US20060070345A1

US20060070345A1 - Reinforced structural assembly having a tee joint and method for forming the same

Info

Publication number: US20060070345A1
Application number: US10/955,577
Authority: US
Inventors: Keith Young; Kevin Waymack; Ryan Hanks
Original assignee: Boeing Co
Current assignee: Boeing Co
Priority date: 2004-09-30
Filing date: 2004-09-30
Publication date: 2006-04-06

Abstract

Reinforced structural assemblies and methods for forming such assemblies are disclosed. In one embodiment, a ribbed portion includes rib segments having a vertical height that extend laterally between junctions to form a network coupled to a supporting substrate. The rib segments include a plurality of flanged portions coupled to a lateral edge of the rib segments. In another embodiment, the ribbed portion includes rib segments having flanged portions on opposing lateral edges that receive opposing substrates. Similarly, a method includes forming a ribbed portion having a plurality of rib segments extending laterally between junctions. The rib segments include a plurality of flanged portions on at least one of the first and second lateral edges. First and second substrates are coupled to opposing sides of the ribbed portion.

Description

FIELD OF THE INVENTION

This invention relates generally to materials construction, and more particularly to reinforced structural assemblies and methods for forming such assemblies.

BACKGROUND OF THE INVENTION

Reinforced structures are widely used in many industries and in many diverse applications. For example, aircraft, spacecraft, terrestrial and marine vehicles often employ a variety of planar, curved and multiple-contoured reinforced structures. The foregoing reinforced structures generally include a lightweight core material that is positioned between a pair of spaced apart and generally parallel face sheets. Since the bending stiffness of the reinforced structure substantially increases as the core thickness is increased, such structures advantageously provide a lightweight and effective means for resisting bending loads.
One commonly used reinforced structure includes an interconnected honeycomb core structure having a selected thickness that is positioned between the face sheets. Although the foregoing reinforced structure is effective in resisting high bending loads, some disadvantages nevertheless exist. For example, since the core material must be bonded to the face sheets by adhesives, brazing or other similar processes at many discrete locations, portions of the core material may be insufficiently bonded to the face sheets during fabrication of the structure that result in localized weaknesses within the structure. Moreover, if the structure sustains physical damage while in service, the structure is typically repaired by cutting the face sheets and the core material to remove the damaged portion. Repair procedures of this type may cause further debonding of the core material from the face sheets, which is not readily detectable by commonly used inspection procedures.
Another commonly used reinforced structure employs a closed network of discrete ribs that extend between opposed and spaced apart face sheets. The ribs are generally coupled to the face sheets by fixedly positioning edges of the ribs into receiving grooves that are machined or otherwise formed in the face sheets. One example of the foregoing reinforced structure is the GRID-LOCK structural system available from Rohr, Inc. of Chula Vista Calif. Although the foregoing system addresses some of the shortcomings present in structures having a honeycomb core material, still other shortcomings are present. For example, the machined receiving grooves require a small diameter tool to form the elongated grooves, which is time consuming and generally increases the production costs associated with the fabrication of the reinforced structure. Moreover, the relatively thin ribs are typically positioned in relatively shallow receiving grooves that provide a limited bond contact area. Accordingly, such structures must include a relatively large number of ribs and/or thicker face sheets in order to provide the desired flexural strength.
Accordingly, what is needed in the art is a lightweight reinforced structure that is conveniently and inexpensively fabricated, while providing high flexural rigidity.

SUMMARY OF THE INVENTION

The present invention is directed to reinforced structural assemblies and methods for forming such assemblies. In one aspect, the invention includes a reinforced structural assembly having a ribbed portion that includes rib segments having a predetermined vertical height and that extend laterally between junctions to form a closed network of the rib segments fixedly coupled to a supporting substrate. The rib segments include a plurality of flanged portions fixedly coupled to the lateral edges of the rib segments. A substrate is fixedly coupled to the flanged portions.
In another aspect, the reinforced structural assembly includes a ribbed portion having rib segments of predetermined vertical height that extend laterally between junctions to form a closed network of the rib segments. The rib segments include flanged portions on opposing lateral edges. The assembly also includes opposing substrates fixedly coupled to the flanged portions.
In still another aspect, a method for constructing a reinforced structural assembly includes forming a ribbed portion having a plurality of rib segments extending laterally between junctions to form a closed network. The rib segments also include first lateral edges and opposing second lateral edges forming a ribbed portion including a plurality of rib segments extending laterally between junctions to form a closed network of the rib segments, the rib segments having first lateral edges and opposing second lateral edges. The method also includes forming a plurality of flanged portions on at least one of the first and second lateral edges of the rib segments that extend along at least a portion of the lateral edges. First and second substrates are coupled to opposing sides of the ribbed portion.
In yet another aspect, the invention includes an aerospace vehicle having a fuselage, wing assemblies and an empennage operatively coupled to the fuselage. At least a portion of the fuselage, the wing assemblies and the empennage include a reinforced structural assembly. The assembly includes a ribbed portion having rib segments with a predetermined vertical height and that extend laterally between junctions to form a closed network of the rib segments fixedly coupled to a supporting substrate. A plurality of flanged portions are fixedly coupled to at least one of the lateral edges of the rib segments, and a substrate is fixedly coupled to the flanged portions.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred and alternate embodiments of the present invention are described in detail below with reference to the following drawings.
FIG. 1 is a is a partial plan view of a reinforced structural assembly according to an embodiment of the invention;
FIG. 2 is an exploded, partial isometric view of the embodiment of FIG. 1;
FIG. 3 is a partial cross sectional view along a section line of FIG. 2;
FIG. 4 is another partial cross sectional view along a section line of FIG. 2;
FIG. 5 is an exploded, partial isometric view of a reinforced structural assembly according to another embodiment of the invention;
FIG. 6 is a partial cross sectional view along a section line of FIG. 5;
FIG. 7 is another partial cross sectional view along a section line of FIG. 5; and
FIG. 8 is a side elevation view of an aircraft having one or more of the disclosed embodiments of the present invention.

DETAILED DESCRIPTION

The present invention relates to reinforced structural assemblies and methods for forming such assemblies. Many specific details of certain embodiments of the invention are set forth in the following description and in FIGS. 1 through 8 to provide a thorough understanding of such embodiments. One skilled in the art, however, will understand that the present invention may have additional embodiments, or that the present invention may be practiced without several of the details described in the following description.
FIG. 1 is a partial plan view of a reinforced structural assembly 10 according to an embodiment of the invention, which shows respective disengaged portions of the assembly 10. The assembly 10 includes a ribbed portion 12 that includes a plurality of ribs 14 that extend laterally between junctions 13, forming a generally closed network of the ribs 14 that extend outwardly from a supporting substrate 16. The ribs 14 are fixedly coupled to the supporting substrate 16 on a first lateral edge of the ribs 14. An opposing second lateral edge of the ribs 14 include flanged portions 18 that face outwardly from the network of ribs 14 so that the ribs 14 and the flanged portions 18 form a tee-shaped member when viewed in cross-section. The flanged portions 18 may include one or more recesses 20 that partially extend into a thickness of the flanged portions 18. Although the ribs 14 shown in FIG. 1 generally comprise a rectangular network of ribs 14, it should be understood that the ribs 14 may be arranged in still other patterns. For example, the ribs 14 may be arranged to form a closed network of ribs 14 having a regular polygonal shape, such as a closed network of ribs 14 that are arranged in a triangular shape. The assembly 10 also includes a substrate 22 that is configured to be coupled to the flanged portions 18 so that the supporting substrate 16 and the substrate 22 form opposing external sides of the reinforced structural assembly 10. The assembly 10 may thus form a portion of an aircraft structural panel, such as a floor panel, a portion of a wing panel, or any other suitable structures.
In some embodiments, the ribbed portion 12 and the substrate 22 may be formed from any suitable, substantially rigid material, which may include any ferrous material, or alternately any non-ferrous material, such as aluminum, a stainless alloy or titanium. The ribbed portion 12 and the substrate 22 may also be formed from selected polymeric materials, which may also include polymeric materials that are reinforced by fiber elements embedded in the polymeric material, such as carbon fibers, or other like materials. The ribbed portion 12 may also be formed as a composite structure, wherein the ribs 14 and the flanged portions 18 are formed as separate elements and then fixedly positioned onto the supporting substrate 16. The ribs 14 and the flanged portions 18 may be applied to the substrate 16 by a variety well-known material joining methods. For example, the ribs 14 and the substrate 16 may be joined by various fusion processes, such as welding or brazing. Similarly, the flanged portions 18 and the substrate 22 may also be joined by a fusion process. Alternately, a suitable adhesive material may be employed to bond the ribs 14 to the supporting substrate 16, and to bond the flanged portions 18 to the substrate 22.
FIG. 2 is an exploded, partial isometric view of assembly 10 of FIG. 1 that will be used to describe the assembly 10 in further detail. As briefly described above, the flanged portions 18 of the ribs 14 may include one or more recesses 20 that are configured to retain a volume of an adhesive material, such as an epoxy resin, that is applied to the flanged portion 18. Alternately, the one or more recesses 20 may also be used to retain a portion of a brazing alloy that may be used to fixably couple the flanged portions 18 to the substrate 22. In either case, the recesses 20 may be formed in the flanged portions 18 by a machining process, or by other known methods, such as electrochemical machining. In the embodiment shown in FIG. 1, the recesses 20 are shown extending along an entire length of the flanged portions 18. It is nevertheless understood that the recesses 20 may extend along only a portion of the flanged portions 18. In other embodiments, the recesses 20 may be omitted entirely.
Still referring to FIG. 2, the flanged portions 18 are shown extending along a portion of the lateral edges of the ribs 14. It is understood, however, that the flanged portions 18 may extend along the entire lateral edge of the ribs 14 so that the flanged portions 18 extend across the junctions 13. Further, although the flanged portions 18 in FIG. 1 are shown having a relatively uniform width, the width of the flanged portions 18 may be varied as the flanged portion 18 extends along the edge of the rib 14.
FIG. 3 is a cross sectional view of the ribbed portion 12 along the section line 3-3 of FIG. 2. The rib 14 may be formed to have any suitable height h to provide an assembly 10 having a desired flexural stiffness. Similarly, a width w may be selected to provide a desired resistance to shearing forces that may be applied to the assembly 10. The width w may be approximately constant as the rib 14 extends between the substrate 16 and the flange 18, or it may vary. The recesses 20 formed in the flanged portions 18 may include various configurations other than the linear segments shown in FIGS. 1 and 2. For example, the recesses 20 may be formed as continuous undulating segments, or sawtooth-shaped segments. Further, the recesses 20 may also be formed as a non-continuous arrangement of recessed regions.
FIG. 4 is a cross sectional view of the ribbed portion 12 of FIG. 3 having the substrate 22 applied to the flanged portion 18. An adhesive material is applied to the flanged portion 18 so that the adhesive material is at least partially retained within the recesses 20. Alternately, in one particular embodiment, the recesses 20 may be omitted from the flanged portion 18, and the recesses 20 may be formed in a surface of the substrate 22 in a predetermined pattern. In still another particular embodiment, the flanged portion 18 may be formed with holes that project through the flanged portion 18 that correspond with holes formed in the substrate 22. The substrate 22 may then be fixedly coupled to the flanged portion 18 by various well-known fasteners that allow fastener tensioning from one side.
FIG. 5 is an exploded, partial isometric view of a reinforced structural assembly 30 according to another embodiment of the invention. The assembly 30 includes a first substrate 32, an opposing second substrate 34, and a ribbed portion 36 interposed between the first substrate 32 and the second substrate 34. The ribbed portion 36 includes a plurality of ribs 38 that form a generally closed network. The ribs 38 include opposing flanged portions 40 positioned along respective lateral edges of the ribs 38. The flanged portions 40 may include one or more recesses 42 that partially extend into a thickness of the flanged portions 40. The ribbed portion 36 and the first substrate 32 and the second substrate 34 may be formed from any desired materials, including, for example, a substantially rigid material, which may include any ferrous material, or alternately any non-ferrous material, such as aluminum, a stainless alloy or titanium. The ribbed portion 36 and the first and second substrates 32 and 34 may also be formed from selected polymeric materials, which may also include polymeric materials that are reinforced by fiber elements embedded in the polymeric material, such as carbon fibers, or other like materials. The ribbed portion 36 may also be formed as a composite structure, wherein the ribs 38 and the flanged portions 40 are formed as separate elements and then fixedly joined prior to the ribbed portion 36 being fixedly coupled to the first and second substrates 32 and 34.
FIG. 6 is a cross sectional view of the ribbed portion 36 along the section line 6-6 of FIG. 5. The recesses 42 formed in the flanged portions 40 may again include various configurations other than the linear segments shown in FIG. 5, and may include continuous segments, or a non-continuous arrangement of recessed regions. FIG. 7 is a cross sectional view of the ribbed portion 36 of FIG. 6 having the first substrate 32 and the second substrate 34 applied to respective flanged portions 40. As in the prior embodiment, an adhesive material is applied to the flanged portions 40 so that the adhesive material is retained within the recesses 42. Alternately, and in still another particular embodiment, the recesses 42 may be omitted from the flanged portions 40, and the recesses 42 may be formed in surfaces of the first substrate 32 and the second substrate 34 in a predetermined pattern.
Those skilled in the art will also readily recognize that the foregoing embodiments may be incorporated into a wide variety of different systems. Referring now in particular to FIG. 8, a side elevation view of an aircraft 300 having one or more of the disclosed embodiments of the present invention is shown. With the exception of the embodiments according to the present invention, the aircraft 300 includes components and subsystems generally known in the pertinent art, and in the interest of brevity, will not be described in detail. The aircraft 300 generally includes one or more propulsion units 302 that are coupled to wing assemblies 304, or alternately, to a fuselage 306 or even other portions of the aircraft 300. Additionally, the aircraft 300 also includes a tail assembly 308 and a landing assembly 310 coupled to the fuselage 306. The aircraft 300 further includes other systems and subsystems generally required for the proper operation of the aircraft 300. For example, the aircraft 300 includes a flight control system 312 (not shown in FIG. 8), as well as a plurality of other electrical, mechanical and electromechanical systems that cooperatively perform a variety of tasks necessary for the operation of the aircraft 300. Accordingly, the aircraft 300 is generally representative of a commercial passenger aircraft, which may include, for example, the 737, 747, 757, 767 and 777 commercial passenger aircraft available from The Boeing Company of Chicago, Ill. Although the aircraft 300 shown in FIG. 8 generally shows a commercial passenger aircraft, it is understood that the various embodiments of the present invention may also be incorporated into flight vehicles of other types. Examples of such flight vehicles may include manned or even unmanned military aircraft, rotary wing aircraft, ballistic flight vehicles or orbital vehicles, as illustrated more fully in various descriptive volumes, such as Jane's All The World's Aircraft, available from Jane's Information Group, Ltd. of Coulsdon, Surrey, UK. Additionally, those skilled in the art will readily recognize that the various embodiments of the present invention may also be incorporated into terrestrial or even marine vehicles.
With reference still to FIG. 8, the aircraft 300 may include one or more of the embodiments of the reinforced structural assembly 314 according to the present invention, which may be incorporated into various structural portions of the aircraft 300. In addition, the various embodiments of the present invention may also be incorporated into the various systems and sub-systems of the aircraft 300.
While preferred and alternate embodiments of the invention have been illustrated and described, as noted above, many changes can be made without departing from the spirit and scope of the invention. Accordingly, the scope of the invention is not limited by the disclosure of these preferred and alternate embodiments. Instead, the invention should be determined entirely by reference to the claims that follow.

Claims

1. A reinforced structural assembly, comprising:

a ribbed portion that includes rib segments having a predetermined vertical height and that extend laterally between junctions to form a network of the rib segments fixedly coupled to a supporting substrate;

a plurality of flanged portions fixedly coupled to at least one of the lateral edges of the rib segments; and

a second substrate configured to be fixedly coupled to the flanged portions.

2. The reinforced structural assembly of claim 1, wherein each flanged portion extends at least partially along each lateral edge of the rib segment.

3. The reinforced structural assembly of claim 1, wherein each flanged portion extends along each lateral edge of the rib segment and into the junction.

4. The reinforced structural assembly of claim 1, wherein each flanged portion further comprises at least one recess that extends along a length of the flanged portion.

5. The reinforced structural assembly of claim 1, wherein the network of the rib segments further comprises a closed network having a regular polygonal shape.

6. The reinforced structural assembly of claim 5, wherein the network of the rib segments further comprises a closed network having a rectangular shape.

7. The reinforced structural assembly of claim 5, wherein the network of the rib segments further comprises a closed network having a triangular shape.

8. The reinforced structural assembly of claim 1, wherein the substrate is fixedly coupled to the flanged portions using an adhesive material.

9. The reinforced structural assembly of claim 1, wherein the substrate is fixedly coupled to the flanged portions using a fusion process.

10. The reinforced structural assembly of claim 1, wherein the assembly is comprised of a non-ferrous material.

11. The reinforced structural assembly of claim 10, wherein the non-ferrous material comprises aluminum and titanium.

12. The reinforced structural assembly of claim 1, wherein the assembly is comprised of a polymeric material.

13. A reinforced structural assembly, comprising:

a ribbed portion that includes rib segments having a predetermined vertical height and that extend laterally between junctions to form a network of the rib segments, at least some of the rib segments having flanged portions on opposed lateral edges; and

a pair of opposing substrates fixedly coupled to the flanged portions.

14. The reinforced structural assembly of claim 13, wherein each flanged portion extends at least partially along each lateral edge of the rib segment.

15. The reinforced structural assembly of claim 13, wherein each flanged portion extends along each lateral edge of the rib segment and into the junction.

16. The reinforced structural assembly of claim 13, wherein each flanged portion further comprises at least one recess that extends along a length of the flanged portion.

17. The reinforced structural assembly of claim 13, wherein the network of the rib segments further comprises a network having a regular polygonal shape.

18. The reinforced structural assembly of claim 17, wherein the network of the rib segments further comprises a network having a rectangular shape.

19. The reinforced structural assembly of claim 17, wherein the network of the rib segments further comprises a network having a triangular shape.

20. The reinforced structural assembly of claim 13, wherein the substrate is fixedly coupled to the flanged portions using an adhesive material.

21. The reinforced structural assembly of claim 13, wherein the substrate is fixedly coupled to the flanged portions using a fusion process.

22. The reinforced structural assembly of claim 13, wherein the assembly is comprised of a non-ferrous material.

23. The reinforced structural assembly of claim 22, wherein the non-ferrous material comprises aluminum and titanium.

24. The reinforced structural assembly of claim 13, wherein the assembly is comprised of a polymeric material.

25. A method for constructing a reinforced structural assembly, comprising:

forming a ribbed portion including a plurality of rib segments extending laterally between junctions to form a network of the rib segments, the rib segments having first lateral edges and opposing second lateral edges defining respective first and second sides of the ribbed portion;

forming a plurality of flanged portions on at least one of the first and second lateral edges of at least some of the rib segments that extend along at least a portion of the lateral edges;

fixably coupling a first substrate to the first side; and

fixably coupling a second substrate to the second side.

26. The method of claim 25, wherein forming a ribbed portion including a plurality of rib segments extending laterally between junctions to form a network of the rib segments further comprises forming a ribbed portion having a regular polygonal shape.

27. The method of claim 26, wherein forming a ribbed portion having a regular polygonal shape further comprises forming a ribbed portion having a rectangular shape.

28. The method of claim 26, wherein forming a ribbed portion having a regular polygonal shape further comprises forming a~ribbed portion having a triangular shape.

29. The method of claim 26, wherein forming a plurality of flanged portions on at least one of the first and second lateral edges further comprises forming a plurality of flanged portions on at least one of the first and second lateral edges that extend at least partially along each lateral edge of the rib segment.

30. The method of claim 26, wherein forming a plurality of flanged portions on at least one of the first and second lateral edges further comprises forming a plurality of flanged portions on at least one of the first and second lateral edges that extend along lateral edge of the rib segment and into the junction.

31. The method of claim 26, wherein forming a plurality of flanged portions further comprises forming at least one recess in each of the plurality of flanged portions.

32. The method of claim 26, wherein forming a plurality of flanged portions further comprises forming flanged portions on the first and the second lateral edges.

33. The method of claim 26, wherein fixably coupling a first substrate further comprises adhesively coupling the first substrate.

34. The method of claim 26, wherein fixably coupling a first substrate further comprises fusing the first substrate to the first side.

35. The method of claim 26, wherein fixably coupling a second substrate further comprises adhesively coupling the second substrate.

36. The method of claim 26, wherein fixably coupling a second substrate further comprises fusing the second substrate to the second side.

37. An aerospace vehicle, comprising:

a fuselage;

wing assemblies and an empennage operatively coupled to the fuselage; and

a reinforced structural assembly comprising at least a portion of the fuselage, the wing assemblies and the empennage, the reinforced structural assembly further comprising:

a substrate configured to be fixedly coupled to the flanged portions.

38. The aerospace vehicle of claim 37, wherein each flanged portion extends at least partially along each lateral edge of the rib segment.

39. The aerospace vehicle of claim 37, wherein each flanged portion extends along each lateral edge of the rib segment and into the junction.

40. The aerospace vehicle of claim 37, wherein each flanged portion further comprises at least one recess that extends along a length of the flanged portion.

41. The aerospace vehicle of claim 37, wherein the network of the rib segments further comprises a closed network having a regular polygonal shape.

42. The aerospace vehicle of claim 41, wherein the network of the rib segments further comprises a closed network having a rectangular shape.

43. The aerospace vehicle of claim 41, wherein the network of the rib segments further comprises a closed network having a triangular shape.

44. The aerospace vehicle of claim 37, wherein the substrate is fixedly coupled to the flanged portions using an adhesive material.

45. The aerospace vehicle of claim 37, wherein the substrate is fixedly coupled to the flanged portions using a fusion process.

46. The aerospace vehicle of claim 37, wherein the assembly is comprised of a non-ferrous material.

47. The aerospace vehicle of claim 46, wherein the non-ferrous material comprises aluminum and titanium.

48. The aerospace vehicle of claim 37, wherein the assembly is comprised of a polymeric material.