# US 10,482,865 B2 · Vibration damped sound shield

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- Number: US 10,482,865 B2
- Document ID: US10482865B2
- Status: Granted
- Kind: B2
- Application number: 15/402,470
- Filed: 2017-01-10
- Published: 2017-04-27
- Granted: 2019-11-19
- Earliest claimed: 2014-08-20
- Assignees: The Hong Kong University of Science and Technology
- Applicants: The Hong Kong University of Science and Technology
- Inventors: Zhiyu Yang; Ping Sheng; Min Yang; Liang Sun; Guancong Ma
- Web page: https://patentgrep.com/patent/US10482865B2

## CPC

- G10K 11/172: using resonance effects
- B32B 3/085: {spaced apart pieces on the surface of a layer}
- B32B 27/08: of synthetic resin
- G10K 11/162: Selection of materials
- G10K 11/165: Particles in a matrix
- G10K 11/168: Plural layers of different materials, e.g. sandwiches
- 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
- B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM

## Abstract

A sound absorption panel (201) is constructed on an acoustically thin sheet (203) to provide an acoustic/vibrational energy absorption metamaterial structure. A plurality of dampers (101) are fixed to the acoustically thin sheet (203), and at least a subset of said dampers (101) comprise a support (103) and a flexible membrane (105) supported by the support. The flexible membrane (105) has one or more masses or platelets (107) attached. The dampers (101) in combination with the sheet (203) result in absorption of energy of movement of the sheet (203) resulting from sound transmission or vibrations across the sheet.

## Claims

### Claim 1

An acoustic/vibrational energy absorption metamaterial comprising:
a substantially air impermeable flexible sheet (203); and
a plurality of dampers (101) fixed to the flexible sheet, at least a subset of the dampers comprising:
an enclosed planar frame (103);
an flexible, membrane (105) attached to said frame; and
at least one rigid or semi-rigid mass or platelet (107) having an asymmetrical shape when taken in a plan view facing the thin sheet and fixedly attached to said flexible membrane by an asymmetrical hinge attachment so as to induce a flapping motion about the hinge attachment, the masses or platelets providing a restoring force exerting by the flexible membrane upon displacement of the dampers on the sheet, wherein at least a subset of the dampers present plural resonant modes with tunable resonant frequencies.

### Claim 2 (depends on 1)

A sound absorption panel comprising:
the acoustic/vibrational energy absorption metamaterial of claim 1, wherein the dampers in combination with the sheet result in absorption of energy of movement of the sheet resulting from sound transmission or vibrations across the sheet,
and wherein the dampers provide a tunable function by varying at least one of the Young's modulus and the Poisson ratio of the flexible membrane.

### Claim 3 (depends on 1)

The acoustic/vibrational energy absorption metamaterial of claim 1, further comprising:
the subset of said dampers arranged in a substantially regular pattern.

### Claim 4 (depends on 1)

A sound absorption panel comprising:
the acoustic/vibrational energy absorption metamaterial of claim 1, wherein the dampers in combination with the sheet result in absorption of energy of movement of the sheet resulting from sound transmission or vibrations across the sheet,
wherein the dampers provide a tunable function by varying at least one of the Young's modulus and the Poisson ratio of the flexible membrane,
and wherein the masses or platelets provide a tunable function based on tunable resonant frequencies, said resonant frequencies tunable by varying the distance of separation between asymmetric plates, or the thickness and elasticity of the membrane, the mass of the plates, and the damper dimensions.

### Claim 5 (depends on 1)

The acoustic/vibrational energy absorption metamaterial of claim 1,
wherein the dampers comprise masses subject to vibratory motion and the vibratory motion has resonant frequencies that increases or decreases by varying the lateral dimensions of the flexible membrane, elasticity of the flexible membrane, a distance of separation between adjacent ones of the masses, and the material type and dimension of the damper bodies, thereby permitting selection of the resonant frequency as a lossy core,
wherein the dampers provide a tunable function by varying at least one of the Young's modulus and the Poisson ratio of the flexible membrane,
and wherein the masses or platelets provide a tunable function based on tunable resonant frequencies, said resonant frequencies tunable by varying the distance of separation between asymmetric plates, or the thickness and elasticity of the membrane, the mass of the plates, and the damper dimensions.

### Claim 6 (depends on 1)

The acoustic/vibrational energy absorption metamaterial of claim 1, wherein at least a plurality of the masses have a rigid attachment to the flexible membrane.

### Claim 7 (depends on 1)

The acoustic/vibrational energy absorption metamaterial of claim 1, wherein at least a plurality of the masses have a hinged attachment to the flexible membrane.

### Claim 8 (depends on 1)

The acoustic/vibrational energy absorption metamaterial of claim 1, wherein the dampers have a rigid adhesive attachment to the sheet.

### Claim 9 (depends on 1)

The acoustic/vibrational energy absorption metamaterial of claim 1, further comprising:
the sheet formed with dampers having different weights from other said dampers on the sheet.

### Claim 10

A method of attenuating sound or vibrations, the method comprising:
providing a substantially air impermeable acoustically thin sheet; and
providing a plurality of dampers fixed to the acoustically thin sheet, wherein at least a subset of said dampers each comprise a support and a flexible membrane supported by the support and have a plurality rigid or semi-rigid of masses or platelets having an asymmetrical shape when taken in a plan view facing the thin sheet and fixedly attached thereto by an asymmetrical hinge attachment so as to induce a flapping motion about the hinge attachment, wherein the dampers in combination with the sheet absorb energy of movement of the sheet resulting from sound transmission or vibrations across the sheet.

### Claim 11 (depends on 10)

The method of claim 10, wherein the masses or platelets provide a tunable function based on tunable resonant frequencies, said resonant frequencies tunable by varying the distance of separation between asymmetric plates, or the thickness and elasticity of the membrane, the mass of the plates, and the damper dimensions.

### Claim 12 (depends on 10)

The method of claim 10,
wherein the dampers comprise masses subject to vibratory motion and the vibratory motion has resonant frequencies that increases or decreases by varying the lateral dimensions of the flexible membrane, elasticity of the flexible membrane, a distance of separation between adjacent ones of the masses, and the material type and dimension of the damper bodies, thereby permitting selection of the resonant frequency as a lossy core,
wherein the dampers provide a tunable function by varying at least one of the Young's modulus and the Poisson ratio of the flexible membrane,
and wherein the masses or platelets provide a tunable function based on tunable resonant frequencies, said resonant frequencies tunable by varying the distance of separation between asymmetric plates, or the thickness and elasticity of the membrane, the mass of the plates, and the damper dimensions.

### Claim 13 (depends on 10)

The method claim 10, further comprising:
providing the subset of said dampers in a substantially regular pattern.

### Claim 14 (depends on 10)

The method claim 10, further comprising:
providing at least a plurality of the dampers rigidly attached to the acoustically thin sheet.

### Claim 15 (depends on 10)

The method claim 10, further comprising:
providing the plurality of dampers fixed to the acoustically thin sheet so that at least a plurality of the masses have a hinged attachment to the flexible membrane.

### Claim 16 (depends on 10)

The method claim 10, further comprising:
providing at least a plurality of the dampers with a rigid adhesive attachment to the sheet.

### Claim 17 (depends on 10)

The method claim 10, further comprising:
providing the sheet formed with dampers having different weights from other said dampers on the sheet.

### Claim 18 (depends on 1)

The acoustic/vibrational energy absorption metamaterial of claim 1,
wherein sound transmission or vibrations incident onto an air-impermeable sheet excite vibration of the sheet and causes the sheet to emit sound waves or vibrations to both sides of the sheet, with the dampers absorbing the sound waves or vibrations,
and wherein the absorbing the sound waves or vibrations increase transmission loss.

### Claim 19 (depends on 2)

The sound absorption panel of claim 2, further comprising:
the flexible sheet allowing rolling up the sound shields for transport, and rolling out the sound shields to shield the noise sources to provide for easy transport of the sound shields.

### Claim 20 (depends on 10)

The method of claim 10,
wherein sound transmission or vibrations incident onto an air-impermeable sheet excite vibration of the sheet and causes the sheet to emit sound waves or vibrations to both sides of the sheet, with the dampers absorbing the sound waves or vibrations,
and wherein the absorbing the sound waves or vibrations increase transmission loss.