Higher-order free vibrations of sandwich beams with a locally damaged core

摘要

The dynamical equations describing the free vibration of sandwich beams with a locally damaged core are derived using the higher-order theory approach. The nonlinear acceleration fields in the core are accounted for in the derivations, which is essential for the vibration analysis of the locally damaged sandwich beams. A local damage in the core, arbitrarily located along the length of the sandwich beam, is assumed to preclude the transition of stresses through the core between the undamaged parts of the beam. The damage is assumed to exist before the vibration starts and not to grow during oscillations. The numerical analysis based on the derived equations has been verified with the aid of the commercial finite element software ABAQUS. The numerical simulations reveal that a small local damage causes significant changes in the natural frequencies and corresponding vibration modes of the sandwich beams. An important practical consequence of the present work is that the vibration measurements can be successfully used as a nondestructive damage tool to assess local damages in sandwich beams. (C) 2004 Elsevier Ltd. All rights reserved.