Composite sandwich structure with integrated reinforcement area and method of producing the same

A method of producing a local reinforcement area in a core structure of a composite sandwich structure, comprising:

• a) providing a composite sandwich structure including an open three-dimensional core structure and first and second cover layers applied on opposite first and second sides of said core structure, wherein said core structure comprises a folded core element having fold valleys forming open channels that are bounded between said folded core element and said first and second cover layers and that extend in a longitudinal direction of said open channels continuously along and parallel to said first and second cover layers;
• b) forming a hole having a hole diameter in at least said first cover layer and in said core structure;
• c) forming a hollow space having a hollow space diameter in said core structure, wherein said hollow space diameter is at least twice as large as said hole diameter, said hollow space is bounded at least partially by bounding parts of said core structure at a perimeter of said hollow space, said hollow space communicates into an adjoining open channel of said open channels, and said bounding parts of said core structure at said perimeter of said hollow space are cut edges of webs of said folded core element that were cut during said forming of said hollow space;
• d) introducing a spatial boundary device comprising a spiral sleeve through said hole in said first cover layer into said hollow space in said core structure, wherein at least a partial area of said spiral sleeve is a material strip of a perforated sheet, a net, a mesh, or a woven web that has a regular pattern of openings passing therethrough;
• e) outwardly expanding and seating said spiral sleeve in said hollow space so that said spiral sleeve at least partially contacts outwardly against said bounding parts of said core structure;
• f) introducing a filler material into a bounded space formed within said spiral sleeve, wherein said openings serve to permit a limited discharge of said filler material out of said bounded space and into said adjoining open channel to fix said spiral sleeve in said core structure, and then hardening said filler material so as to form thereof a local reinforcement area, and
• g) integrating a securing element into said local reinforcement area after the formation of said local reinforcement area.