A spatial double-layer coil acoustic metamaterial structure for enhanced acoustic sensing

Abstract

The present invention provides a spatial double-layer coil acoustic metamaterial structure for enhanced acoustic sensing, relating to the technical field of acoustic sensing enhancement devices, comprising: a base plate, and inner and outer Mie resonators vertically arranged on the base plate. When sound waves are transmitted from the outside to the inside, they pass through a first channel and a second channel in sequence. The first and second channels are arranged in a serpentine manner, which prolongs the propagation distance and propagation time of the sound waves and increases the refractive index of the sound waves, thereby concentrating and amplifying sound waves within a specific frequency range, thereby better extracting weak signals from the sound waves. Compared with existing gradient acoustic metamaterials, the Mie resonator has a smaller overall structural size. After proportionally scaling the entire structure, the enhanced frequency can be shifted left and right. The frequency enhancement range can be achieved from 470Hz to 1764Hz, while substantially maintaining the magnitude of the enhanced sound pressure amplitude, and the enhancement multiple remains at approximately 24 times.

Description

Technical Field

[0001] The present invention relates to the technical field of acoustic sensing enhancement devices, and in particular to a spatial double-layer coil acoustic metamaterial structure for enhancing acoustic sensing. Background Art

[0002] Acoustic signal detection is widely used in structural health monitoring, fault diagnosis, underwater acoustic communication, sound source localization, and other fields. However, the useful signal in the acoustic signal is relatively weak and easily drowned out by background noise signals. Therefore, acoustic enhancement sensors are needed to assist in extracting the useful signal.

[0003] Gradient acoustic metamaterials can be considered acoustically enhanced sensors and applied to weak signal detection. For example, gradient-wound metamaterials are used to enhance broadband acoustic sensing and effectively identify and recover harmonic signals, extracting useful information from strong background noise. A trapezoidal structure with a gradient refractive index effectively enhances the pressure field through the compression effect of acoustic waves. Due to the improved signal-to-noise ratio, harmonics and periodic pulse signals can be effectively recovered from background noise. Using a trapezoidal structure with a gradient refractive index, the pressure field is effectively enhanced through the compression effect of acoustic waves. Due to the improved signal-to-noise ratio, harmonics and periodic pulse signals can be effectively recovered from background noise. Subsequently, researchers have applied these metamaterials' frequency-selective enhancement to fault diagnosis. Using a trumpet-shaped acoustic metamaterial, they have demonstrated the potential of metamaterials for enhancing micro-fault signals in acoustic sensors. A new method for bearing fault diagnosis using gradient acoustic metamaterials has been developed. However, acoustic signal detection devices based on gradient acoustic metamaterials are bulky and not portable.

[0004] Mie resonators, another type of acoustic metamaterial, can also be used to enhance acoustic sensing and detect weak signals. However, when the signal-to-noise ratio is low, Mie resonators cannot effectively detect fault signatures and have therefore not yet been applied in the field of fault diagnosis.

[0005] In view of this, how to design a sensing device that can still extract useful signals after being miniaturized and can effectively detect fault characteristics when the signal-to-noise ratio is low is an urgent problem that needs to be solved by technical personnel in this field. Summary of the Invention

[0006] The purpose of the present invention is to provide a spatial double-layer coil acoustic metamaterial structure for enhancing acoustic sensing, so as to solve the problems existing in the prior art.

[0007] To achieve the above-mentioned objectives, the present invention provides a spatial double-layer coil acoustic metamaterial structure for enhanced acoustic sensing, comprising: a base plate and an inner Mie resonator and an outer Mie resonator vertically arranged on the base plate, wherein the inner Mie resonator and the outer Mie resonator are both annular, and the inner Mie resonator is located on the inner side of the outer Mie resonator.

[0008] Furthermore, the outer Mie resonator defines a first channel, and the inner Mie resonator defines a second channel. The first channel connects the inner and outer areas of the outer Mie resonator, and the second channel connects the inner and outer areas of the inner Mie resonator. Both the first channel and the second channel are arranged in a winding manner.

[0009] Furthermore, the distance between the outer Mie resonator and the inner Mie resonator is d=10 mm.

[0010] Furthermore, the width of the first channel is twice that of the second channel.

[0011] Furthermore, the width of the first channel is w2 = 3 mm, and the width of the second channel is w1 = 1.5 mm.

[0012] Furthermore, the thickness of the bottom plate is h1=10 mm.

[0013] Furthermore, the inner Mie resonator and the outer Mie resonator are both composed of a plurality of partitions arranged at intervals. In the outer Mie resonator, adjacent partitions are arranged at intervals to form a first channel. In the inner Mie resonator, adjacent partitions are arranged at intervals to form a second channel.

[0014] Furthermore, the height of the partition is h2 = 60 mm, and the thickness is t = 1 mm.

[0015] Furthermore, the bottom plate, inner Mie resonator and outer Mie resonator are integrally formed by 3D printing of photosensitive resin, and its density is ρ=1130kg / m 3 , elastic modulus E = 2.65 × 10 3 MPa, shear modulus G = 2.22 × 10 3 MPa.

[0016] The present invention discloses the following technical effects:

[0017] 1. The acoustic metamaterial structure is composed of two Mie resonators arranged inside and outside. When the sound wave enters from the outside to the inside, it passes through the first channel and the second channel in sequence. The first and second channels are arranged in a winding manner, which extends the propagation distance and time of the sound wave and increases the refractive index of the sound wave. The sound waves within a specific frequency range are concentrated and amplified, thereby better extracting weak signals from the sound waves. Compared with existing gradient acoustic metamaterials, the overall structure of Mie is smaller in size. After proportionally scaling the entire structure, the enhanced frequency can be shifted left and right. The frequency enhancement range can be achieved from 470Hz to 1764Hz, and the magnitude of the enhanced sound pressure amplitude is basically unchanged. The enhancement factor is maintained at around 24 times.

[0018] 2. When the signal-to-noise ratio is low, if the frequency of the useful signal happens to be within the frequency band enhancement range of the acoustic metamaterial, the amplitude of the useful signal can be multiplied, thereby facilitating detection. The amplitude of the useful signal detected using the structure of the present application is approximately 14 times higher than the amplitude in free space. In other words, the present application can effectively detect fault characteristics, making the device applicable in the field of fault diagnosis. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 This is a schematic diagram of the structure of the present invention, wherein: 1. bottom plate; 2. inner Mie resonator; 3. outer Mie resonator;

[0021] Figure 2 A top view of the present invention;

[0022] Figure 3 The pressure frequency response diagram of the spatial double-layer coil acoustic metamaterial structure when the scale factors are 0.6, 0.8, and 1.0;

[0023] Figure 4 The pressure distribution diagram of the acoustic field when the incident sound wave frequency is 705 Hz and the scale factor of the corresponding spatial double-layer coil acoustic metamaterial structure is 1.0;

[0024] Figure 5 The maximum sound pressure amplitude of the Gaussian pulse signal at different scale factors in the simulation. The scale factor 0.6 uses a line with a circle, the scale factor 0.8 uses a line with an asterisk, and the scale factor 1 uses a line with a cross.

[0025] Figure 6is the amplitude of the target signal in the signal spectrum under different signal-to-noise ratios when the scale factor is 1. DETAILED DESCRIPTION

[0026] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0027] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] like Figure 1 and Figure 2 As shown, an embodiment of the present invention provides a spatial double-layer coil acoustic metamaterial structure for enhanced acoustic sensing, comprising: a base plate 1, and an inner Mie resonator 2 and an outer Mie resonator 3 vertically disposed on the base plate 1. The inner Mie resonator 2 and the outer Mie resonator 3 are both annular in shape, and the inner Mie resonator 2 is concentrically disposed inside the outer Mie resonator 3. The base plate 1 is circular and matches the shape of the outer Mie resonator 3.

[0029] In this embodiment, both the inner Mie resonator 2 and the outer Mie resonator 3 are composed of multiple spaced-apart baffles. In the outer Mie resonator 3, adjacent spaced-apart baffles form a first channel, while in the inner Mie resonator 2, adjacent spaced-apart baffles form a second channel. The first channel connects the inner and outer regions of the outer Mie resonator 3, while the second channel connects the inner and outer regions of the inner Mie resonator 2. Both the first and second channels are arranged in a serpentine pattern. In both the inner Mie resonator 2 and the outer Mie resonator 3, eight groups of baffles are provided, corresponding to eight circumferentially arranged first and second channels. The channel openings of each channel are evenly spaced and distributed circumferentially.

[0030] In this embodiment, the width of the first channel is twice that of the second channel. The width of the first channel is w2 = 3 mm, the width of the second channel is w1 = 1.5 mm, and the thickness of the bottom plate 1 is h1 = 10 mm. The height of the partition is h2 = 60 mm, the thickness is t = 1 mm, and the distance between the outer and inner Mie resonators is d = 10 mm.

[0031] In this embodiment, the bottom plate 1, the inner Mie resonator 2 and the outer Mie resonator 3 are integrally formed by 3D printing of photosensitive resin, and its density is ρ = 1130 kg / m 3 , elastic modulus E = 2.65 × 103 MPa, shear modulus G = 2.22 × 10 3 MPa.

[0032] Figure 3 This is a pressure-frequency response graph, derived from experimental data generated in the pressure acoustics domain. The graph shows the frequency responses for scale factors of 0.6, 0.8, and 1. The pressure ratio is the ratio of the sound pressure amplitude when a sound wave propagates through the metamaterial structure to the sound pressure amplitude when the wave propagates in air without the metamaterial. When the size of the metamaterial and the distance from the incident wave to the center of the metamaterial are proportionally varied, the resonant frequency can shift left and right, with the peak amplitude ratio reaching approximately 24 times.

[0033]

[0034] Table 1

[0035] As shown in Table 1, the frequency enhancement range can be achieved from 470 Hz to 1764 Hz, and the enhancement multiple is maintained at around 24 times, corresponding to a scaling factor of 0.4-1.5.

[0036] Figure 4 This is the acoustic field pressure distribution diagram, also generated from experimental data in the pressure acoustics domain. It can be seen that the pressure value at the inner Mie resonator 2 is higher than that at the outer Mie resonator 3. This is because when sound waves enter the spatial dual-coil acoustic metamaterial structure, they pass through the first and second channels in sequence. The winding arrangement of the first and second channels extends the propagation distance and time of the sound waves, increases the refractive index of the sound waves, and concentrates and amplifies sound waves within a specific frequency range, thereby better extracting weak signals from the sound waves.

[0037] Figure 5 is the maximum sound pressure amplitude of the Gaussian pulse signal under different simulated scale factors. It can be seen that when the center frequency of the Gaussian pulse signal is set to 705Hz, the sound pressure amplitude is maximum when the scale factor is 1. Similarly, when the center frequency is set to 882Hz and 1176Hz, the maximum sound pressure amplitude is observed at scale factors of 0.8 and 0.6, respectively.

[0038] Figure 6is the amplitude of the target signal in the signal spectrum at different signal-to-noise ratios when the scale factor is 1. The results show that when the signal-to-noise ratio is -5dB, the sound pressure amplitude at the center frequency of the spatial dual-coil structure signal is 0.63Pa, which is 15.7 times higher than the 0.04Pa sound pressure amplitude in free space. Similarly, when the signal-to-noise ratio is -25, -20, -15, and -10dB, the sound pressure amplitude at the center frequency of the spatial dual-coil structure signal is more than 14 times higher than that in free space. This proves that when the signal-to-noise ratio is low, the spatial dual-coil structure can be used to detect weak signals in a strong noise background and can effectively detect fault characteristics, making the device applicable to the field of fault diagnosis.

[0039] In the description of the present invention, it should be understood that the terms "longitudinal", "transverse", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0040] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A spatial double-layer coil acoustic metamaterial structure for enhanced acoustic sensing, characterized in that: include: A bottom plate (1) and an inner Mie resonator (2) and an outer Mie resonator (3) vertically arranged on the bottom plate (1), wherein the inner Mie resonator (2) and the outer Mie resonator (3) are both annular, and the inner Mie resonator (2) is located on the inner side of the outer Mie resonator (3); The outer Mie resonator (3) defines a first channel, and the inner Mie resonator (2) defines a second channel, the first channel connects the inner and outer areas of the outer Mie resonator (3), and the second channel connects the inner and outer areas of the inner Mie resonator (2), the first channel and the second channel are both arranged in a serpentine manner, and the width of the first channel is twice that of the second channel; The inner Mie resonator (2) and the outer Mie resonator (3) are both composed of a plurality of partitions arranged at intervals. In the outer Mie resonator (3), adjacent partitions are arranged at intervals to form a first channel. In the inner Mie resonator (2), adjacent partitions are arranged at intervals to form a second channel.

2. The spatial double-layer coil acoustic metamaterial structure for enhancing acoustic sensing according to claim 1, characterized in that: The width of the first channel is 3 mm, and the width of the second channel is 1.5 mm.

3. The spatial double-layer coil acoustic metamaterial structure for enhancing acoustic sensing according to claim 2, characterized in that: The thickness of the bottom plate (1) is 10 mm.

4. The spatial double-layer coil acoustic metamaterial structure for enhanced acoustic sensing according to claim 1, characterized in that: The partition has a height of 60 mm and a thickness of 1 mm.

5. The spatial double-layer coil acoustic metamaterial structure for enhancing acoustic sensing according to claim 4, characterized in that: The bottom plate (1), the inner Mie resonator (2) and the outer Mie resonator (3) are integrally formed by 3D printing using photosensitive resin, and the density is , elastic modulus , shear modulus .

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