Methods for forming composite structures

Patent metadata

Field	Value
Publication number	US-2020016880-A1
Application number	US-201816036228-A
Country	US
Kind code	A1
Filing date	Jul 16, 2018
Priority date	Jul 16, 2018
Publication date	Jan 16, 2020
Grant date	—

Abstract

A method is provided in one example embodiment and may include forming a ply stack comprising a plurality of uncured composite plies, wherein one or more uncured composite ply of the plurality of uncured composite plies comprises a plurality of perforations that extend, at least partially, through a thickness of the one or more uncured composite ply; and compacting the ply stack to form a composite structure. The plurality of perforations may provide paths for volatiles to be removed through the thickness of the one or more uncured composite ply of the ply stack during the compacting. Volatiles may also be removed through edges of the ply stack during the compacting. In some instances, all uncured composite plies of the ply stack may include a plurality of perforations that extend, at least partially, through the thickness of each uncured composite ply.

First claim

What is claimed is:

1 . A method comprising:
forming a ply stack comprising a plurality of uncured composite plies, wherein one or more uncured composite ply of the plurality of uncured composite plies comprises a plurality of perforations that extend, at least partially, through a thickness of the one or more uncured composite ply; and compacting the ply stack to form a composite structure.

2 . The method of claim 1 , wherein compacting the ply stack further comprises:
encapsulating the ply stack within a bag; and increasing a vacuum level within the bag to increase external pressure on the bag and the composite structure.

3 . The method of claim 1 , wherein the plurality of perforations provide paths for volatiles to be removed through the thickness of the one or more uncured composite ply of the ply stack during the compacting.

4 . The method of claim 3 , wherein volatiles are also removed through edges of the ply stack during the compacting.

5 . The method of claim 1 , wherein the ply stack comprises at least 14 uncured composite plies.

6 . The method of claim 1 , wherein the plurality of perforations are provided for one or more areas of the one or more uncured composite ply of the plurality of uncured composite plies, and the one or more areas correspond to one or more of:
one or more curved portions of the composite structure; one or more angled portions of the composite structure; and one or more corner portions of the composite structure.

7 . The method of claim 1 , wherein the plurality of perforations are provided for an overall area of at least one uncured composite ply of the plurality of uncured composite plies.

8 . The method of claim 1 , wherein the plurality of perforations for at least one uncured composite ply extend completely through the thickness of the least one uncured composite ply.

9 . The method of claim 1 , wherein at least one perforation of the plurality of perforations for a particular uncured composite ply intersects at least one evacuation channel for the particular uncured composite ply.

10 . The method of claim 1 , wherein compacting the ply stack further comprises:
providing a bleeder material along sides of the ply stack, wherein the bleeder material extends laterally away from the sides of the ply stack; providing a perforated release film over the ply stack, wherein the perforated release film extends laterally away from the sides of the ply stack; providing a breather material over the perforated release film, wherein the breather material extends laterally away from the sides of the ply stack, and the release film is between at least a portion of the breather material and the bleeder material; encapsulating the ply stack, the bleeder material, the perforated release film, and the breather material within a bag; and increasing a vacuum level within the bag to increase external pressure on the bag and the composite structure.

11 . The method of claim 10 , wherein compacting the ply stack further comprises:
providing roving material between the bleeder material and at least one side of the ply stack.

12 . The method of claim 1 , wherein forming the ply stack further comprises:
forming plurality of perforations for the one or more uncured composite ply of the plurality of uncured composite plies; and assembling the one or more uncured composite ply on a tool to form the ply stack after the plurality of perforations are formed for the one or more uncured composite ply.

13 . The method of claim 1 , wherein the perforations are formed for a side of the one or more uncured composite ply that has a backing layer.

14 . The method of claim 1 , wherein forming the ply stack further comprises:
assembling one or more uncured composite ply on a tool to form the ply stack; and forming perforations for the one or more assembled uncured composite plies on the tool.

15 . The method of claim 14 , wherein forming the ply stack further comprises:
assembling one or more additional uncured composite ply on the ply stack, wherein the one or more additional uncured composite ply does not have a plurality of perforations.

16 . The method of claim 15 , wherein forming the ply stack further comprises:
forming perforations for the one or more assembled uncured composite plies on the tool.

17 . The method of claim 1 , wherein all uncured composite plies of the ply stack comprise a plurality of perforations that extend, at least partially, through the thickness of each uncured composite ply.

18 . The method of claim 1 , wherein the compacting is performed at room temperature.

19 . The method of claim 18 , wherein the compacting is performed at one or more elevated temperatures following the room temperature compacting.

20 . The method of claim 1 , further comprising:
curing the composite structure.

Assignees

• Bell Helicopter Textron Inc

Inventors

• Mishra Suvankar
• Wrabel Jesse J
• Cribb Iii Vance N

Classifications

• B29C70/545

  Perforating, cutting or machining during or after moulding · CPC title

• B29C2793/0081

  before shaping · CPC title

• B29C2793/0045

  Perforating · CPC title

• B32B2605/18

  Aircraft · CPC title

• B32B2305/77

  Uncured, e.g. green · CPC title