Methods and apparatus for curing composite nacelle structure

Patent metadata

Field	Value
Publication number	US-10137607-B2
Application number	US-201414503593-A
Country	US
Kind code	B2
Filing date	Oct 1, 2014
Priority date	Oct 1, 2014
Publication date	Nov 27, 2018
Grant date	Nov 27, 2018

Abstract

Methods and apparatus for curing curved cylinder-like workpieces (e.g., in the shape of a half or full barrel) made of composite material, such as nacelle honeycomb core composite sandwich structures. These methods enable tailored curing of composite nacelle structures, to significantly reduce capital cost and fabrication cycle time. In lieu of an autoclave or oven, a pressurized ring-shaped cure volume is defined by a partitioned enclosure that mimics the cylinder-like shape of the composite nacelle structure with only limited clearance (e.g., a partitioned enclosure comprising inner and outer concentric cylinder-like walls). A tool (e.g., a mandrel) and at least one composite nacelle structure supported thereon are placed in the cure volume for curing. Integrally heated tooling, optionally in combination with other heating methods, such as infrared heaters, is utilized to provide the temperature profile necessary for cure.

First claim

The invention claimed is:

1. An apparatus for curing a composite structure, comprising:
an enclosure comprising a top plate, a base, and an outer wall disposed between said top plate and said base, said outer wall having a closed contour;
an inner wall disposed between said top plate and said base and surrounded by said outer wall, said inner wall having a closed contour, wherein surfaces of said inner and outer walls, said top plate, and said base define a ring-shaped cure volume; and
a hollow tool made of metal or composite material, said hollow tool comprising a surface having a closed contour and embedded heating elements, wherein said hollow tool surrounds said inner wall and is surrounded by said outer wall.

2. The apparatus as recited in claim 1 , wherein said heating elements carry heated fluid.

3. The apparatus as recited in claim 1 , further comprising a heater attached to an outer surface of said inner wall.

4. The apparatus as recited in claim 1 , further comprising a heater attached to an inner surface of said outer wall.

5. The apparatus as recited in claim 1 , wherein said inner and outer walls are supported by and extend from said top plate to form a unit that is separable from said base.

6. The apparatus as recited in claim 1 , further comprising a first seal disposed between said inner wall and said base and a second seal disposed between said outer wall and said base.

7. The apparatus as recited in claim 6 , wherein said base comprises first and second recesses in which said first and second seals are respectively seated.

8. An apparatus for curing a composite structure, comprising: an enclosure comprising a top plate, a base, and a wall disposed between said top plate and said base, said wall having a closed contour and; a hollow tool made of metal or composite material, said hollow tool being disposed between said top plate and said base and surrounded by said wall, said hollow tool comprising a surface having a closed contour and embedded heating elements, wherein said surface of said hollow tool and respective surfaces of said wall and said top plate at least partly define a ring-shaped cure volume.

9. The apparatus as recited in claim 8 , wherein said cure volume is further partly defined by a surface of said base.

10. The apparatus as recited in claim 8 , further comprising means for coupling said heating elements in said tool to a source of energy.

11. The apparatus as recited in claim 10 , wherein said heating elements transform electric current into heat and said source of energy is a current generator electrically coupled to said heating elements.

12. The apparatus as recited in claim 10 , wherein said heating elements carry heated fluid and said source of energy is a source of heated fluid.

13. The apparatus as recited in claim 8 , further comprising a heater attached to an inner surface of said wall.

14. A system comprising: an enclosure comprising a top plate, a base, and an outer wall disposed between said top plate and said base, said outer wall having a closed contour that forms an outer boundary of an internal volume of said enclosure; a hollow tool for partitioning said internal volume of said enclosure to form a ring-shaped cure volume disposed between said wall and said hollow tool, said hollow tool being made of metal or composite material; an uncured composite structure disposed within said ring-shaped cure volume, said uncured composite structure being in contact with a surface of the hollow tool and not in contact with the outer wall; heating elements embedded in said hollow tool for heating said uncured composite structure by heat transfer during a cure cycle; and means for producing a specified pressure inside said ring-shaped cure volume during the cure cycle.

15. The system as recited in claim 14 , wherein said hollow tool comprises a surface having a closed contour, said heating elements being integrated in said tool, and said surface of said tool being surrounded by said outer wall and thermally coupled to the uncured composite structure to allow heat transfer from said heating elements to the uncured composite structure.

16. A system comprising:
an enclosure comprising a top plate, a base, and an outer wall disposed between said top plate and said base, said outer wall having a closed contour that forms an outer boundary of an internal volume of said enclosure;
an inner wall for partitioning said internal volume of said enclosure to form a ring-shaped cure volume disposed between said inner and outer walls;
a hollow tool made of metal or composite material, said tool comprising a surface having a closed contour, said surface of said hollow tool surrounding said inner wall and being surrounded by said outer wall;
an uncured composite structure disposed within said ring-shaped cure volume, said uncured composite structure being in contact with the surface of the hollow tool and not in contact with the outer wall;
heating elements embedded in said hollow tool for heating said uncured composite structure by heat transfer during a cure cycle; and
means for producing a specified pressure inside said ring-shaped cure volume during the cure cycle.

17. The apparatus as recited in claim 1 , further comprising an uncured composite structure that is in contact with the surface of the hollow tool and not in contact with the outer wall.

18. The apparatus as recited in claim 8 , further comprising an uncured composite structure that is in contact with the surface of the tool and not in contact with the wall.

Assignees

• Boeing Co

Inventors

• Riedel Brian L

Classifications

• B29C35/04

  using liquids, gas or steam · CPC title

• B29C2035/0822

  using IR radiation · CPC title

• B29C2035/043

  oil · CPC title

• B29C2035/0211

  resistance heating (B29C2035/0811 takes precedence) · CPC title

• B29C35/049

  using steam or damp · CPC title