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WO1993008560A1 - A sound control device - Google Patents

A sound control device Download PDF

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Publication number
WO1993008560A1
WO1993008560A1 PCT/GB1992/001916 GB9201916W WO9308560A1 WO 1993008560 A1 WO1993008560 A1 WO 1993008560A1 GB 9201916 W GB9201916 W GB 9201916W WO 9308560 A1 WO9308560 A1 WO 9308560A1
Authority
WO
WIPO (PCT)
Prior art keywords
actuator
barrier member
sound
control
transmitted
Prior art date
Application number
PCT/GB1992/001916
Other languages
French (fr)
Inventor
Anthony John Salloway
Robert Christopher Twiney
Original Assignee
Gec-Marconi Limited
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Gec-Marconi Limited filed Critical Gec-Marconi Limited
Publication of WO1993008560A1 publication Critical patent/WO1993008560A1/en

Links

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
    • G10K11/175—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound
    • G10K11/178—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound by electro-acoustically regenerating the original acoustic waves in anti-phase
    • G10K11/1785—Methods, e.g. algorithms; Devices
    • 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
    • G10K11/175—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound
    • G10K11/178—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound by electro-acoustically regenerating the original acoustic waves in anti-phase
    • G10K11/1785—Methods, e.g. algorithms; Devices
    • G10K11/17857—Geometric disposition, e.g. placement of microphones
    • 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
    • G10K11/175—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound
    • G10K11/178—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound by electro-acoustically regenerating the original acoustic waves in anti-phase
    • G10K11/1787—General system configurations
    • G10K11/17875—General system configurations using an error signal without a reference signal, e.g. pure feedback
    • 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
    • G10K2210/00—Details of active noise control [ANC] covered by G10K11/178 but not provided for in any of its subgroups
    • G10K2210/10—Applications
    • G10K2210/102—Two dimensional
    • 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
    • G10K2210/00—Details of active noise control [ANC] covered by G10K11/178 but not provided for in any of its subgroups
    • G10K2210/10—Applications
    • G10K2210/12—Rooms, e.g. ANC inside a room, office, concert hall or automobile cabin
    • 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
    • G10K2210/00—Details of active noise control [ANC] covered by G10K11/178 but not provided for in any of its subgroups
    • G10K2210/10—Applications
    • G10K2210/129—Vibration, e.g. instead of, or in addition to, acoustic noise
    • G10K2210/1291—Anti-Vibration-Control, e.g. reducing vibrations in panels or beams
    • 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
    • G10K2210/00—Details of active noise control [ANC] covered by G10K11/178 but not provided for in any of its subgroups
    • G10K2210/30—Means
    • G10K2210/301—Computational
    • G10K2210/3011—Single acoustic input
    • 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
    • G10K2210/00—Details of active noise control [ANC] covered by G10K11/178 but not provided for in any of its subgroups
    • G10K2210/30—Means
    • G10K2210/321—Physical
    • G10K2210/3223—Materials, e.g. special compositions or gases
    • 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
    • G10K2210/00—Details of active noise control [ANC] covered by G10K11/178 but not provided for in any of its subgroups
    • G10K2210/30—Means
    • G10K2210/321—Physical
    • G10K2210/3229—Transducers
    • G10K2210/32291—Plates or thin films, e.g. PVDF

Definitions

  • the invention relates to a sound control device for controlling sound transmitted through and/or reflected from a barrier member.
  • a low volume/low mass system capable of producing significant acoustic isolation and/or absorption would be of significant use in vehicle cabins, workshop 's , engine rooms and radiated noise of ships, and the l ike where reduction of noise is desired.
  • An active noise reduction system is known to be very effective at low frequencies where wavelengths are long, so that little phase difference occurs between the generated and sensed sounds.
  • this type of system has a good attenuation at low frequencies and can complement a passive system (good attenuation at h ⁇ oi frequencies) to achieve a good overall reduction across a wide frequency range.
  • Active noise control systems have been used in the past to demonstrate control of reflection coefficient but have used discrete transducers for example conventional moving coil transducers such as loudspeakers.
  • a sound control device for controll ing sound transmitted through and/or reflected from a barrier member, the device comprising sensor means to sense said transmitted and/or reflected sound and to produce a signal representing the transmitted and/or reflected sound, an actuator mounted on said barrier member and arranged to conform to at least one surface of the barrier member and control means responsive to said signal to provide a control signal to the actuator.
  • the present invention uses an active method to control the radiated and/or reflected noise from the barrier member by the use of an active system comprising the acoustic sensor, control electronics and the distributed actuator as a conformal layer or coating arranged on at least one surface of the support member or barrier member.
  • the principal advantage is that the acoustic impedance match to the surrounding medium can either be i ⁇ proved which reduces the acoustic reflection or decreased which increases the decoupl ing between the two surfaces.
  • the actuator may be made of a flexible piezo-electri c material , such as a piezo-ceramic/polymer composite.
  • the composite includes ceramic materials such as PT (Lead Titanate) or PZT (Lead Zirconate Titanate) dispersed in a polymer.
  • the piezo-electric material may be a polymer of vinyl idene fluoride or a copolymer of vinyl idene fluoride and trifluoroethylene.
  • the actuator may be in the form of a flexible layer or coating provided on at least one surface of said barrier member.
  • the actuator and sensor are integrated into a single structure arranged to conform to the surface of said barrier member.
  • the actuator, sensor and control means may be integrated into a combined unit.
  • the control means may provide a phased control signal to the acuator so as to cancel the signal sensed by said sensor means.
  • Figure 1 il lustrates a noise control device embodying the present invention.
  • Figure 2 il lustrates another embodiment of the noise control device of the present invention.
  • the noise control device as shown in Figures 1 and 2 is arranged on one side of the support member or barrier member 10.
  • the device includes an actuator 11 of a flexible piezoelectric material for example piezoceramic material embedded in polymer matrix.
  • the flexible layer of piezoelectric material is arranged to conform to a surface 14 of the barrier member 10 and a pressure sensor 11 is arranged over the actuator 12 as shown in Figure 1.
  • the sensor 11 and the actuator 12 are formed as an integral unit in which the sensor 11 is surrounded by the actuator 12 and the flexible integral unit is arranged to conform to the surface 14 of the barrier member 10.
  • the sensor 11 in both embodiments is connected to a control device or processing electronic 13.
  • the sensor 11 produces a signal representing the noise detected by the sensor.
  • the acoustic noise detected by the sensor may be a noise transmitted through the barrier member to the surface 14 or it may be the noise reflected from the surface 14 of the barrier member 10.
  • the control device in response to the detected signal received from the sensor, may provide an inverted phase signal to the actuator to cancel the acoustic noise signal received from the sensor.
  • a conformal actuator as part of the noise control system, it is possible to produce large area noise control systems as illustrated schematically in Figures 1 and 2.
  • the output from the pressure sensor which may be mechanically decoupled or directly coupled to the actuator is electrically filtered and amplified to provide drive to the actuator material.
  • the system may feeback phase inverted or same phase signals to the actuator compared to the sensor output.
  • the phase of the electronic control loop it is possible to produce a material interface with an apparently improved acoustic impedance match to the surrounding medium (water or air), and thus reduce acoustic reflection from the interface.
  • the system can increase the decoupling between the two surfaces by decreasing the acoustic impedance match.
  • the use of a large area transducer which is conformal allows the system to be applied to non-planar surfaces and greatly simplifies the implementation of the system.
  • the control electronics may be physically remote from the sensor/actuator combi nat on or may be integrated into the combined unit to provide a so-cal led 'smart ' material .
  • Distributed actuator materials which offer particular advantage are dispersions of piezoelectric ceramic in a polymer carrier (so-cal led '0-3' composite) , ceramic rods in polymer with or without a glass reinforcement phase and pure piezoelectric polymers.
  • the use of a large area transducer material allows tranducers elements to be defined by electrode definition and even allows sensor and actuator functions to be integrated into the same material .
  • the noise control layer (sensor/actuator) may be appl ied as a conformal coating to the required structure where it can then control the reflected and/or radiated sound.

Landscapes

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

Abstract

The invention relates to a sound control device for controlling sound transmitted through and/or reflected from a barrier member (10). The device includes a sensor (11) to sense said transmitted and/or reflected sound and to produce a signal representing the transmitted and/or reflected sound, an actuator (12) mounted on said barrier member (10) and arranged to conform to at least one surface (14) of the barrier member (10) and control means (13) responsive to said signal to provide a control signal to the actuator (12). The actuator may be made of a piezoelectric ceramic dispersed in a polymer material.

Description

A Sound Control Device
The invention relates to a sound control device for controlling sound transmitted through and/or reflected from a barrier member.
The isol ation and absorption of low frequency acoustic noise has been a recognised problem for many years. In situations such as vehi cle cabins and ships engine rooms , high levels of low frequency acoustic noise are generated which may be transferred to the rest of the vehicle/building structure throuoi partition walls such as single leaf walls. The sound transmission of a single leaf wall can be approximated by the mass law which gives a transmission loss which is proportional to frequency and the mass per unit area of the partition. Good isolation at low frequency requires a high density wall . Iπprove ents can be made by providing multiple layout isolation structures, but these result in increased coπplexity, cost and volume/weight for the final appl ication. Conventional porous absorber materials also tend to be poor at deal ing with low frequencies. It is possible to use resonant lossy plates as low frequency absorbers , but these need to be large and mounted away from a rigid support structure. In many instances, such as vehicle cabs, and exteriors of ships hulls, their use is impractical.
A low volume/low mass system capable of producing significant acoustic isolation and/or absorption would be of significant use in vehicle cabins, workshop 's , engine rooms and radiated noise of ships, and the l ike where reduction of noise is desired.
An active noise reduction system is known to be very effective at low frequencies where wavelengths are long, so that little phase difference occurs between the generated and sensed sounds. Thus, this type of system has a good attenuation at low frequencies and can complement a passive system (good attenuation at hϊoi frequencies) to achieve a good overall reduction across a wide frequency range.
Active noise control systems have been used in the past to demonstrate control of reflection coefficient but have used discrete transducers for example conventional moving coil transducers such as loudspeakers.
The use of discrete anti-noise sources limits the physical spacing of separate generators and so l imits the upper frequency of operation for non-normal incidence of the sound. The use of discrete actuators also produces a massive structure with complex mounting arrangements. Similar cons derations apply when such a system is appl ied underwater.
According to the invention there is provided a sound control device for controll ing sound transmitted through and/or reflected from a barrier member, the device comprising sensor means to sense said transmitted and/or reflected sound and to produce a signal representing the transmitted and/or reflected sound, an actuator mounted on said barrier member and arranged to conform to at least one surface of the barrier member and control means responsive to said signal to provide a control signal to the actuator. The present invention uses an active method to control the radiated and/or reflected noise from the barrier member by the use of an active system comprising the acoustic sensor, control electronics and the distributed actuator as a conformal layer or coating arranged on at least one surface of the support member or barrier member. The principal advantage is that the acoustic impedance match to the surrounding medium can either be iπproved which reduces the acoustic reflection or decreased which increases the decoupl ing between the two surfaces.
The actuator may be made of a flexible piezo-electri c material , such as a piezo-ceramic/polymer composite. The composite includes ceramic materials such as PT (Lead Titanate) or PZT (Lead Zirconate Titanate) dispersed in a polymer. The piezo-electric material may be a polymer of vinyl idene fluoride or a copolymer of vinyl idene fluoride and trifluoroethylene. The actuator may be in the form of a flexible layer or coating provided on at least one surface of said barrier member.
Preferably the actuator and sensor are integrated into a single structure arranged to conform to the surface of said barrier member. The actuator, sensor and control means may be integrated into a combined unit. The control means may provide a phased control signal to the acuator so as to cancel the signal sensed by said sensor means.
The invention wil l now be described further by way of example with reference to the accompanying drawings in which:
Figure 1 il lustrates a noise control device embodying the present invention; and
Figure 2 il lustrates another embodiment of the noise control device of the present invention.
The noise control device as shown in Figures 1 and 2 is arranged on one side of the support member or barrier member 10. The device includes an actuator 11 of a flexible piezoelectric material for example piezoceramic material embedded in polymer matrix. The flexible layer of piezoelectric material is arranged to conform to a surface 14 of the barrier member 10 and a pressure sensor 11 is arranged over the actuator 12 as shown in Figure 1. In the embodiment shown in Figure 2 the sensor 11 and the actuator 12 are formed as an integral unit in which the sensor 11 is surrounded by the actuator 12 and the flexible integral unit is arranged to conform to the surface 14 of the barrier member 10. The sensor 11 in both embodiments is connected to a control device or processing electronic 13. The sensor 11 produces a signal representing the noise detected by the sensor. The acoustic noise detected by the sensor may be a noise transmitted through the barrier member to the surface 14 or it may be the noise reflected from the surface 14 of the barrier member 10. The control device, in response to the detected signal received from the sensor, may provide an inverted phase signal to the actuator to cancel the acoustic noise signal received from the sensor. By using a conformal actuator as part of the noise control system, it is possible to produce large area noise control systems as illustrated schematically in Figures 1 and 2. The output from the pressure sensor which may be mechanically decoupled or directly coupled to the actuator is electrically filtered and amplified to provide drive to the actuator material. Dependent upon whether it is desired to produce a system which reduces reflected sound, or reduces transmitted sound, the system may feeback phase inverted or same phase signals to the actuator compared to the sensor output. Dependent upon the phase of the electronic control loop, it is possible to produce a material interface with an apparently improved acoustic impedance match to the surrounding medium (water or air), and thus reduce acoustic reflection from the interface. Alternatively the system can increase the decoupling between the two surfaces by decreasing the acoustic impedance match.
The use of a large area transducer which is conformal allows the system to be applied to non-planar surfaces and greatly simplifies the implementation of the system. The control electronics may be physically remote from the sensor/actuator combi nat on or may be integrated into the combined unit to provide a so-cal led 'smart ' material . Distributed actuator materials which offer particular advantage are dispersions of piezoelectric ceramic in a polymer carrier (so-cal led '0-3' composite) , ceramic rods in polymer with or without a glass reinforcement phase and pure piezoelectric polymers. The use of a large area transducer material allows tranducers elements to be defined by electrode definition and even allows sensor and actuator functions to be integrated into the same material . The noise control layer (sensor/actuator) may be appl ied as a conformal coating to the required structure where it can then control the reflected and/or radiated sound.

Claims

1. A sound control device for controlling sound transmitted through and/or reflected from a barrier member, the device comprising sensor means to sense said transmitted and/or reflected sound and to produce a signal representing the transmitted and/or reflected sound, an actuator mounted on said barrier member and arranged to conform to at least one surface of the barrier member and control means responsive to said signal to provide a control signal to the actuator.
2. A device as claimed in Claim 1, wherein the actuator is made of a piezo-electric material.
3. A device as claimed in Claim 2, wherein the piezo-electric material is a piezo-ceramic/polymer composite.
4. A device as claimed in Claim 3, wherein said composite includes PT or PZT ceramic material dispersed in a polymer,
5. A device as claimed in Claim 2, wherein the piezo-electric material is a polymer of vinyl idene fluoride or a copoly er of vinylidene fluoride and trifluoroethylene.
6. A device as claimed in Claim 2, wherein said actuator is in the form of a coating provided on at least one surface of said barrier member.
7. A device as claimed in Claim 1, wherein said actuator and sensor means are integrated into a single structure arranged to conform to the surface of said barrier member.
8. A device as claimed in any one of claims 1 to 6, wherein said actuator, sensor means and control means are integrated into a combined unit.
9. A device as claimed in any one of the preceding claims wherein the control means provides a phased control signal to the acuator so as to cancel the signal sensed by said sensor means.
10. A sound control device substantial ly as hereinbefore described with reference to the accompanying drawings.
PCT/GB1992/001916 1991-10-21 1992-10-19 A sound control device WO1993008560A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB9122323.0 1991-10-21
GB9122323A GB2260874A (en) 1991-10-21 1991-10-21 A sound control device

Publications (1)

Publication Number Publication Date
WO1993008560A1 true WO1993008560A1 (en) 1993-04-29

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB1992/001916 WO1993008560A1 (en) 1991-10-21 1992-10-19 A sound control device

Country Status (3)

Country Link
EP (1) EP0563355A1 (en)
GB (1) GB2260874A (en)
WO (1) WO1993008560A1 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6648750B1 (en) 1999-09-03 2003-11-18 Titon Hardware Limited Ventilation assemblies
CN107146600A (en) * 2017-06-30 2017-09-08 武汉理工大学 Comprehensive Noise Treatment Device and Method for Marine Diesel Engines

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5315661A (en) * 1992-08-12 1994-05-24 Noise Cancellation Technologies, Inc. Active high transmission loss panel
US5498127A (en) * 1994-11-14 1996-03-12 General Electric Company Active acoustic liner
IT1268204B1 (en) * 1994-12-28 1997-02-21 Fiat Auto Spa SYSTEM FOR THE REDUCTION OF NOISE DUE TO VIBRATIONS OF A VEHICLE.
GB2312972B (en) * 1996-05-11 2000-02-09 Marconi Gec Ltd Vibration control
GB9927131D0 (en) * 1999-11-16 2000-01-12 Royal College Of Art Apparatus for acoustically improving an environment and related method
AT411367B (en) * 2001-01-17 2003-12-29 M2 Master Man Gesmbh NOISE PROTECTION DEVICE CONSISTING OF ACTIVE BROADBAND SILENCERS

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3713780A1 (en) * 1986-04-30 1987-11-05 Elin Union Ag Arrangement for the attenuation, reduction or compensation of sound waves or noise
US5024092A (en) * 1990-08-16 1991-06-18 Westinghouse Electric Corp. Method and apparatus for selective transmission and reflection of sound through a solid

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2814093C2 (en) * 1978-04-01 1980-05-14 Messerschmitt-Boelkow-Blohm Gmbh, 8000 Muenchen Anti-noise generator
EP0041954A1 (en) * 1979-11-10 1981-12-23 Sound Attenuators Limited The cancelling of vibrations transmitted through a fluid in a containing vessel
JPS5827313A (en) * 1981-08-11 1983-02-18 Hitachi Ltd Vibration reduction method for stationary induction equipment
JPS5895806A (en) * 1981-12-02 1983-06-07 Hitachi Ltd Noiseproof device for stationary induction apparatus
US4565940A (en) * 1984-08-14 1986-01-21 Massachusetts Institute Of Technology Method and apparatus using a piezoelectric film for active control of vibrations
EP0434468A3 (en) * 1989-12-22 1992-05-27 Bridgestone Corporation Vibration control system

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3713780A1 (en) * 1986-04-30 1987-11-05 Elin Union Ag Arrangement for the attenuation, reduction or compensation of sound waves or noise
US5024092A (en) * 1990-08-16 1991-06-18 Westinghouse Electric Corp. Method and apparatus for selective transmission and reflection of sound through a solid

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA. vol. 90, no. 3, 1 September 1991, NEW YORK US pages 1230 - 1237 L.DWYNN LAFLEUR E.A, 'Acoustically active surfaces us' *
JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA. vol. 91, no. 2, 1 February 1992, NEW YORK US pages 823 - 831 T.R.HOWARTH E.A. 'Piezocomposite coating for active underwater sound reduction' *
SOVIET PHYSICS ACOUSTICS. vol. 30, no. 6, 1 November 1984, NEW YORK US pages 440 - 443 V.N.BELYI E.A. 'Influence of an electric field on the reflection of an ultrasonic wave from a ceramic plate in a fluid' *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6648750B1 (en) 1999-09-03 2003-11-18 Titon Hardware Limited Ventilation assemblies
CN107146600A (en) * 2017-06-30 2017-09-08 武汉理工大学 Comprehensive Noise Treatment Device and Method for Marine Diesel Engines

Also Published As

Publication number Publication date
GB2260874A (en) 1993-04-28
EP0563355A1 (en) 1993-10-06
GB9122323D0 (en) 1992-11-18

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