Mandrel forming for discrete wing skin stiffeners

• US 9,701,070 B2
• Filed: 11/06/2014
• Issued: 07/11/2017
• Est. Priority Date: 11/06/2014
• Status: Active Grant

• Current Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Original Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Inventors: Ballester, Jaime, Huddleston, Nicholas Lee
• Primary Examiner(s): HUSON, MONICA ANNE
• Application Number:
  US14/534,747
• Publication Number:
  US 20160129989A1
• Time in Patent Office: 978 Days
• Field of Search: None
• CPC Class Codes: B29C 70/443 and impregnating by vacuum or injection
• CPC Class Codes: B29C 70/70 Completely encapsulating inserts B29C70/86 takes precedence
• CPC Class Codes: B29K 2309/08 Glass
• CPC Class Codes: B29K 2663/00 Use of EP, i.e. epoxy resins or derivatives thereof for preformed parts, e.g. for inserts
• CPC Class Codes: B29K 2683/00 Use of polymers having silicon, with or without sulfur, nitrogen, oxygen or carbon only, in the main chain, for preformed parts, e.g. for inserts
• CPC Class Codes: B29L 2031/001 Profiled members, e.g. beams, sections
• CPC Class Codes: B29L 2031/3085 Wings
• CPC Class Codes: B64F 5/10 Manufacturing or assembling aircraft, e.g. jigs therefor
• CPC Class Codes: Y02T 50/40 Weight reduction

Abstract

In one embodiment, a stiffener may be formed by inserting a plurality of flexible mandrels into a channel of a tool having a three-dimensional contour, placing a vacuum bag over the flexible mandrels and the tool, with the mandrels disposed between the vacuum bag and the tool, and applying vacuum pressure between the vacuum bag and the tool. A hardening substance may be inserted into each of the plurality of flexible mandrels and then may be hardened while the plurality of mandrels are inserted in the one or more channels of the tool. Finally, the mandrels may be wrapped with a stiffener material with stiffeners being formed from the stiffener material.

Claims

1. A method for forming panel stiffeners, comprising:

inserting one or more flexible mandrels into each of one or more channels of a tool having a three-dimensional contour, the one or more flexible mandrels being composed of silicone rubber;

hardening the flexible mandrels while inserted in the one or more channels of the tool; and

forming stiffeners using the hardened one or more mandrels.

2. The method of claim 1, wherein hardening the flexible mandrels while inserted in the one or more channels comprises inserting a hardening substance into the flexible mandrels.

3. The method of claim 2, wherein inserting a hardening substance into the flexible mandrels comprises applying vacuum pressure at one end of the flexible mandrels to draw the hardening substance into the mandrel.

5. The method of claim 1, wherein forming stiffeners using the hardened one or more mandrels comprises:

wrapping the mandrels with a stiffener material; and

forming the stiffener material into a stiffener shape.

6. The method of claim 5, wherein the stiffener shape is selected from the group consisting of an I-stiffener, a J-stiffener, and a blade stiffener.

7. The method of claim 1, further comprising:

placing a vacuum bag over the flexible mandrels and the tool, wherein the mandrels are disposed between the vacuum bag and the tool; and

applying vacuum pressure between the vacuum bag and the tool.

8. The method of claim 7, further comprising placing a breathable material over the flexible mandrels, wherein the breathable material is disposed between the flexible mandrels and the vacuum bag.

9. The method of claim 1, wherein the tool is formed using a panel having a three-dimensional contour, and the method further comprises coupling the stiffeners to the panel.

4. A method for forming panel stiffeners, comprising:

inserting one or more flexible mandrels into each of one or more channels of a tool having a three-dimensional contour, wherein the tool is composed of foam;

hardening the flexible mandrels while inserted in the one or more channels of the tool; and

forming stiffeners using the hardened one or more mandrels.

10. The method of claim 4, wherein hardening the flexible mandrels while inserted in the one or more channels comprises inserting a hardening substance into the flexible mandrels.

11. The method of claim 10, wherein inserting a hardening substance into the flexible mandrels comprises applying vacuum pressure at one end of the flexible mandrels to draw the hardening substance into the mandrel.

12. The method of claim 4, wherein forming stiffeners using the hardened one or more mandrels comprises:

wrapping the mandrels with a stiffener material; and

forming the stiffener material into a stiffener shape.

13. The method of claim 12, wherein the stiffener shape is selected from the group consisting of an I-stiffener, a J-stiffener, and a blade stiffener.

14. The method of claim 4, further comprising:

placing a vacuum bag over the flexible mandrels and the tool, wherein the mandrels are disposed between the vacuum bag and the tool; and

applying vacuum pressure between the vacuum bag and the tool.

15. The method of claim 14, further comprising placing a breathable material over the flexible mandrels, wherein the breathable material is disposed between the flexible mandrels and the vacuum bag.

16. The method of claim 4, wherein the tool is formed using a panel having a three-dimensional contour, and the method further comprises coupling the stiffeners to the panel.