Unconstrained Treatment

A mastic deadener in the form of a homogeneous, uniform adhesive layer is a common unconstrained damping treatment. This treatment has been analyzed assuming the base plate to be nondissipative and the overall loss factor of the composite plate thus arrived at has been found to be accurate. The overall loss factor has also been obtained by assuming, in addition, that the extensional stiffness of the viscoelastic layer is much less than that of the base plate. This overall loss factor is given by

where
= loss factor of the viscoelastic layer in longitudinal deformation,
,        

with = Storage Young's modulus of the viscoelastic layer,
       = Young's modulus of the base layer,
       = Thickness of the viscoelastic layer,
       = Thickness of the base layer.