Damping material coat on steel plate

[S1mul4t0r101]

Hello.
I am trying to simulate sound pessure levels in air with acoustic structural analysis. I get pressure values from steady state Modal analysis. But when i apply a skin to the plate the pressure values don't get damped. I want to reduce the sound produced and am using a skin with shell thickness of 5mm but no change in the POR results. Please tell me how i can simulate a rubber coating on the plate that reduces vibration.
here are the models and material specs.

 

[btrueblood]

Google "constrained layer damping" - you need a stiff plate on the opposite side of the rubbery skin, so that the skin gets flexed in shear, where the rubber's damping properties are maximized.

edit: oh, and you need to make sure you properly model (nonlinear?) the rubber material to see the damping effects...I know very little of that process.