Composite with infusion film systems and methods

Patent metadata

Field	Value
Publication number	US-11433625-B2
Application number	US-201916669263-A
Country	US
Kind code	B2
Filing date	Oct 30, 2019
Priority date	Oct 30, 2019
Publication date	Sep 6, 2022
Grant date	Sep 6, 2022

Abstract

Described are methods and systems for a composite structure that allows for out of autoclave curing. Due to the layout of the composite structure, voids within the composite structure, formed out of autoclave, is reduced. The composite structure includes a composite laminate and one or more infusion films. The composite laminate includes a plurality of fiber tows that each include a plurality of fiber strands and a resin. The resin has a first viscosity within a first temperature range. The infusion film is disposed on a surface of the composite laminate and has a second viscosity lower than the first viscosity within the first temperature range. Methods of curing the composite structure are also described.

First claim

The invention claimed is:

1. A composite structure comprising:
a composite laminate, comprising a first laminate surface, a second laminate surface, and a plurality of fiber tows disposed between the first laminate surface and the second laminate surface,
wherein each of the plurality of fiber tows comprises a plurality of fiber strands and a resin,
wherein each of the plurality of fiber tows comprises a first portion and a second portion,
wherein the resin is disposed within the first portion of each of the plurality of fiber tows and the second portion of each of the plurality of fiber tows is free of resin,
wherein each of the plurality of fiber tows is disposed proximate to a different one of the plurality of fiber tows,
wherein the resin has a first viscosity within a first temperature range and is configured to not flow into the second portion when in the first temperature range, and
wherein the resin is configured to flow into the second portion when in a second temperature range greater than the first temperature range; and

an infusion film, disposed on the first laminate surface of the composite laminate,
wherein the infusion film has a second viscosity that is lower than the first viscosity of the resin within the first temperature range, and
wherein the infusion film is configured to flow into the composite laminate when the infusion film is within the first temperature range.

2. The composite structure of claim 1 , wherein the composite laminate further comprises a void, disposed between the plurality of fiber tows, and wherein the infusion film is configured to flow into the void when the infusion film is within the first temperature range.

3. The composite structure of claim 1 , wherein the first portion is an outer portion of each of the plurality of fiber tows.

4. The composite structure of claim 1 , wherein the first laminate surface is an upper surface of the composite laminate.

5. The composite structure of claim 1 , wherein the infusion film is further configured to migrate into one or more voids created by the resin flowing into the second portion when in the second temperature range.

6. The composite structure of claim 1 , wherein the second portion is a center portion of the plurality of fiber tows.

7. The composite structure of claim 1 , wherein the infusion film is a first infusion film and the composite structure further comprises:
a second infusion film, disposed on the second laminate surface, wherein the second infusion film has the second viscosity that is lower than the first viscosity of the resin within the first temperature range and is configured to flow into the composite laminate when the second infusion film is within the first temperature range, and wherein the second laminate surface is opposite of the first laminate surface.

8. The composite structure of claim 1 , wherein the composite laminate is a first composite laminate comprising a first plurality of fiber tows, and wherein the composite structure further comprises:
a second composite laminate comprising a second plurality of fiber tows, wherein the infusion film is disposed between the first composite laminate and the second composite laminate.

9. The composite structure of claim 1 , wherein the composite structure is configured to be coupled to a portion of an aircraft.

10. A composite structure comprising:
a first composite laminate;
a second composite laminate, wherein each of the first composite laminate and the second composite laminate comprises a plurality of fiber tows,
wherein each of the plurality of fiber tows comprises a plurality of fiber strands and a resin,
wherein each of the plurality of fiber tows comprises a first portion and a second portion,
wherein the resin is disposed within the first portion of each of the plurality of fiber tows and the second portion of each of the plurality of fiber tows is free of resin,
wherein each of the plurality of fiber tows is disposed proximate to a different one of the plurality of fiber tows,
wherein the resin has a first viscosity within a first temperature range and is configured to not flow into the second portion when in the first temperature range, and
wherein the resin is configured to flow into the second portion when in a second temperature range greater than the first temperature range; and

an infusion film, disposed between the first composite laminate and the second composite laminate,
wherein the infusion film has a second viscosity that is lower than the first viscosity of the resin within the first temperature range, and
wherein the infusion film is configured to flow into the first composite laminate, the second composite laminate, or both when the infusion film is within the first temperature range.

11. A method comprising:
disposing a vacuum bag around a composite structure, the composite structure comprising:
a composite laminate, comprising a first laminate surface, a second laminate surface, and a plurality of fiber tows disposed between the first laminate surface and the second laminate surface,
wherein each of the plurality of fiber tows comprises a plurality of fiber strands and a resin,
wherein each of the plurality of fiber tows comprises a first portion and a second portion,
wherein the resin is disposed within the first portion of each of the plurality of fiber tows and the second portion of each of the plurality of fiber tows is free of resin,
wherein each of the plurality of fiber tows is disposed proximate to a different one of the plurality of fiber tows,
wherein the resin has a first viscosity within a first temperature range and is configured to not flow into the second portion when in the first temperature range, and
wherein the resin is configured to flow into the second portion when in a second temperature range greater than the first temperature range; and

an infusion film, disposed on the first laminate surface of the composite laminate,
wherein the infusion film has a second viscosity that is lower than the first viscosity of the resin within the first temperature range, and
wherein the infusion film is configured to flow into the composite laminate when the infusion film is within the first temperature range;

reducing pressure inside the vacuum bag to provide a compressive force on the composite structure; and
heating the composite structure to the first temperature range to flow the infusion film into the composite laminate.

12. The method of claim 11 , further comprising:
filling a void within the composite laminate with the infusion film.

13. The method of claim 11 , further comprising:
heating the composite structure to the second temperature range to migrate the resin into the second portion of the fiber tows.

14. The method of claim 11 , wherein the second portion is a center portion of the fiber tows.

15. The method of claim 13 , wherein the migrating of the resin into the second portion displaces air from the second portion.

16. The method of claim 13 , wherein the migrating of the resin into the second portion further flows the infusion film into the composite laminate.

17. The method of claim 11 , further comprising:
laying up the composite laminate.

18. The method of claim 11 , further comprising:
applying the infusion film to the first laminate surface; and
applying the infusion film to the second laminate surface.

19. The method of claim 18 , wherein the reducing the pressure and the heating the composite structure are performed out of autoclave.

Assignees

• Boeing Co

Inventors

• Spalding John F
• Hays Kelsi M
• Huang Derek

Classifications

• B32B37/10

  characterised by the pressing technique, e.g. using action of vacuum or fluid pressure · CPC title

• B32B27/12

  next to a fibrous or filamentary layer · CPC title

• B32B5/02 Primary

  characterised by structural features of a {fibrous or filamentary} layer {(layer formed of metallic wires B32B15/02; layer formed of natural mineral fibres B32B19/02; layer formed of wood fibres B32B21/02)} · CPC title

• B32B33/00

  Layered products characterised by particular properties or particular surface features, e.g. particular surface coatings; Layered products designed for particular purposes not covered by another single class · CPC title

• B32B7/12

  using interposed adhesives or interposed materials with bonding properties · CPC title