CN116261089A - Structure-borne sound device for realizing large-non-reciprocal transmission of sound energy by NES and verification method - Google Patents

Structure-borne sound device for realizing large-non-reciprocal transmission of sound energy by NES and verification method Download PDF

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CN116261089A
CN116261089A CN202211596414.6A CN202211596414A CN116261089A CN 116261089 A CN116261089 A CN 116261089A CN 202211596414 A CN202211596414 A CN 202211596414A CN 116261089 A CN116261089 A CN 116261089A
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sound
cavity
film
acoustic
pipeline
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金江明
肖岳鹏
黄景啸
卢奂采
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Zhejiang University of Technology ZJUT
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    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04RLOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R29/00Monitoring arrangements; Testing arrangements
    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02DCLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
    • Y02D30/00Reducing energy consumption in communication networks
    • Y02D30/70Reducing energy consumption in communication networks in wireless communication networks

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Abstract

The structural sound device for realizing the large nonreciprocal transmission of the sound energy by utilizing NES comprises a first sound cavity, a pipeline, a second sound cavity, a film and a third sound cavity, wherein two ends of the pipeline are respectively connected with the first sound cavity and the second sound cavity, the second sound cavity is centrally arranged on the top surface of the third sound cavity, and a through hole III is formed in the center of the connection of the two sound cavities; the film is arranged between the second acoustic cavity and the third acoustic cavity through the clamp and completely shields the third through hole. The sound cavity I and the sound cavity III are respectively provided with a through hole I and a through hole II, and a volume velocity sound source is connected with the sound cavity I through the through hole I and seals the through hole II during forward excitation; and the volume velocity sound source is connected with the third sound cavity through the second through hole and seals the first through hole during reverse excitation. The invention also provides a verification method of the structural sound device for realizing the large nonreciprocal transmission of the sound energy by using the NES. The invention realizes the large nonreciprocal transmission of acoustic energy by utilizing the characteristic that the targeted energy transfer occurs during forward excitation and the targeted energy transfer does not occur during reverse excitation, and provides a method for controlling the low-frequency noise of the pipeline.

Description

Structure-borne sound device for realizing large-non-reciprocal transmission of sound energy by NES and verification method
Technical Field
The invention relates to a sound artificial structure regulation and control sound energy control technology, in particular to a structure sound device for realizing large non-reciprocal transmission of sound energy by NES and a verification method.
Background
In the elastic medium, due to the lack of the effect of achieving electromagnetic rectification bias, the elastic medium system strictly follows the rule of Rayleigh Li Huyi. The reciprocity of the system prevents the realization of asymmetric unidirectional transmission of sound waves, and if the asymmetric large non-reciprocal transmission of sound energy is realized, novel acoustic elements such as an acoustic diode, an acoustic unidirectional lens, a sound insulator, a topological insulator and the like can be designed. In electromagnetics, the occurrence of the diode brings about a second industrial revolution, and the novel acoustic element has wide application value in the fields of acoustic communication, sonar system structural design, noise control, imaging control and the like, and is a research hot spot in the fields of structural acoustics and acoustic metamaterials.
Nonlinear acoustic systems have characteristics that are not possessed by linear systems, such as bifurcation, resonant frequencies that vary with system energy, and so on, and thus can achieve large nonreciprocal transfer of acoustic energy. Cochelin et al scholars research the energy transfer phenomenon in a structural acoustic system, couple a large-amplitude nonlinear film with a linear acoustic system, construct a nonlinear energy trap to realize the targeted energy transfer in the acoustic system, and research shows that the directional transmission of sound waves can be realized by utilizing a nonlinear energy trap mechanism, thereby providing a new method for low-frequency noise control.
The noise reduction performance experimental device and method for the acoustic cavity of the coupling film nonlinear energy trap disclosed by the publication No. CN 112857553A are combined with the targeting energy transfer characteristic of the film nonlinear energy trap to further inhibit low-frequency noise in the acoustic cavity. According to the thin plate radiation noise suppression device based on the electroacoustic nonlinear energy trap disclosed by the publication No. CN 114758642A, parameters such as back cavity volume, speaker back cavity volume, feedback gain and the like are optimally designed by adding an electroacoustic structure, so that the excitation lower threshold of the optimal target energy transfer phenomenon of the nonlinear energy trap is reduced by 19 times. However, the above schemes mainly study the suppression or transmission of acoustic energy in one direction, and do not study the bidirectional transmission of acoustic energy.
The Duffing vibrator type structural sound device for realizing the nonreciprocal transmission of the sound energy disclosed by the invention with the publication number of CN 114613349A utilizes a nonlinear film to simplify the nonlinear resonance of a single free Duffing vibrator in a weak nonlinear region and the bifurcation mechanism of a strong nonlinear region to realize the nonreciprocal transmission of the sound energy, and provides a new thought for the asymmetrical transmission of the sound energy in an air medium.
Disclosure of Invention
For the further development of the research of the existing acoustic energy nonreciprocal transmission device, a structure-borne sound device for realizing large acoustic energy nonreciprocal transmission by using NES is provided, and a new method is provided for realizing acoustic energy nonreciprocal transmission and pipeline low-frequency noise control in an air medium.
The technical scheme adopted by the invention is as follows: the structural sound device for realizing the large nonreciprocal transmission of sound energy by utilizing NES comprises a pipeline (2), a film (5), and a first square sound cavity (1), a second square sound cavity (4) and a third square sound cavity (6) which are different in size, wherein the length of the pipeline (2) is far greater than the diameter of the pipeline, two ends of the pipeline (2) are respectively and hermetically connected with the first sound cavity (1) and the second sound cavity (4), and the first sound cavity (1) is communicated with the second sound cavity (4) through the pipeline (2);
the second acoustic cavity (4) is arranged on the top surface of the third acoustic cavity (6) in a central and overlapping mode, an end cover (3) which is convenient for installing a film (5) is arranged on the top surface of the second acoustic cavity (4), and the end cover (3) is connected with the second acoustic cavity (4) in a sealing mode; a through hole III (H) for communicating the second acoustic cavity (4) with the third acoustic cavity (6) is arranged at the middle part of the wall surface of the second acoustic cavity (4) and the third acoustic cavity (6) 3 ) Through-hole III (H 3 ) The inner seal is connected with a film clamp (7); the film clamp (7) comprises an annular upper clamping cover and an annular lower clamping cover, the film (5) is clamped between the upper clamping cover and the lower clamping cover, and the film clamp (7) and the film (5) completely shield the through hole III (H) 3 ) The method comprises the steps of carrying out a first treatment on the surface of the The surface of one side of the first acoustic cavity (1) far away from the pipeline (2) is provided with a first through hole (H) 1 ) A second through hole (H) is arranged on the surface of one side of the third acoustic cavity (6) facing the pipeline (2) 2 ) The method comprises the steps of carrying out a first treatment on the surface of the The transmission mediums in the first acoustic cavity (1), the pipeline (2), the second acoustic cavity (4) and the third acoustic cavity (6) are all air;
the volumetric velocity sound source passes through the through-hole one (H 1 ) Is connected with the first acoustic cavity (1) and is sealed with the second through hole (H) 2 ) The method comprises the steps of carrying out a first treatment on the surface of the Internal resonance is formed inside the device when the device is excited in the forward direction, and the acoustic energy is targeted to target energy transfer fromThe linear vibrator pipeline (2) is irreversibly and efficiently transferred to the nonlinear vibrator film (5), and is transferred to the acoustic cavity III (6) by the film (5), and the higher response sound pressure can be measured in the acoustic cavity III (6);
when excited in reverse, the volumetric velocity sound source passes through the through-hole II (H 2 ) Is connected with the third acoustic cavity (6) and is sealed with the first through hole (H) 1 ) The input sound wave wavelength is far larger than the sizes of the first square sound cavity (1), the second square sound cavity (4) and the third square sound cavity (6); the device does not generate internal resonance when in reverse excitation, most of sound energy still stays in the third acoustic cavity (6), the sound energy transmission efficiency is low, and the response sound pressure measured in the first acoustic cavity (1) is low; the device has a large non-reciprocity when there is a large difference in system response when excited in the forward direction and excited in the reverse direction.
Further, the pipeline (2) is made of stainless steel, the section radius of the inner diameter of the pipeline (2) is 17.5mm, and the length of the pipeline (2) is 1.75m; the first acoustic cavity (1), the second acoustic cavity (4) and the third acoustic cavity (6) are all made of acrylic and are all square; the side lengths of the cavity bodies of the first acoustic cavity (1) and the second acoustic cavity (4) are 0.2m, and the side length of the cavity body of the third acoustic cavity (6) is 0.3m; the film (5) is made of silica gel, the thickness of the film (5) is 0.1mm, and the radius of the film (5) is 19mm.
Further, given the radius R of the pipe t Length L of pipe, radius R of film m Density ρ of film m The thickness h of the film, the Poisson's ratio V of the film, the Young's modulus E of the film, the damping coefficient eta of the film, the volume V of the square acoustic cavity I 1 Volume V of square acoustic cavity two 2 Volume V of square acoustic chamber three 3 Amplitude Q of excitation of sound source s Excitation frequency omega s Density ρ of air a And sound velocity c 0 Theoretical modeling is carried out, then simulation and experimental verification are carried out, and the steps are as follows:
1) Respectively establishing theoretical models of three types of constituent units of a pipeline, a nonlinear film and an acoustic cavity, and a system control equation expression formed by coupling the three types of units, wherein the judgment formula of the nonreciprocal quantity of acoustic energy is as follows:
theoretical model of the pipeline: since the length of the pipe is much greater than its diameter,thus can be assumed to be one-dimensional waveguides, assuming u a and px For the displacement of the sound medium at the tail end of the pipeline and the sound pressure in the pipeline, the wave equation of sound wave and Rayleigh-Ritz simplification are combined, and an air damping coefficient c is introduced f The pipeline control equation can be obtained:
Figure BDA0003993010820000041
wherein ,
Figure BDA0003993010820000051
theoretical model of film: a Von Karman nonlinear plate-shell model is adopted, and a Kelvin-Viogt viscoelasticity constitutive model is combined to establish a control equation of the film; then adopting a parabolic function as a first-order mode shape function of the film, and obtaining a control equation of the nonlinear film through a Rayleigh-Ritz valence-decreasing modeling method:
Figure BDA0003993010820000052
wherein qm For lateral displacement of the centre of the film, p m Sound pressure applied to the film; f (f) 1m Is the linear first-order natural frequency of the film with prestress, and is obtained by experimental measurement, f 0m A resonance frequency of the film without prestressing; k (k) 1 and k3 Respectively the linear rigidity and the cubic nonlinear rigidity of the film, S m Is the area of the film; m is m a0 The additional mass of the film which moves in a large amplitude way to drive the surrounding air to move is determined according to the experimental result; other parameters are given by the following formulas:
Figure BDA0003993010820000053
theoretical model of acoustic cavity: when the sound wave wavelength is far greater than the size of the sound cavity, the sound pressure in the sound cavity enclosed by the rigid wall can be considered to be uniformly distributed, and the sound pressure equation in the sound cavity can be obtained:
Figure BDA0003993010820000054
the system control equation can be obtained by combining equations (1), (3) and (5):
upon forward excitation:
Figure BDA0003993010820000061
Figure BDA0003993010820000062
upon reverse excitation:
Figure BDA0003993010820000063
Figure BDA0003993010820000064
wherein ,
Figure BDA0003993010820000065
the square acoustic cavity III (6) is a response acoustic cavity during forward excitation, the square acoustic cavity I (1) is a response acoustic cavity during reverse excitation, and the sound pressures in the square acoustic cavities are respectively:
Figure BDA0003993010820000066
Figure BDA0003993010820000067
the reciprocity NR of the acoustic energy transfer of the device system is defined by:
Figure BDA0003993010820000068
it can be determined whether the device is a large nonreciprocal system according to equation (11).
The principle of the invention is as follows: under the excitation of fixed frequency, the first-order acoustic mode resonance of the pipeline 2 can be simplified into a single-degree-of-freedom linear vibrator, the large deformation vibration of the film 5 can be regarded as a nonlinear vibrator with nonlinear rigidity being dominant, and the pipeline 2 and the film 5 are coupled through air in the acoustic cavity two 4 with the linear rigidity, so that the structural acoustic system can be simplified into a two-degree-of-freedom system consisting of the linear vibrator and the nonlinear vibrator. From theoretical research analysis, it can be found that: in a certain sound source high excitation range, internal resonance is formed in the system during forward excitation, the sound energy is subjected to targeted target energy transfer, is irreversibly and efficiently transferred from the linear vibrator pipeline 2 to the nonlinear vibrator film 5 and is transferred from the film 5 to the square sound cavity III 6, and the square sound cavity III 6 can be used for measuring higher response sound pressure; when the system is excited reversely, no internal resonance occurs, most of the sound energy still stays in the square acoustic cavity III 6, the sound energy transmission efficiency is low, and the response sound pressure measured in the square acoustic cavity I1 is low; the acoustic system is highly nonreciprocal due to the significant differences in system response between forward and reverse excitation.
According to the definition of reciprocity in an acoustic system, the invention provides a method for verifying the system nonreciprocity by adopting the positions of an interchange excitation point and a response point and according to the ratio of the response sound pressures of the two points, in particular to interchange the positions of an excitation input point and a response output point under the condition that the intensity of an input sound source of the system is unchanged, respectively measuring the sound pressures at the response points before and after interchange, then determining the magnitude of the nonreciprocal quantity according to the ratio of the response sound pressures of the two points, and judging the nonreciprocal system as a large nonreciprocal system when the ratio of the two points is larger.
The beneficial effects of the invention are as follows: the invention constructs the structure-borne sound device capable of realizing the large non-reciprocal transmission of the sound energy by utilizing the nonlinear energy trap mechanism in the structure-borne sound system, provides a new design thought for realizing the non-reciprocal transmission of the sound energy in the air medium, and has great application value in the field of low-frequency noise control of pipelines.
Drawings
Fig. 1 is a schematic view of the structure of the device of the present invention.
Fig. 2 is a schematic structural view of the film clamp of the present invention.
Figure 3 is a simplified two-degree-of-freedom system schematic diagram of the apparatus of the present invention.
FIG. 4 is a graph comparing the experimental and simulation results of the device of the present invention for the average speed of the thin film under the same frequency and different strong excitation.
FIG. 5 is a graph comparing experimental and simulation results of the device of the present invention in response to sound pressure at the same frequency and different source strong excitations.
FIG. 6 is a graph comparing experimental and simulation results of the device of the present invention for non-reciprocal amounts of acoustic energy at the same frequency and different source strong excitations.
Reference numerals illustrate: 1. an acoustic cavity I; 2. a pipe; 3. an end cap; 4. a second acoustic cavity; 5. a film; 6. an acoustic cavity III; 7. and (3) a film clamp.
Detailed Description
The following description of the embodiments of the present invention will be made more apparent and fully hereinafter with reference to the accompanying drawings, in which some, but not all embodiments of the invention are shown. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
In the description of the present invention, it should be noted that, as the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," "outer," and the like are used for convenience in describing the present invention and simplifying the description based on the azimuth or positional relationship shown in the drawings, it should not be construed as limiting the present invention, but rather should indicate or imply that the devices or elements referred to must have a specific azimuth, be constructed and operated in a specific azimuth. Furthermore, the terms "first," "second," "third," and the like, as used herein, are used for descriptive purposes only and are not to be construed as indicating or implying any relative importance.
In the description of the present invention, it should be noted that unless explicitly stated and limited otherwise, the terms "mounted," "connected," and "connected" should be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present invention will be understood in specific cases by those of ordinary skill in the art.
As shown in fig. 1, the device consists of an acoustic cavity I1, a pipeline 2, an acoustic cavity II 4, a film 5 and an acoustic cavity III 6; two ends of the pipeline 2 are respectively in sealing connection with the first acoustic cavity 1 and the second acoustic cavity 4, the second acoustic cavity 4 is arranged on the top surface of the third acoustic cavity 6 in a centering way, the top surface of the second acoustic cavity 4 is provided with an end cover 3 for conveniently installing a film 5, and the end cover 3 is in sealing connection with the second acoustic cavity 4 through a sealing ring and a bolt; a through hole tri-H is arranged at the middle part of the connection between the second acoustic cavity 4 and the third acoustic cavity 6 3 The film 5 is arranged between the second acoustic cavity 4 and the third acoustic cavity 6 through a clamp and completely shields the through hole III H 3 The film clamp 7 is in sealing connection with the acoustic cavity through a screw and a sealing ring. The side surfaces of the first acoustic cavity 1 and the third acoustic cavity 6 are respectively provided with a through hole H 1 And through hole II 2 The volume velocity sound source passes through the through hole H during forward excitation 1 Is connected with the first acoustic cavity 1 and is sealed with the second through hole H 2 Volume velocity sound source passes through hole II during reverse excitation 2 Is connected with the third acoustic cavity 6 and is sealed with the through hole H 1
The transmission medium in the acoustic cavity and the pipeline is air. The pipeline 2 is made of stainless steel, the radius of the section of the inner diameter of the pipeline 2 is 17.5mm, and the length of the pipeline 2 is 1.75m; the acoustic cavity materials are acrylic and square, wherein the side lengths of the cavity bodies of the acoustic cavity I1 and the acoustic cavity II 4 are 0.2m, and the side length of the cavity body of the acoustic cavity III 6 is 0.3m; the material of the film 5 is silica gel, the thickness of the film 5 is 0.1mm, and the action radius of the film 5 is 19mm.
As shown in fig. 2, the film fixture 7 is composed of an upper part and a lower part, the film is uniformly and evenly installed in the middle of the fixture, so as to reduce the prestress generated during installation, and meanwhile, in order to ensure the stability of the boundary condition of the film, a rubber pad is required to be installed on the inner ring of the fixture; then the upper part and the lower part of the clamp are fastened by screws.
As shown in fig. 3, under the excitation of a fixed frequency, the first-order acoustic mode resonance of the pipeline 2 can be simplified into a single-degree-of-freedom linear vibrator, the large deformation vibration of the film 5 can be regarded as a nonlinear vibrator with nonlinear rigidity being dominant, and the pipeline 2 and the film 5 are coupled through air in the acoustic cavity two 4 with the linear rigidity, so that the structural acoustic system can be simplified into a two-degree-of-freedom system consisting of the linear vibrator and the nonlinear vibrator. In a certain sound source intensity excitation range, internal resonance is formed in the system during forward excitation, the sound energy is subjected to targeted target energy transfer, is irreversibly and efficiently transferred from the linear vibrator pipeline 2 to the nonlinear vibrator film 5 and is transferred from the film 5 to the sound cavity III 6, and the high response sound pressure can be measured in the sound cavity III 6; when the system is excited reversely, no internal resonance occurs, most of the sound energy still stays in the third acoustic cavity 6, the sound energy transmission efficiency is low, and the response sound pressure measured in the first acoustic cavity 1 is low; the acoustic system is highly nonreciprocal due to the significant differences in system response between forward and reverse excitation.
The structural acoustic device verification method for realizing large nonreciprocal transmission of acoustic energy by using NES according to claim 1 or 2, wherein the method comprises the following steps: radius R of given pipe 2 t Length L of pipe 2, radius R of film 5 m Density ρ of film 5 m The thickness h of the film 5, the Poisson ratio V of the film 5, the Young's modulus E of the film 5, the damping coefficient eta of the film 5 and the volume V of the square acoustic cavity 1 1 Volume V of square acoustic cavity two 4 2 Volume V of square acoustic chamber three 6 3 Amplitude Q of excitation of sound source s Excitation frequency omega s Density ρ of air a And sound velocity c 0 Theoretical modeling is carried out, then simulation and experimental verification are carried out, and the steps are as follows:
1) Respectively establishing theoretical models of three types of constituent units of a pipeline, a nonlinear film and an acoustic cavity, and a system control equation expression formed by coupling the three types of units, wherein the judgment formula of the nonreciprocal quantity of acoustic energy is as follows:
theoretical model of the pipeline: since the length of the pipe is much greater than its diameter, it can be assumed to be a one-dimensional waveguide, assuming u a and px For the displacement of the sound medium at the tail end of the pipeline and the sound pressure in the pipeline, the wave equation of sound wave and Rayleigh-Ritz simplification are combined, and an air damping coefficient c is introduced f The pipeline control equation can be obtained:
Figure BDA0003993010820000111
wherein ,
Figure BDA0003993010820000112
theoretical model of film: a Von Karman nonlinear plate-shell model is adopted, and a Kelvin-Viogt viscoelasticity constitutive model is combined to establish a control equation of the film; then adopting a parabolic function as a first-order mode shape function of the film, and obtaining a control equation of the nonlinear film through a Rayleigh-Ritz valence-decreasing modeling method:
Figure BDA0003993010820000121
wherein qm For lateral displacement of the centre of the film, p m Sound pressure applied to the film; f (f) 1m Is the linear first-order natural frequency of the film with prestress, and is obtained by experimental measurement, f 0m A resonance frequency of the film without prestressing; k (k) 1 and k3 Respectively the linear rigidity and the cubic nonlinear rigidity of the film, S m Is the area of the film; m is m a0 The additional mass of the film which moves in a large amplitude way to drive the surrounding air to move is determined according to the experimental result; other parameters are given by the following formulas:
Figure BDA0003993010820000122
theoretical model of acoustic cavity: when the sound wave wavelength is far greater than the size of the sound cavity, the sound pressure in the sound cavity enclosed by the rigid wall can be considered to be uniformly distributed, and the sound pressure equation in the sound cavity can be obtained:
Figure BDA0003993010820000123
the system control equation can be obtained by combining equations (1), (3) and (5):
upon forward excitation:
Figure BDA0003993010820000124
Figure BDA0003993010820000125
upon reverse excitation:
Figure BDA0003993010820000131
Figure BDA0003993010820000132
wherein ,
Figure BDA0003993010820000133
the square acoustic cavity III (6) is a response acoustic cavity during forward excitation, the square acoustic cavity I (1) is a response acoustic cavity during reverse excitation, and the sound pressures in the square acoustic cavities are respectively:
Figure BDA0003993010820000134
Figure BDA0003993010820000135
the reciprocity NR of the acoustic energy transfer of the device system is defined by:
Figure BDA0003993010820000136
it can be determined whether the device is a large nonreciprocal system according to equation (11).
The invention respectively establishes theoretical models of three types of constituent units of a pipeline, a nonlinear film and an acoustic cavity, and a system control equation expression formed by coupling the three types of units, and a judgment formula of nonreciprocal quantity of acoustic energy:
the length of the pipe in the present invention is much longer than its diameter, so it can be assumed as a one-dimensional waveguide, assuming u a and px For the displacement of the sound medium at the tail end of the pipeline and the sound pressure in the pipeline, the wave equation of sound wave and Rayleigh-Ritz simplification are combined, and an air damping coefficient c is introduced f The pipe control equation is obtained as formula (1).
The vibration of the film is large-amplitude, and the linear theory is not applicable any more, so that a Von Karman nonlinear plate-shell model is adopted, and a Kelvin-Viogt viscoelastic constitutive model is combined to establish a control equation of the film; and then adopting a parabolic function as a first-order mode shape function of the film, and obtaining a control equation of the nonlinear film as a formula (3) through a Rayleigh-Ritz reduced price modeling method.
The size of the sound cavity is far smaller than the wavelength of sound waves, so that the sound pressure in the sound cavity enclosed by the rigid wall can be considered to be uniformly distributed, and the sound pressure equation in the sound cavity can be obtained as formula (5).
By combining the theoretical models of the components respectively established, the system control equation of the system in forward and reverse excitation is respectively shown as a formula (6) and a formula (7), and the sound pressure response formula of the response sound cavity is respectively shown as a formula (9) and a formula (10). The reciprocity of the transfer of system acoustic energy NR is defined by equation (11).
The system acoustic energy transfer can be calculated by equation (11) to determine whether it is a nonreciprocal system.
In the experiment, the first-order natural frequency of the film is 62Hz through sweep frequency measurement under low-source strong excitation; the nonlinear cubic stiffness of the film is determined by fitting the measurement result of the film large deformation data, in the invention, the PDMS film with the thickness of 100um is adopted, and the cubic nonlinear stiffness k of the film is obtained by fitting experimental data 3 Is 3.0X10 6 N/m 3
In the experiment, in order to output high-source-intensity excitation, a high-intensity excitation system consisting of 8-inch JL subwofer and Bruel was designed&
Figure BDA0003993010820000151
A high-source high-volume-velocity sound source consisting of a volume-velocity source high-intensity probe; by using Bruel&/>
Figure BDA0003993010820000152
1/4 inch microphone to measure the sound pressure of the response sound cavity and the central point of the pipeline of the system when the forward and reverse excitation are performed; the vibration velocity of the center point of the film was measured using a laser Doppler vibrometer (model: polytech PSV 400).
Experimental results and theoretical study results analysis:
as shown in fig. 4-6, at low source intensities, the average velocity of the film and the response sound pressure increase nearly linearly with increasing input source intensity, at which time the system has a lower non-reciprocal amount of acoustic energy. However, because the system has nonlinearity, the sound pressure response of the pipeline is limited by the hardening effect of the nonlinear film, the phenomenon that the sound pressure response of the pipeline is limited is more obvious when the input source is stronger until the input energy exceeds a threshold value, the system enters a strong nonlinear interaction area, and the non-reciprocal quantity of the sound energy reaches the maximum value. Under high-source strong excitation, the average speed of the film and the response sound pressure still linearly increase during reverse excitation, while during forward excitation, the average speed of the film and the response sound pressure gradually increase, and the nonreciprocal transmission quantity of sound energy is reduced.
The theoretical analysis results and the experimental results in fig. 4-6 are generally identical, a system theoretical model is verified, a mechanism of the structural sound device for realizing the nonreciprocal transmission of sound energy is disclosed, a large nonreciprocal transmission effect of sound energy which is approximately 3.5 times is realized, and a new method is provided for controlling low-frequency noise of a pipeline.
The embodiments described in the present specification are merely examples of implementation forms of the inventive concept, and the scope of protection of the present invention should not be construed as being limited to the specific forms set forth in the embodiments, and the scope of protection of the present invention and equivalent technical means that can be conceived by those skilled in the art based on the inventive concept.

Claims (3)

1. Utilize NES to realize the structure-borne sound device that the acoustic energy is big non-reciprocal to transmit, its characterized in that: the three-dimensional sound cavity comprises a pipeline (2), a film (5), and a first cube sound cavity (1), a second cube sound cavity (4) and a third cube sound cavity (6) which are different in size, wherein the length of the pipeline (2) is far greater than the diameter of the pipeline, two ends of the pipeline (2) are respectively connected with the first sound cavity (1) and the second sound cavity (4) in a sealing mode, and the first sound cavity (1) is communicated with the second sound cavity (4) through the pipeline (2);
the second acoustic cavity (4) is arranged on the top surface of the third acoustic cavity (6) in a central and overlapping mode, an end cover (3) which is convenient for installing a film (5) is arranged on the top surface of the second acoustic cavity (4), and the end cover (3) is connected with the second acoustic cavity (4) in a sealing mode; a through hole III (H) for communicating the second acoustic cavity (4) with the third acoustic cavity (6) is arranged at the middle part of the wall surface of the second acoustic cavity (4) and the third acoustic cavity (6) 3 ) Through-hole III (H 3 ) The inner seal is connected with a film clamp (7); the film clamp (7) comprises an annular upper clamping cover and an annular lower clamping cover, the film (5) is clamped between the upper clamping cover and the lower clamping cover, and the film clamp (7) and the film (5) completely shield the through hole III (H) 3 ) The method comprises the steps of carrying out a first treatment on the surface of the The surface of one side of the first acoustic cavity (1) far away from the pipeline (2) is provided with a first through hole (H) 1 ) A second through hole (H) is arranged on the surface of one side of the third acoustic cavity (6) facing the pipeline (2) 2 ) The method comprises the steps of carrying out a first treatment on the surface of the The transmission mediums in the first acoustic cavity (1), the pipeline (2), the second acoustic cavity (4) and the third acoustic cavity (6) are all air;
the volumetric velocity sound source passes through the through-hole one (H 1 ) Is connected with the first acoustic cavity (1) and is sealed with the second through hole (H) 2 ) The method comprises the steps of carrying out a first treatment on the surface of the Internal resonance is formed inside the device when the device is excited in the forward direction, and the sound energy is targeted to the target energyTransferring, namely irreversibly and efficiently transferring the sound pressure from the linear vibrator pipeline (2) to the nonlinear vibrator film (5), and transferring the sound pressure from the film (5) to the acoustic cavity III (6), wherein the acoustic cavity III (6) can measure higher response sound pressure;
when excited in reverse, the volumetric velocity sound source passes through the through-hole II (H 2 ) Is connected with the third acoustic cavity (6) and is sealed with the first through hole (H) 1 ) The input sound wave wavelength is far larger than the sizes of the first square sound cavity (1), the second square sound cavity (4) and the third square sound cavity (6); the device does not generate internal resonance when in reverse excitation, most of sound energy still stays in the third acoustic cavity (6), the sound energy transmission efficiency is low, and the response sound pressure measured in the first acoustic cavity (1) is low; the device has a large non-reciprocity when there is a large difference in system response when excited in the forward direction and excited in the reverse direction.
2. The structural acoustic device for achieving high non-reciprocal transmission of acoustic energy using NES according to claim 1, wherein: the pipeline (2) is made of stainless steel, the radius of the section of the inner diameter of the pipeline (2) is 17.5mm, and the length of the pipeline (2) is 1.75m; the first acoustic cavity (1), the second acoustic cavity (4) and the third acoustic cavity (6) are all made of acrylic and are all square; the side lengths of the cavity bodies of the first acoustic cavity (1) and the second acoustic cavity (4) are 0.2m, and the side length of the cavity body of the third acoustic cavity (6) is 0.3m; the film (5) is made of silica gel, the thickness of the film (5) is 0.1mm, and the radius of the film (5) is 19mm.
3. The structural acoustic device verification method for realizing large nonreciprocal transmission of acoustic energy by using NES according to claim 1 or 2, wherein the method comprises the following steps: radius R of a given pipe (2) t Length L of the pipe (2), radius R of the film (5) m Density ρ of film (5) m The thickness h of the film (5), the Poisson ratio V of the film (5), the Young modulus E of the film (5), the damping coefficient eta of the film (5) and the volume V of the square acoustic cavity I (1) 1 Volume V of square acoustic cavity two (4) 2 Volume V of square acoustic chamber three (6) 3 Amplitude Q of excitation of sound source s Excitation frequency omega s Density ρ of air a And sound velocity c 0 Theoretical modeling is carried out, and then imitation is carried outVerification of true and experimental tests, the steps are as follows:
1) Respectively establishing theoretical models of three types of constituent units of a pipeline, a nonlinear film and an acoustic cavity, and a system control equation expression formed by coupling the three types of units, wherein the judgment formula of the nonreciprocal quantity of acoustic energy is as follows:
theoretical model of the pipeline: since the length of the pipe is much greater than its diameter, it can be assumed to be a one-dimensional waveguide, assuming u a and px For the displacement of the sound medium at the tail end of the pipeline and the sound pressure in the pipeline, the wave equation of sound wave and Rayleigh-Ritz simplification are combined, and an air damping coefficient c is introduced f The pipeline control equation can be obtained:
Figure FDA0003993010810000031
wherein ,
Figure FDA0003993010810000032
theoretical model of film: a Von Karman nonlinear plate-shell model is adopted, and a Kelvin-Viogt viscoelasticity constitutive model is combined to establish a control equation of the film; then adopting a parabolic function as a first-order mode shape function of the film, and obtaining a control equation of the nonlinear film through a Rayleigh-Ritz valence-decreasing modeling method:
Figure FDA0003993010810000033
wherein qm For lateral displacement of the centre of the film, p m Sound pressure applied to the film; f (f) 1m Is the linear first-order natural frequency of the film with prestress, and is obtained by experimental measurement, f 0m A resonance frequency of the film without prestressing; k (k) 1 and k3 Respectively the linear rigidity and the cubic nonlinear rigidity of the film, S m Is the area of the film; m is m a0 Is an additional mass for driving the peripheral air to move by the large-amplitude movement of the filmThe amount is determined according to the experimental result; other parameters are given by the following formulas:
Figure FDA0003993010810000041
theoretical model of acoustic cavity: when the sound wave wavelength is far greater than the size of the sound cavity, the sound pressure in the sound cavity enclosed by the rigid wall can be considered to be uniformly distributed, and the sound pressure equation in the sound cavity can be obtained:
Figure FDA0003993010810000042
the system control equation can be obtained by combining equations (1), (3) and (5):
upon forward excitation:
Figure FDA0003993010810000043
Figure FDA0003993010810000044
upon reverse excitation:
Figure FDA0003993010810000045
Figure FDA0003993010810000046
wherein ,
Figure FDA0003993010810000047
the square acoustic cavity III (6) is a response acoustic cavity during forward excitation, the square acoustic cavity I (1) is a response acoustic cavity during reverse excitation, and the sound pressures in the square acoustic cavities are respectively:
Figure FDA0003993010810000051
/>
Figure FDA0003993010810000052
the reciprocity NR of the acoustic energy transfer of the device system is defined by:
Figure FDA0003993010810000053
it can be determined whether the device is a large nonreciprocal system according to equation (11).
CN202211596414.6A 2022-12-12 2022-12-12 Structure-borne sound device for realizing large-non-reciprocal transmission of sound energy by NES and verification method Pending CN116261089A (en)

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