Failsafe injected adhesive joint

• US 7,670,527 B2
• Filed: 05/09/2006
• Issued: 03/02/2010
• Est. Priority Date: 05/09/2006
• Status: Active Grant

• Current Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Original Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Inventors: Malis, Michael B.
• Primary Examiner(s): Del Sole; Joseph S.
• Assistant Examiner(s): KENNEDY, TIMOTHY J
• Application Number:
  US11/430,404
• Publication Number:
  US 20070261787A1
• Time in Patent Office: 1,393 Days
• Field of Search: 156/293, 156/297, 156/303.1, 264/34, 264/35, 264/261, 264/263, 264/266, 264/267
• US Class Current: 264/261
• CPC Class Codes: B29C 65/00 Joining or sealing of preformed parts , e.g. welding of plastics materials; Apparatus therefor general aspects of processes or apparatus for joining preformed parts B29C66/00; using porous material formed by internal pressure generated therein for joining preformed parts B29C44/1228, B29C44/326
• CPC Class Codes: B29C 65/483 Reactive adhesives, e.g. chemically curing adhesives
• CPC Class Codes: B29C 65/542 by injection
• CPC Class Codes: B29C 65/7855 Provisory fixing
• CPC Class Codes: B29C 66/112 Single lapped joints
• CPC Class Codes: B29C 66/12441 being a single wall
• 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 66/221 being in the form of a sinusoidal wave B29C66/2272 takes precedence
• CPC Class Codes: B29C 66/43441 with two right angles, e.g. for making T-shaped pieces, H-shaped pieces
• CPC Class Codes: B29C 66/474 said single elements being substantially non-flat
• CPC Class Codes: B29C 66/712 the composition of one of the parts to be joined being different from the composition of the other part
• 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: B29K 2307/04 Carbon
• CPC Class Codes: B29L 2031/3076 Aircrafts blades, propellers B29L2031/08
• CPC Class Codes: F16B 11/006 by gluing gluing of plastics material B29C65/48
• CPC Class Codes: Y10T 156/1089 of discrete laminae to single face of additional lamina

Abstract

A composite member is joined to another composite or noncomposite member, using liquid or paste adhesive resin that cures in the joint. The joint is configured in such a way that the adhesive forms an interlocking key within recesses in the joined members that prevents joint disassembly once the adhesive has cured and hardened. Both of the members are provided with recesses extending along their lengths in the joint. The recesses register with each other to define a cavity and may undulate. The recessed are designed in such a way as to take the full load capability if the joint, even if there is no adhesion to the joined members. Adhesive is injected into the cavity through injection ports spaced periodically along the length of the joint.

Claims

1. A method of joining a structural member to an aircraft skin, comprising:

(a) providing the structural member with a bonding surface having a first end and a second end and a groove that extends along the bonding surface of the structural member from the first end to the second end;

(b) providing an interface member with a base and a leg, the leg having a bonding surface with a first end and a second end and a groove that extends along the bonding surface of the leg from the first end to the second end of the leg;

(c) placing the bonding surfaces of the structural member and the leg in contact with each other so that the grooves mate to define a cavity extending from the first ends to the second ends of the bonding surfaces;

(d) injecting adhesive into the cavity; and

(e) bonding the base of the interface member to the skin.

2. The method according to claim 1, wherein the structural member comprises a resin composite laminate, and wherein the method further comprises curing the resin in the structural member prior to steps (c), (d) and (e).

3. The method according to claim 1, wherein the interface member comprises a woven preform, and step (b) comprises pre-impregnating the preform with a resin and curing the preform during step (e).

4. The method according to claim 1, further comprising:

providing first and second communication channels that extend from the cavity at spaced apart distances between the first and second ends of the bonding surfaces; and

wherein step (d) comprises;

injecting the adhesive into the first communication channel until the adhesive begins to flow from the second communication channel.

5. The method according to claim 1, further comprising:

providing first and second communication channels that extend from the cavity at spaced apart distances between the first and second ends of the bonding surfaces;

providing first and second locator pin holes through the skin, though the base of the interface member, and into the structural member, the first and second locator pin holes registering with the first and second communication channels, respectively;

inserting locator pins into the locator holes in the structural member; and

wherein step (c) comprises;

inserting the locator pins into the locator holes; and

step (d) comprises;

removing the locator pins, injecting the adhesive into the first locator hole and the first communication channel until the adhesive begins to flow from the second locator hole of the skin.

6. The method according to claim 1, wherein the grooves have undulations that define a sinuous path between the first and the second ends of the bonding surfaces of the structural member and the interface member.

7. The method according to claim 1, wherein the interface member comprises a woven preform;

and the perform is cured prior to step (c).

8. A method of joining a structural member to an aircraft skin, comprising:

(a) providing the structural member with opposite sides that are parallel to each other and face in opposite directions from each other, and providing a pair of grooves, the grooves being on the opposite sides of the structural member and extending lengthwise along the structural member;

(b) providing an interface member having a base and a pair of legs extending orthogonally therefrom, each of the legs having an inside surface, the inside surfaces being parallel to and facing each other, and providing a groove on each of the inside surfaces extending lengthwise along the interface member;

(c) inserting the structural member between the legs such that the opposite sides of the structural member are in contact with the inside surfaces of the interface member, the grooves of the structural member aligning with the grooves of the legs to define elongated cavities;

(d) injecting adhesive into each of the cavities; and

(e) curing the adhesive and bonding the interface member to the skin.

9. The method according to claim 8, wherein the interface member is a woven preform containing a resin, and wherein the resin is also cured prior to step (c).

10. The method according to claim 8, wherein steps (a) and (b) comprises providing the grooves with undulations that define a sinuous path from one end of the interface member to another end of the interface member.

11. The method according to claim 8, wherein the structural member and the skin comprise resin composite laminates and steps (a) and (b) comprise curing resin in the structural member and the skin before step (c).

12. The method according to claim 8, wherein steps (a) and (b) comprise:

providing first and second communication channels that extend from the cavity at lengthwise spaced apart distances; and

wherein step (d) comprises;

injecting the adhesive into the first communication channel until the adhesive begins to flow from the second communication channel.

13. The method according to claim 8, wherein steps (a) and (b) comprise:

providing the structural member with first and second communication channels spaced apart lengthwise along the structural member, each communication channel having a side section that extends from one of the grooves on the structural member and a base section on an edge of the structural member that joins the side sections to each other; and

wherein step (d) comprises;

injecting the adhesive into the first communication channel until the adhesive begins to flow from the second communication channel.

14. The method according to claim 8, further comprising:

providing first and second communication channels that extend from the cavity at lengthwise spaced apart distances;

providing first and second locator holes through the skin, through the base of the interface member between the legs, and into the structural member, the first and second locator holes registering with the first and second communication channels, respectively;

inserting locator pins into the locator holes in the structural member; and

wherein step (c) comprises;

stabbing the locator pins into the locator holes in the interface member and the skin; and

step (d) comprises;

removing the locator pins and injecting the adhesive into the first locator holes in the skin, which flows through the first locator hole in the perform, the first communication channel and the cavities to the second locator holes; and

stopping the injection of adhesive into the first locator holes when the adhesive begins to flow from the second locator hole of the skin.