Considering the vibrational damping of bubble wrap. My basic premise is that there are three main contributors to the damping effect:
1) Surface tension of the sheet structure and the bubbles themselves when subject to applied force causes dissipation of force away from applied direction
2) The change of volume of the bubble chambers (filled with air) requires work to be done: energy loss!
3) Reflexion at boundary layers: a very small portion of the propagating vibrations (mechanical waves) are reflected back at each boundary.
I'm wondering if refraction would also contribute. Any ideas would be appreciated.