# US 11,028,774 B2 · Acoustic panel for a turbomachine and method for the manufacturing thereof

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 11,028,774 B2
- Document ID: US11028774B2
- Status: Granted
- Kind: B2
- Application number: 16/321,426
- Filed: 2017-07-28
- Published: 2020-12-03
- Granted: 2021-06-08
- Earliest claimed: 2016-07-29
- Assignees: Safran
- Applicants: Safran
- Inventors: Nicola Piccirelli
- Web page: https://patentgrep.com/patent/US11028774B2

## CPC

- F02C 7/045: having provisions for noise suppression
- B64D 29/00: Power-plant nacelles, fairings or cowlings
- B64D 33/02: of combustion air intakes
- F02K 1/827: {Sound absorbing structures or liners}
- G10K 11/172: using resonance effects
- B33Y 10/00: Processes of additive manufacturing
- B33Y 80/00: Products made by additive manufacturing
- B64D 2033/0206: {comprising noise reduction means, e.g. acoustic liners}
- F05D 2260/96: Preventing, counteracting or reducing vibration or noise
- F05D 2260/963: by Helmholtz resonators
- Y02T 50/60: Efficient propulsion technologies, e.g. for aircraft
- F02C: GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS (construction of turbines F01D; jet-propulsion plants F02K; construction of compressors or fans F04; generating combustion products of high pressure or high velocity F23R; using gas turbines in compression refrigeration plants F25B11/00)
- B64D: EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLIGHT SUITS; PARACHUTES; ARRANGEMENT OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT
- F02K: JET-PROPULSION PLANTS (features of jet-propulsion plants common to gas-turbine plants, air intakes or fuel supply control of air-breathing jet-propulsion plants F02C7/00, F02C9/00)
- G10K: SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- B33Y: ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
- F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

An acoustic panel for a turbomachine, in particular for an aircraft, includes two skins that are substantially parallel and between which extend cavities forming Helmholtz resonators, one of the skins being perforated by orifices opening into the cavities and forming necks of the Helmholtz resonators, vibrating masses being provided in at least some of the cavities and connected to cavity walls by an elastic junction housed in the cavity.

## Claims

### Claim 1

An acoustic panel for a turbomachine, the acoustic panel comprising:
a first skin and a second skin, said first and second skins being parallel;
a plurality of cavities formed between said first and second skins, said plurality of cavities forming a plurality of Helmholtz resonators; and
a plurality of vibrating masses, wherein at least one vibrating mass of the plurality of vibrating masses is provided within each cavity of said plurality of cavities,
wherein said first skin is perforated by orifices, said orifices opening into said plurality of cavities and forming necks of said plurality of Helmholtz resonators,
wherein said second skin is unperforated and defines a cavity wall in each cavity of said plurality of cavities,
wherein in each cavity of said plurality of cavities, said at least one vibrating mass is connected to said cavity wall by an elastic junction housed in said cavity.

### Claim 2 (depends on 1)

The acoustic panel of claim 1, wherein the elastic junction is one of a plurality of elastic junctions, and the cavity wall is one of a plurality of cavity walls.

### Claim 3 (depends on 2)

The acoustic panel of claim 2, wherein each vibrating mass is connected by one of the elastic junctions to one of the first and second skins.

### Claim 4 (depends on 3)

The acoustic panel of claim 3, wherein the second skin is opposite of the plurality of cavities from the first skin.

### Claim 5 (depends on 2)

The acoustic panel according to claim 2, wherein each vibrating mass has a vibration direction that is substantially perpendicular to the first and second skins.

### Claim 6 (depends on 2)

The acoustic panel according to claim 2, wherein a plurality of gaps in the plurality of cavity walls separate the plurality of vibrating masses.

### Claim 7 (depends on 1)

The acoustic panel according to claim 1, wherein said elastic junction includes a mesh or a cellular structure.

### Claim 8 (depends on 1)

The acoustic panel according to claim 1, wherein said elastic junction is configured to give said vibrating mass a vibrating property.

### Claim 9 (depends on 1)

A turbomachine for an aircraft, including at least one acoustic panel according to claim 1.

### Claim 10 (depends on 1)

The acoustic panel according to claim 1, wherein the plurality of cavities extend longitudinally between the first and second skins.

### Claim 11 (depends on 1)

The acoustic panel according to claim 1, wherein each cavity of the plurality of cavities is formed by a first wall defined by the first skin, a second wall defined by the second skin, a first sidewall, and a second sidewall, wherein said first and second sidewalls extend perpendicularly to said first and second walls.

### Claim 12 (depends on 11)

The acoustic panel according to claim 11, wherein within each cavity, the vibrating mass is separated by gaps from the first and second sidewalls of said cavity, said gaps being sized to allow vibration of the vibrating mass.

### Claim 13

A method of manufacturing an acoustic panel for a turbomachine comprising a first skin and a second skin, said first and second skins being parallel, a plurality of cavities formed between said first and second skins, said plurality of cavities forming a plurality of Helmholtz resonators, and a plurality of vibrating masses, wherein at least one vibrating mass of the plurality of vibrating masses is provided within each cavity of said plurality of cavities, wherein said first skin is perforated by orifices, said orifices opening into said plurality of cavities and forming necks of said plurality of Helmholtz resonators, wherein said second skin is unperforated and defines a cavity wall in each cavity of said plurality of cavities, and wherein in each cavity of said plurality of cavities, said at least one vibrating mass is connected to said cavity wall by an elastic junction housed in said cavity, the method comprising:
producing said plurality of vibrating masses and said elastic junction by additive manufacturing.

### Claim 14 (depends on 13)

The method of claim 13, further comprising additively manufacturing said first and second skins.

### Claim 15 (depends on 14)

The method of claim 14, wherein said first and said second skins and said cavity wall comprise a first material and said vibrating mass and said elastic junction comprise a second material, different from the first material.

### Claim 16

An acoustic panel for a turbomachine, comprising:
a plurality of parallel skins including a first skin perforated by a plurality of orifices, and a second skin that is unperforated;
a plurality of cavities extending between the plurality of parallel skins, each cavity forming a Helmholtz resonator, wherein the plurality of orifices of the first skin open into the plurality of cavities, each orifice forming a Helmholtz resonator neck; and
a plurality of vibrating masses, each vibrating mass being located in one cavity of the plurality of cavities and each vibrating mass being connected by an elastic junction to a wall of said cavity in which the elastic junction is located,
wherein in each cavity of the plurality of cavities, the vibrating mass is connected by the elastic junction to the second skin opposite to the first skin, and the vibrating mass and elastic junction are separated by gaps with respect to two sidewalls of the cavity.

### Claim 17 (depends on 13)

The method of claim 13, wherein producing said plurality of vibrating masses and said elastic junction by additive manufacturing comprises successively depositing a molten material.

### Claim 18 (depends on 14)

The method of claim 14, wherein the said first and second skins and said cavity wall comprise a first thermoplastic material and said vibrating mass and said elastic junction comprise a second thermoplastic material.