Placement of Prepreg Tows in High Angle Transition Regions

Patent metadata

Field	Value
Publication number	US-2016176122-A1
Application number	US-201414220725-A
Country	US
Kind code	A1
Filing date	Mar 20, 2014
Priority date	Mar 20, 2014
Publication date	Jun 23, 2016
Grant date	—

Abstract

Prepreg tows are placed on a substrate having a bend with a curvature extending over a transition region in the substrate. The tows are steered and laid on the substrate in at least a first section and a second section within the transition region, wherein each of the first and second sections has an angular orientation that is less than the curvature of the bend in order to reduce gathering of the tows.

First claim

What is claimed is:

1 . A method of placing a prepreg tow on a substrate having a bend with a curvature extending over a transition region in the substrate, comprising:
laying the tow in at least a first section and a second section within the transition region, wherein each of the first and second sections has an angular orientation that is less than the curvature of the bend.

2 . The method of claim 1 , wherein the first section and the second section of the tow at least partially span the transition region.

3 . The method of claim 1 , wherein the bend has a bend angle, and each of the first and second sections of the tow is curved and has an angle of curvature that is less than the bend angle.

4 . The method of claim 1 , wherein the tow has a shape that approximates a shape of the bend in the transition region.

5 . The method of claim 1 , wherein at least one of the first and second sections of the tow is substantially straight, and another of the first and second sections of the tow is curved.

6 . The method of claim 1 , further comprising:
programming a numeric controller; and using the controller to control an advanced fiber placement machine, and wherein laying the tow is performed by the advanced fiber placement machine.

7 . The method of claim 1 , wherein laying the tow includes:
steering the tow in a first direction from a beginning point along the first section to an ending point along the first section, changing the direction of steering of the tow at the ending point of the first section, steering the tow in a second direction from the ending point of the first section to an ending point of the second section.

8 . The method of claim 1 , wherein each of the first and second sections is a substantially straight section.

9 . A composite laminate structure formed by prepreg tows placed according the method of claim 1 .

10 . A composite laminate aircraft spar produced by placing prepreg tows according to claim 1 .

11 . A method of placing prepreg tows on a substrate having a bend angle extending over a transition region, comprising:
placing each of the tows on the substrate in a plurality of sections, wherein at least certain of the sections of each of the tows has an angular orientation that is less than the bend angle.

12 . The method of claim 11 , wherein at least one of the sections is a substantially straight section.

13 . The method of claim 11 , wherein placing each of the tows on the substrate includes:
steering the tow in a direction along the section from a beginning point of the section to an ending point of the section, and changing the direction of steering at each of the ending points.

14 . The method of claim 11 , wherein the sections include at least two curved sections and a substantially straight section connecting the two curved sections.

15 . The method of claim 11 , wherein each of the sections is curved.

16 . The method of claim 11 , wherein each of the sections is substantially straight.

17 . A method of placing a prepreg tow on a substrate having a bend angle θ extending over a transition region, comprising:
dividing the bend angle θ into n individual sections, wherein each of the sections has an angle of curvature of approximately θ/n; and
placing the tow on the substrate, including steering the tow along each of the sections.

18 . A method of producing a one-piece composite structure having at least one transition region containing a bend angle, comprising:
forming a composite laminate layup by laying up prepreg tows on a substrate, including dividing the bend angle into multiple sections and steering the prepreg tows along each of the sections.

19 . The method of claim 18 , wherein steering the prepreg tows along each of the sections includes steering the tows along angles that are each less than the bend angle.

20 . The method of claim 18 , wherein steering the prepreg tows is performed using a numerically controlled, advanced fiber placement machine.

21 . The method of claim 20 , further comprising:
programming a numeric controller to automatically control the numerically controlled, advanced fiber placement machine, including programming the numeric controller to steer the prepreg tows within each of the sections of the bend angle.

22 . A composite laminate aircraft airframe member produced by the method of claim 18 .

Assignees

• Boeing Co

Inventors

• Anderson Donald A
• Hughes Jessica R

Classifications

• B29C70/382 Primary

  Automated fiber placement [AFP] · CPC title

• B29K2105/0872

  Prepregs · CPC title

• B29C70/38 Primary

  Automated lay-up, e.g. using robots, laying filaments according to predetermined patterns {(application heads for tyres B29D30/28)} · CPC title

• B29C70/302 Primary

  Details of the edges of fibre composites, e.g. edge finishing or means to avoid delamination · CPC title

• Y02T50/40

  Weight reduction · CPC title