Dynamical behavior of a double-beam system interconnected by a viscoelastic layer

• A semi-analytical method is proposed to study the natural and forced vibration of a double beam system interconnected by the viscoelastic layer with arbitrary beam masses, beam flexural rigidities and boundary conditions, as well as with and without the Winkler layer below the lower beam.
• A specific orthogonality condition for the viscous double-beam system is derived, and further applied to decouple the differential equations of motion.
• Numerical examples are demonstrated to verify the efficiency of the proposed methodology.

As an idealized model of modern beam-type structures, the double-beam system has been specified in recent decades. While there have been various research efforts on the double-beam system, most of them are over-simplified, among which the viscoelastic damping mechanism of interlayer is often neglected. This paper presents a semi-analytical method to investigate the natural frequencies and mode shapes of a double-beam system interconnected by a viscoelastic layer. The two beams can be with different beam-masses, beam flexural rigidities and boundary conditions, as well as with and without the Winkler layer below lower beam, indicating that there is no restriction or assumptions on beams connected with the viscoelastic layer damping. The modal-expansion iterated method is further applied to determine the forced vibration responses in the double-beam system based on the natural frequencies and mode shapes obtained from the free-vibration analysis. A specific orthogonality condition for the double-beam system is derived, and then applied to decouple the differential equations of motion. Numerical examples are demonstrated and discussed in details to verify the efficiency of the proposed methodology, which can further help characterize the dynamic responses and design work for double-beam structures.