Panel assembly having multi-layer patch for sound damping

A method of making a panel assembly, comprising the steps of:

• (a) providing a main panel, a first individual patch, and a second individual patch that is smaller than the first individual patch;
• (b) attaching the first individual patch to the main panel via a primary adhesive layer and attaching the smaller second individual patch to the first individual patch via an auxiliary adhesive layer so that a flat pre-formed panel assembly is formed where only a portion of the first individual patch is covered by the smaller second individual patch;
• and
• (c) subjecting the pre-formed panel assembly to a metal forming operation so that the main panel, the first individual patch, the second individual patch, the primary adhesive layer and the auxiliary adhesive layer are formed together into a post-formed panel assembly.

A panel assembly, comprising:

• a main metal panel;
• a primary viscoelastic adhesive layer;
• and
• a multi-layer metal patch having at least two individual metal patches and at least one auxiliary viscoelastic adhesive layer, wherein the primary viscoelastic adhesive layer attaches the multi-layer metal patch to the main metal panel at the acoustically active region for sound damping, and the auxiliary viscoelastic adhesive layer attaches an outer one of the individual metal patches to an inner one of the individual metal patches such that a stacked layer profile of the multi-layer metal patch has a plurality of areas of overall increased material thickness, and at least two of the areas of overall increased material thickness have a different shape.