# US 11,897,234 B2 · Composite materials for damping acoustic vibrations

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- Number: US 11,897,234 B2
- Document ID: US11897234B2
- Status: Granted
- Kind: B2
- Application number: 17/755,073
- Filed: 2020-10-14
- Published: 2022-12-08
- Granted: 2024-02-13
- Earliest claimed: 2019-10-24
- Assignees: University of Limerick
- Applicants: University of Limerick
- Inventors: Souvik Chakraborty; Mark Simms; Ioannis Manolakis; Ananda Roy
- Web page: https://patentgrep.com/patent/US11897234B2

## CPC

- B32B 25/08: of synthetic resin
- F16F 15/04: using elastic means (single elements or their attachment F16F1/00 - F16F13/00); {(F16F15/023, F16F15/03 take precedence)}
- B32B 5/022: {Non-woven fabric}
- B32B 5/024: {Woven fabric}
- B32B 5/18: characterised by features of a layer {of} foamed material
- B32B 5/32: {at least two} layers being foamed {and next to each other}
- B32B 7/022: Mechanical properties
- B32B 7/12: using interposed adhesives or interposed materials with bonding properties
- B32B 25/10: next to a fibrous or filamentary layer
- B32B 25/14: comprising {synthetic rubber copolymers (B32B25/18 and B32B25/20 take precedence)}
- B32B 27/08: of synthetic resin
- B32B 27/18: characterised by the use of special additives
- B32B 27/20: using fillers, pigments, thixotroping agents
- B32B 27/308: {comprising acrylic (co)polymers}
- B32B 27/38: comprising epoxy resins
- B29C 70/443: {and impregnating by vacuum or injection}
- B32B 2260/02: Composition of the impregnated, bonded or embedded layer
- B32B 2260/021: Fibrous or filamentary layer
- B32B 2260/04: Impregnation, embedding, or binder material
- B32B 2260/046: Synthetic resin
- B32B 2262/101: Glass fibres
- B32B 2262/106: Carbon fibres, e.g. graphite fibres
- B32B 2262/14: Mixture of at least two fibres made of different materials
- B32B 2264/10: Inorganic particles
- B32B 2266/0235: Vinyl halide, e.g. PVC, PVDC, PVF, PVDF
- B32B 2266/025: Polyolefin
- B32B 2266/0264: Polyester
- B32B 2266/0278: Polyurethane
- B32B 2266/06: Open cell foam
- B32B 2266/08: Closed cell foam
- B32B 2270/00: Resin or rubber layer containing a blend of at least two different polymers
- B32B 2307/102: Insulating
- B32B 2307/3065: Flame resistant or retardant, fire resistant or retardant
- B32B 2307/56: Damping, energy absorption
- B32B 2307/718: Weight, e.g. weight per square meter
- B32B 2307/732: Dimensional properties
- B32B 2319/00: Synthetic rubber
- B32B 2323/04: Polyethylene
- B32B 2323/10: Polypropylene
- B32B 2327/06: PVC, i.e. polyvinylchloride
- B32B 2363/00: Epoxy resins
- B32B 2367/00: Polyesters, e.g. PET, i.e. polyethylene terephthalate
- B32B 2375/00: Polyureas; Polyurethanes
- B32B 2605/00: Vehicles
- B32B 2605/08: Cars
- F16F 2224/0225: Cellular, e.g. microcellular foam
- F16F 2224/0241: Fibre-reinforced plastics [FRP]
- F16F 2232/08: Linear
- F16F 2234/06: plane or flat
- F16F 2236/10: Shear
- B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- F16F: SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
- B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00)

## Abstract

An article for damping vibrations by constrained layer damping comprising: a first constraining layer; a second constraining layer; and a damping layer disposed between the first and second constraining layers, wherein the first and second constraining layers each independently comprise a fibre-reinforced composite material, wherein the first and second constraining layers each independently have a thickness from 1.5 to 5 mm, wherein the damping layer comprises a viscoelastic material, wherein the damping layer has a thickness from 1 to 10 mm and wherein the article has a thickness from 6 to 50 mm. The invention also relates to the use of said article for damping vibrations in a vehicle.

## Claims

### Claim 1

An article for damping vibrations by constrained layer damping comprising:
a first constraining layer,
a second constraining layer, and
a damping layer disposed between the first and second constraining layers,
wherein the first and second constraining layers each independently comprise a fibre-reinforced composite material;
wherein the first and second constraining layers each independently have a thickness from 1.5 to 5 mm;
wherein the damping layer comprises a viscoelastic material;
wherein the damping layer has a thickness from 1 to 10 mm; and
wherein the article has a thickness from 6 to 50 mm.

### Claim 2 (depends on 1)

An article according to claim 1, wherein the article has a thickness of up to 15 mm.

### Claim 3 (depends on 1)

An article according to claim 1, wherein the article has a thickness from 6 to 10 mm.

### Claim 4 (depends on 1)

An article according to claim 1, wherein the first and second constraining layers each independently have a thickness from 2 to 4 mm.

### Claim 5 (depends on 1)

An article according to claim 1, wherein the thicknesses of the first and second constraining layers are within 10% of each other.

### Claim 6 (depends on 1)

An article according to claim 1, wherein the damping layer has a thickness from 1.5 to 5 mm, such as from 2 to 4 mm.

### Claim 7 (depends on 1)

An article according to claim 1, wherein the fibre-reinforced composite material comprises carbon fibre, glass fibre or combinations thereof.

### Claim 8 (depends on 1)

An article according to claim 1, wherein the fibre-reinforced composite material comprises an epoxy resin, a urethane acrylate resin or combinations thereof.

### Claim 9 (depends on 1)

An article according to claim 1, wherein the viscoelastic material comprises a thermoplastic resin.

### Claim 10 (depends on 9)

An article according to claim 9, wherein the viscoelastic material comprises a thermoplastic resin, a rubber, such as an ethylene propylene rubber (EPR).

### Claim 11 (depends on 1)

An article according to claim 1, wherein the article further comprises one or more foam layer(s) and/or one or more thermal layer(s).

### Claim 12 (depends on 1)

An article according to claim 1, wherein the article further comprises one of more adhesive layer(s).

### Claim 13 (depends on 1)

An article according to claim 1, wherein the article has a thickness from 6 to 20 mm and consists essentially of a first constraining layer, a second constraining layer, and a damping layer disposed between the first and second constraining layers.

### Claim 14 (depends on 1)

An article according to claim 1, wherein the article consists essentially of a first constraining layer, a second constraining layer, a damping layer disposed between the first and second constraining layers, and one or more adhesive layers disposed between adjacent layers of the article.

### Claim 15 (depends on 14)

An article according to claim 14, wherein the article is a body and/or floor panel of a vehicle.

### Claim 16

A method of producing an article for damping vibrations by constrained layer damping, the article comprising:
a first constraining layer,
a second constraining layer, and
a damping layer disposed between the first and second constraining layers,
wherein the first and second constraining layers each independently comprise a fibre-reinforced composite material comprising one or more fibre(s) and a polymer composition;
wherein the first and second constraining layers each independently have a thickness from 1.5 to 5 mm;
wherein the damping layer comprises a viscoelastic material; wherein the damping layer has a thickness from 1 to 10 mm; and
wherein the article has a thickness from 6 to 50 mm;
wherein the method comprises the step of:
(i) providing the damping layer, said damping layer having a first and second surface;
(ii) disposing one or more fibre(s) on the first and second surfaces of said damping layer;
(iii) infusing the damping layer and/or one or more fibre(s) with a polymer composition; and
(iv) curing said polymer composition to form the fibre-reinforced composite material of the first and second composite layers.

### Claim 17 (depends on 16)

A method according to claim 16, wherein step (iii) is performed under vacuum.

### Claim 18 (depends on 1)

A vehicle, the vehicle comprising an article according to claim 1.

### Claim 19 (depends on 18)

A vehicle according to claim 18, wherein the article is a body and/or floor panel of said vehicle.