Continuous degree of freedom acoustic cores

Patent metadata

Field	Value
Publication number	US-11227576-B2
Application number	US-201916415754-A
Country	US
Kind code	B2
Filing date	May 17, 2019
Priority date	Feb 1, 2017
Publication date	Jan 18, 2022
Grant date	Jan 18, 2022

Abstract

An acoustic liner and a method of attenuating noise are provided. The acoustic liner includes a face sheet, a back sheet spaced from the face sheet, and a core layer extending between the face sheet and the back sheet. The core layer includes a plurality of resonant cells, each resonant cell including at least one cell wall coupled to the back sheet along a cell wall base edge. The at least one cell wall extends from the back sheet at an angle toward the face sheet. The at least one cell wall further coupled to the face sheet along a cell wall top edge. The resonant cell is formed in a predetermined shape and contains a volume in a space defined by the at least one cell wall, the back sheet, and the face sheet. The cell wall base edge length is greater than the cell wall top edge length.

First claim

What is claimed is:

1. An acoustic liner comprising:
a face sheet;
a back sheet spaced from said face sheet; and
a core layer comprising:
a plurality of adjacent cavities extending between said face sheet and said back sheet;
a thickness defined by a distance between said face sheet and said back sheet, said core layer further comprising:
a plurality of first resonant cells, each first resonant cell of said plurality of first resonant cells comprising:
at least one first cell wall coupled to said back sheet along a first cell wall base edge, said at least one cell wall extending from said back sheet at a first angle toward said face sheet, said at least one first cell wall further coupled to said face sheet along a first cell wall top edge, said first resonant cell formed in a first shape, said first resonant cell containing a first volume in a space defined by said at least one first cell wall, said back sheet, and said face sheet, said first cell wall base edge comprising a first length, and said first cell wall top edge comprising a second length, said second length less than said first length.

2. The acoustic liner of claim 1 , wherein said plurality of first resonant cells are positioned on said back sheet in a grid arrangement.

3. The acoustic liner of claim 1 , wherein said plurality of first resonant cells are positioned on said back sheet in an offset arrangement.

4. The acoustic liner of claim 1 , wherein the second length is approximately equal to zero.

5. The acoustic liner of claim 1 , wherein said back sheet, said face sheet, and said core layer are formed as at least one of:
a substantially flat acoustic liner;
an arcuate cylindrical acoustic liner;
a complexly curved acoustic liner.

6. The acoustic liner of claim 1 , wherein said first length defines a first perimeter and said first shape defines a pyramid, said at least one first cell wall comprising at least three faces of said pyramid, said each first resonant cell further comprising a first polygonal base having at least three sides and said first perimeter, said at least one first cell wall further coupled to said back sheet along said first perimeter.

7. The acoustic liner of claim 6 , wherein said first shape further defines at least one of a right pyramid, an oblique pyramid, a regular pyramid, and an irregular pyramid.

8. The acoustic liner of claim 6 , wherein said first shape further defines a truncated pyramid comprising a frustum, and wherein said second length is defined by a second perimeter of said frustum, said at least one first cell wall further coupled to said face sheet along said second perimeter.

9. The acoustic liner of claim 1 , wherein said first length defines a first circumference and said first shape defines a cone, said each first resonant cell further comprising an annular base having said first circumference, said at least one first cell wall coupled to said back sheet along said first circumference.

10. The acoustic liner of claim 9 , wherein said first shape further defines at least one of a right circular cone, an oblique circular cone, a right elliptical cone, and an oblique elliptical cone.

11. The acoustic liner of claim 9 , wherein said first shape further defines a truncated cone comprising an annular frustum, and wherein said second length is defined by a second circumference of said annular frustum, said at least one first cell wall coupled to said face sheet along said second circumference.

12. The acoustic liner of claim 1 , said core layer further comprising a plurality of second resonant cells, each second resonant cell of said plurality of second resonant cells comprising:
at least two second cell walls, each second cell wall of said at least two second cell walls coupled to said face sheet along a second cell wall base edge, said each second cell wall extending from said face sheet at a second angle toward said back sheet, said each second cell wall further coupled to said back sheet along a second cell wall top edge, said each second resonant cell formed in a second shape, said each second resonant cell containing a second volume in a space defined by said at least two second cell walls, said back sheet, said face sheet, and at least two adjacent first resonant cells of said plurality of first resonant cells, said second cell wall base edge comprises a third length, and said second cell wall top edge comprising a fourth length, said fourth length is less than said third length.

13. The acoustic liner of claim 12 , wherein said third length defines a third perimeter and said second shape defines a polyhedron, said at least two second cell walls comprising at least three faces of said polyhedron, said each second resonant cell further comprising a second polygonal base having at least three sides and said third perimeter, said at least one second cell wall further coupled to said face sheet along said third perimeter.

14. The acoustic liner of claim 12 , wherein said second shape defines at least one of a regular polyhedron and an irregular polyhedron.

15. The acoustic liner of claim 12 , said core layer further comprising a plurality of third resonant cells, each third resonant cell of said plurality of third resonant cells formed in a third shape, said each third resonant cell containing a third volume in a space defined by at least two second cell walls, said back sheet, said face sheet, and said at least two adjacent first resonant cells.

16. The acoustic liner of claim 15 , wherein each of said first shape, said second shape, and said third shape have a different shape relative to one another.

17. The acoustic liner of claim 15 , wherein said first shape and said third shape alternate in an axial direction, the axial direction substantially perpendicular to a circumferential direction.

18. The acoustic liner of claim 15 , wherein said first shape and said third shape alternate in a circumferential direction, the circumferential direction substantially perpendicular to an axial direction.

19. The acoustic liner of claim 15 , wherein said third shape defines at least one of a regular non-pyramidal polyhedron, an irregular non-pyramidal polyhedron, a right pyramid, an oblique pyramid, a regular pyramid, and an irregular pyramid.

20. An acoustic structure comprising:
a core layer comprising:
an inner side and an outer side spaced opposite said inner side across a thickness defined therebetween; and
a plurality of first resonant cells occupying the thickness of said core layer, each first resonant cell of said plurality of first resonant cells comprising:
at least one first cell wall extending at a first angle from a first cell wall base edge along the outer side to a first cell wall top edge along the inner side, said first resonant cell formed in a first shape, said first resonant cell containing a first volume in a space defined by said at least one cell wall, the inner side, and the outer side, said first cell wall base edge comprising a first length, and said first cell wall top edge comprising a second length, said second length less than said first length.

21. A method of attenuating noise from a source generating a sound wave stream, said method comprising:
receiving a sound wave stream including a plurality of frequency components at a first surface of a core layer of an acoustic structure, the core layer comprising a plurality of resonant cells occupying a thickness of the core layer;
channeling the sound wave stream into the core layer;
reflecting the sound wave

Assignees

• Gen Electric
• Mra Systems Llc

Inventors

• Lin Wendy Wenling
• Martinez Michael Moses
• Majjigi Rudramuni Kariveerappa
• Calder David Patrick
• Goldsholl Aaron

Classifications

• F02C7/24 Primary

  Heat or noise insulation (air intakes having provisions for noise suppression F02C7/045; turbine exhaust heads, chambers, or the like F01D25/30; silencing nozzles of jet-propulsion plants F02K1/00) · CPC title

• F02C7/045

  having provisions for noise suppression · CPC title

• B32B27/12

  next to a fibrous or filamentary layer · CPC title

• B32B2307/102

  Insulating · CPC title

• B32B15/095

  comprising polyurethanes · CPC title