Composite laminate including beta-reinforcing fibers

Patent metadata

Field	Value
Publication number	US-9592650-B2
Application number	US-201414252764-A
Country	US
Kind code	B2
Filing date	Apr 14, 2014
Priority date	Mar 31, 2005
Publication date	Mar 14, 2017
Grant date	Mar 14, 2017

Abstract

A composite laminate comprises a plurality of plies of reinforcing fibers. At least some of the plies have reinforcing fibers oriented at ±α with respect to an axis of primary loading, where α is between 2 and 12 degrees. At least some of the plies have reinforcing fibers oriented at ±β with respect to the axis of primary loading, where β is between 50 and 85 degrees.

First claim

The invention claimed is:

1. A composite laminate comprising a plurality of plies of reinforcing fibers; at least some of the plies having reinforcing fibers oriented at ±α with respect to an axis of primary loading, where α is between 2 and 12 degrees; at least some of the plies having reinforcing fibers oriented at ±β with respect to the axis of primary loading, where β is between 50 and 85 degrees.

2. The laminate of claim 1 , wherein α is between 2 and 8 degrees.

3. The laminate of claim 1 , wherein α is between 3 and 5 degrees.

4. The laminate of claim 1 , wherein the reinforcing fibers oriented at ±α constitute at least 50% of the total number of fibers.

5. The laminate of claim 1 , further comprising a polymer matrix, wherein the fibers include carbon fibers in a polymer matrix.

6. The laminate of claim 1 , wherein all fibers in the laminate consist of the fibers oriented at ±α and ±β; and wherein 20-30% of the total fibers are oriented at ±β to reach bearing strength levels similar to traditional 0/+45/−45/90 degree hard laminates.

7. A system comprising the laminate of claim 1 .

8. A composite beam comprising plies of α-reinforcing fibers oriented at ±α with respect to an axis of primary loading, where α is between 2 and 12 degrees; and plies having β-reinforcing fibers oriented at ±β with respect to the axis of primary loading, where β is between 50 and 85 degrees.

9. The beam of claim 8 , including a base and a web, at least one of the base and web including the plies of the α-reinforcing and the plies of the β-reinforcing fibers, at least 50% of the reinforcing fibers being the α-reinforcing fibers.

10. The beam of claim 8 , wherein the base has fastener apertures, whereby the α-reinforcing fibers in the base are oriented at ±α degrees to suppress or delay splitting caused by the fastener apertures.

11. The beam of claim 8 , wherein α is between 2 and 8 degrees.

12. The beam of claim 8 , wherein α is between 3 and 5 degrees.

13. The beam of claim 9 , wherein the β-reinforcing fibers are biased towards outer surfaces of the webs to increase stiffness in buckling and transverse bending.

14. The beam of claim 8 , further comprising a polymer matrix; wherein the α-reinforcing and the β-reinforcing fibers include carbon fibers embedded in the polymer matrix.

15. A system comprising the beam of claim 8 .

16. A system comprising a beam including a base and a web, the web including plies of reinforcing fibers for providing strength in tension and compression along an axis of primary loading, the web also including plies of reinforcing fibers oriented at ±β degrees with respect to the axis of primary loading, where β is between 50 and 85 degrees, wherein the fibers oriented at ±β degrees are biased towards outer surfaces of the web to increase stiffness in buckling and transverse loading.

17. The system of claim 16 , wherein the reinforcing fibers for providing strength in tension and compression are oriented at ±α with respect to the axis of primary loading, where α is between 2 and 12 degrees.

18. The system of claim 16 , wherein the reinforcing fibers are carbon fibers embedded in a polymer matrix.

19. The system of claim 16 , wherein the reinforcing fibers oriented at ±β degrees are biased towards an outer surface of the web to increase stiffness in buckling and transverse bending.

20. The system of claim 16 , wherein α is between 3 and 5 degrees.

Assignees

• Boeing Co

Inventors

• Kismarton Max U

Classifications

• B29C70/202

  arranged in parallel planes or structures of fibres crossing at substantial angles, e.g. cross-moulding compound [XMC] (B29C70/207 takes precedence) · CPC title

• B64C1/064

  Stringers; Longerons · CPC title

• B29C66/524

  Joining profiled elements · CPC title

• B29C65/562

  using extra joining elements, i.e. which are not integral with the parts to be joined (using plastic snap elements B29C65/58; using plastic rivets B29C65/601) · CPC title

• B32B2260/023

  Two or more layers · CPC title