Method of fabricating a reinforced composite structure

• US 4,331,495 A
• Filed: 02/27/1981
• Issued: 05/25/1982
• Est. Priority Date: 01/19/1978
• Status: Expired due to Term

• Current Assignee: Rockwell International Corporation
• Original Assignee: Rockwell International Corporation
• Inventors: Hill, John A., Lackman, Leslie M.
• Primary Examiner(s): Kimlin, Edward C.
• Assistant Examiner(s): Dawson, Robert A.
• Application Number:
  US06/238,716
• Time in Patent Office: 452 Days
• Field of Search: 28/141, 52/309.1, 52/309.2, 52/764, 52/765, 156/91-93, 156/197, 156/252, 156/253, 428/102-104, 428/116-118, 428/286, 428/408, 428/119, 83/30, 83/660, 112/262.1, 112/423, 112/438, 112/440, 244/123, 244/132
• US Class Current: 156/93
• CPC Class Codes: B29C 70/865 completely encapsulated
• CPC Class Codes: B29D 99/0014 provided with ridges or ribs, e.g. joined ribs
• CPC Class Codes: B32B 3/12 characterised by a layer of regularly- arranged cells, e.g. a honeycomb structure
• CPC Class Codes: B32B 3/266 characterised by an apertured layer, the apertures going through the whole thickness of the layer, e.g. expanded metal, perforated layer, slit layer regular cells B32B3/12
• CPC Class Codes: B32B 7/06 permitting easy separation
• CPC Class Codes: B32B 7/12 using interposed adhesives or interposed materials with bonding properties
• CPC Class Codes: B64C 1/06 Frames; Stringers; Longerons ; Fuselage sections
• CPC Class Codes: B64C 1/12 Construction or attachment of skin panels
• CPC Class Codes: B64C 2001/0072 from composite materials
• CPC Class Codes: Y02T 50/40 Weight reduction
• CPC Class Codes: Y10T 156/1057 Subsequent to assembly of laminae
• CPC Class Codes: Y10T 428/236 Honeycomb type cells extend perpendicularly to nonthickness layer
• CPC Class Codes: Y10T 428/24033 including stitching and discrete fastener[s], coating or bond
• CPC Class Codes: Y10T 428/24149 Honeycomb-like
• CPC Class Codes: Y10T 428/24174 including sheet or component perpendicular to plane of web or sheet
• CPC Class Codes: Y10T 428/30 Self-sustaining carbon mass or layer with impregnant or other layer

Abstract

A composite structure has two composite panels which are bonded together at a joint. The joint is reinforced by composite thread being sewn in a series of stitches through the panels. Sewing the panels while they are in a staged condition allows the structure to be co-cured as assembled.

Claims

1. A method of forming a reinforced composite structure which comprises:

staging a first composite panel and a second composite panel, each of said panels having a plurality of fiber composite plies, said plies being adhesively bonded together;

joining said first panel to said second panel by sewing a series of stitches of uncured flexible composite thread through said first panel and said second panel;

co-curing said panels and said thread as joined.

2. The method of claim 1 wherein said stitches are positioned to reinforce said structure when cured.

3. The method of claim 2 also including forming a series of aligned holes through said panels, said composite thread passing through said aligned holes in order to sew said first panel to said second panel.

4. The method of claim 3 wherein said holes are formed by a high-speed rotating awl.

5. The method of claim 3 wherein said holes are formed by an awl which is forced through said panels by an ultrasonic gun.

6. The method of claim 2 wherein said second panel is a web, said web having three portions, a first portion and a second portion which are divided by a fillet portion;

and also including positioning said first panel relative to said web such that said first portion is positioned parallel to said first panel and said second portion is positioned transversely to said first panel.

7. The method of claim 6 wherein said thread is sewn through said first portion of said web and said second panel adjacent to said fillet portion.

8. The method of claim 7 also including sewing a series of stitches through said second portion adjacent to said fillet portion.