Septumization of honeycomb sandwiches

Patent metadata

Field	Value
Publication number	US-9643392-B2
Application number	US-201313953456-A
Country	US
Kind code	B2
Filing date	Jul 29, 2013
Priority date	Jul 29, 2013
Publication date	May 9, 2017
Grant date	May 9, 2017

Abstract

An acoustic liner having a honeycomb core is fabricated by forming septa in a sheet of material, and assembling the sheet of material and the core. During the assembly process, the septa are respectively inserted as a group into cells of the core.

First claim

What is claimed is:

1. A method of producing an acoustic liner having a honeycomb core comprising cells, the method comprising:
forming an inner facesheet comprising perforations:
forming a septa insert comprising an array of septum in a sheet comprising a porous material, the septa insert comprising integrally formed, one-piece unitary construction containing the array of septum, each septum comprising sides angling, relative to sound waves propagating into the honeycomb core from the perforations in the inner facesheet, and every side of each septum joining at a tip of the each septum;
nesting, in at least one septum in the array of septum, a nested septum comprising perforated sides angling, relative to sound waves propagating into the honeycomb core from the perforations in the inner facesheet, every side of the nested septum joining at a tip of the nested septum, and a cross-sectional shape different than a cross-sectional shape of the at least one septum; and
septumizing the honeycomb core via inserting the septa insert, tips first, into the cells of the honeycomb core, such that each cell of the cells of the honeycomb core receives a septum of the septa insert; and
adhering the inner facesheet to the septa insert.

2. The method of claim 1 , wherein forming the septa insert is performed by one of:
injection molding a plastic; and
thermo-forming a sheet of plastic.

3. The method of claim 1 , wherein inserting the septa insert is performed by inserting the septa insert substantially simultaneously into the cells of the honeycomb core.

4. The method of claim 1 , wherein inserting the septa insert is performed by inserting the septa insert as a group through a top of the honeycomb core.

5. The method of claim 1 , wherein inserting the septa insert is performed by inserting the septa insert as a group through a bottom of the honeycomb core.

6. The method of claim 1 , wherein forming the septa insert includes:
forming a plurality of substantially hollow cones, and
selecting volumes for the hollow cones that form resonant cavities.

7. The method of claim 6 , further comprising:
bonding the septa insert to the honeycomb core by placing a reticulated film adhesive between the septa insert and edges of cells in the honeycomb core.

8. A method for attenuating sound in a honeycomb core comprising cells, the method comprising:
forming an inner facesheet comprising perforations:
adhering the inner facesheet across one side of the honeycomb core;
forming a single continuous septa sheet, comprising a porous material, the septa sheet comprising an array of septum, each septum comprising sides angling relative to sound waves propagating into the honeycomb core from the perforations in the inner facesheet, and every side of each septum joining at a tip of the each septum;
nesting, in at least one septum in the array of septum, a nested septum comprising perforated sides angling, relative to sound waves propagating into the honeycomb core from the perforations in the inner facesheet, every side of the nested septum joining at a tip of the nested septum, and a cross-sectional shape different than a cross-sectional shape of the at least one septum;
installing the septa sheet, tips first, into the honeycomb core from a side of the honeycomb core opposite the inner facesheet, such that each cell of the cells of the honeycomb core receives a septum of the septa sheet;
adhering an outer facesheet to the septa sheet.

9. The method of claim 8 , further comprising:
choosing a size and shape for each septum resulting in the each septum functioning as Helmholtz resonators.

10. The method of claim 8 , further comprising:
forming the sheet comprising a nested septum within at least one of the each septum, such that the nested septum comprises a perforated material selected from at least one of: a plastic sheet, and a metal sheet, that differs from the porous material and the cross-sectional shape of the at least one of the each septum.

11. The method of claim 8 , further comprising:
using the each septum to form multiple acoustic cell inserts based on acoustic requirements and geometric cell tolerances of the honeycomb core.

12. The method of claim 8 , further comprising:
forming the each septum with substantially uniform heights.

13. The method of claim 8 , further comprising:
forming the each septum with non-uniform heights to adjust acoustic performance based on characteristics of a noise source.

14. The method of claim 8 , further comprising:
providing a sheet of porous material; and
forming the each septum into the sheet.

15. A method of septumizing a honeycomb core, the method comprising:
attaching a porous inner facesheet to the honeycomb core comprising cells comprising polygon shapes;
installing a sheet comprising an array of septum into the honeycomb core, such that each cell of the cells of the honeycomb core receives a septum of the sheet; the sheet comprising a porous material such that a size, shape, depth, and porosity of each septum in the array of septum vary depending upon a desired tuning attenuation desired respectively for each cell in the honeycomb core occupied respectively by each septum in the array of septum, each septum comprising sides angling relative to sound waves propagating into the honeycomb core from perforations in the porous inner facesheet, and every side of each septum joining at a tip of the each septum, and at least one septum in the array of septum comprising a nested septum comprising perforated sides angling, relative to sound waves propagating into the honeycomb core from the perforations in the inner facesheet, every side of the nested septum joining at a tip of the nested septum, within the at least one septum.

16. The method of claim 15 , wherein installing the sheet includes adhesively bonding the sheet to the honeycomb core.

17. The method of claim 16 , wherein adhesively bonding the sheet to the honeycomb core includes placing a reticulated film adhesive between edges of the cells of the honeycomb core and the sheet.

18. The method of claim 15 , wherein installing the sheet includes inserting the septum respectively into the cells of the honeycomb core.

Assignees

• Boeing Co

Inventors

• Butler Geoffrey Allen
• Lan Justin Honshune
• Gerken Noel T
• Duschl Garry M
• Day Benjamin Julius

Classifications

• B32B15/02

  Layer formed of wires, e.g. mesh · CPC title

• B32B27/06

  as the main or only constituent of a layer, {which is} next to another layer of {the same or of} a {different material (next to a layer of a particular substance B32B9/045; next to a bituminous or tarry layer B32B11/046; next to a water setting substance layer B32B13/12; next to a metal layer B32B15/08; next to a glass layer B32B17/10; next to a layer formed of natural mineral fibres or particles B32B19/045; next to a wood layer B32B21/08; next to a cellulosic plastic layer B32B23/08; next to a natural or synthetic rubber layer B32B25/08)} · CPC title

• F02C7/045

  having provisions for noise suppression · CPC title

• B64D2033/0206

  comprising noise reduction means, e.g. acoustic liners · CPC title

• B29D99/0021

  provided with plain or filled structures, e.g. cores, placed between two or more plates or sheets, e.g. in a matrix · CPC title