Frequencies and Loss Factors of Multicored Sandwich Beams

Abstract

The sandwich beam analyzed in the present paper consists of layers of elastic and viscoelastic material of arbitrary thickness and material. No restrictive assumptions are made on the bending and shear rigidities of the cores. Higher-order effects like rotatory inertia, bending, and extension of the core, which were ignored in previous theories, are included in the equations of motion presented herein. Exact equations for finding resonant frequencies and loss factors are given for simply-supported beams, while for other boundary conditions, these quantities are computed by variational method. Analysis of numerical results indicates that unsymmetricizing the face layers is superior to unsymmetricizing the core layers. It also showed that uniformly high damping over a wide frequency range can be obtained only by the use of stiff cores, but this is followed by a reduction in the maximum loss factor.