Zheng H., Cai C.

Sound radiation from a beam structure with varying constrained layer damping (CLD) treatment is examined analytically. Energy-based approach and assumed-mode method are used to derive the equations governing the displacement response of the system. Through solving the governing equations, the vibration responses at different locations of the damped structure are obtained in a frequency range of interest and these results are further used for determining the modal damping loss factors of a few of acoustically-dominant modes by employing direct frequency response model. Furthermore, by using Rayleigh’s integral, the obtained vibration response results are also used for the calculation of the baffled beam’s radiated sound power into half free-space. A parametric study is ultimately performed to study the effect of the CLD location over a simply-supported beam on damped modal parameters and radiated sound power. In particular, the influence of the damping treatment on the restructured damped mode shape is addressed. This influence has been seldom included in existing studies of CLD treatment for structural vibration suppression, but it is important to some cases of CLD treatment for noise control purpose.