was found that the frequency parameter has different sensitivity to the geometry parameters, i.e. the slenderness ratio of corrugated member, the face sheet thickness ratio and the relative density of filling honeycomb.