# US 5,348,601 A · Method of making an offset corrugated sandwich construction

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- Number: US 5,348,601 A
- Document ID: US5348601A
- Status: Granted
- Kind: A
- Application number: 08/082,068
- Filed: 1993-06-23
- Granted: 1994-09-20
- Earliest claimed: 1993-06-23
- Assignees: The United States of America as represented by the Secretary of the Navy
- Inventors: Hemen Ray
- Web page: https://patentgrep.com/patent/US5348601A

## CPC

- B29D 24/004: {the structure having vertical or oblique ribs}
- B29C 53/22: Corrugating
- Y10S 264/44: using destructible molds or cores in molding processes
- Y10T 156/1025: to form undulated to corrugated sheet and securing to base with parts of shaped areas out of contact
- B29D: PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE (making granules B29B9/00; making preforms B29B11/00)
- B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00)
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A method for making an offset corrugated core sandwich construction is diosed. Mandrels of preestablished form and size are arranged into a pattern in a confined area. After covering the mandrels with a release film, strips of pliable, uncured composite material are arranged in a "peak-to-valley" pattern with adjacent strips being out of phase by 180 degrees. Selected mandrels are replaced by a granular mixture and top and bottom face sheets are fitted to the arrangement. After curing, all mandrels are removed from the construction.

## Claims

### Claim 1

A method for making an off-set corrugated core sandwich construction comprising the steps of:
placing shaping mandrels into a prearranged pattern wherein each mandrel has an exterior surface;
wrapping a release film over the exterior surface of each of said mandrels;
arranging a first strip of pliable composite material to bend over and around said mandrels to from alternating crests and troughs;
arranging subsequent strips of pliable composite material to form alternating crests and troughs wherein each strip is approximately 180.degree. out of phase with an adjacent strip;
attaching a face sheet to the crests of the strips and attaching a face sheet to the troughs of the strips to form an off-set corrugated core sandwich construction;
replacing selected of said mandrels with a granular mixture;
curing the construction; and
removing the granular mixture and release films.

### Claim 2 (depends on 1)

The method according to claim 1 wherein said shaping mandrels are hexagonal and triangular solid forms.