Fabrication of gap fillers for composite parts that exhibit varying radii of curvature

Patent metadata

Field	Value
Publication number	US-10717239-B2
Application number	US-201715718704-A
Country	US
Kind code	B2
Filing date	Sep 28, 2017
Priority date	Sep 28, 2017
Publication date	Jul 21, 2020
Grant date	Jul 21, 2020

Abstract

Systems and methods are provided for fabricating preforms. One embodiment is a method comprising acquiring tows of fiber reinforced material, selecting a number of tows to utilize for a bundle having an aggregate shape, assembling the tows together into the bundle, curving the assembled tows by slipping the assembled tows with respect to each other, drawing the bundle through a die to bind the bundle into a preform, enforcing a longitudinally varying cross section along the preform, and locking in a curvature of the preform.

First claim

What is claimed is:

1. A method comprising:
acquiring tows of dry fiber reinforced material that are stabilized by a binding agent;
selecting a number of the tows to utilize for a bundle having an aggregate shape;
assembling the tows together into the bundle;
enforcing a curvature onto the bundle by slipping tows within the bundle with respect to each other;
heating the bundle to a sticking point temperature of the binding agent;
drawing the bundle through a die while the binding agent is heated to the sticking point temperature, to bind the bundle into a preform, enforcing a longitudinally varying cross section along the preform;
locking in a curvature of the preform by cooling the binding agent below the sticking point temperature while the tows remain dry fiber reinforced material;
applying the preform to a laminate while the curvature is locked in; and
hardening the laminate and the preform into an integral composite part.

2. The method of claim 1 wherein:
inducing slip planes between the tows of the bundle is by applying different amounts of tension to each of the tows.

3. The method of claim 2 wherein:
the curvature is defined by the different amounts of tension.

4. The method of claim 2 wherein:
the amounts of tension applied to each tow are selected based on a desired curvature for the preform.

5. The method of claim 2 further comprising:
varying tensions to the tows via tension drives that each adjustably control tension at a specific tow.

6. The method of claim 1 further comprising:
selecting a number of tows to utilize for the bundle is based upon a height for the preform at a particular longitudinal location.

7. The method of claim 1 further comprising:
heating the bundle to a tacking temperature at which the tows bind together.

8. The method of claim 1 further comprising:
controlling tension at the tows by operating clutches at rollers that dispense the tows.

9. The method of claim 1 further comprising:
impregnating the preform with resin.

10. The method of claim 1 wherein:
cooling the binding agent comprises directing air below the tacking temperature onto the preform.

11. The method of claim 1 wherein:
the tows are assembled together along multiple axes; and
slip planes are induced between the tows along the axes.

12. The method of claim 1 further comprising:
altering slip planes while continuously fabricating the preform, resulting in adjusting a radius of the curvature of the preform.

13. The method of claim 1 wherein:
assembling the tows together into a bundle results in an aggregate shape that is not circular.

14. The method of claim 1 further comprising:
performing the acquiring, assembling, inducing, and drawing continuously and concurrently.

15. The method of claim 1 further comprising:
rotating pinch rollers that pinch the preform to pull the bundle through the die.

16. The method of claim 1 further comprising:
pulling a tension puller attached to the integral preform to draw the bundle through the die.

17. The method of claim 1 further comprising:
selecting a number of tows for the preform based on an areal weight of the fiber reinforced material.

18. The method of claim 1 further comprising:
adjusting a speed of drawing the bundle through the die based on a temperature of the bundle prior to entering the die.

19. The method of claim 1 further comprising:
varying the aggregate shape by trimming the tows.

20. A non-transitory computer readable medium embodying programmed instructions which, when executed by a processor, are operable for performing a method of:
directing a drive system to acquire tows of dry fiber reinforced material that are stabilized by a binding agent;
directing the drive system to draw the tows through a guide that selects a number of tows and assembles the tows together into a bundle having an aggregate shape;
directing tension drives to curve the assembled tows by slipping the assembled tows with respect to each other;
heating the bundle to a sticking point temperature of the binding agent;
directing the drive system to draw the bundle through a die while the binding agent is heated to the sticking point temperature, to bind the bundle into a preform, enforcing a longitudinally varying cross section along the preform;
locking in a curvature of the preform by cooling the binding agent below the sticking point temperature while the tows remain dry fiber reinforced material;
applying the preform to a laminate while the curve is locked in; and
hardening the laminate and the preform into an integral composite part.

Assignees

• Boeing Co

Inventors

• Gordon Christian
• Klimovski Andrew

Classifications

• B29D99/0005

  Producing noodles, i.e. composite gap fillers, characterised by their construction · CPC title

• B29C70/527

  Pulling means · CPC title

• B29C70/525

  Component parts, details or accessories; Auxiliary operations · CPC title

• B29C70/52

  Pultrusion, i.e. forming and compressing by continuously pulling through a die · CPC title

• B29B11/16 Primary

  comprising fillers or reinforcement {(non-woven fabrics per se D04H1/00, D04H3/00)} · CPC title