Composite mandrel for autoclave curing applications

• US 10,286,577 B2
• Filed: 05/02/2016
• Issued: 05/14/2019
• Est. Priority Date: 07/10/2008
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Robins, Brian G., Rotter, Daniel M., Washburn, Todd J., George, Panagiotis E.
• Primary Examiner(s): Gupta, Yogendra N
• Assistant Examiner(s): Luk, Emmanuel S
• Application Number:
  US15/144,808
• Publication Number:
  US 20160243730A1
• Time in Patent Office: 1,107 Days
• CPC Class Codes: B29C 33/3814 Porous moulds adapted for vacuum forming B29C51/365
• CPC Class Codes: B29C 33/505 cores or mandrels, e.g. inflatable B29C33/0016 takes precedence; for winding and joining B29C53/824; for supporting articles during joining B29C66/634; flexible cores for vulcanizing tyres B29D30/0654
• CPC Class Codes: B29C 70/865 completely encapsulated
• CPC Class Codes: B29D 99/0014 provided with ridges or ribs, e.g. joined ribs
• CPC Class Codes: B29L 2031/3076 Aircrafts blades, propellers B29L2031/08
• CPC Class Codes: B29L 2031/757 Moulds, cores, dies

Abstract

A composite mandrel includes a generally elongated mandrel body comprising a resilient mandrel core and an elastomeric mandrel outer layer disposed outside the mandrel core. A method for fabricating a contoured stiffened composite panel is also disclosed.

Claims

1. A composite mandrel, comprising:

a generally elongated mandrel body comprising;

a resilient mandrel core; and

an elastomeric mandrel outer layer disposed outside the resilient mandrel core, wherein a cross-sectional area and type of foam used for the resilient mandrel core is engineered to impart compression compliance under autoclave pressure to offset a combined thermal expansion behavior of the resilient mandrel core and the elastomeric mandrel outer layer.

2. The composite mandrel of claim 1, wherein the resilient mandrel core comprises foam.

3. The composite mandrel of claim 1 wherein the generally elongated mandrel body has a generally triangular cross-section.

4. The composite mandrel of claim 3 wherein the resilient mandrel core comprises a core base, a pair of core sides extending from said core base and a core apex extending between said pair of core sides.

5. The composite mandrel of claim 4 wherein the core apex of the resilient mandrel core is rounded.

6. The composite mandrel of claim 4 wherein the elastomeric mandrel outer layer comprises a mandrel base disposed adjacent to the core base of the resilient mandrel core;

a pair of mandrel sides disposed adjacent to the pair of core sides, respectively, of the resilient mandrel core; and

a mandrel apex disposed adjacent to the core apex of the resilient mandrel core.

7. The composite mandrel of claim 6 wherein the mandrel apex of the elastomeric mandrel outer layer is rounded.

8. The composite mandrel of claim 1, wherein the generally elongated mandrel body has a trapezoidal cross-section.

9. The composite mandrel of claim 1, wherein the elastomeric mandrel outer layer has a substantially constant thickness, and wherein the elastomeric mandrel outer layer is configured to expand uniformly during curing.

10. The composite mandrel of claim 1, wherein the elastomeric mandrel outer layer is configured to be deformed for removal from a composite structure.

11. The composite mandrel of claim 1, wherein the elastomeric mandrel outer layer conforms to pad-ups and ramps.

12. The composite mandrel of claim 1, wherein the elastomeric mandrel outer layer is in contact with and substantially co-extensive with the resilient mandrel core.

13. A composite mandrel for fabricating an aircraft part, comprising:

a generally elongated one-piece mandrel body configured to provide structural support to a cavity of the aircraft part during a curing step in an autoclave and configured to be extracted from the cavity after the curing step, the generally elongated one-piece mandrel body comprising;

a resilient mandrel core; and

an elastomeric mandrel outer layer disposed outside and in contact with the resilient mandrel core.

14. The composite mandrel of claim 13 wherein the resilient mandrel core comprises foam.

15. The composite mandrel of claim 13, wherein the generally elongated one-piece mandrel body has a generally trapezoidal cross-section, wherein the resilient mandrel core comprises a core base, a pair of core sides extending from the core base and a generally planar core top extending between the pair of core sides.

16. The composite mandrel of claim 15 wherein the elastomeric mandrel outer layer comprises a mandrel base disposed adjacent to the core base of the resilient mandrel core;

a pair of mandrel sides disposed adjacent to the pair of core sides, respectively, of the resilient mandrel core; and

a mandrel top surface disposed adjacent to the core top of the resilient mandrel core.

17. The composite mandrel of claim 13, wherein the elastomeric mandrel outer layer is configured to be deformed for removal from the cavity.

18. The composite mandrel of claim 13, wherein a cross-sectional area and type of foam used for the resilient mandrel core is engineered to impart compression compliance under autoclave pressure to offset a combined thermal expansion behavior of the resilient mandrel core and the elastomeric mandrel outer layer.

19. A composite mandrel for fabricating an aircraft part, comprising:

a generally elongated mandrel body configured to provide structural support to a cavity of the aircraft part during a curing step in an autoclave and configured to be extracted from the cavity after the curing step, the generally elongated mandrel body having a generally trapezoidal cross-section and comprising;

a resilient foam mandrel core having a core base, a pair of core sides extending from said core base and a generally planar core top extending between said pair of core sides; and

an elastic rubber mandrel outer layer disposed outside and in contact with the resilient foam mandrel core and having a mandrel base disposed adjacent to said core base of the resilient foam mandrel core;

a pair of mandrel sides disposed adjacent to said core sides, respectively, of the resilient foam mandrel core; and

a mandrel top surface disposed adjacent to said core top of the resilient foam mandrel core.