Space double-layer coil acoustic metamaterial structure for enhancing acoustic sensing

Abstract

The invention provides a spatial double-layer coil acoustic metamaterial structure for enhancing acoustic sensing, which relates to the technical field of acoustic sensing enhancing devices and comprises a bottom plate, an inner-layer Mie resonator and an outer-layer Mie resonator, and the inner-layer Mie resonator and the outer-layer Mie resonator are vertically arranged on the bottom plate. When sound waves are transmitted from outside to inside, the sound waves pass through the first channel and the second channel in sequence, the first channel and the second channel are arranged in a winding mode, the propagation distance and the propagation time of the sound waves are prolonged, the refractive index of the sound waves is improved, the sound waves in a specific frequency range are concentrated and amplified, and therefore weak signals in the sound waves are better extracted; compared with an existing gradient acoustic metamaterial, the Mie resonator is small in overall structure size, left-right translation of enhanced frequency can be achieved after the overall structure is scaled at equal proportion, the frequency enhancement range can be from 470 Hz to 1764 Hz, the amplitude of enhanced sound pressure is basically not changed, and the enhancement multiple is kept at about 24 times.

Description

Technical Field

[0001] The 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 detection, fault diagnosis, underwater acoustic communication, sound source localization, etc. However, the useful signal in the acoustic signal is relatively weak and easily submerged by the background noise signal, so it is necessary to use acoustic enhancement sensors to assist in extracting useful signals.

[0003] Gradient acoustic metamaterials can be regarded as acoustically enhanced sensors and applied to weak signal detection. For example, gradient winding metamaterials are used to enhance broadband acoustic sensing, and harmonic signals are effectively identified and recovered to obtain useful information from strong background noise; the pressure field is effectively enhanced by the compression effect of sound waves using a trapezoidal structure with a gradient refractive index. Due to the improvement of the signal-to-noise ratio, harmonic 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 by the compression effect of sound waves. Due to the improvement of the signal-to-noise ratio, harmonic and periodic pulse signals can be effectively recovered from background noise. After that, the researchers applied the frequency selective enhancement of these metamaterials to the field of fault diagnosis. The use of trumpet-shaped acoustic metamaterials demonstrated the potential of metamaterials in enhancing micro-fault signals in acoustic sensors. A new method for bearing fault diagnosis using gradient acoustic metamaterials. However, the acoustic signal detection equipment based on gradient acoustic metamaterials is large and not easy to carry.

[0004] Mie resonators are another type of acoustic metamaterial that 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, so they have not yet been used in the field of fault diagnosis.

[0005] In view of this, how to design a sensor device that can still extract useful signals after miniaturization and can effectively detect fault characteristics when the signal-to-noise ratio is low is an urgent problem that technical personnel in this field need to solve. 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 in shape, 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, the second channel connects the inner and outer areas of the inner Mie resonator, and 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, and 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, the inner Mie resonator and the outer Mie resonator are integrally formed by 3D printing with a photosensitive resin, and the density ρ is 1130 kg / 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 is transmitted from the outside to the inside, it passes through the first channel and the second channel in sequence. The first channel and the second channel are arranged in a winding manner, which prolongs the propagation distance and propagation time of the sound wave and improves the refractive index of the sound wave, so that the sound wave in a specific frequency range can be concentrated and amplified, thereby better extracting weak signals in the sound wave; compared with the existing gradient acoustic metamaterial, the overall structure size of Mie is smaller. After the overall structure is proportionally scaled, the enhanced frequency can be shifted left and right. The frequency enhancement range can be achieved from 470Hz to 1764Hz, and the enhanced sound pressure amplitude is basically unchanged, and the enhancement multiple is maintained at about 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 by the structure of the present application is about 14 times higher than the amplitude in free space, that is, the present application can effectively detect fault characteristics, so that the device can be used 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 drawings required for use in the embodiments will be briefly introduced below. 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 creative work.

[0020] Figure 1 It 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 factor is 0.6, 0.8, and 1.0;

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

[0024] Figure 5 The maximum sound pressure amplitude of the Gaussian pulse signal under 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 be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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 creative work 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 enhancing acoustic sensing, comprising: a bottom plate 1, and an inner Mie resonator 2 and an outer Mie resonator 3 vertically arranged on the bottom plate 1, the inner Mie resonator 2 and the outer Mie resonator 3 are both annular, and the inner Mie resonator 2 is concentrically arranged on the inner side of the outer Mie resonator 3. The bottom plate 1 is circular and the bottom plate 1 and the outer Mie resonator 3 are adapted in shape.

[0029] In this embodiment, 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, and in the inner Mie resonator 2, adjacent partitions are arranged at intervals to form a second channel. The first channel connects the areas on both sides of the outer Mie resonator 3, and the second channel connects the areas on both sides of the inner Mie resonator 2. Both the first channel and the second channel are arranged in a winding manner. In the inner Mie resonator 2 and the outer Mie resonator 3, eight groups of partitions are provided, and eight corresponding first channels and second channels are provided along the circumferential direction, and the channel openings of each channel are evenly spaced and distributed along the circumferential direction.

[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 Mie resonator and the inner Mie resonator 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 using photosensitive resin, and its density ρ=1130kg / m 3 , elastic modulus E = 2.65 × 103 MPa, shear modulus G = 2.22 × 10 3 MPa.

[0032] Figure 3 It is a pressure frequency response diagram. The pressure frequency response diagram is the test data made in the pressure acoustics domain. The response diagram shows the frequency response when the scale factor is 0.6, 0.8 and 1. The pressure ratio refers to the ratio of the sound pressure amplitude when the sound wave propagates in the metamaterial structure to the sound pressure amplitude when the sound wave propagates in the air domain without the metamaterial. When the size of the metamaterial and the distance from the incident wave to the center of the metamaterial change proportionally, the resonant frequency can move left and right, and the amplitude ratio at the peak is about 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 about 24 times, and the corresponding scale factor is 0.4-1.5.

[0036] Figure 4 It is the sound field pressure distribution diagram, which is also the test data made in the pressure acoustics domain. It can be seen that the pressure value at the inner Mie resonator 2 is higher than the pressure value at the outer Mie resonator 3. The reason is that when the sound wave enters the spatial double-coil acoustic metamaterial structure, it passes through the first channel and the second channel in sequence. The first channel and the second channel are set in a winding manner, which prolongs the propagation distance and propagation time of the sound wave, increases the refractive index of the sound wave, and makes the sound wave in a specific frequency range to be concentrated and amplified, so as to better extract the weak signal in the sound wave.

[0037] Figure 5 is the maximum sound pressure amplitude of the Gaussian pulse signal under different simulation 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 the largest when the scale factor is 1. Similarly, when the center frequency is set to 882 and 1176Hz, the maximum sound pressure amplitude is observed when the scale factor is 0.8 and 0.6, respectively.

[0038] Figure 6It is 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 of 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 of 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, so that the device can be used in the field of fault diagnosis.

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

[0040] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined 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).

2. The spatial double-layer coil acoustic metamaterial structure for enhancing acoustic sensing according to claim 1, characterized in that: 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). Both the first channel and the second channel are arranged in a winding manner.

3. The spatial double-layer coil acoustic metamaterial structure for enhancing acoustic sensing according to claim 2, characterized in that: The first channel is twice as wide as the second channel.

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

5. The spatial double-layer coil acoustic metamaterial structure for enhancing acoustic sensing according to claim 4, characterized in that: The thickness of the bottom plate (1) is 10 mm.

6. The spatial double-layer coil acoustic metamaterial structure for enhancing acoustic sensing according to claim 5, characterized in that: 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.

7. The spatial double-layer coil acoustic metamaterial structure for enhancing acoustic sensing according to claim 6, characterized in that: The partition has a height of 60 mm and a thickness of 1 mm.

8. The spatial double-layer coil acoustic metamaterial structure for enhancing acoustic sensing according to claim 7, 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 ρ is 1130 kg / m 3 , elastic modulus E = 2.65 × 10 3 MPa, shear modulus G = 2.22 × 10 3 MPa.

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