A test validated model of plates with constrained viscoelastic materials

Surface damping treatments by viscoelastic materials are often considered nowadays to enhance dissipation in sheet metal and laminated glass parts. Constraining layers are needed to increase shear levels in the viscoelastic which is the primary source of dissipation. The damping behavior of such sandwich types structures is strongly influenced by the characteristics of the constraining layer and the deformation modes of the structure. It is first shown that finite element models based on classical laminated plate theory (CLPT) do not allow a proper representation of boundary conditions of the viscoelastic and the constraining layer which leads to an inaccurate prediction of the behavior of the damped structure. A layered shell/solid/shell model is introduced and shown to correct these shortcomings. The validity of the proposed model is demonstrated by correlation with experimental results obtained on the GARTEUR SM-AG-19 testbed. The damping treatment of this structure is a layer of ISD112 (a viscoelastic manufactured by 3M) constrained by an aluminum plate. Test and analysis damping levels are first shown to be very well correlated. Temperature dependence and computational times are finally discussed to give further insight in the proposed methodology.