Patent ID: 8070994

Claim:
A method of forming an interior panel structure for providing sound absorption, damping, or attenuation comprising: providing a first panel formed at least partially of an epoxy/glass composite material, the first panel being an inner panel of an aircraft; providing a second panel formed at least partially of a porous material that includes a metal, the second panel being an outer panel of an aircraft; locating a honeycomb support intermediate the first panel and the second panel, such that the support includes a plurality of openings, a first surface and a second surface; locating a layer of heat activated foamable material including an elastomer on the first surface of the honeycomb support so that the heat activated material enters each of the plurality of openings; placing the first panel in contact with the layer of foamable heat activated material and the first surface of the honeycomb support; placing the second panel in contact with the second surface of the honeycomb support; exposing the heat activated material to a temperature in the range of about 150Â° F. to about 550Â° F. for at least about 10 minutes to cause the epoxy glass composite to cure and the heat activated foamable material to expand to create a foam material and to occupy a volume that is at least 400% of the volume occupied by the first layer of heat activated material prior to expansion and bond to at least the first panel, the side surface of the panels, the honeycomb support, and the sides of the honeycomb support whereby after expansion and cure the foam material remains in a softened state post-cure and fills from about 5% to about 90% of each of the plurality of openings within the honeycomb support so that space remains between the foam material and the second panel so that sound is absorbed by the space and foam material.