Patent ID: 7755876

Claim:
A composite structure comprising: a composite skin; an internal substructure, said composite skin being attached to said internal substructure, said internal substructure including metal substructure; a plurality of holes through said composite skin; and a fastening assembly attaching said composite skin to said metal substructure through ones of said holes, said fastening assembly providing lightning strike protection internal to said composite structure, said fastening assembly comprising: a fastener passing through one said hole to said metal substructure, a washer with concentric grooves in both sides, said fastener further passing through said washer, a sleeve, said fastener further passing through said sleeve, said sleeve fixed to said fastener against said washer and holding said fastener in place, and a soft dielectric material on both sides of said washer, said soft dielectric material filling each concentric groove and radiating outward and inward from said each concentric groove, wherein said hole is sealed internally by said washer and said soft dielectric material.