One-dimensional single-port phonon crystal structure for enhancing acoustic signal
By adopting a one-dimensional single-port phonon crystal structure based on local states in acoustic sensing technology, the band gap and local state in the energy band structure are used to solve the problem of detection of weak acoustic signals in noise, and the effective enhancement and detection of acoustic signals are achieved.
Patent Information
- Application Number
- CN202510219082.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-26
- Publication Date
- 2025-05-30
AI Technical Summary
Existing acoustic sensing technologies are difficult to detect weak acoustic signals, especially in the case of external noise interference and long-distance transmission, resulting in the research on acoustic signal enhancement still not achieving satisfactory results.
A one-dimensional single-port phonon crystal structure based on local state is adopted, which includes a first plate and a second plate composed of a waveguide and an acoustic rigid material. By arranging and distance the perimeter intervals of the plates, an energy band structure with a band gap is formed, so that a local state with concentrated energy appears between the second end of the waveguide and the one-dimensional phonon crystal, thereby achieving enhancement of the acoustic signal.
This structure can enhance the acoustic signal within a range near a specific frequency, effectively improve the detection ability of weak acoustic signals in strong noise, and has good engineering application prospects.
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Figure CN120071886A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of acoustic sensing, and particularly to a one-dimensional single-port phononic crystal structure for enhancing acoustic signals. Background Art
[0002] Acoustic sensing technology has a wide range of applications in real life. In the medical field, acoustic sensing technology can detect physiological parameters such as a patient's breathing and heartbeat to provide health monitoring of the patient. In the industrial field, acoustic sensing technology can detect fault signals of machine equipment to diagnose faulty parts or structures of the equipment. In the underwater detection field, acoustic sensing technology can detect the position of underwater submarines to safeguard marine security. However, in some cases, the acoustic signals containing information are relatively weak and cannot be detected by an acoustic sensing system, which severely limits the practical applications of acoustic sensing technology. For example, the acoustic signals inside the human body are very weak and easily interfered by external noises, and acoustic sensing technology cannot detect the physiological parameters of patients. The fault acoustic signals caused by damage to bearing and gear parts are easily submerged by the strong noises of machines in a factory, and acoustic sensing technology cannot detect the fault signals of the equipment. Long-distance transmission causes severe attenuation of acoustic signals, and acoustic sensing technology cannot detect the positioning signals of submarines. Therefore, how to enhance acoustic signals is a research focus in acoustic sensing technology.
[0003] Acoustic metamaterials are artificially designed acoustic structures with rich and novel acoustic properties, such as acoustic invisibility, acoustic imaging, acoustic directional propagation, and acoustic enhancement. Due to the acoustic enhancement property among them, acoustic metamaterials can be used to achieve the enhancement of acoustic signals. So far, multiple acoustic metamaterials have successfully achieved the enhancement of acoustic signals based on the acoustic enhancement property. For example, a two-dimensional phononic crystal structure with point defects and line defects has a good acoustic wave localization effect, and the enhancement of acoustic signals is achieved at the defect where the sound field is enhanced. The anisotropic gradient metamaterial structure has a wave compression effect, and the enhancement of acoustic signals is achieved between the partitions where the sound pressure increases. The coiled unit cell structure similar to an ultraslow fluid has Mie resonance, and the enhancement of acoustic signals is achieved at the center of the structure where the acoustic energy is concentrated. The single-cavity sensing structure has a quasi-bound state in the continuum, and the enhancement of acoustic signals is achieved at the top of the resonance cavity where the sound pressure is the largest. However, the research on the enhancement of acoustic signals based on a one-dimensional single-port phononic crystal structure has not been reported yet. Summary of the Invention
[0004] The objective of the present invention is: aiming at the deficiencies existing in the above background art, to provide a one-dimensional single-port phononic crystal structure based on local states, capable of achieving sound pressure enhancement and applicable to the enhancement of acoustic signals.
[0005] To achieve the above object, the present invention provides a one-dimensional single-port phononic crystal structure for enhancing acoustic signals, including a waveguide, a first plate, and a second plate. The first end of the waveguide is open, and the second end is closed. The waveguide is integrally arranged in a slender strip shape, and the length of the waveguide can be changed according to requirements. The end face and cross-section of the waveguide are square or rectangular.
[0006] Both the first plate and the second plate are made of acoustically rigid materials. The first plate and the second plate are arranged at intervals periodically near the second end of the waveguide to form a one-dimensional phononic crystal. The lengths of the first plate and the second plate are both less than the side length of the cross-section of the waveguide. The distance between the first plate and the second plate is set as d, and the distance between the second plate closest to the second end of the waveguide and the second end of the waveguide is set as d / 2. There is a band gap in the energy band structure of the formed one-dimensional phononic crystal, so that a localized state with energy concentration appears between the second end of the waveguide and the one-dimensional phononic crystal.
[0007] Further, the length of the waveguide is set as l = 400 mm, the end face and cross-sectional shape of the waveguide are square, and the side length is set as s = 60 mm.
[0008] Further, the thicknesses of both the first plate and the second plate are set as w = 10 mm, and the lengths are respectively set as l 1 = 30 mm and l 2 = 50 mm.
[0009] Further, the distance between the first plate and the second plate is set as d = 27 mm, and the distance between the second plate closest to the second end of the waveguide and the second end of the waveguide is set as d / 2 = 13.5 mm.
[0010] Further, the one-dimensional single-port phononic crystal structure has a resonance peak at 1380 Hz, so as to achieve a large sound pressure gain in the range near 1380 Hz.
[0011] Further, the one-dimensional single-port phononic crystal structure can enhance the acoustic signal in the range near the preset frequency, and the harmonic noise signal, periodic pulse noise signal, and modulated noise signal can be enhanced through the one-dimensional single-port phononic crystal structure.
[0012] Further, a single first plate and a single second plate form a unit cell of the one-dimensional phononic crystal.
[0013] Further, the number of unit cells of the one-dimensional phononic crystal is set as 3.
[0014] The above scheme of the present invention has the following beneficial effects:
[0015] The one-dimensional single-port phononic crystal structure for enhancing acoustic signals provided by the present invention can create a band gap in the energy band structure of the formed one-dimensional phononic crystal through the corresponding arrangement of the first plate and the second plate in the waveguide. As a result, a localized state with concentrated energy appears between the second end of the waveguide and the one-dimensional phononic crystal. Based on this localized state, the one-dimensional single-port phononic crystal structure can enhance acoustic signals in a range near a specific frequency. At the same time, harmonic noise signals, periodic pulse noise signals, and modulated noise signals can be enhanced by the one-dimensional single-port phononic crystal structure, enabling the detection of weak acoustic signals in strong noise. This structure is relatively simple and has a low manufacturing cost, showing good prospects for engineering applications;
[0016] Other beneficial effects of the present invention will be described in detail in the subsequent specific implementation section. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Figure 1 is a schematic diagram of the overall structure of the present invention;
[0018] Figure 2 (a) is a diagram of the unit cell structure and size parameters of the one-dimensional phononic crystal of the present invention, Figure 2 (b) is the energy band diagram of the one-dimensional phononic crystal of the present invention;
[0019] Figure 3 (a) is a schematic plan view of the one-dimensional single-port phononic crystal structure of the present invention, Figure 3 (b) is the distribution diagram of the pressure field of the localized state;
[0020] Figure 4 (a) is a schematic diagram of the simulation calculation of the sound pressure gain spectrum of the present invention, and the dot indicates the signal receiving position, Figure 4 (b) is the sound pressure gain spectrum diagram;
[0021] Figure 5 (a) and (b) are respectively the time-domain diagram and frequency-spectrum diagram of the harmonic signal, and the upper figure is the incident signal, and the lower figure is the signal enhanced by the one-dimensional single-port phononic crystal structure;
[0022] Figure 6 (a) and (b) are respectively the time-domain diagram and frequency-spectrum diagram of the harmonic noise signal, and the upper figure is the incident signal, and the lower figure is the signal enhanced by the one-dimensional single-port phononic crystal structure;
[0023] Figure 7 (a), (b), and (c) are respectively the time-domain diagram, frequency-spectrum diagram, and envelope spectrum diagram of the periodic pulse signal, and the upper figure is the incident signal, and the lower figure is the signal enhanced by the one-dimensional single-port phononic crystal structure;
[0024] Figure 8(a), (b), and (c) are respectively the time-domain diagram, frequency-spectrum diagram, and envelope-spectrum diagram of the periodic pulse noise signal. The upper figure is the incident signal, and the lower figure is the signal enhanced by the one-dimensional single-port phononic crystal structure;
[0025] Figure 9 (a), (b), and (c) are respectively the time-domain diagram, frequency-spectrum diagram, and envelope-spectrum diagram of the modulation signal. The upper figure is the incident signal, and the lower figure is the signal enhanced by the one-dimensional single-port phononic crystal structure;
[0026] Figure 10 (a), (b), and (c) are respectively the time-domain diagram, frequency-spectrum diagram, and envelope-spectrum diagram of the modulation noise signal. The upper figure is the incident signal, and the lower figure is the signal enhanced by the one-dimensional single-port phononic crystal structure. Specific implementation manners
[0027] The following uses specific specific examples to illustrate the implementation manners of the present disclosure. Those skilled in the art can easily understand other advantages and effects of the present disclosure from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, rather than all the embodiments. The present disclosure can also be implemented or applied through other different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present disclosure. It should be noted that, without conflict, the following embodiments and the features in the embodiments can be combined with each other. Based on the embodiments in the present disclosure, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present disclosure.
[0028] It should be noted that the following describes various aspects of the embodiments within the scope of the appended claims. It should be obvious that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is illustrative only. Based on the present disclosure, those skilled in the art should understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects described herein can be used to implement the device and / or practice the method. In addition, this device and / or this method can be implemented using other structures and / or functions in addition to one or more of the aspects described herein.
[0029] It should also be noted that the illustrations provided in the following embodiments only schematically illustrate the basic concept of the present disclosure. The illustrations only show the components related to the present disclosure, rather than being drawn according to the number, shape, and size of the components in actual implementation. The type, quantity, and proportion of each component in actual implementation can be arbitrarily changed, and the component layout type may also be more complex. Additionally, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, those skilled in the art will understand that the described aspects can be practiced without these specific details.
[0030] As Figure 1 shown, an embodiment of the present invention provides a one-dimensional single-port phononic crystal structure for enhancing acoustic signals, including a waveguide and two types of plates, a first plate and a second plate. Among them, the second end (right end) of the waveguide is closed, while the first end (left end) is open. The waveguide is overall slender and strip-shaped, and the length of the waveguide can be changed according to requirements. In a specific implementation manner of this embodiment, the length of the waveguide is set to l = 400 mm. The end face and cross-sectional shape of the waveguide are set to be square or rectangular, and when it is square, the side length is set to s = 60 mm. In this embodiment, both the first plate and the second plate are made of acoustic rigid materials. Acoustic rigid materials refer to materials that exhibit high reflection and low transmission characteristics under the action of sound waves. The first plate and the second plate are arranged periodically at intervals near the second end of the waveguide to form a one-dimensional phononic crystal. In a specific implementation manner of this embodiment, the thicknesses of both the first plate and the second plate are set to w = 10 mm, and the lengths are respectively set to l 1 = 30 mm and l 2 = 50 mm, both of which are less than the side lengths of the end face and cross-section of the waveguide. The distance between the first plate and the second plate is set to d = 27 mm. Additionally, the distance between the second plate closest to the second end of the waveguide in the one-dimensional phononic crystal and the second end of the waveguide is set to d / 2 = 13.5 mm.
[0031] Therefore, with such a size setting of the first plate and the second plate, a bandgap can exist in the energy band structure of the formed one-dimensional phononic crystal. As a result, a localized state with energy concentration appears between the second end of the waveguide and the one-dimensional phononic crystal. Based on the localized state, the one-dimensional single-port phononic crystal structure can achieve the enhancement of acoustic signals in a range near a specific frequency. At the same time, harmonic noise signals, periodic pulse noise signals, and modulated noise signals can achieve the detection of weak acoustic signals in strong noise through the enhancement of acoustic signals by the one-dimensional single-port phononic crystal structure.
[0032] In this embodiment, the effect is verified through simulation means. In the simulation software COMSOL, a single-cell air domain of a one-dimensional phononic crystal composed of a first plate and a second plate is modeled, and its lattice constant (i.e., the single-cell length) is set to a = 74 mm, and other parameters are w = 10 mm, l 1 = 30 m, l2 = 50 mm, d = 27 mm, as Figure 2 (a) shown. Considering the thermo-viscous loss of sound waves, a thermo-viscous acoustic module is adopted. The upper and lower boundaries of the single-cell air domain are wall boundary conditions, and the left and right boundaries are periodic boundary conditions. By analyzing the characteristic frequencies, the band structure of the single cell in the interval of wave vector k in [-π / a, π / a] is calculated, and it can be seen that there is a band gap [1217.7 Hz, 1957.2 Hz], as Figure 2 (b) shown.
[0033] The single cells are arranged periodically along the waveguide length direction to obtain a one-dimensional phononic crystal. The one-dimensional phononic crystal in this simulation case is composed of three single cells, as Figure 3 (a) shown. The one-dimensional phononic crystal is set at a position close to the second end of the waveguide to obtain a one-dimensional single-port phononic crystal structure. The distance between the second plate closest to the second end of the waveguide and the second end of the waveguide is d / 2 = 13.5 mm. Calculate the characteristic modes of the one-dimensional single-port phononic crystal structure. The pressure acoustic module is used for the empty waveguide part in the waveguide, and the thermo-viscous acoustic module is used for the phononic crystal part. The first end of the waveguide is a plane wave radiation boundary, and the other boundaries are hard sound field boundaries or wall boundaries.
[0034] Perform a frequency response analysis on the one-dimensional single-port phononic crystal structure. The pressure field of the local state shows that the sound energy accumulates near the second end of the waveguide, as Figure 3 (b) shown. Therefore, the sound wave is input from the first end of the waveguide and received near the second end of the waveguide. The incident sound pressure is p i , and the received sound pressure is p, and the sound pressure gain is p / p i , as Figure 4 (a) shown. The sound pressure gain spectrum shows that due to the local state, the one-dimensional single-port phononic crystal structure has a resonance peak at 1380 Hz, and a relatively large sound pressure gain can be achieved in the range near 1380 Hz, as Figure 4 (b) shown. It should be noted that the characteristic frequency of the local state is within the band gap range of the one-dimensional phononic crystal. Adjusting the value of the distance d / 2 between the second plate closest to the second end of the waveguide and the second end of the waveguide will change the characteristic frequency of the local state, but it needs to be within a certain range to keep the characteristic frequency of the local state within the band gap range, otherwise the local state will not have the effect of energy accumulation.
[0035] At the same time, as Figure 5 、 Figure 6As shown in the figure, a transient analysis is performed on the one-dimensional single-port phononic crystal structure. In the simulation, the incident signal is set as the harmonic signal S(t) = cos(2π×1380×t), and the signal is received near the second end of the waveguide. The simulation results show that after passing through the one-dimensional single-port phononic crystal structure, the amplitude of the harmonic signal is enhanced. Then, noise is added to the incident signal, and the signal-to-noise ratio is set to -35 dB. The simulation results indicate that the one-dimensional single-port phononic crystal structure enhances the harmonic signal in the noise, making the harmonic signal easy to identify.
[0036] At the same time, as Figure 7 , Figure 8 shown, the incident signal is set as the periodic pulse signal S(t) = e 0 ×cos(2π×1380×t) with a periodic frequency f -100t = 10 Hz, and the signal is received near the second end of the waveguide. The simulation results show that the one-dimensional single-port phononic crystal structure enhances the frequency component of the periodic pulse signal near 1380 Hz, making the characteristic frequency component in the envelope spectrum also enhanced. Then, noise is added to the incident signal, and the signal-to-noise ratio is set to -25 dB. The simulation results indicate that through the one-dimensional single-port phononic crystal structure, the characteristic signal in the envelope spectrum of the periodic pulse noise signal becomes obvious.
[0037] At the same time, as Figure 9 , Figure 10 shown, the incident signal is set as the modulation signal S(t) = [1 + 0.5×cos(2π×f 1 = 10 Hz)×cos(2π×1380×t + 1.2×cos(2π×f 1 ×t)]×cos[2π×1380×t + 1.2×cos(2π×f 1 ×t)], and the signal is received near the right end of the waveguide. The simulation results indicate that the one-dimensional single-port phononic crystal structure enhances the frequency component of the modulation signal near 1380 Hz, and further enhances the characteristic signal frequency component in the envelope spectrum. Then, noise is added to the incident signal, and the signal-to-noise ratio is set to -20 dB. The simulation results indicate that the one-dimensional single-port phononic crystal structure makes the characteristic signal in the envelope spectrum of the modulation noise signal easier to identify. Therefore, the one-dimensional single-port phononic crystal structure with localized states can be used for the enhanced detection of weak acoustic signals.
[0038] Therefore, the one-dimensional single-port phononic crystal structure provided in this embodiment successfully enhances the harmonic signal, periodic pulse signal, and modulation signal under strong noise based on localized states, making the signal characteristics more obvious and easy to identify, and realizing the detection of weak acoustic signals in strong noise.
[0039] It should be noted that in practical applications, due to the acoustic impedance mismatch between the waveguide and the outside world, a structure should be designed at the first port of the waveguide to match the impedance between the outside world and the waveguide, such as a horn structure.
[0040] The technical features of the above embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.
[0041] The above embodiments only express several implementation manners of the present application, and the description is relatively specific and detailed. However, it should not be construed as a limitation on the scope of the application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.
Claims
1. A one-dimensional single-port phononic crystal structure for enhancing acoustic signals, characterized in that: It comprises a waveguide and a first plate and a second plate. The first end of the waveguide is open and the second end is closed. The waveguide is in the shape of an elongated strip as a whole. The length of the waveguide is changed according to the demand. The end face and the cross section of the waveguide are in the shape of a square or a rectangle. The first plate and the second plate are both made of acoustic rigid materials. The first plate and the second plate are periodically arranged near the second end of the waveguide to form a one-dimensional phononic crystal. The lengths of the first plate and the second plate are both smaller than the side length of the cross section of the waveguide. The distance between the first plate and the second plate is set to d, and the distance between the second plate closest to the second end of the waveguide and the second end of the waveguide is set to d / 2. A band gap exists in the energy band structure of the formed one-dimensional phononic crystal, so that a localized state with concentrated energy appears between the second end of the waveguide and the one-dimensional phononic crystal.
2. The one-dimensional single-port phononic crystal structure for enhancing acoustic signals according to claim 1, characterized in that: The length of the waveguide is set to l=400 mm, the end face and cross-sectional shape of the waveguide are set to be square, and the side length is set to s=60 mm.
3. The one-dimensional single-port phononic crystal structure for enhancing acoustic signals according to claim 2, characterized in that: The thickness of the first plate and the second plate are both set to w=10 mm, and the lengths are set to l1=30 mm and l2=50 mm respectively.
4. The one-dimensional single-port phononic crystal structure for enhancing acoustic signals according to claim 3, characterized in that: The distance between the first plate and the second plate is set to d=27 mm, and the distance between the second plate closest to the second end of the waveguide and the second end of the waveguide is set to d / 2=13.5 mm.
5. The one-dimensional single-port phononic crystal structure for enhancing acoustic signals according to claim 4, characterized in that: The one-dimensional single-port phononic crystal structure has a resonance peak at 1380 Hz, thereby achieving a large sound pressure gain in the range near 1380 Hz.
6. The one-dimensional single-port phononic crystal structure for enhancing acoustic signals according to any one of claims 1 to 4, characterized in that: The one-dimensional single-port phononic crystal structure can enhance the acoustic signal in the vicinity of a preset frequency, and harmonic noise signals, periodic pulse noise signals and modulated noise signals can be enhanced through the one-dimensional single-port phononic crystal structure.
7. A one-dimensional single-port phononic crystal structure for enhancing acoustic signals according to any one of claims 1 to 4, characterized in that: A single first plate and a single second plate constitute a unit cell of the one-dimensional phononic crystal.
8. The one-dimensional single-port phononic crystal structure for enhancing acoustic signals according to claim 7, characterized in that: The number of unit cells of the one-dimensional phononic crystal is set to 3.
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