Precise formulation of the vibroacoustic effects of an added constrained damping layer on a plane structure.

The model proposed here describes the SAV behavior of a sandwich plate (elastic–visoelastic–elastic) and uses the following hypothetisis, inspired by the discrete layer theory: The viscoelastic layer takes into account bending, shear, and traction compression; normal strain and torsional motion are neglected; using the continuity of the displacement at the visoelastic layer interfaces, the displacement field of the viscoelastic layer is written as a function of the elastic layer displacement field. A variational method is used to find the displacement equations. The radiation impedance is calculated via a formulation recently proposed by Atalla and Nicolas [J. Acoust. Soc. Am. (1994)]. This formulation allows one to calculate, for a large frequency range, the quadratic velocity, the radiation efficiency, and the radiated power. Emphasis is then put on precise experimental validation. A fully instrumented setup using a laser vibrometer for probing the displacement field has been developed. The basic plate ...