Stiffened composite panels

Patent metadata

Field	Value
Publication number	US-2016176500-A1
Application number	US-201314902850-A
Country	US
Kind code	A1
Filing date	Aug 9, 2013
Priority date	Aug 9, 2013
Publication date	Jun 23, 2016
Grant date	—

Abstract

A stiffened panel comprises a composite panel, and a stiffener including a base flange on the composite panel. The base flange is tapered towards the panel. The stiffened panel further comprises a composite overwrap layer on only the composite panel and a tapered surface of the base flange.

First claim

1 . A stiffened panel comprising:
a composite panel; a stiffener including a base flange on the composite panel, the base flange tapered towards the panel; and a composite overwrap layer on only the composite panel and a tapered surface of the base flange.

2 . The stiffened panel of claim 1 , wherein the overwrap layer is co-bonded to the base flange and co-cured with the composite panel.

3 . The stiffened panel of claim 1 , wherein the overwrap layer, the base flange and the composite panel are co-cured.

4 . The stiffened panel of claim 1 , wherein the overwrap layer is co-cured with the stiffener, and the co-cured stiffener and overwrap layer are co-bonded with the composite panel.

5 . The stiffened panel of claim 1 , wherein a first and a second side of the base flange are tapered; and wherein a first overwrap layer is on both the composite panel and a tapered surface of the first side, and a second overwrap layer is on the composite panel and a tapered surface of the second side.

6 . (canceled)

7 . The stiffened panel of claim 1 , wherein the base flange is tapered to a knife-edge.

8 . The stiffened panel of claim 1 , wherein the base flange terminates in a step having a height of no more than 0.050 inches; wherein a volume is between the composite panel, the base flange, and the overwrap layer; and wherein a ply wrinkle is within the volume.

9 . (canceled)

10 . The stiffened panel of claim 1 , wherein the taper is a straight.

11 . The stiffened panel of claim 1 , wherein the taper is a radius.

12 . The stiffened panel of claim 1 , wherein the taper is compound.

13 . (canceled)

14 . (canceled)

15 . The stiffened panel of claim 1 , wherein the stiffener is made of composite material.

16 . The stiffened panel of claim 1 , wherein the composite panel is one of an aircraft skin and an aircraft web.

17 . The stiffened panel of claim 1 , wherein the composite panel is a skin of an aircraft wing; and wherein the stiffener is one of a spar, rib and stringer.

18 . A method comprising placing a stiffener and an overwrap layer on an uncured composite panel, the stiffener including a tapered base flange, the overwrap layer on only a tapered surface of the base flange and on an adjacent portion of the composite panel.

19 . The method of claim 18 , further comprising co-bonding the base flange to both the panel and the overwrap layer and co-curing the overwrap layer with the panel.

20 . The method of claim 18 , wherein the stiffener is made of a composite material comprising fiber-reinforced plastic that is cured and machined to produce the tapered base flange, the curing and machining performed prior to placing the stiffener on the panel.

21 . The method of claim 18 , further comprising fabricating the stiffener, including forming a composite ply stack having a tapered base flange; and curing the ply stack.

22 . The method of claim 18 , wherein placing the stiffener on the panel includes placing a composite ply stack on the uncured panel, the ply stack having a tapered base flange; wherein placing the overwrap layer includes placing uncured plies on the tapered surface of the base flange; and wherein the method further comprises co-curing the panel, stiffener and overwrap layer.

23 . (canceled)

24 . An aircraft assembly having a direction of primary loading, the assembly comprising:
composite skin; a stiffening substructure for the skin, the stiffening substructure including base flanges that are tapered in the direction of primary loading; and a plurality of overwrap layers, each overwrap layer starting from a tapered surface of a corresponding base flange and extending to the skin.

25 . The aircraft assembly of claim 24 , wherein the skin is wing skin; and wherein the stiffening substructure includes at least one of spars, ribs and stringers having the base flanges.

26 . (canceled)

Assignees

• Boeing Co

Inventors

• Ross Joshua Amory
• Cuda Shane Frank
• Mclaughlin Mark Ronald
• Rush Michael Robert
• Farr Colin Lee
• Smith David Bruce
• Desai Nihar Ashokkumar
• Kennedy Thomas Joseph
• Deobald Lyle Ray

Classifications

• B29K2105/0872

  Prepregs · CPC title

• B64C3/18

  Spars; Ribs; Stringers · CPC title

• B64C3/26 Primary

  Construction, shape, or attachment of separate skins, e.g. panels · CPC title

• B29D99/0014 Primary

  provided with ridges or ribs, e.g. joined ribs · CPC title

• B29C70/302

  Details of the edges of fibre composites, e.g. edge finishing or means to avoid delamination · CPC title