Estimation of loss factors of a constrained layer plate using viscoelastic layer

Abstract

A finite element method is developed and validated for the estimation of loss factors of a viscoelastically damped plate. Viscoelastic layer is used as constrained layer and is sandwiched between an aluminum base plate and a constraining layer. Frequency-dependent material properties are used for the viscoelastic material in the finite element model. The derived dynamic equations of motion are used to carry out harmonic analysis to determine the natural frequencies and loss factors of sandwich plate and validated with experimental results for cantilever boundary condition. The validated finite element model is then used to estimate the loss factors of sandwich plate with various boundary conditions and different thicknesses of constraining and constrained layer for a given base plate thickness. The results show that the loss factor is maximum for a constraining layer to sandwich plate thickness ratio of 0.40–0.45 and is independent of boundary condition. The loss factor increases with increase in thickness of the viscoelastic layer. The loss factor increases for higher mode for all boundary conditions.