Co-curing process for the joining of composite structures

• US 9,731,453 B2
• Filed: 03/04/2015
• Issued: 08/15/2017
• Est. Priority Date: 03/04/2015
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Humfeld, Keith D., Nelson, Karl M.
• Primary Examiner(s): Gross, Carson
• Application Number:
  US14/639,112
• Publication Number:
  US 20160257427A1
• Time in Patent Office: 895 Days
• Field of Search: 1563041, 1563046
• CPC Class Codes: B29C 35/0266 Local curing for repairing B29C73/34
• CPC Class Codes: B29C 65/02 by heating, with or without pressure
• CPC Class Codes: B29C 65/14 using wave energy , i.e. electromagnetic radiation, or particle radiation using mechanical waves B29C65/06; using ultrasonic waves B29C65/08; pressing means transparent to electromagnetic radiation B29C66/81267
• CPC Class Codes: B29C 65/18 using heated tools
• CPC Class Codes: B29C 65/5014 being fibre-reinforced B29C65/5028 takes precedence
• CPC Class Codes: B29C 65/5021 being multi-layered
• CPC Class Codes: B29C 65/505 and placed in a recess formed in the parts to be joined, e.g. in order to obtain a continuous surface
• CPC Class Codes: B29C 66/112 Single lapped joints
• CPC Class Codes: B29C 66/12821 comprising at least two overlap joint-segments
• CPC Class Codes: B29C 66/12822 comprising at least three overlap joint-segments
• CPC Class Codes: B29C 66/12841 comprising at least two butt joint-segments
• CPC Class Codes: B29C 66/131 Single flanged joints, i.e. one of the parts to be joined being rigid and flanged in the joint area
• CPC Class Codes: B29C 66/342 Preventing air-inclusions
• CPC Class Codes: B29C 66/43 Joining a relatively small portion of the surface of said articles B29C66/45 takes precedence
• CPC Class Codes: B29C 66/524 Joining profiled elements
• CPC Class Codes: B29C 66/61 Joining from or joining on the inside for making tubes by bending sheets and joining from the inside B29C53/387
• CPC Class Codes: B29C 66/63 Internally supporting the article during joining B29C66/49 takes precedence
• CPC Class Codes: B29C 66/634 using an inflatable core
• CPC Class Codes: B29C 66/71 characterised by the composition of the plastics material of the parts to be joined welding bar compositions B29C65/125
• CPC Class Codes: B29C 66/721 Fibre-reinforced materials B29C66/729 takes precedence
• CPC Class Codes: B29C 66/7212 : characterised by the composition of the fibres
• CPC Class Codes: B29C 66/72141 : Fibres of continuous length
• CPC Class Codes: B29C 66/72143 : Fibres of discontinuous lengths
• CPC Class Codes: B29C 66/723 : being multi-layered B29C66/7292, B29C66/72941 take precedence
• CPC Class Codes: B29C 66/73752 : the to-be-joined areas of both parts to be joined being uncured
• CPC Class Codes: B29C 66/73921 : characterised by the materials of both parts being thermoplastics
• CPC Class Codes: B29C 66/73941 : characterised by the materials of both parts being thermosets
• CPC Class Codes: B29C 66/81455 : being a fluid inflatable bag or bladder, a diaphragm or a vacuum bag for applying isostatic pressure inflatable element positioned between the joining tool and a backing-up part B29C66/82421
• CPC Class Codes: B29C 70/304 : In-plane lamination by juxtaposing or interleaving of plies, e.g. scarf joining
• CPC Class Codes: B29K 2023/06 : PE, i.e. polyethylene
• CPC Class Codes: B29K 2023/12 : PP, i.e. polypropylene
• CPC Class Codes: B29K 2027/12 : containing fluorine
• CPC Class Codes: B29K 2063/00 : Use of EP, i.e. epoxy resins or derivatives thereof, as moulding material
• CPC Class Codes: B29K 2067/00 : Use of polyesters or derivatives thereof, as moulding material
• CPC Class Codes: B29K 2069/00 : Use of PC, i.e. polycarbonates or derivatives thereof, as moulding material
• CPC Class Codes: B29K 2075/00 : Use of PU, i.e. polyureas or polyurethanes or derivatives thereof, as moulding material
• CPC Class Codes: B29K 2079/085 : Thermoplastic polyimides, e.g. polyesterimides, PEI, i.e. polyetherimides, or polyamideimides; Derivatives thereof
• CPC Class Codes: B29K 2223/00 : Use of polyalkenes or derivatives thereof as reinforcement
• CPC Class Codes: B29K 2271/00 : Use of polyethers , e.g. PEEK, i.e. polyether-etherketone or PEK, i.e. polyetherketone or derivatives thereof, as reinforcement
• CPC Class Codes: B29K 2277/10 : Aromatic polyamides [Polyaramides] or derivatives thereof
• CPC Class Codes: B29K 2305/00 : Use of metals, their alloys or their compounds, as reinforcement
• CPC Class Codes: B29K 2307/02 : Boron
• CPC Class Codes: B29K 2307/04 : Carbon
• CPC Class Codes: B29K 2309/02 : Ceramics
• CPC Class Codes: B29K 2309/08 : Glass
• CPC Class Codes: B29L 2031/3076 : Aircrafts blades, propellers B29L2031/08
• CPC Class Codes: B29L 2031/3085 : Wings
• CPC Class Codes: B29L 2031/7172 : Fuel tanks, jerry cans
• CPC Class Codes: B32B 2605/18 : Aircraft blades, propellers B32B2603/00
• CPC Class Codes: B64C 3/20 : Integral or sandwich constructions
• CPC Class Codes: B64C 3/26 : Construction, shape, or attachment of separate skins, e.g. panels
• CPC Class Codes: B64C 5/02 : Tailplanes
• CPC Class Codes: B64F 5/10 : Manufacturing or assembling aircraft, e.g. jigs therefor
• CPC Class Codes: Y02T 50/40 : Weight reduction

Abstract

A method of fabricating a composite assembly may include providing a first laminate and a second laminate respectively formed of first and second composite plies, and having a respective first and second cured section and a respective first and second uncured section. The method may further include interleaving the first composite plies in the first uncured section with the second composite plies in the second uncured section to form an interfacial region. The method may additionally include curing the interfacial region to join the first laminate to the second laminate and form a unitized composite assembly.

Claims

1. A method of fabricating a composite assembly, including:

providing a first laminate and a second laminate respectively formed of first and second composite plies and having a respective first and second cured section and a respective first and second uncured section;

interleaving at least one of the first composite plies in the first uncured section with the second composite plies in the second uncured section to form an interfacial region, the interleaving of the at least one of the first composite plies with the second composite plies forming an interleaved ply;

laying up one or more splice plies over the interleaved ply in the interfacial region, the splice plies being different plies from those of the first laminate and the second laminate; and

curing the interfacial region to join the first laminate to the second laminate and form a unitized composite assembly.

2. The method of claim 1, wherein the step of interleaving includes:

inserting at least one of the first composite plies in the first uncured section between a pair of immediately adjacent second composite plies in the second uncured section.

3. The method of claim 1, wherein the step of curing the interfacial region includes:

heating the interfacial region; and

wherein the heating of the first and second cured section is less than the heating of the interfacial region when heating the interfacial region.

4. The method of claim 1, wherein the step of interleaving includes:

at least partially overlapping at least one of the first composite plies of the first uncured section with at least one of the second composite plies of the second uncured section to form the interfacial region.

5. The method of claim 1, wherein the step of interleaving includes:

staggering at least two ply joints joining the first and second laminate.

6. The method of claim 1, wherein the first composite plies and the second composite plies each include at least one 0-degree ply, the step of interleaving including:

overlapping a 0-degree ply in the first uncured section of the first laminate with a 0-degree ply in the second uncured section of the second laminate to form an overlap joint.

7. The method of claim 1, wherein the first composite plies and the second composite plies each include at least one non-0-degree ply, the step of interleaving including:

butting a non-0-degree ply in the first uncured section of the first laminate with a non-0-degree ply in the second uncured section of the second laminate to form a butt joint.

8. The method of claim 1, wherein the step of interleaving includes:

interleaving an additional uncured section of at least one additional layup with the first and second uncured section to form the interfacial region.

9. The method of claim 1, wherein the step of laying up one or more splice plies includes:

overlapping at least one of the splice plies over a ply end of at least one of the first composite plies and over a ply end of at least one of the second composite plies.

10. The method of claim 9, wherein the step of laying up one or more splice plies includes:

laying up a plurality of splice plies over the first and second composite plies with a ramp rate of greater than 1;

1.

11. The method of claim 1, wherein the step of curing the interfacial region is performed using at least one of an autoclave, a press clave, an oven, and thermal blankets.

12. The method of claim 1, wherein the step of curing the interfacial region comprises:

supporting the interfacial region on interfacial region cure tool, a remainder of at least a portion of the first laminate and the second laminate being unsupported by the interfacial region cure tool.

13. The method of claim 1, wherein at least one of the composite plies in the first and second laminates is a non-0-degree ply or a non-90-degree ply formed of unidirectional tape and forming a crenulated edge in the respective first and second uncured section, the step of interleaving including:

inserting a tape end of the unidirectional tape of a first composite ply between a pair of the second composite plies.

19. The method of claim 1, wherein the step of curing the interfacial region is performed without the use of an autoclave.

14. A method of fabricating a composite assembly, including:

laying up a plurality of first composite plies to form a first layup;

laying up a plurality of second composite plies to form a second layup;

inserting a ply separator between at least one pair of the first composite plies and/or between at least one pair of the second composite plies;

at least partially curing the respective first and second layup to form a respective first and second cured section and a respective first and second uncured section containing the ply separator between the at least one pair of the first composite plies and/or between the at least one pair of the second composite plies;

preventing, due to insertion of the ply separator, bonding between the at least one pair of the first composite plies and/or between the at least one pair of the second composite plies during the at least partial curing of the respective first and second cured section;

removing, after the at least partial curing, the ply separator from between the at least one pair of the first composite plies and/or from between the at least one pair of the second composite plies;

interleaving the first composite plies in the first uncured section with the second composite plies in the second uncured section to form an interfacial region;

and

curing the interfacial region to join the first layup to the second layup and form a unitized composite assembly.

15. The method of claim 14, wherein the steps of curing the first and second layup include:

heating a respective portion of the first and second layup defining the respective first and second cured section; and

wherein the heating of the portion of the first and second layup defining the first and second uncured section is less than the heating of the first and second cured section when heating the respective portion of the first and second layup defining the respective first and second cured section.

16. The method of claim 14, wherein the steps of curing the first and second layup include:

partially curing at least one of the first and second uncured sections to a partial cure state of less than approximately 10 percent.

17. The method of claim 16, wherein the step of partially curing includes:

partially curing at least one of the first and second uncured sections such that tack is reduced.

18. A method of fabricating a composite assembly, including:

laying up a plurality of first composite plies and a plurality of second composite plies to respectively form a first layup and a second layup;

curing to full cure a first cured section and a second cured section of the respective first and second layup;

partially curing to approximately 5 percent a first uncured section and a second uncured section of the respective first and second layup;

interleaving at least one of the first composite plies in the first uncured section between a pair of second composite plies in the second uncured section to form an interfacial region, the interleaving of the at least one of the first composite plies with the second composite plies forming an interleaved ply;

laying up one or more splice plies over the interleaved ply in the interfacial region, the splice plies being different plies from those of the first layup and the second layup; and

curing the interfacial region to form a unitized composite assembly.

20. The method of claim 18, wherein the step of curing the interfacial region is performed without the use of an autoclave.