Band-gap-adjustable acoustic metamaterial structure and vehicle

Abstract

An acoustic metamaterial structure with an adjustable band gap and a vehicle relate to the technical field of low-frequency noise control, the structure comprises a main body structure and vibrators, the main body structure is a multi-layer plate body structure, all layers of plate bodies are the same in overall shape and size, a gap is arranged between every two adjacent plate bodies, each vibrator is clamped in each gap, and the vibrators are arranged on the main body structure. The inner end of the vibrator is rotatably connected with the main body structure, the outer end of the vibrator is exposed out of the range of the main body structure, and the exposed length of the vibrator can be changed along with rotation; the vehicle comprises the acoustic metamaterial with the adjustable band gap. The structure is simple, the mass size is small, the application environment is wide, the change of the action frequency range of the acoustic metamaterial can be achieved, meanwhile, multiple sets of unit structures can be connected in series, broadband vibration control is achieved, the application scene of the acoustic metamaterial is widened, and effective control over low-frequency broadband vibration noise in a complex environment is achieved; the problems of small application range, non-adjustable working frequency or inconvenient adjustment in the prior art can be effectively solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of low-frequency noise control, and in particular to a band gap adjustable acoustic metamaterial structure and a vehicle. BACKGROUND

[0002] Low-frequency vibration noise has always been a difficulty in the field of vibration noise control due to its long wavelength, high energy, and limited treatment effect of traditional vibration and noise reduction methods (such as dynamic vibration absorbers and sound-absorbing materials). Traditional vibration noise control is usually achieved by applying sound insulation materials, constraint damping, and dynamic vibration absorbers. However, sound insulation materials and constraint damping measures have limited effect in the low-frequency band, and dynamic vibration absorbers have the problems of narrow control frequency band and large mass, which leads to certain limitations in their application in vehicle environments.

[0003] In recent years, the proposal of acoustic metamaterial structure has brought new ideas for low-frequency vibration noise control. However, traditional acoustic metamaterial structures have relatively fixed structures and relatively narrow band gaps, and cannot adapt to changing and wide excitation environments after being manufactured, making it difficult to solve the problems of variable frequency vibration control caused by changes in excitation frequency and wide frequency vibration caused by wide frequency excitation, and their use scenarios have always been limited.

[0004] CN111833837B belongs to the technical field of acoustic metamaterials and discloses an adjustable single-stage multi-band gap acoustic metamaterial structure and an adjustment method. The base structure is connected to the concentrated mass through a plurality of vibration-absorbing springs and vibration-absorbing dampers at different positions. The vibration-absorbing dampers are located on one side of the corresponding vibration-absorbing springs. The vibration-absorbing springs, vibration-absorbing dampers, and concentrated mass form a single-stage oscillator. A plurality of single-stage oscillators are periodically arranged on the base structure to form a single-stage adjustable multi-band gap acoustic metamaterial. The method for generating the number of band gaps and adjusting the position of the band gaps of the acoustic metamaterial includes: periodically adding the supermaterial structure to a classical beam, plate, or shell, and adjusting the number of band gaps and the position of the band gaps generated by the acoustic metamaterial by adjusting the stiffness of the vibration-absorbing springs, the damping coefficient of the vibration-absorbing dampers, and the installation position of the vibration-absorbing springs. However, this existing technology is mainly used in building engineering and cannot be applied to the automotive field.

[0005] CN117524180A provides an adjustable working frequency acoustic metamaterial basic unit and its array structure, which includes a film, a through hole, a support frame, and an oscillator. The through hole is provided on the film. One end of the support frame is mounted on the surface of a structure to be suppressed and the other end supports the film. The oscillator is closely attached to the film to form a mass-spring system. When the vibration substrate is excited by external excitation to produce vibration and acoustic radiation, the film and the oscillator produce local resonance at the corresponding frequency, open the local resonance band gap, and thus suppress vibration and acoustic radiation. However, the structure of this existing technology is relatively complex, and the adjustment of the working frequency is not convenient. SUMMARY

[0006] The application aims to provide a band gap adjustable acoustic metamaterial structure and a vehicle, which has simple structure, small mass and size, wide application environment, can change the action frequency range of the acoustic metamaterial, can be connected in series with multiple unit structures to realize wide-frequency vibration control, widens the application scene of the acoustic metamaterial, and realizes effective control of low-frequency wideband vibration and noise in a complex environment.

[0007] The application provides the following scheme

[0008] The application provides a band gap adjustable acoustic metamaterial structure, which comprises a main body structure and a vibrator, the main body structure is at least two stacked plate body structures, the overall shape and size of each plate body are the same, a gap is arranged between adjacent plate bodies, and a vibrator is clamped in each gap, the inner end of the vibrator is rotatably connected with the main body structure, and the outer end of the vibrator is exposed outside the range of the main body structure, and the length of the exposed vibrator and the outside of the main body structure can change with the shape of the outer contour of the main body structure.

[0009] Further, the main body structure comprises a top plate and a positioning plate, the overall shape and size of the top plate are the same as those of the positioning plate, the upper surfaces of the top plate and the positioning plate are arranged in parallel and opposite directions, and the outer contours are consistent, a gap is arranged between the top plate and the positioning plate, and the top plate and the positioning plate are connected through a fixing component arranged at the rotation center; a vibrator is clamped in the gap between the top plate and the positioning plate, and the inner end of the vibrator is rotatably sleeved on the fixing component; a plurality of semispherical pits are arranged on the upper surface of the positioning plate in a circumferential direction with the rotation center as the center and with the same radius length, a semispherical protrusion is arranged at the corresponding position of the middle part of the vibrator and matches the semispherical pit, the semispherical protrusion can be slid into the semispherical pit to fix the vibrator relative to the positioning plate; the semispherical protrusion of the vibrator is fixed in different semispherical pits, and the exposed lengths corresponding to different semispherical pits are different, and the exposed length is the length of the part of the vibrator exposed outside the outer contour of the main body structure.

[0010] The top plate and the positioning plate are similar in structure, and the difference lies in that the top plate is free of semispherical pits, and the top plate cooperates with the bottom plate to fix the position of the vibrator; the different semispherical pits on the positioning plate correspond to different lengths of the vibrator exposed outside the range of the main body structure, the exposed lengths are different, the vibration frequencies of the vibrators are different, therefore, by manually rotating the vibrator and fixing it with different semispherical pits, the length of the vibrator exposed outside the range of the main body structure can be controlled, and the adjustment of the band gap frequency is realized.

[0011] Further, the vibrator is in a word-shaped sheet structure, including a connecting part, a scale part and a mass part from the inner end to the outer end; the inner end of the connecting part is provided with a circular through hole, the vibrator is rotatably sleeved on the fixed part through the circular through hole, the other end of the connecting part is fixedly connected with the scale part, and the semispherical protrusion is arranged at the middle part of the connecting part or one end connected with the scale part; the scale part is located at the middle section of the vibrator, and the upper surface of the scale part is provided with scale lines and corresponding band gap frequency values along the length direction; the mass part is located at the outermost end, is fixedly connected with the scale part and has a width greater than that of the scale part.

[0012] According to the scale line reading of the position where the vibrator coincides with the bottom plate, the band gap information can be directly read and adjusted to the ideal band gap frequency position; the mass part is used for simulating the additional mass of the superstructure to realize the mass function of the vibrator.

[0013] Further, the band gap adjustable acoustic metamaterial structure comprises a top plate and at least one unit structure, and the top plate and the at least one unit structure are connected in series through a fixed part; each unit structure comprises a positioning plate and a vibrator matched with the positioning plate.

[0014] The series connection of a plurality of unit structures can realize wide-frequency vibration control, so as to solve the problems of variable-frequency vibration control caused by the change of excitation frequency and wide-frequency vibration caused by wide-frequency excitation existing in the prior art acoustic metamaterial structure technology.

[0015] Further, the main structure comprises a top plate and at least two identical positioning plates, the positioning plates are arranged in parallel and have consistent outer contours, and the top plate is arranged in parallel on the upper surface of the uppermost positioning plate; gaps are left between the top plate and the positioning plates and between adjacent positioning plates, the top plate and the positioning plates are connected in series through a fixed part arranged at the rotation center, and a vibrator is arranged in each gap.

[0016] The series connection of the positioning plates and the vibrators with the same structure can rotate each vibrator to different angles corresponding to different band gap frequencies, and ensures that the vibrators do not interfere with each other, so as to realize the wide-frequency vibration control effect.

[0017] Further, the fixed part is a cylindrical pin, and the top plate and the positioning plates are fixedly connected through the cylindrical pin.

[0018] The fixed connection mode makes the connection between the unit structures and the top plate more stable, and the rotation adjustment of the vibrator is also more convenient.

[0019] Further, the fixed part is a bolt and a nut matched with each other, and the top plate and the positioning plates are detachably connected through the bolt and the nut.

[0020] Compared with the cylindrical pin fixed connection, the bolt nut connection can increase and decrease the number of unit structures according to the requirement, and the manufacturing cost is saved.

[0021] Further, the outer contour of the positioning plate is in the shape of a nautilus shell as a whole.

[0022] The vibrator can rotate by 360 degrees, and the frequency value can be adjusted more and the continuity of adjustment is good.

[0023] Further, the positioning plate is in a semicircular structure as a whole, the rotation center is arranged near the straight edge of the positioning plate and deviates from the center position, and a plurality of semispherical pits (121) are arranged in a semicircular distribution around the rotation center on the positioning plate (12).

[0024] The vibrator is convenient to manufacture, the difference between the maximum and minimum exposed lengths of the vibrator is large, and therefore the adjustment range of the band gap frequency is large.

[0025] A vehicle comprises the band gap adjustable acoustic metamaterial structure, and the band gap adjustable acoustic metamaterial structure is mounted on a sheet metal of the vehicle.

[0026] Compared with the prior art, the present application has the following advantages:

[0027] The band gap adjustable acoustic metamaterial structure and the vehicle provided by the present application are suitable for a wide range of environments, can change the action frequency range of the acoustic metamaterial structure, can be connected in series with multiple unit structures to realize wideband vibration control, can widen the application scenarios of the acoustic metamaterial structure, and can effectively control low-frequency wideband vibration and noise in a complex environment; the structure is simple, the quality and size are small, and the present application is convenient to manufacture and maintain; and the present application can effectively solve the problems of the prior art, such as small application range, unadjustable or inconveniently adjustable working frequency. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings needed to be used in the specific embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without any creative effort.

[0029] FIG. 1 is a plan view of the band gap adjustable acoustic metamaterial structure according to the present application; Figure 1

[0030] FIG. 2 is an exploded view of the band gap adjustable acoustic metamaterial structure according to the present application; Figure 2

[0031] FIG. 3 is a schematic view of the band gap adjustable acoustic metamaterial structure according to the present application; and Figure 3 ​​Structure diagram of the positioning plate according to the embodiment 1 of the present application;

[0032] Figure Figure 4 Structure diagram of the vibrator according to the present application;

[0033] Figure Figure 5 Structure diagram of the multiple unit structures connected in series according to the present application;

[0034] Figure Figure 6 Structure diagram of the semicircular positioning plate according to the embodiment of the present application;

[0035] Figure Figure 7 Structure diagram of the semicircular positioning plate according to the embodiment of the present application;

[0036] Figure Figure 8 Structure diagram of the semicircular positioning plate according to the embodiment of the present application;

[0037] Figure Figure 9 Structure diagram of the semicircular positioning plate according to the embodiment of the present application.

[0038] Figure

[0039] 1, main structure; 11, top plate; 12, positioning plate; 121, semispherical pit; 13, fixed part; 2, vibrator; 21, connecting part; 211, circular through hole; 212, semispherical protrusion; 22, scale part; 23, mass part. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application will be described in further detail below with the accompanying drawings. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0041] The terms used in the embodiments of the present application are only for the purpose of describing the specific embodiments, and are not intended to limit the present application. The singular forms "a", "an" and "the" used in the embodiments of the present application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise. "Multiple" generally includes at least two.

[0042] It should be understood that the term "and / or" used herein is only to describe the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent the three cases of A alone, A and B together, and B alone. In addition, the character " / " herein generally represents an "or" relationship between the front and rear associated objects.

[0043] It should be understood that although the terms first, second, third, etc., may be used in the embodiments of this application, these descriptions should not be limited to these terms. These terms are only used to distinguish the descriptions. For example, first may also be referred to as second without departing from the scope of the embodiments of this application, and similarly, second may also be referred to as first.

[0044] Depending on the context, the words “if” or “suppose” as used here can be interpreted as “when” or “in response to determination” or “in response to detection.” Similarly, depending on the context, the phrases “if determination” or “if detection (of the stated condition or event)” can be interpreted as “when determination” or “in response to determination” or “when detection (of the stated condition or event)” or “in response to detection (of the stated condition or event).”

[0045] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or device. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or device that includes said element.

[0046] It should be noted that any symbols and / or numbers present in the specification that are not marked in the accompanying drawings are not reference numerals.

[0047] Example 1, please refer to Figure 1 As shown, this embodiment provides a bandgap adjustable acoustic metamaterial structure, including a main structure 1 and an oscillator 2. The main structure 1 is a multi-layer plate structure, and the overall shape and size of each plate are the same. A gap is provided between adjacent plates, and an oscillator 2 is sandwiched in each gap. The inner end of the oscillator 2 is rotatably connected to the main structure 1, and the outer end of the oscillator 2 is exposed outside the range of the main structure 1. The exposed length of the oscillator 2 can change with rotation.

[0048] Specifically, please refer to Figures 1 to 3As shown, in this embodiment, the main structure 1 includes a top plate 11 and a positioning plate 12. The outer contour of the positioning plate 12 is generally shaped like a nautilus shell. The top plate 11 is arranged parallel to the upper surface of the positioning plate 12. The overall shape and size of the top plate 11 are the same as those of the positioning plate 12. A gap is left between the top plate 11 and the positioning plate 12. The top plate 11 and the positioning plate 12 are fixedly connected by a cylindrical pin set at the center of the spiral. An oscillator 2 is sandwiched in the gap between the top plate 11 and the positioning plate 12. The inner end of the oscillator 2 The oscillator 2 is rotatably sleeved on the cylindrical pin, and its outer end is exposed outside the range of the positioning plate 12 and the top plate 11. The upper surface of the positioning plate 12 has a plurality of hemispherical recesses 121 arranged circumferentially around the cylindrical pin. The corresponding position in the middle of the oscillator 2 is provided with a hemispherical protrusion 212 that cooperates with the hemispherical recesses 121. The hemispherical protrusion 212 can slide into the hemispherical recesses 121 to fix the oscillator 2 relative to the positioning plate 12. A positioning plate 12 and the oscillator 2 that cooperates with it together constitute a unit structure.

[0049] Specifically, please refer to Figure 4 As shown, the oscillator 2 is a flat, one-line structure, which can be divided into three parts from the inner end to the outer end: a connecting part 21, a scale part 22, and a mass part 23. The connecting part 21 is located at the innermost part of the main structure 1. The inner end of the connecting part 21 has a circular through hole 211, which is rotatably fitted onto a cylindrical pin. The other end of the connecting part 21 is fixedly connected to the scale part 22. A hemispherical protrusion 212 is provided near the scale part 22. The scale part 22 is located in the middle section of the oscillator 2 and has scale lines and corresponding bandgap frequency values ​​distributed along the axial direction. The mass part 23 is located at the outermost end and its width is greater than that of the scale part 22. It is used to simulate additional mass and realize the mass function of the oscillator 2.

[0050] The working principle of this embodiment is as follows: the spiral center of the positioning plate 12, whose outer contour is shaped like a nautilus shell, is the rotation center. The distance between the spiral center and the edge of the main structure 1 is different at different points. Different hemispherical recesses 121 on the positioning plate 12 correspond to different lengths of the oscillator 2 extending out, and also correspond to different scale lines and bandgap frequency values ​​on the oscillator 2. The bandgap frequency is a specific frequency range in which the propagation of sound waves is completely suppressed in acoustic metamaterials. Its essence originates from the periodic structural design of metamaterials, forming an acoustic bandgap through local resonance or Bragg scattering effect. Since the top plate 11, the positioning plate 12, and the oscillator 2 are all relatively thin plate-shaped or sheet-shaped structures, they have a certain degree of elasticity. Under the action of external force, the hemispherical protrusions 212 can slide in and out of the hemispherical recesses 121. Therefore, by manually rotating the oscillator 2 and fixing it with different hemispherical recesses 121, the length of the oscillator 2 exposed outside the main body range can be controlled, thereby realizing the adjustment of the bandgap frequency.

[0051] Example 2, please refer to Figure 6As shown, this embodiment provides a bandgap adjustable acoustic metamaterial structure, which adopts different top plate 11 and positioning plate 12 structures based on embodiment 1.

[0052] Specifically, in this embodiment, the main structure 1 includes a top plate 11 and a positioning plate 12. The positioning plate 12 is generally semi-circular, and the top plate 11 is arranged parallel to the upper surface of the positioning plate 12. The overall shape and size of the top plate 11 are the same as those of the positioning plate 12. A gap is left between the top plate 11 and the positioning plate 12. The top plate 11 and the positioning plate 12 are fixedly connected by a cylindrical pin, which is located near the straight edge of the positioning plate 12, offset from the center. A vibrator 2 is sandwiched in the gap between the top plate 11 and the positioning plate 12. The inner end of the vibrator 2 is rotatably sleeved on the cylindrical pin, and the outer end of the vibrator 2 is exposed outside the range of the positioning plate 12 and the top plate 11. The upper surface of the positioning plate 12 has a plurality of hemispherical recesses 121 arranged in the semi-circular direction with the cylindrical pin as the center. The corresponding position in the middle of the vibrator 2 is provided with a hemispherical protrusion 212 that cooperates with the hemispherical recesses 121. The hemispherical protrusion 212 can slide into the hemispherical recesses 121 to fix the vibrator 2 relative to the positioning plate 12. A positioning plate 12 and the vibrator 2 that cooperates with it together constitute a unit structure.

[0053] Specifically, the oscillator 2 has a single-piece structure, which can be divided into three parts from the inner end to the outer end: a connecting part 21, a scale part 22, and a mass part 23. The connecting part 21 is located at the innermost part of the main structure 1. The inner end of the connecting part 21 has a circular through hole 211, which is rotatably sleeved on a cylindrical pin. The other end of the connecting part 21 is fixedly connected to the scale part 22. A hemispherical protrusion 212 is provided near the scale part 22. The scale part 22 is located in the middle section of the oscillator 2 and has scale lines and corresponding bandgap frequency values ​​distributed along the axial direction. The mass part 23 is located at the outermost end and its width is greater than that of the scale section. It is used to simulate additional mass and realize the mass function of the oscillator 2.

[0054] The working principle of this embodiment is as follows: since the position of the cylindrical pin is off-center, the distance between the cylindrical pin and the arc-shaped edge of the main body structure 1 is different at different points. Different hemispherical recesses 121 on the positioning plate 12 correspond to different lengths of the oscillator 2 extending out, and also correspond to different scale lines and bandgap frequency values ​​on the oscillator 2. Therefore, by manually rotating the oscillator 2 and fixing it with different hemispherical recesses 121, the length of the oscillator 2 exposed outside the main body range can be controlled, thereby realizing the adjustment of the bandgap frequency.

[0055] Please see Figures 7 to 9 As shown, in some embodiments, the top plate 11 and the positioning plate 12 can be in the shape of an arc, a circle, an ellipse, etc., and the rotation center of the vibrator 2 is set off from the geometric center so that the vibrator 2 has different exposed lengths during rotation. These are not listed one by one.

[0056] Example 3, please refer to Figure 5 As shown, this embodiment provides a bandgap adjustable acoustic metamaterial structure, which adds a series connection function based on embodiment 1 or 2.

[0057] Specifically, in this embodiment, the main structure 1 includes a top plate 11 and multiple positioning plates 12. A positioning plate 12 and the oscillator 2 that cooperates with it together constitute a unit structure. In this embodiment, multiple unit structures can be connected in series below the top plate 11 to achieve multi-bandgap characteristics.

[0058] Specifically, in this embodiment, the main structure 1 includes a top plate 11 and multiple identical positioning plates 12. Each adjacent positioning plate 12 is arranged parallel to each other. The top plate 11 is arranged parallel to each other on the uppermost positioning plate 12. The overall shape and size of the top plate 11 are the same as those of the positioning plates 12. Gaps are left between the top plate 11 and the positioning plates 12, as well as between each adjacent positioning plate 12. The top plate 11 and each positioning plate 12 are fixedly connected by a cylindrical pin located at the rotation center. An oscillator 2 is sandwiched in each gap, and the inner end of the oscillator 2 is rotatably sleeved. The outer end of the vibrator 2 is exposed outside the range of the positioning plate 12 and the top plate 11, attached to the cylindrical pin. The upper surface of the positioning plate 12 has a plurality of hemispherical recesses 121 arranged circumferentially around the cylindrical pin. The corresponding position of the middle part of the vibrator 2 is provided with a hemispherical protrusion 212 that cooperates with the hemispherical recesses 121. The hemispherical protrusion 212 can slide into the hemispherical recesses 121 to fix the vibrator 2 relative to the positioning plate 12. A positioning plate 12 and the vibrator 2 that cooperates with it together constitute a unit structure. This acoustic metamaterial structure has multiple unit structures connected in series.

[0059] Multiple positioning plates 12 can be connected in series by cylindrical pins or by bolts and nuts.

[0060] Specifically, the main structure 1 includes a top plate 11 and multiple identical positioning plates 12. Each adjacent positioning plate 12 is arranged parallel to each other. The top plate 11 is arranged parallel to each other on the uppermost positioning plate 12. The overall shape and size of the top plate 11 are the same as those of the positioning plates 12. Gaps are left between the top plate 11 and the positioning plates 12, as well as between each adjacent positioning plate 12. The top plate 11 and each positioning plate 12 are detachably connected by bolts located at the rotation center. An oscillator 2 is clamped in each gap. The inner end of the oscillator 2 is rotatably sleeved on the bolt, and the outer end of the oscillator 2 protrudes outside the area of ​​the positioning plates 12 and the top plate 11. The upper surface of the positioning plate 12 has multiple hemispherical recesses 121 arranged circumferentially around the center of the cylindrical pin. At the corresponding position in the center of the vibrator 2, a hemispherical protrusion 212 is provided to mate with the hemispherical recesses 121. The hemispherical protrusion 212 can slide into the hemispherical recesses 121 to fix the vibrator 2 relative to the positioning plate 12. One positioning plate 12 and its mating vibrator 2 together constitute a unit structure. This acoustic metamaterial structure has multiple unit structures connected in series. Bolts protrude from the lower surface of the lowest positioning plate 12 and are threaded with nuts. After adjusting the positions of all the vibrators 2, tightening the nuts fixes each unit structure and the top plate 11. Compared to the cylindrical pin fixing connection, the bolt and nut connection allows for the increase or decrease of the number of unit structures as needed, saving manufacturing costs.

[0061] This invention also provides a vehicle comprising the above-described bandgap adjustable acoustic metamaterial structure, mounted on the vehicle's sheet metal, and possessing all the advantages of the bandgap adjustable acoustic metamaterial structure.

[0062] Specifically, the above-mentioned bandgap adjustable acoustic metamaterial structure with different bandgap frequencies is installed at different locations on the vehicle sheet metal as needed; first, the vibrator 2 is adjusted to the required bandgap frequency value and then fixed; then, the acoustic metamaterial structure with the fixed bandgap frequency is installed on the corresponding sheet metal; finally, the vehicle parts other than the sheet metal are installed and the paint is applied to hide the bandgap adjustable acoustic metamaterial structure.

[0063] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A bandgap-tunable acoustic metamaterial structure, characterized in that, The structure includes a main structure (1) and an oscillator (2). The main structure (1) is a plate structure with at least two layers. The overall shape and size of each plate are the same. There are gaps between adjacent plates. An oscillator (2) is sandwiched in each gap. The inner end of the oscillator (2) is rotatably connected to the main structure (1). The outer end of the oscillator (2) is exposed outside the main structure (1). The length of the oscillator (2) exposed outside the main structure (1) can vary with the outer contour shape of the main structure (1).

2. The bandgap-tunable acoustic metamaterial structure according to claim 1, characterized in that, The main structure (1) includes a top plate (11) and a positioning plate (12). The overall shape and size of the top plate (11) are the same as those of the positioning plate (12). The upper surfaces of the top plate (11) and the positioning plate (12) are parallel to each other and their outer contours face the same direction. A gap is provided between the top plate (11) and the positioning plate (12). The top plate (11) and the positioning plate (12) are connected by a fixing component (13) located at the rotation center. A vibrator (2) is sandwiched in the gap between the top plate (11) and the positioning plate (12). The inner end of the vibrator (2) is rotatably sleeved on the fixing component (13). The positioning plate ( The upper surface of 12) has multiple hemispherical recesses (121) arranged circumferentially with the rotation center as the center and the same radius length. The corresponding position of the middle part of the oscillator (2) is provided with a hemispherical protrusion (212) that cooperates with the hemispherical recesses (121). The hemispherical protrusion (212) can slide into the hemispherical recesses (121) to fix the oscillator (2) relative to the positioning plate (12). The exposed lengths of the hemispherical protrusions (212) of the oscillator (2) fixed to different hemispherical recesses (121) are different. The exposed length is the length of the part of the oscillator (2) exposed outside the outer contour of the main structure (1).

3. The bandgap tunable acoustic metamaterial structure according to claim 2, characterized in that, The oscillator (2) is a single-piece structure, consisting of a connecting part (21), a scale part (22), and a mass part (23) from the inner end to the outer end. The inner end of the connecting part (21) is provided with a circular through hole (211), through which the oscillator (2) is rotatably sleeved onto the fixed component (13). The other end of the connecting part (21) is fixedly connected to the scale part (22). The hemispherical protrusion (212) is located in the middle of the connecting part (21) or at the end connected to the scale part (22). The scale part (22) is located in the middle section of the oscillator (2), and the upper surface of the scale part (22) is distributed with scale lines and corresponding bandgap frequency values ​​along the length direction. The mass part (23) is located at the outermost end, and is fixedly connected to the scale part (22) with a width greater than that of the scale part (22).

4. The bandgap tunable acoustic metamaterial structure according to claim 2, characterized in that, The bandgap adjustable acoustic metamaterial structure includes a top plate (11) and at least one unit structure, which are connected in series by a fixing component (13); each unit structure includes a positioning plate (12) and a vibrator (2) that cooperates with it.

5. The bandgap tunable acoustic metamaterial structure according to claim 4, characterized in that, The main structure (1) includes a top plate (11) and at least two identical positioning plates (12). Each positioning plate (12) is arranged in parallel and has the same outer contour orientation. The top plate (11) is arranged in parallel opposite to the upper surface of the uppermost positioning plate (12). There are gaps between the top plate (11) and the positioning plates (12) as well as between each adjacent positioning plate (12). The top plate (11) and each positioning plate (12) are connected in series by a fixing component (13) located at the rotation center. Each gap is clamped with an oscillator (2).

6. The bandgap tunable acoustic metamaterial structure according to claim 5, characterized in that, The fixing component (13) is a cylindrical pin, and the top plate (11) and each positioning plate (12) are fixedly connected by the cylindrical pin.

7. The bandgap tunable acoustic metamaterial structure according to claim 5, characterized in that, The fixing component (13) consists of bolts and nuts that cooperate with each other, and the top plate (11) and each positioning plate (12) are detachably connected by bolts and nuts.

8. The bandgap tunable acoustic metamaterial structure according to claim 2, characterized in that, The outer contour of the positioning plate (12) is generally shaped like a nautilus shell.

9. The bandgap tunable acoustic metamaterial structure according to claim 2, characterized in that, The positioning plate (12) has a semi-circular structure. The rotation center is located near the straight edge of the positioning plate (12) and is offset from the center of the circle. Multiple hemispherical pits (121) are distributed in a semi-circular pattern around the rotation center on the positioning plate (12).

10. A vehicle, characterized in that, Includes a bandgap tunable acoustic metamaterial structure as described in any one of 1-9, said bandgap tunable acoustic metamaterial structure being mounted on the sheet metal of a vehicle.

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