Composite Loss Factor of Viscoelastic Sandwich Beams

Abstract

The effects of axial force on the composite loss factor and natural frequency of a viscoelastic sandwich beam which is composed of a core layer of viscoelastic material and thin elastic outer layers are investigated. Assuming the vibratory energy dissipation to take place due to the shear deformation of the viscoelastic layer, the equation of motion and boundary conditions for a viscoelastic sandwich beam is derived from Hamilton's principle. The value of the composite loss factor of the sandwich beam increases as the compressive force increases and decreases as the axial tensile force increases. Experiments have been carried out with a cantilever sandwich beam subjected to no axial forces and the fixed ends one subjected to axial force. Good agreement has been found between the experiments and calculations.