US-12623377-B2 - Systems and methods for curing composite structures

Abstract

A composite curing system includes system includes a constraining container and an expandable medium. The constraining container includes a base and a cover and has an interior volume. The constraining container is configured to enclose at least a portion of a composite structure. The expandable medium configured to be disposed within the interior volume between at least a portion of the constraining container and the composite structure. The interior volume of the constraining container is selectively variable.

Inventors

• Xiaoxi Wang
• Jonathan Y. Ahn
• Jill E. Seebergh
• Shuonan Dong

Assignees

• THE BOEING COMPANY

Dates

Publication Date

20260512

Application Date

20240506

Claims (20)

1. 1 . A system comprising: a constraining container comprising a base and a cover and having an interior volume, wherein the constraining container is configured to enclose at least a portion of a composite structure; and an expandable medium configured to be disposed within the interior volume between at least a portion of the constraining container and the composite structure, wherein the cover comprises a plurality of walls and wherein at least one of the walls is movable relative to at least another one of the walls to selectively vary the interior volume of the constraining container.
2. 2 . The system of claim 1 , wherein the cover of the constraining container further comprises an overlay.
3. 3 . The system of claim 1 , further comprising an actuator configured to move the at least the one of the walls relative to at least another one of the walls to selectively vary the interior volume of the constraining container.
4. 4 . The system of claim 1 , wherein the expandable medium is disposed between at least the one of the walls of the cover and the composite structure.
5. 5 . The system of claim 1 , wherein: the plurality of walls comprises: side walls; and a top wall; and the top wall is movable relative to the side walls to selectively vary the interior volume of the constraining container.
6. 6 . The system of claim 5 , further comprising an actuator configured to move the top wall relative to the side walls.
7. 7 . The system of claim 5 , wherein the expandable medium is disposed between the top wall and the composite structure.
8. 8 . The system of claim 1 , wherein: the plurality of walls comprises: side walls; a top wall; and a cap; and the cap is sealed to the side walls and is movable relative to the side walls and the top wall to selectively vary the interior volume of the constraining container.
9. 9 . The system of claim 8 , wherein the expandable medium is disposed between the top wall and the cap.
10. 10 . The system of claim 1 , wherein the expandable medium is configured to expand to a predetermined volume when a predetermined change is produced in an attribute of the expandable medium such that the expandable medium applies positive pressure to the composite structure and the cover of the constraining container.
11. 11 . The system of claim 10 , further comprising a sensor configured to detect the positive pressure.
12. 12 . The system of claim 10 , wherein: the expandable medium comprises expandable pellets; the expandable pellets are thermally activated at an activation temperature; and the expandable pellets are configured to expand when a temperature of the expandable pellets is raised up to the activation temperature.
13. 13 . The system of claim 1 , further comprising a casting disposed between the expandable medium and the composite surface of the composite structure, wherein the casting is configured to harden.
14. 14 . The system of claim 1 , wherein: the plurality of walls comprises: side walls; and a top wall; and at least one of the side walls is movable relative to at least another one of the side walls and the top wall to selectively vary the interior volume of the constraining container.
15. 15 . The system of claim 14 , further comprising an actuator configured to move the at least one of the side walls relative to the at least another one of the side walls and the top wall.
16. 16 . The system of claim 14 , wherein the expandable medium is disposed between the at least one of the side walls and the composite structure.
17. 17 . A system comprising: a constraining container configured to enclose at least a portion of a composite structure and comprising a base and a cover and having an interior volume, wherein the cover comprises a plurality of walls and at least one of the walls is movable relative to at least another one of the walls; an actuator configured to move the at least the one of the walls relative to at least another one of the walls to selectively vary the interior volume of the constraining container; and an expandable medium disposed within the interior volume between at least one of the walls and the composite structure.
18. 18 . A system comprising: a constraining container comprising a base and a cover and having an interior volume, wherein the constraining container is configured to enclose at least a portion of a composite structure; and an expandable medium configured to be disposed within the interior volume between at least a portion of the constraining container and the composite structure, wherein the cover comprises a plurality of side walls and an overlay, and wherein at least one of the side walls is movable relative to at least another one of the side walls to selectively vary the interior volume of the constraining container.
19. 19 . The system of claim 18 , further comprising an actuator configured to move the at least the one of the side walls relative to at least another one of the side walls to selectively vary the interior volume of the constraining container.
20. 20 . The system of claim 18 , wherein the expandable medium is disposed between the overlay and the composite structure.

Description

FIELD The present disclosure relates generally to composite manufacturing and, more particularly, to systems and methods for curing composite structures. BACKGROUND Engineered composite materials are used in many applications, typically where the composite material can be made stronger, lighter, and/or less expensively than a traditional material. A variety of modern composite materials exist, but the most common are varieties of fiber-reinforced polymer composites, such as fiberglass or carbon fiber composites. For many composite materials, the manufacturing process includes curing the composite structure, typically under elevated temperatures and pressures. An industrial autoclave is often used for curing composite materials, as autoclaves permit the application of both temperature and pressure under controlled conditions. However, processes requiring an autoclave may lead to bottlenecks in the manufacturing process, because throughput is dependent upon the capacity of the autoclave and requires transport of raw materials or uncured components to the autoclave and subsequent transport of the cured composite from the autoclave. Accordingly, those skilled in the art continue with research and development efforts in the field of predictive assembly. SUMMARY Disclosed are examples of a system for curing a composite structure, a method for curing a composite structure, and a composite workpiece. The following is a non-exhaustive list of examples, which may or may not be claimed, of the subject matter according to the present disclosure. In an example, the disclosed system includes a constraining container and an expandable medium. The constraining container includes a base and a cover and has an interior volume. The constraining container is configured to enclose at least a portion of a composite structure. The expandable medium configured to be disposed within the interior volume between at least a portion of the constraining container and the composite structure. The interior volume of the constraining container is selectively variable. In an example, the disclosed method includes steps of: (1) enclosing at least a portion of a composite structure in constraining container; (2) selectively varying an interior volume of the constraining container; (3) expanding an expandable medium disposed within the interior volume; and (4) curing the composite structure. In an example, the disclosed composite workpiece includes a composite structure including a plurality of composite layers. At least a portion of the plurality of composite layers is uncured. The composite structure is supported by a base of a constraining container. At least a portion of the composite structure is enclosed by a cover of the constraining container including a plurality of walls and having an interior volume. At least one of the walls is movable relative to at least another one of the walls to selectively vary the interior volume. An expandable medium is disposed within the interior volume of the cover between the cover and the composite structure and is configured to expand to a predetermined volume when a predetermined change is produced in an attribute of the expandable medium such that the expandable medium applies positive pressure to the composite structure and the cover. Other examples of the disclosed system, method, and composite workpiece will become apparent from the following detailed description, the accompanying drawings, and the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic block diagram of a system for curing a composite structure; FIG. 2 is a flow diagram of an example of a method for curing a composite structure; FIG. 3 is a schematic, sectional view of an example of a constraining container of the system applied to a composite structure; FIG. 4 is a schematic, sectional view of an example of the system shown in FIG. 3 with an expandable medium disposed within an interior volume of the constraining container; FIG. 5 is a schematic, sectional view of an example of the system shown in FIG. 4 after expansion of the expandable medium; FIG. 6 is a schematic, sectional view of an example of the system; FIG. 7 is a schematic, sectional view of an example of the system; FIG. 8 is a schematic, sectional view of an example of the system; FIG. 9 is a schematic, sectional view of an example of the system; FIG. 10 is a schematic, sectional view of an example of the system; FIG. 11 is a schematic, sectional view of an example of the system; FIG. 12 is a schematic, perspective view of an example of an aircraft hat stiffener; FIG. 13 is a schematic, perspective view of an example of an aircraft wing including stiffeners; FIG. 14 is a flow diagram of an example of an aircraft manufacturing and service method; and FIG. 15 is a schematic block diagram of an example of an aircraft. DETAILED DESCRIPTION Referring generally to FIGS. 1-11, by way of examples, the present disclosure is directed to a system 100 and a meth