Vibroacoustic behavior of cylindrical shell: Comparison of numerical approach and experimental measurement.

Abstract

The control of the vibratory and sound level inside the planes is a significant commercial argument which has direct consequences on comfort, health, and safety of the users. Viscoelastic multilayered patches, called systems passive constrained layer damping (PCLD), based on the damping brought by viscoelastic materials are passive systems used to reduce the vibratory levels. The objective of this presentation is to show, using numerical and experimental studies, that this damping applied to the structure has an influence on the sound transmission (outside/inside), which makes it possible to increase the noise reduction. The experimental study is carried out on a model made up of a cylindrical shell coupled to a cavity and excited by a white noise. The cylindrical shell is equipped with a damping device implying viscoelastic materials which work in shearing. Parallel to this, a numerical study was carried out to (1) predict the vibroacoustic behavior of the stiffened cylindrical shell coupled with the cavity and (2)validate the vibration attenuation brought by the PCLD technology in terms of acoustic performances. The high modal density and the big vibroacoustic size of the model are two problems for numerical modeling. These studies show that numerical and experimental results are similar.