Ultra-thin films inter-facial shear effects on modal damping characterization of laminated plate

This paper deals with a new numerical model for predicting the dynamical behaviour of a laminated plate composed of two glass skins and a viscoelastic core (PVB: butyral polyvinyl) assembled by two adhesive ultra-thin films. In order to introduce the effect of the ultra-thin films, some suggestions are considered in the kinematic hypothesis. Therefore, a new dynamic model is highlighted by mixing Kirchhoff and Mindlin plate's theories, respectively for the two skins and the core with a specific behaviour law for the adhesive ultra-thin films. Then, the finite element method is used to calculate the elastic eigenmodes which are compared to those corresponding to the experimental study. Besides, a hysteretic structural damping is considered in the viscoelastic core model. Hence, the aim of this work is to characterize the modal damping due to the coupling between the different layers of the complex structure. Thus, a dynamic modal analysis is carried out via both, the calculation of the vibratory responses and the modal recombination method. The influence of some parameters such as; the thickness of the core, the length, the width and the area of laminate on the modal structural plate damping have been investigated in details. Then, numerical results show the importance of the adhesive film shear effects on the modal damping of the studied structure.