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Viscoelastic layered systems provide a simple and flexible solution for damping vibration of sheet metal panels. They also help to effectively eliminate noise from resonant structures and surfaces. This article presents an analytical formulation to predict the stiffness and damping of three layered beams with two different viscoelastic materials adjacent to each other. The complex modulus approach is used to model the elastic and shear moduli of the viscoelastic material and closed-form equations are derived for predicting system stiffness and damping. The model is derived for unsymmetrical setups using variational methods. Experiments are conducted on simply supported three-layered beams at different temperatures to validate theoretical results. Similar results are obtained from both the theoretical model and the experiments. A procedure for the optimization of structural and material parameters for maximizing the damping and minimizing the system mass for a given temperature and frequency range is also presented. [ABSTRACT FROM AUTHOR]

An analytical formulation Is presented for predicting the stiffness and damping of constrained layered beams that have multiple viscoelastic damping layers. A model is derived for symmetrical setups using variational methods. The equations to evaluate the stiffness and damping are derived in closed form and can be evaluated for different boundary conditions. The complex modulus approach is used to model the elastic and shear moduli of the viscoelastic material. A parametric analysis has been conducted to study the effects of different parameters on the damping and stiffness of the system under simply supported boundary conditions. The optimization process to obtain structural and material parameters maximizing system damping for a given temperature and frequency range is also presented. [ABSTRACT FROM AUTHOR]

In this paper, the application of passive damping technology using viscoelastic materials to control noise and vibration in vehicles and commercial airplanes is described. Special damped laminates and spray paints suitable for mass production and capable of forming with conventional techniques are now manufactured in a continuous manner using advanced processes. These are widely used in the automotive and aerospace industry in a variety of applications to reduce noise and vibration and to improve interior sound quality. Many of these recent applications are not readily available for dissemination in academe and archival literature. It is hoped that the material presented in this paper will be useful for instruction and further research in developing new and innovative applications in other industries. [Copyright &y& Elsevier]