Low Stress Stiffener Runout in Pi Bonded Structure

Patent metadata

Field	Value
Publication number	US-2016009355-A1
Application number	US-201314099048-A
Country	US
Kind code	A1
Filing date	Dec 6, 2013
Priority date	Nov 15, 2013
Publication date	Jan 14, 2016
Grant date	—

Abstract

A stringer for having a runout with a raised area configured to reduces stress while improving drainage across the runout when utilized in a close structural component of a vehicle such as an aileron of an aircraft. In one or more configurations, the raised area of the runout of the stringer includes multiple tapered surfaces adjacent to one another oriented and configured as ramps to collectively guide water up, over and down the raised area of the stringer.

First claim

What is claimed is:

1 . A first stringer comprising a web having a web height and a runout at a distal end of the web, the runout defined at least by a raised area extending beyond the distal end of the web and a tapered distal edge of the web continuing into the raised area as the web height decreases, wherein opposite sides of the raised area each include an inverse taper such that the raised area widens substantially perpendicular to the web as the web tapers into the raised area and as the raised area extends beyond the distal end of the web.

2 . The first stringer of claim 1 , wherein the raised area comprises a plurality of tapered surfaces adjacent to one another oriented and configured as ramps to collectively guide water over the raised area.

3 . The first stringer of claim 2 , wherein the raised area further comprises a radius curvature between the web of the stringer and a skin wherein the radius curvatures extends along a length of the stringer and along a transverse raised portion of a skin bonded to a rib.

4 . The first stringer of claim 1 , wherein the tapered distal edge of the web terminates into the raised area.

5 . The first stringer of claim 1 , wherein the tapered distal edge of the web continues into a transverse raised portion of a skin.

6 . The first stringer of claim 1 , wherein the inverse taper of the opposite sides of the raised area is straight.

7 . The first stringer of claim 1 , wherein the tapered distal edge of the web begins at a point substantially corresponding with the inverse taper beginning on the opposite sides of the raised area.

8 . The first stringer of claim 1 , wherein the web height is smallest where the raised area is widest.

9 . The first stringer of claim 1 , wherein the first stringer is substantially longitudinally aligned with a second stringer and the first and second stringers are bisected by a transverse rib, and wherein the raised area of the first stringer and a raised area of the second stringer continue into transverse raised portions of a skin bonded to the rib, and the raised areas of the first and second stringers are widest where the raised areas of the first and second stringers continue into the rib.

10 . The first stringer of claim 1 , wherein a skin, the web and the raised area of the first stringer, and transverse raised portions of the skin, are integrally formed from a single workpiece.

11 . A stringer assembly comprising:
a transverse rib; a first stringer comprising a web having a web height and a runout at a distal end of the web, the runout defined at least by a raised area extending beyond the distal end of the web and a tapered distal edge of the web continuing into the raised area as the web height decreases, wherein opposite sides of the raised area each include an inverse taper such that the raised area widens substantially perpidicularly to the web as the web tapers into the raised area and as the raised area extends beyond the distal end of the web; and a second stringer longitudinally aligned with the first stringer, the second stringer comprising a web having a web height and a runout at a distal end of the web, the runout defined at least by a raised area extending beyond the distal end of the web and a tapered distal edge of the web continuing into the raised area as the web height decreases, wherein opposite sides of the raised area each include an inverse taper such that the raised area widens substantially perpidicularly to the web as the web tapers into the raised area and as the raised area extends beyond the distal end of the web, and wherein the raised areas of the first and second stringers continue into transverse raised portions of a skin bonded to the transverse rib, and the distal ends of the first and second stringers are bisected by the transverse rib.

12 . The stringer assembly of claim 11 , wherein the raised areas of the first and second stringers each comprise a plurality of tapered surfaces adjacent to one another oriented and configured as ramps to collectively guide water.

13 . The stringer assembly of claim 11 , wherein the raised area of the first stringer further comprises a radius curvature between the web of the first stringer and the skin and wherein the radius curvature extends along a length of the first stringer and along one of the transverse raised portions of the skin bonded to the transverse rib, and wherein the raised area of the second stringer comprises a radius curvature between the web of the second stringer and the skin and wherein the radius curvature extends along a length of the second stringer and along another of transverse raised portions of the skin bonded to the transverse rib.

14 . The stringer assembly of claim 11 , wherein the tapered distal edges of the webs of the first and second stringers terminates into the raised areas of the first and second stringers.

15 . The stringer assembly of claim 11 , wherein the tapered distal edges of the webs of the first and second stringers continue into the transverse raised portions of the skin.

16 . The stringer assembly of claim 11 , wherein the inverse taper of the opposite sides of each of the raised areas is straight.

17 . The stringer assembly of claim 11 , wherein the web height of the web of each of the first and second stringers is smallest where the raised areas of the first and second stringers are widest.

18 . The stringer assembly of claim 11 , wherein a width of each of the raised areas of the first and second stringers beyond the tapered distal edge of the webs of the first and second stringers corresponds with the web height of each of the webs of the first and second stringers.

19 . The stringer assembly of claim 11 , wherein a width of each of the raised areas beyond the tapered distal edge of the webs of the first and second stringers is substantially equal to the web height of each of the webs of the first and second stringers.

20 . The stringer assembly of claim 11 , wherein a width of each of the raised areas beyond the tapered distal edge of the webs of the first and second stringers is greater than the web height of each of the webs of the first and second stringers.

21 . A method of reducing stress loads and controlling water drainage around a stringer, the method comprising:
providing a stringer comprising a web having a web height and a runout at a distal end of the web; providing a raised area extending longitudinally and laterally beyond the distal end of the web; tapering a distal edge of the web and continuing the distal edge into the raised area as the web height decreases; inverse tapering opposite sides of the raised area such that the raised area widens substantially perpendicularly to the web as the distal edge continues into the raised area and as the raised area extends beyond the distal end of the web; and guiding water over the raised area of the stringer.

22 . The method of claim 21 , wherein providing the raised area comprises providing a plurality of tapered surfaces adjacent to one another and orienting the tapered surfaces as ramps to collectively guide the water over the raised area.

Assignees

• Boeing Co

Inventors

• Jansen Jan T
• Stott Ryan
• Vallellanes William
• Van Es Jack

Classifications

• B64C3/182 Primary

  Stringers, longerons · CPC title

• B64G1/22

  Parts of, or equipment specially adapted for fitting in or to, cosmonautic vehicles · CPC title

• B63B3/00

  Hulls characterised by their structure or component parts (non-metallic hulls B63B5/00; designing, building, maintaining or repairing methods B63B71/00 - B63B83/00) · CPC title

• B64C1/064 Primary

  Stringers; Longerons · CPC title