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US3132714A - Acoustic panel - Google Patents

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Publication number
US3132714A
US3132714A US16348362A US3132714A US 3132714 A US3132714 A US 3132714A US 16348362 A US16348362 A US 16348362A US 3132714 A US3132714 A US 3132714A
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US
United States
Prior art keywords
acoustic panel
strip
panel
sound
cavities
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
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Inventor
Jr Wright W Gary
Max A Nadler
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Aerojet Rocketdyne Inc
Original Assignee
Aerojet General Corp
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Publication date
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Priority to US16348362 priority Critical patent/US3132714A/en
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Publication of US3132714A publication Critical patent/US3132714A/en
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Classifications

    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • 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
    • G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/172—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using resonance effects
    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
    • E04B1/00—Constructions in general; Structures which are not restricted either to walls, e.g. partitions, or floors or ceilings or roofs
    • E04B1/62—Insulation or other protection; Elements or use of specified material therefor
    • E04B1/74—Heat, sound or noise insulation, absorption, or reflection; Other building methods affording favourable thermal or acoustical conditions, e.g. accumulating of heat within walls
    • E04B1/82—Heat, sound or noise insulation, absorption, or reflection; Other building methods affording favourable thermal or acoustical conditions, e.g. accumulating of heat within walls specifically with respect to sound only
    • E04B1/84—Sound-absorbing elements
    • E04B1/86—Sound-absorbing elements slab-shaped
    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
    • E04B1/00—Constructions in general; Structures which are not restricted either to walls, e.g. partitions, or floors or ceilings or roofs
    • E04B1/62—Insulation or other protection; Elements or use of specified material therefor
    • E04B1/74—Heat, sound or noise insulation, absorption, or reflection; Other building methods affording favourable thermal or acoustical conditions, e.g. accumulating of heat within walls
    • E04B1/82—Heat, sound or noise insulation, absorption, or reflection; Other building methods affording favourable thermal or acoustical conditions, e.g. accumulating of heat within walls specifically with respect to sound only
    • E04B1/84—Sound-absorbing elements
    • E04B2001/8457—Solid slabs or blocks
    • E04B2001/8461—Solid slabs or blocks layered
    • E04B2001/8471—Solid slabs or blocks layered with non-planar interior transition surfaces between layers, e.g. faceted, corrugated
    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
    • E04B1/00—Constructions in general; Structures which are not restricted either to walls, e.g. partitions, or floors or ceilings or roofs
    • E04B1/62—Insulation or other protection; Elements or use of specified material therefor
    • E04B1/74—Heat, sound or noise insulation, absorption, or reflection; Other building methods affording favourable thermal or acoustical conditions, e.g. accumulating of heat within walls
    • E04B1/82—Heat, sound or noise insulation, absorption, or reflection; Other building methods affording favourable thermal or acoustical conditions, e.g. accumulating of heat within walls specifically with respect to sound only
    • E04B1/84—Sound-absorbing elements
    • E04B2001/8457—Solid slabs or blocks
    • E04B2001/8476—Solid slabs or blocks with acoustical cavities, with or without acoustical filling
    • E04B2001/848—Solid slabs or blocks with acoustical cavities, with or without acoustical filling the cavities opening onto the face of the element
    • E04B2001/8485—Solid slabs or blocks with acoustical cavities, with or without acoustical filling the cavities opening onto the face of the element the opening being restricted, e.g. forming Helmoltz resonators
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/24—Structurally defined web or sheet [e.g., overall dimension, etc.]
    • Y10T428/24273—Structurally defined web or sheet [e.g., overall dimension, etc.] including aperture
    • Y10T428/24322—Composite web or sheet
    • Y10T428/24331—Composite web or sheet including nonapertured component
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/24—Structurally defined web or sheet [e.g., overall dimension, etc.]
    • Y10T428/24479—Structurally defined web or sheet [e.g., overall dimension, etc.] including variation in thickness
    • Y10T428/2457—Parallel ribs and/or grooves
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/249921—Web or sheet containing structurally defined element or component
    • Y10T428/249953—Composite having voids in a component [e.g., porous, cellular, etc.]
    • Y10T428/249987—With nonvoid component of specified composition

Definitions

  • FIG. -2 ACOUSTIC PANEL Filed Jan. 2, 1962 FIG FIG. -2
  • This invention relates to soundproofing and more particularly to an acoustic damping panel.
  • an acoustic panel with a plurality of Helmholtz resonating cavities formed therein.
  • Each Holmholtz resonating cavity will absorb sound at its fundamental resonant frequency and at its overtone resonant frequencies. If such an acoustic panel is formed with a large number of Helmholtz cavities which have different sizes and shapes, the resulting acoustic panel will have wideband frequency absorption characteristics.
  • the fabrication of an acoustic panel with a large number of differently shaped Helmholtz cavities is diflicult and somewhat expensive using prior construction techniques.
  • What is needed, therefore, and comprises a principle object of this invention, is to provide an acoustic panel having a large number of differently shaped Helmholtztype cavities formed therein which can be easily and economically fabricated without the use of complex and expensive machinery.
  • the invention in its broadest aspect, comprises the fabrication of an acoustic panel formed from an inner perforate strip, an outer imperforate strip, and an intermediate strip of a low modulus open-celled foam structure.
  • the perforations in the inner strip communicate with the cells in the foam structure to form the acoustic equivalent of a large number of Helmholtz cavities in the acoustic panel. Consequently, the resulting acoustic panel will have a Wideband frequency absorption characteristic.
  • FIGURE 1 is a side sectional view of an acoustic panel constructed according to the principles of this invention and FIGURE 2 is an enlarged sectional view of a portion of the acoustic panel shown in FIGURE 1, and showing the path of sound therethrough.
  • an acoustic panel indicated generally by the reference numeral 10 comprises an inner perforate strip 12 preferably formed from a low modulus cellulose material.
  • the acoustic panel includes a spaced parallel outer imperforate strip 14 which may also be formed from a suitable cellulose material.
  • the inner and outer strips are secured to an intermediate strip of an open-celled foam material 16 by any suitable means such as gluing.
  • This material may be an open-celled urethane material, an open-celled polyester, an open-celled styrene, or other materials having generally similar properties. These materials all have a low modulus of elasticity so that the sound absorption characteristics of the panel is augmented by the increased surface area caused by the cells or cavities in the low modulus material.
  • each of the perforations 18 in the inner perforate strip 12 communicates with the open cells 20 in the open-celled foam structure 16. These perforations are smaller than the size of the open cells so that the combination of the perforations 18 and open cells 20 is the acoustic equivalent of Helmholtz resonating cavities. Since there is a large natural variation in the size and shape of the cavities or cells in the open-celled foam structure 16, there will be a large variation in the size,
  • the open-celled foam structure is also formed from a low modulus material, as described above, the increased pathway followed by the reflected sound will cause a substantially greater quantity of sound to be absorbed in the material 16.
  • Surface 19 of the inner perforate strip 12 may also be serrated as suggested in FIGS. 1 and 2 to further increase losses in sound intensity in the sound reflected from surface 22 and passing through the opencelled foam structure to surface 19.
  • the serrations on the inner surface 22 of the outer imperforate strip may be different in shape from the serrations on the inner surface 19 of the inner perforate strip.
  • An acoustic panel comprising an inner perforate strip, an outer imperforate strip, and an intermediate layer of low modulus open-celled foam material secured together, the perforations in the inner strip communicating with the cells in the foam structure and defining thereby a plurality of Helmholtz cavities, the variation in the size of the cells causing a wide variation in the dimensions of the Helmholtz cavities and causing a wide variation in the fundamental sound absorption frequencies and the overtone absorption frequencies of the Helmholtz cavities in the panel, whereby the acoustic panel will have wideband sound absorption characteristics, and serrations on the inner surface of the outer imperforate strip so that sound penetrating said acoustic panel to said serrations is reflected thereby at an angle to the normal of said surface to increase the path length of the sound through the low modulus open-celled foam structure in order to augment the sound absorption characteristics of the panel.
  • An acoustic panel as in claim 1 including further serrations on the inner surface of the inner perforate strip.

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  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Engineering & Computer Science (AREA)
  • Architecture (AREA)
  • Multimedia (AREA)
  • Electromagnetism (AREA)
  • Civil Engineering (AREA)
  • Structural Engineering (AREA)
  • Soundproofing, Sound Blocking, And Sound Damping (AREA)

Description

y 1964 w. w. GARY, JR., ETAL 3, ,714
ACOUSTIC PANEL Filed Jan. 2, 1962 FIG FIG. -2
INVENTOR. WRlGHT w. GARY, JR. LIONEL ISENBERG I B? MAX A. NADL ATTOR L Y 3,132,714 ACOUSTIC PANEL Wright W. Gary, In, Arcadia, Lionel Isenberg, Downey,
and Max A. Nadler, Glendora, Califi, assignors to Aerojet-General Corporation, 'Azusa, Calif., a corporation of Ohio Filed Jan. 2, 1962, Ser. No. 163,483 6 Claims. (Cl. 18133) This invention relates to soundproofing and more particularly to an acoustic damping panel.
It has been proposed to form an acoustic panel with a plurality of Helmholtz resonating cavities formed therein. Each Holmholtz resonating cavity will absorb sound at its fundamental resonant frequency and at its overtone resonant frequencies. If such an acoustic panel is formed with a large number of Helmholtz cavities which have different sizes and shapes, the resulting acoustic panel will have wideband frequency absorption characteristics. However, the fabrication of an acoustic panel with a large number of differently shaped Helmholtz cavities is diflicult and somewhat expensive using prior construction techniques.
What is needed, therefore, and comprises a principle object of this invention, is to provide an acoustic panel having a large number of differently shaped Helmholtztype cavities formed therein which can be easily and economically fabricated without the use of complex and expensive machinery.
The invention, in its broadest aspect, comprises the fabrication of an acoustic panel formed from an inner perforate strip, an outer imperforate strip, and an intermediate strip of a low modulus open-celled foam structure. The perforations in the inner strip communicate with the cells in the foam structure to form the acoustic equivalent of a large number of Helmholtz cavities in the acoustic panel. Consequently, the resulting acoustic panel will have a Wideband frequency absorption characteristic.
This and other objects of this invention will become more apparent when understood in the light of the specification and the accompanying drawings wherein:
FIGURE 1 is a side sectional view of an acoustic panel constructed according to the principles of this invention and FIGURE 2 is an enlarged sectional view of a portion of the acoustic panel shown in FIGURE 1, and showing the path of sound therethrough.
Referring now to FIGURE 1 of the drawings, an acoustic panel indicated generally by the reference numeral 10 comprises an inner perforate strip 12 preferably formed from a low modulus cellulose material. The acoustic panel includes a spaced parallel outer imperforate strip 14 which may also be formed from a suitable cellulose material. The inner and outer strips are secured to an intermediate strip of an open-celled foam material 16 by any suitable means such as gluing. This material may be an open-celled urethane material, an open-celled polyester, an open-celled styrene, or other materials having generally similar properties. These materials all have a low modulus of elasticity so that the sound absorption characteristics of the panel is augmented by the increased surface area caused by the cells or cavities in the low modulus material.
As best seen in FIGURE 2, each of the perforations 18 in the inner perforate strip 12 communicates with the open cells 20 in the open-celled foam structure 16. These perforations are smaller than the size of the open cells so that the combination of the perforations 18 and open cells 20 is the acoustic equivalent of Helmholtz resonating cavities. Since there is a large natural variation in the size and shape of the cavities or cells in the open-celled foam structure 16, there will be a large variation in the size,
. 3,132,714 Patented MayIZ, 1964 the acoustic panel to serrated surface 22 to be reflected by the serrated surface at an angle to the normal to this surface, see the arrows 25 and 26 in FIGURE 2. With this arrangement, sound reflected from the inner surface 22 of the imperforate strip 14 travels a long path back through the open-celled foam material 16.
If the open-celled foam structure is also formed from a low modulus material, as described above, the increased pathway followed by the reflected sound will cause a substantially greater quantity of sound to be absorbed in the material 16. Surface 19 of the inner perforate strip 12 may also be serrated as suggested in FIGS. 1 and 2 to further increase losses in sound intensity in the sound reflected from surface 22 and passing through the opencelled foam structure to surface 19. As shown in FIGS. 1 and 2, the serrations on the inner surface 22 of the outer imperforate strip may be different in shape from the serrations on the inner surface 19 of the inner perforate strip.
It is to be understood that the form of the invention herewith shown and described is to be taken as a preferred example of the same and that various changes in the shape, size, and arrangement of the parts may be resorted to without departing fromthe spirit of this invention or the scope of the claims.
We claim:
1. An acoustic panel comprising an inner perforate strip, an outer imperforate strip, and an intermediate layer of low modulus open-celled foam material secured together, the perforations in the inner strip communicating with the cells in the foam structure and defining thereby a plurality of Helmholtz cavities, the variation in the size of the cells causing a wide variation in the dimensions of the Helmholtz cavities and causing a wide variation in the fundamental sound absorption frequencies and the overtone absorption frequencies of the Helmholtz cavities in the panel, whereby the acoustic panel will have wideband sound absorption characteristics, and serrations on the inner surface of the outer imperforate strip so that sound penetrating said acoustic panel to said serrations is reflected thereby at an angle to the normal of said surface to increase the path length of the sound through the low modulus open-celled foam structure in order to augment the sound absorption characteristics of the panel.
2. The acoustic panel described in claim 1 wherein said intermediate layer is formed from an open-celled urethane foam.
3. The acoustic panel described in claim 1 wherein said intermediate layer is formed from an open-celled polyester.
4. The acoustic panel described in claim 1 wherein said intermediate layer is formed from an open-celled styrene.
5. An acoustic panel as in claim 1 including further serrations on the inner surface of the inner perforate strip.
6. An acoustic panel as in claim 5 wherein the serrations on the inner surface of the outer imperforate strip are of a shape different from said serrations on the inner surface of the inner perforate strip.
(References on following page) References Cited in the file of this patent UNITED STATES PATENTS James Dec. 10, 1929 Mazer May 21, 1935 Kanengeiser Apr. 13, 1937 Harvey Aug. 23, 1938 Lindvig Apr. 16, 1957 Gross Oct. 7, 1958 Brisley et a1 May 16, 1961 4 FOREIGN PATENTS 572,072 Canada Mar. 10, 1959 OTHER REFERENCES V. L. Jordan: The Application of Helmholtz Resonators to Sound-Absorbing Structures, The Journal of the Acoustical Society of America, Vol. 19, No. 6, November 1947, pages 972-981.

Claims (1)

1. AN ACOUSTIC PANEL COMPRISING AN INNER PERFORATE STRIP, AN OUTER IMPERFORATE STRIP, AND AN INTERMEDIATE LAYER OF LOW MODULUS JOPEN-CELLED FOAM MATERIAL SECURED TOGETHER, THE PERFORATIONS IN THE INNER STRIP COMMUNICATING WITH THE CELLS IN THE FOAM STRUCTURE AND DEFINING THEREBY A PLURALITY OF HELMHOLTZ CAVITIES, THE VARIATION IN THE SIZE OF THE CELLS CAUSING A WIDE VARIATION IN THE DIMENSIONS OF THE HELMHOLTZ CAVITIES AND CAUSING A WIDE VARIATION IN THE FUNDAMENTAL SOUND ABSORPTION FREQUENCIES AND THE OVERTONE ABSORPTION FREQUENCIES OF THE HELMHOLTZ CAVITIES IN THE PANEL, WHEREBY THE ACOUSTIC PANEL WILL HAVE WIDEBAND SOUND ABSORPTION CHARACTERISTICS, AND SERRATIONS ON THE INNER SURFACE JOF THE OUTER IMPERFORATE STRIP SO THAT SOUND PENETRATING SAID ACOUSTIC PANEL TO SAID SERRATIONS IS REFLECTED THEREBY AT AN ANGLE TO THE NORMAL OF SAID SURFACE TO INCREASE THE PATH LENGTH OF THE SOUND THROUGH THE LOW MODULUS JOPEN-CELLED FOAM STRUCTURE IN ORDER TO AUGMENT THE SOUND ABSORPTION CHARACTERISTICS OF THE PANEL.
US16348362 1962-01-02 1962-01-02 Acoustic panel Expired - Lifetime US3132714A (en)

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Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4441580A (en) * 1980-10-17 1984-04-10 Steelcase Inc. Acoustical control media
US4832152A (en) * 1988-03-22 1989-05-23 Herman Miller, Inc. Acoustic tile
WO1993000262A1 (en) * 1991-06-27 1993-01-07 Harco Steel, Inc. Sound absorbing wall panel for use along highways
ES2046931A2 (en) * 1991-07-01 1994-02-01 Arroyo Ordonez Fernando Sound-absorbing panel of cement conglomerate and a procedure for its manufacture.
EP0678634A1 (en) * 1994-04-20 1995-10-25 Deutsche Pittsburgh Corning GmbH Sound damping construction element
US5777947A (en) * 1995-03-27 1998-07-07 Georgia Tech Research Corporation Apparatuses and methods for sound absorption using hollow beads loosely contained in an enclosure
WO2000023668A1 (en) * 1998-10-16 2000-04-27 Teloni Spandotel Di Spano' Domenico Composite sound-deadening element and panel realized with said element
WO2002065447A2 (en) * 2001-02-09 2002-08-22 Dow Global Technologies Inc. Sound absorbing foam
US6601673B2 (en) * 2000-09-06 2003-08-05 Nichias Corporation Sound absorbing structure
US20040099476A1 (en) * 2000-08-15 2004-05-27 Swift Mark Jonathan Sound absorbing material
US20060111512A1 (en) * 2004-11-24 2006-05-25 Dunham John D Energy-absorbent material and method of making
WO2012150896A1 (en) * 2011-05-05 2012-11-08 Scania Cv Ab Device for damping of sounds and motor vehicle comprising such a device
EP1274779B1 (en) * 2000-03-17 2014-08-27 Sealed Air Corporation (US) Preparation of a macrocellular acoustic foam
US9637916B1 (en) 2016-07-15 2017-05-02 Frank Lytle Work-station
US10978037B2 (en) * 2015-04-29 2021-04-13 Centre National De La Recherche Scientifique Acoustic metamaterial for isolation and method for the production thereof

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1738654A (en) * 1925-10-10 1929-12-10 Maurice Haydis Acoustic control wall
US2001916A (en) * 1929-07-23 1935-05-21 Mazer Jacob Sound absorbing material
US2076994A (en) * 1934-11-01 1937-04-13 Fred R Kanengeiser Sound absorbing material
US2127867A (en) * 1936-03-26 1938-08-23 Allen M Harvey Method of forming porous bodies
US2789095A (en) * 1952-11-22 1957-04-16 Du Pont Process for preparing urea-formaldehyde solid foam
US2855039A (en) * 1953-07-22 1958-10-07 Edward H Gross Sound-absorbent structure
CA572072A (en) * 1959-03-10 Farbenfabriken Bayer Aktiengesellschaft Sound-absorbing system
US2984312A (en) * 1959-04-24 1961-05-16 Owens Corning Fiberglass Corp Acoustical wall board

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA572072A (en) * 1959-03-10 Farbenfabriken Bayer Aktiengesellschaft Sound-absorbing system
US1738654A (en) * 1925-10-10 1929-12-10 Maurice Haydis Acoustic control wall
US2001916A (en) * 1929-07-23 1935-05-21 Mazer Jacob Sound absorbing material
US2076994A (en) * 1934-11-01 1937-04-13 Fred R Kanengeiser Sound absorbing material
US2127867A (en) * 1936-03-26 1938-08-23 Allen M Harvey Method of forming porous bodies
US2789095A (en) * 1952-11-22 1957-04-16 Du Pont Process for preparing urea-formaldehyde solid foam
US2855039A (en) * 1953-07-22 1958-10-07 Edward H Gross Sound-absorbent structure
US2984312A (en) * 1959-04-24 1961-05-16 Owens Corning Fiberglass Corp Acoustical wall board

Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4441580A (en) * 1980-10-17 1984-04-10 Steelcase Inc. Acoustical control media
US4832152A (en) * 1988-03-22 1989-05-23 Herman Miller, Inc. Acoustic tile
WO1993000262A1 (en) * 1991-06-27 1993-01-07 Harco Steel, Inc. Sound absorbing wall panel for use along highways
ES2046931A2 (en) * 1991-07-01 1994-02-01 Arroyo Ordonez Fernando Sound-absorbing panel of cement conglomerate and a procedure for its manufacture.
EP0678634A1 (en) * 1994-04-20 1995-10-25 Deutsche Pittsburgh Corning GmbH Sound damping construction element
US5777947A (en) * 1995-03-27 1998-07-07 Georgia Tech Research Corporation Apparatuses and methods for sound absorption using hollow beads loosely contained in an enclosure
WO2000023668A1 (en) * 1998-10-16 2000-04-27 Teloni Spandotel Di Spano' Domenico Composite sound-deadening element and panel realized with said element
EP1274779B1 (en) * 2000-03-17 2014-08-27 Sealed Air Corporation (US) Preparation of a macrocellular acoustic foam
US7721846B2 (en) * 2000-08-15 2010-05-25 Ventures And Consultancy Bradford Limited Sound absorbing material
US20040099476A1 (en) * 2000-08-15 2004-05-27 Swift Mark Jonathan Sound absorbing material
US6601673B2 (en) * 2000-09-06 2003-08-05 Nichias Corporation Sound absorbing structure
WO2002065447A3 (en) * 2001-02-09 2002-11-14 Dow Chemical Co Sound absorbing foam
WO2002065447A2 (en) * 2001-02-09 2002-08-22 Dow Global Technologies Inc. Sound absorbing foam
US7456245B2 (en) 2004-11-24 2008-11-25 Battelle Memorial Institute Energy-absorbent material and method of making
US20060111512A1 (en) * 2004-11-24 2006-05-25 Dunham John D Energy-absorbent material and method of making
WO2012150896A1 (en) * 2011-05-05 2012-11-08 Scania Cv Ab Device for damping of sounds and motor vehicle comprising such a device
US8863891B2 (en) 2011-05-05 2014-10-21 Scania Cv Ab Device for damping of sounds and motor vehicle comprising such a device
US10978037B2 (en) * 2015-04-29 2021-04-13 Centre National De La Recherche Scientifique Acoustic metamaterial for isolation and method for the production thereof
US9637916B1 (en) 2016-07-15 2017-05-02 Frank Lytle Work-station

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