Foam stiffened hollow composite stringer

• US 8,419,402 B2
• Filed: 01/13/2011
• Issued: 04/16/2013
• Est. Priority Date: 11/08/2007
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Guzman, Juan C., McCarville, Douglas A., Rotter, Daniel M., VanWest, Barry P.
• Primary Examiner(s): Del Sole, Joseph S
• Assistant Examiner(s): Sultana, Nahida
• Application Number:
  US13/005,786
• Publication Number:
  US 20110111183A1
• Time in Patent Office: 824 Days
• Field of Search: 264/241, 264/275, 264/248, 264/156, 264/46.4, 425/393, 425/403, 425/110, 156/182, 244/177.R
• US Class Current: 425/110
• CPC Class Codes: B29C 44/583 for making articles with cavities
• CPC Class Codes: B29C 70/086 and with one or more layers of pure plastics material, e.g. foam layers applying a non-preformed coating, e.g. a gel-coat, B29C37/0025; with foam blocks B29C70/86
• CPC Class Codes: B29C 70/865 completely encapsulated
• CPC Class Codes: B29D 99/0003 Producing profiled members, e.g. beams
• CPC Class Codes: B29K 2715/003 Cellular or porous
• CPC Class Codes: B64C 1/064 Stringers; Longerons
• CPC Class Codes: Y02T 50/40 Weight reduction
• CPC Class Codes: Y10T 428/24744 Longitudinal or transverse tubular cavity or cell

Abstract

A method and apparatus for a composite stringer. A method is used for manufacturing a hollow composite stringer. Foam is formed with a mandrel installed into the foam. A composite material and the foam is laid up onto a tool in a form of a stringer. The composite material and the foam in the form of the stringer is cured to form a cured stringer. The mandrel from the foam is removed to form the hollow composite stringer.

Claims

1. An apparatus comprising:

a skin ply;

a composite stringer placed on the skin ply, wherein the composite stringer comprises a hat shape cross-section comprising a first leg placed on a surface of the skin ply, a second leg placed on the surface of the skin ply, and a concave surface between the first leg and the second leg and wherein the composite stringer defines an elongated first channel between the concave surface of the composite stringer and a portion of the surface of the skin ply between the first leg and the second leg and extending from a first end to a second end of the composite stringer;

foam located in the first channel; and

a set of second channels in the foam such that the foam with the set of second channels in the foam is positioned between the concave surface of the composite stringer and the skin ply.

2. The apparatus of claim 1 further comprising:

a set of removable mandrels located in the set of second channels in the foam.

3. The apparatus of claim 1, wherein the skin ply, the composite stringer, and the foam with the set of second channels is located in an aircraft.

4. The apparatus of claim 1, wherein the set of second channels are elongated channels extending in a direction substantially parallel to an axis extending along the first channel from the first end to the second end of the composite stringer.