SYSTEMS AND METHODS FOR REDUCING NOISE IN AIRCRAFT FUSELAGES AND OTHER STRUCTURES

• US 20100320319A1
• Filed: 08/05/2010
• Published: 12/23/2010
• Est. Priority Date: 03/18/2005
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Montgomery, Joshua M., Liguore, Salvatore L.
• Granted Patent: US 8,042,768 B2
• Time in Patent Office: Days
• US Class Current: 244/119
• CPC Class Codes: B29C 70/088 and with one or more layers of non-plastics material or non-specified material, e.g. supports
• CPC Class Codes: B29C 70/342 using isostatic pressure
• CPC Class Codes: B29C 70/865 completely encapsulated
• CPC Class Codes: B29D 99/0014 provided with ridges or ribs, e.g. joined ribs
• CPC Class Codes: B29K 2995/0002 insulating
• CPC Class Codes: B29K 2995/0091 Damping, energy absorption
• CPC Class Codes: B32B 37/12 characterised by using adhesives
• CPC Class Codes: B64C 1/066 Interior liners
• CPC Class Codes: B64C 1/40 Sound or heat insulation , e.g. using insulation blankets
• CPC Class Codes: B64C 2001/0072 from composite materials
• CPC Class Codes: F16F 9/306 of the constrained layer type, i.e. comprising one or more constrained viscoelastic layers
• CPC Class Codes: Y02T 50/40 Weight reduction
• CPC Class Codes: Y10T 156/10 Methods of surface bonding and/or assembly therefor

Abstract

Systems and methods for reducing noise in aircraft fuselages and other structures are described herein. A noise reduction system configured in accordance with one embodiment of the invention includes an auxetic core, a damping layer, and a constraining layer. In this embodiment, the auxetic core is supported by a structural member, and the damping layer is sandwiched between the auxetic core and the constraining layer. A method for manufacturing a structural assembly in accordance with another embodiment of the invention includes forming a stiffener by positioning a first ply of composite material against a first tool surface, positioning damping material against the first ply, and positioning a second ply of composite material against the damping material to sandwich the damping material between the first and second plies. The method can further include forming a skin by positioning a third ply of composite material against a second tool surface offset from the first tool surface, and attaching the stiffener to the skin by co-curing the first, second and third plies of composite material.

Claims

1-27. -27. (canceled)

28. A structural assembly having an integral damping system, the structural assembly comprising:

a stiffener, the stiffener including;

a first stiffener portion configured to be attached to a skin panel;

a second stiffener portion spaced apart from the first stiffener portion and configured to be offset from the skin panel, the second stiffener portion including at least first and second plies of fiber-reinforced resin material; and

a layer of damping material sandwiched between the first and second plies of fiber-reinforced resin material.

29. The structural assembly of claim 28 wherein the first ply of fiber-reinforced resin material extends from the first stiffener portion to the second stiffener portion.

30. The structural assembly of claim 28 wherein the first and second stiffener portions are composed of fiber-reinforced resin material.

31. The structural assembly of claim 28 wherein the layer of damping material includes a viscoelastic damping material.

32. The structural assembly of claim 28 wherein the layer of damping material includes a viscoelastic adhesive.

33. The structural assembly of claim 28 wherein the first stiffener portion includes a flange portion configured to be bonded to the skin panel, and wherein the second stiffener portion includes a cap portion offset from the flange portion.

34. The structural assembly of claim 28, further comprising the skin panel, wherein the skin panel is composed of fiber-reinforced resin material and the first stiffener portion is attached to the skin panel.

35. The structural assembly of claim 28, further comprising the skin panel, wherein the skin panel is composed of a first portion of fiber-reinforced resin material, wherein the first and second stiffener portions are composed of a second portion of fiber-reinforced resin material, and wherein the first stiffener portion is bonded to the skin panel.

36. The structural assembly of claim 28, further comprising the skin panel, wherein the skin panel is a portion of aircraft fuselage skin composed of fiber-reinforced resin material, and wherein the first stiffener portion is bonded to the portion of aircraft fuselage skin.

37. The structural assembly of claim 28, further comprising the skin panel, wherein the skin panel is composed of a first portion of fiber-reinforced resin material, wherein the first and second stiffener portions are composed of a second portion of fiber-reinforced resin material, wherein the first stiffener portion includes a flange portion bonded to the skin panel, wherein the second stiffener portion includes a cap portion offset from the flange portion, and wherein the layer of damping material includes a viscoelastic damping material.

38. A method for manufacturing a structural assembly with an integral damping system, the method comprising:

positioning a first portion of fiber-reinforced resin material against a first tool surface to at least partially form a stiffener;

positioning a layer of damping material against the first portion of fiber-reinforced resin material;

positioning a second portion of fiber-reinforced resin material against a second tool surface offset from the first tool surface to at least partially form a skin; and

cocuring the first and second portions of fiber-reinforced resin material to bond the stiffener to the skin.

39. The method of claim 38 wherein positioning a layer of damping material against the first portion of fiber-reinforced resin material includes laminating a viscoelastic material with a ply of fiber-reinforced resin fabric.

40. The method of claim 38 wherein positioning a second portion of fiber-reinforced resin material against a second tool surface to at least partially form a skin includes wrapping fiber-reinforced resin material around a mandrel.

41. The method of claim 38 wherein positioning a second portion of fiber-reinforced resin material against a second tool surface to at least partially form a skin includes wrapping fiber-reinforced resin material around a rotating mandrel.

42. The method of claim 38 wherein positioning a second portion of fiber-reinforced resin material against a second tool surface to at least partially form a skin includes winding a fiber-reinforced resin filament around a mandrel.

43. The method of claim 38 wherein positioning a second portion of fiber-reinforced resin material against a second tool surface to at least partially form a skin includes wrapping fiber-reinforced resin tape around a mandrel.

44. The method of claim 38, further comprising positioning a third portion of fiber-reinforced resin material against the layer of damping material to laminate the damping material between the first and third portions of fiber-reinforced resin material.

45. The method of claim 38 wherein positioning a first portion of fiber-reinforced resin material against a first tool surface to at least partially form a stiffener includes laying at least a first ply of fiber-reinforced resin material in an elongate channel to at least partially form a stiffener with a hat-shaped cross-section.

46. The method of claim 38 wherein positioning a first portion of fiber-reinforced resin material against a first tool surface to at least partially form a stiffener includes laying at least a first ply of fiber-reinforced resin material in an elongate channel, and wherein positioning a second portion of fiber-reinforced resin material against a second tool surface to at least partially form a skin includes laying at least a second ply of fiber-reinforced resin material over the channel and in contact with a portion of the first ply of fiber-reinforced resin material.

47. The method of claim 38 wherein positioning a first portion of fiber-reinforced resin material against a first tool surface to at least partially form a stiffener includes laying at least a first ply of fiber-reinforced resin material in an elongate channel, and wherein the method further includes positioning a bladder in the channel to seal the first ply of fiber-reinforced resin material during a vacuum-bagging process.

48. A structural assembly having an integral damping system, the structural assembly comprising:

a skin, the skin including at least a first ply of fiber-reinforced resin material; and

means for stiffening the skin, the means for stiffening the skin including;

a second ply of fiber-reinforced resin material;

at least a third ply of fiber-reinforced resin material; and

means for damping vibration, wherein the means for damping vibration are sandwiched between the second and third plies of fiber-reinforced resin material.

49. The structural assembly of claim 48 wherein the means for stiffening the skin include a first portion attached to the skin and a second portion offset from the skin.

50. The structural assembly of claim 48 wherein the means for stiffening the skin are bonded to the skin by cocurring the first, second, and third plies of fiber-reinforced resin material.

51. The structural assembly of claim 48 wherein the means for damping vibration are viscoelastic.

52. The structural assembly of claim 48 wherein the skin includes an aircraft fuselage skin.

53. The structural assembly of claim 48 wherein the skin includes an aircraft fuselage skin, and wherein the means for stiffening the skin include a stiffener having a flange portion attached to the skin and a cap portion offset from the skin.

54. The structural assembly of claim 48 wherein the skin includes an aircraft fuselage skin, wherein the means for stiffening the skin include a stiffener having a flange portion attached to the skin and a cap portion offset from the skin, and wherein the means for damping vibration are positioned toward the cap portion of the stiffener.