Fuselage wall inner lining plate

• US 5,165,627 A
• Filed: 11/19/1991
• Issued: 11/24/1992
• Est. Priority Date: 10/17/1989
• Status: Expired due to Fees

• Current Assignee: Japan Aircraft Development Corporation, Mitsubishi Jukogyo Kabushiki Kaisha
• Original Assignee: Japan Aircraft Development Corporation, Mitsubishi Jukogyo Kabushiki Kaisha
• Inventors: Matsuzaki, Katsuya, Okura, Kiyoshi, Shibata, Katsuhiko, Izumiyama, Kazuo, Amano, Kanichi
• Primary Examiner(s): Marmor, Charles A.
• Assistant Examiner(s): Mattix, Carla
• Application Number:
  US07/795,251
• Time in Patent Office: 371 Days
• Field of Search: 244/123, 244/124, 244/126, 244/119, 428/188, 428/35.7, 428/36.9
• US Class Current: 244/119
• CPC Class Codes: B64C 1/40 Sound or heat insulation , e.g. using insulation blankets
• CPC Class Codes: Y10T 428/24174 including sheet or component perpendicular to plane of web or sheet

Abstract

The present invention is drawn to an improvement in the configuration of an inner lining plate of an aircraft fuselage wall, which will result in the sound transmission loss (TL) of the inner lining plate to occur in a frequency range covering the frequencies of external noises such as propeller sound, such that external noises transmitted from the inside of the aircraft fuselage can be reduced. The improvement resides in that a tensile rigidity in the circumferential direction of a substantially cylindrical fuselage wall inner lining plate is less than the tensile rigidity in the axial direction thereof. In this respect, the inner lining plate is provided with a large number of parallel crests extending in the axial direction. Alternatively, the substantially cylindrical fuselage wall inner lining plate can be made of fiber-reinforced plastics, in which fibers are woven in the axial direction in a mode different from that in which they are woven in the circumferential direction to provide an anisotropic property in which tensile rigidity in the circumferential direction is less than in the axial direction.

Claims

1. A fuselage wall inner lining comprising a plate of a stiff material having a substantially cylindrical shape, said plate having a tensile rigidity in the direction of the circumferential dimension thereof that is less than the tensile rigidity in the direction of the axial dimension thereof, and said plate having a ring frequency, where transmission loss of the plate becomes minimal, of less than 200 Hz, wherein said ring frequency is represented by

2. A fuselage inner lining comprising a plate of a stiff material having a substantially cylindrical shape, and a plurality of corrugations, the crests of all of said corrugations extending parallel to one another in the direction of the axial dimension of the plate such that said corrugations provide the plate with a tensile rigidity in the direction of the circumferential dimension thereof that is less than the tensile rigidity in the direction of the axial dimension thereof, and said plate having a ring frequency, where transmission loss of the plate becomes minimal, of less than 200 Hz, wherein said ring frequency is represented by

3. A fuselage inner lining comprising a substantially cylindrical plate of fiber-reinforced plastic, some of the fibers of the fiber-reinforced plastic of the plate extending parallel to another in the direction of the axial dimension of the plate and others of the fibers extending at an angle to the direction of the axial dimension of the plate, the arrangement of said fibers being such as to provide an anisotropic property to the plate in which the tensile rigidity of the plate in the direction of the circumferential dimension thereof is less than the tensile rigidity of the plate in the direction of the axial dimension thereof, and said plate having a ring frequency, where transmission loss of the plate becomes minimal, of less than 200 Hz, wherein said ring frequency is represented by

4. In an aircraft powered by a propelling device generating noise in a principal frequency range, an improved fuselage comprising:

a fuselage wall outside plate having a cylindrical shape and forming the outermost part of the fuselage;

a fuselage wall inside plate of a stiff material having a substantially cylindrical shape, said inside plate located radially inwardly of said outside plate and forming the innermost part of the fuselage,

said fuselage wall inside plate also having a tensile rigidity in the direction of the circumferential dimension thereof that is less than the tensile rigidity in the direction of the axial dimension thereof, and

said fuselage wall inside plate having a ring frequency, where transmission loss of the inside plate becomes minimal, which is less than said principal frequency range of the noise generated by the propelling device, wherein said ring frequency is represented by

space="preserve" listing-type="equation">f.sub.R =√

Ey/ρ

/2ρ

R,

Ey being the tensile rigidity of said inside plate in the direction of the axial dimension thereof, ρ

being the density of the material of said inside plate, and R being the radius of said inside plate; and

a frame interposed between and connecting said inside and said outside plates.

5. In an aircraft powered by a propelling device generating noise in a principal frequency range, an improved fuselage comprising:

a fuselage wall outside plate having a cylindrical shape and forming the outermost part of the fuselage;

a fuselage wall inside plate of a stiff material having a substantially cylindrical shape, said inside plate located radially inwardly of said outside plate and forming the innermost part of the fuselage,

said fuselage wall inside plate also having a plurality of corrugations, the crests of all of the corrugations of the inside plate extending parallel to one another in the direction of the axial dimension of the plate such that the corrugations provide said inside plate with a tensile rigidity in the direction of the circumferential dimension thereof that is less than the tensile rigidity in the direction of the axial dimension thereof, and

said fuselage wall inside plate having a ring frequency, where transmission loss of the inside plate becomes minimal, which is less than said principal frequency range of the noise generated by the propelling device, wherein said ring frequency is represented by

space="preserve" listing-type="equation">f.sub.R =√

Ey/ρ

/2ρ

R,

Ey being the tensile rigidity of said inside plate in the direction of the axial dimension thereof, ρ

being the density of the material of said inside plate, and R being the radius of said inside plate; and

a frame interposed between and connecting said inside and said outside plates.

6. In an aircraft powered by a propelling device generating noise in a principal frequency range, an improved fuselage comprising:

a fuselage wall outside plate having a cylindrical shape and forming the outermost part of the fuselage;

a substantially cylindrical fuselage wall inside plate of fiber reinforced plastic, said inside plate located radially inwardly of said outside plate and forming the innermost part of the fuselage;

some of the fibers of the fiber-reinforced plate of the inside plate extending parallel to one another in the direction of the axial dimension of the inside plate and others of the fibers extending at an angle to the direction of the axial dimension of the inside plate, the arrangement of said fibers being such as to provide an anisotropic property to the plate in which the tensile rigidity of the plate in the direction of the circumferential dimension thereof is less than the tensile rigidity of the plate in the direction of the axial dimension thereof and

said fuselage wall inside plate having a ring frequency, where transmission loss of the inside plate becomes minimal, which is less than said principal frequency range of the noise generated by the propelling device, wherein said ring frequency is represented by

space="preserve" listing-type="equation">f.sub.R =√

Ey/ρ

/2ρ

R,

Ey being the tensile rigidity of said inside plate in the direction of the axial dimension thereof, ρ

being the density of the material of said inside plate, and R being the radius of said inside plate; and

a frame interposed between and connecting said inside and said outside plates.