Fused Porogen Process for Acoustic Septa Fabrication

Patent metadata

Field	Value
Publication number	US-2016264231-A1
Application number	US-201514641537-A
Country	US
Kind code	A1
Filing date	Mar 9, 2015
Priority date	Mar 9, 2015
Publication date	Sep 15, 2016
Grant date	—

Abstract

An example method for manufacturing a multicellular structure for acoustic damping is described that includes applying a porogen material to a solid support, inserting a multicellular frame into the solid support and through the porogen material so as to fill cells of the multicellular frame with the porogen material, fusing the porogen material, removing the multicellular frame from the solid support, and the multicellular frame contains a suspended fused porogen network attached to walls of the cells of the multicellular frame. The method also includes applying a solution to the suspended fused porogen network in the cells of the multicellular frame to percolate the suspended fused porogen network, curing the solution, and removing the suspended fused porogen network from the multicellular frame resulting in porous septum membranes of the cured solution in cells of the multicellular frame.

First claim

What is claimed is:

1 . A method for forming porous membranes within a multicellular frame for manufacturing a multicellular structure, the method comprising:
templating the multicellular frame with a fused porogen network so as to create a multicellular frame-porogen assembly; applying a polymer into the fused porogen network of the multicellular frame-porogen assembly; and removing the fused porogen network from the multicellular frame-porogen assembly resulting in polymeric septum membranes within the multicellular frame.

2 . The method of claim 1 , wherein applying the polymer into the fused porogen network of the multicellular frame-porogen assembly comprises:
applying a solution of a polymer precursor material and solvent to the fused porogen network in cells of the multicellular frame to percolate the fused porogen network; and curing the polymer precursor solution.

3 . The method of claim 1 , wherein templating the multicellular frame with the fused porogen network comprises:
applying a porogen material to a solid support; inserting the multicellular frame into the solid support and through the porogen material so as to fill cells of the multicellular frame with the porogen material; fusing the porogen material; and removing the multicellular frame-porogen assembly from the solid support, wherein the multicellular frame-porogen assembly contains a suspended fused porogen network attached to walls of the cells of the multicellular frame.

4 . The method of claim 3 , wherein the porogen material is selected from a type of material consisting of a salt, a sugar, an organic solid, and a polymer particle.

5 . The method of claim 3 , wherein the porogen material is selected from a type of material consisting of a cubic particle, a spherical particle, an amorphous particle, a rod particle, a whisker-like particle, a leachable particle, and a non-removable polymer particle.

6 . The method of claim 3 , wherein the solid support includes a convex surface, and the method comprises:
removing the multicellular frame from the solid support resulting in a suspended convex fused porogen network; and fabricating convex porous septum membranes.

7 . The method of claim 3 , wherein fusing the porogen comprises:
applying a humidity atmosphere for a given amount of time; and applying a thermal atmosphere for a given amount of time to form the suspended fused porogen network that attaches to the walls of the cells of the multicellular frame.

8 . The method of claim 3 , wherein fusing the porogen material comprises a combination of a chemical and a thermal treatment.

9 . The method of claim 1 , wherein applying the polymer into the fused porogen network comprises:
immersing the multicellular frame-porogen assembly into a polymer resin solution to coat the fused porogen network with the polymer resin solution.

10 . The method of claim 9 , wherein the solution is selected from the group consisting of a polymer resin not diluted with a solvent, and a polymer resin diluted with a solvent.

11 . The method of claim 9 , further comprising
applying a thermal atmosphere for a given amount of time to set a microstructure of the solution and to cure the solution.

12 . The method of claim 11 , wherein the microstructure of the solution is configured to create one or more of pressure barriers, flow restrictors, and resonant cavities for controlling transmission of acoustic noise.

13 . The method of claim 1 , wherein removing the suspended fused porogen network from the multicellular frame-porogen assembly comprises:
placing the multicellular frame into a water bath; and drying the porous septum membranes in the cells of the multicellular frame.

14 . The method of claim 1 , wherein the polymeric septum membranes are first polymeric septum membranes within the multicellular frame, and the method further comprises:
templating the multicellular frame with a second fused porogen network; applying a second polymer into the second fused porogen network; and removing the second fused porogen network resulting in second polymeric septum membranes within the multicellular frame.

15 . A method for manufacturing a multicellular structure for acoustic damping, the method comprising:
applying a porogen material to a solid support; inserting a multicellular frame into the solid support and through the porogen material so as to fill cells of the multicellular frame with the porogen material; fusing the porogen material; removing the multicellular frame from the solid support, wherein the multicellular frame contains a suspended fused porogen network attached to walls of the cells of the multicellular frame; applying a solution to the suspended fused porogen network in the cells of the multicellular frame to percolate the suspended fused porogen network; curing the solution; and removing the suspended fused porogen network from the multicellular frame resulting in porous septum membranes of the cured solution in cells of the multicellular frame.

16 . The method of claim 15 , wherein the multicellular frame includes a honeycomb frame comprised of one of aluminum, titanium, carbon composite, aramid, or fiberglass.

17 . An acoustic modifying structure comprising:
a multicellular frame; and at least one porous septum membrane positioned in lumen of cells of the multicellular frame, wherein the at least one porous septum membrane comprises a substantially continuous matrix, and wherein the at least one porous septum membrane includes pores with a size less than about 15% of the thickness of the septum membrane.

18 . The acoustic modifying structure of claim 17 , wherein the at least one porous septum membrane includes pores in a range of about 1 μm to about 175 μm, and a thickness of about 1.0 mm to about 5.0 mm.

19 . The acoustic modifying structure of claim 17 , wherein the pores within one porous membrane within one lumen are interconnected.

20 . The acoustic modifying structure of claim 17 , wherein a single lumen contains two separate porous membranes.

21 . An aircraft comprising an acoustic modifying structure comprising:
a multicellular frame; and at least one porous septum membrane positioned in lumen of cells of the multicellular frame, wherein the at least one porous septum membrane comprises a substantially continuous matrix, and wherein the at least one porous septum membrane includes pores with a size less than about 15% of the thickness of the septum membrane.

Assignees

• Boeing Co

Inventors

• Stache Erin E
• Herrera Eric
• Cumberland Larken E
• Alam Shahriar
• Roper Christopher S
• Mcknight Geoffrey

Classifications

• B32B3/12

  characterised by a layer of regularly- arranged cells, e.g. a honeycomb structure · CPC title

• G10K11/172

  using resonance effects · CPC title

• B64C1/40 Primary

  Sound or heat insulation {, e.g. using insulation blankets} · CPC title

• B29C33/52

  soluble or fusible {(in particular used in injection moulding B29C45/4457)} · CPC title

• F02C7/24

  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