Pressure contact type chiral-negative Poisson's ratio regulation and control acoustic metamaterial

Abstract

The invention discloses a pressure contact type chiral-negative Poisson's ratio regulation and control acoustic metamaterial structure, and relates to the technical field of acoustic metamaterials, the pressure contact type chiral-negative Poisson's ratio regulation and control acoustic metamaterial structure is composed of an array formed by adjacently arranging a plurality of subunits, and each subunit comprises a chiral outer frame; the resonance unit is arranged inside the chiral outer frame and is fixedly connected with the inner surface of the chiral outer frame along the Y-axis direction; the negative Poisson's ratio contact elements are arranged on the left and right sides of the resonance unit in the X-axis direction. Based on the characteristic that the negative Poisson's ratio material expands transversely after being pressed, the negative Poisson's ratio contact elements are arranged on the left side and the right side of the resonance unit in the X-axis direction, the structural dynamic characteristics of the resonance unit are changed in the mode of filling the preset air pressure, and then the real-time regulation and control function of the dynamic characteristics is achieved. Compared with the prior art, the method has the advantages that the structure is simple, a complex peripheral auxiliary system does not need to be arranged, and the like, has a good application prospect, can be widely applied to various engineering fields, and effectively regulates and controls elastic waves.

Description

Technical Field

[0001] The present invention relates to the technical field of acoustic metamaterials, and in particular to a pressure-contact type chirality-negative Poisson's ratio acoustic metamaterial structure. Background Art

[0002] Acoustic metamaterials are artificial periodic or quasi-periodic structural materials that can change the propagation characteristics of sound and elastic waves in a medium through their unique microstructure design. Based on the local resonance mechanism, acoustic metamaterials can effectively control elastic waves, especially low-frequency elastic waves.

[0003] Common acoustic metamaterials use fixed structures, so their dynamic characteristics are usually fixed and difficult to adjust according to actual application scenarios during operation. To address this problem, acoustic metamaterial structures are currently developing in the direction of being controllable. For example, controllable acoustic metamaterial structures based on piezoelectric element control and structural strain control have been proposed and are still under in-depth research.

[0004] However, existing controllable acoustic metamaterial structures usually require the deployment of complex peripheral auxiliary systems, such as piezoelectric control drive systems, strain control systems, etc., which greatly limits their application in actual engineering fields.

[0005] In view of this, how to provide a controllable acoustic metamaterial structure that overcomes the limitations of peripheral auxiliary systems and improves the scope of application of the structure is a technical problem that people in this field urgently need to solve. Summary of the invention

[0006] The purpose of the present invention is to provide a pressure-contact-controlled chirality-negative Poisson's ratio acoustic metamaterial structure to solve the problems existing in the prior art.

[0007] To achieve the above object, the present invention provides a pressure-contact controllable chirality-negative Poisson's ratio acoustic metamaterial structure, which is composed of an array composed of a plurality of adjacent subunits, wherein the subunits include:

[0008] Chiral outer framework;

[0009] A resonance unit is disposed inside the chiral outer frame and fixedly connected to the inner surface of the chiral outer frame along the Y-axis direction;

[0010] A negative Poisson's ratio contact element is arranged on the left and right sides of the resonance unit along the X-axis direction. When the negative Poisson's ratio contact element is filled with a preset air pressure, the negative Poisson's ratio contact element expands along the X-axis direction and comes into close contact with the resonance unit, thereby changing the structural dynamic characteristics of the resonance unit. When the negative Poisson's ratio contact element is not filled with the preset air pressure, it is away from the resonance unit.

[0011] Furthermore, the negative Poisson's ratio contact element comprises:

[0012] A negative Poisson's ratio contact beam is made of a negative Poisson's ratio material and is fixedly arranged on the inner surface of a chiral outer frame to form an air pressure action cavity with the chiral outer frame. The air pressure action cavity is used to be filled with a preset air pressure. When the air pressure action cavity is not filled with the preset air pressure, there is a gap between the negative Poisson's ratio contact beam and the resonance unit.

[0013] Furthermore, the negative Poisson's ratio contact beam includes a contact section and a connecting section, the contact section corresponds to the resonance unit and is adapted to its outer surface shape, the connecting section is used to connect the contact section and the inner surface of the chiral outer frame, and the connecting section is bent toward the direction of the air pressure action chamber.

[0014] Furthermore, the resonance unit includes:

[0015] A suspension beam, defining a mounting chamber therein, with upper and lower ends thereof extending outwardly along the Y-axis direction and fixedly connected to the inner surface of the chiral outer frame;

[0016] A scatterer is embedded in the installation cavity, and an elastic layer is arranged between the scatterer and the inner surface of the installation cavity.

[0017] Furthermore, the upper and lower ends of the suspension beam extend outward along the Y-axis direction to form an upper connecting beam and a lower connecting beam respectively, and the upper connecting beam and the lower connecting beam are arc-shaped structures with opposite bending directions.

[0018] The present invention discloses the following technical effects:

[0019] Based on the property of negative Poisson's ratio material to expand laterally under pressure, the present invention arranges negative Poisson's ratio contact elements on the left and right sides of the resonance unit along the X-axis direction, and changes the structural dynamic characteristics of the resonance unit by filling with preset air pressure, thereby realizing the real-time control function of the dynamic characteristics. Compared with the prior art, the present invention has the advantages of simple structure and no need to arrange complex peripheral auxiliary systems. It has good application prospects and can be widely used in various engineering fields to effectively control elastic waves. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] 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.

[0021] Figure 1 A schematic diagram of an array formed by adjacently arranging a plurality of sub-units;

[0022] Figure 2 is a schematic diagram of the subunit structure;

[0023] Figure 3 It is a schematic diagram of the state of the negative Poisson's ratio contact beam before being filled with a preset air pressure;

[0024] Figure 4 It is a schematic diagram of the state of the negative Poisson's ratio contact beam after being filled with a preset air pressure;

[0025] Figure 5 Schematic diagram of the stiffness of the negative Poisson's ratio contact beam before being filled with a preset air pressure;

[0026] Figure 6 Schematic diagram of the stiffness of the negative Poisson's ratio contact beam after being filled with a preset air pressure;

[0027] Among them, 1. chiral outer frame; 2. negative Poisson's ratio contact beam; 201. air pressure chamber; 202. contact section; 203. connecting section; 3. suspension beam; 301. upper connecting beam; 302. lower connecting beam; 4. scatterer; 5. elastic layer. DETAILED DESCRIPTION

[0028] 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.

[0029] 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.

[0030] An embodiment of the present invention provides a pressure-contact controllable chirality-negative Poisson's ratio acoustic metamaterial structure, which is composed of an array composed of multiple subunits arranged adjacent to each other, and the subunits include: a chiral outer frame 1; a resonance unit, which is arranged inside the chiral outer frame 1 and fixedly connected to the inner surface of the chiral outer frame 1 along the Y-axis direction; a negative Poisson's ratio contact element, which is arranged on the left and right sides of the resonance unit along the X-axis direction. When the negative Poisson's ratio contact element is filled with a preset air pressure, the negative Poisson's ratio contact element expands along the X-axis direction and is in close contact with the resonance unit, thereby changing the structural dynamic characteristics of the resonance unit; when the negative Poisson's ratio contact element is not filled with the preset air pressure, it is away from the resonance unit.

[0031] In this embodiment, the negative Poisson's ratio contact element includes: a negative Poisson's ratio contact beam 2, which is made of a negative Poisson's ratio material, which is fixedly arranged on the inner surface of the chiral outer frame 1, and forms an air pressure chamber 201 with the chiral outer frame 1, the air pressure chamber 201 is a closed structure, which is used to fill the preset air pressure, and when the air pressure chamber 201 is not filled with the preset air pressure, there is a gap between the negative Poisson's ratio contact beam 2 and the resonance unit. Further, the negative Poisson's ratio contact beam 2 includes a contact section 202 and a connecting section 203, the contact section 202 corresponds to the resonance unit and is adapted to the shape of its outer surface, the connecting section 203 is used to connect the contact section 202 and the inner surface of the chiral outer frame 1, and the connecting section 203 is bent in the direction of the air pressure chamber 201.

[0032] In this embodiment, the resonance unit includes: a suspension beam 3, which defines an installation chamber inside, and the upper and lower ends of the suspension beam 3 extend outward along the Y-axis direction to form an upper connecting beam 301 and a lower connecting beam 302 respectively. The upper connecting beam 301 and the lower connecting beam 302 are arc structures with opposite bending directions. The overall shape of the suspension beam 3 is close to S-shaped, ensuring that the upper connecting beam 301 and the lower connecting beam 302 have a small stiffness in the shear direction. A scatterer 4 is embedded in the installation chamber, and an elastic layer 5 is arranged between the scatterer 4 and the inner surface of the installation chamber. Under the premise of fully fixing the elastic layer 5 and the scatterer 4 assembly, the suspension beam 3 reduces its X-direction stiffness as much as possible. In the actual production molding process, the suspension beam 3 is integrally formed, and then the scatterer 4 and the elastic layer 5 are embedded. Among them, the connection between the elastic layer 5 and the suspension beam 3 must be installed by using a surface contact with relatively balanced contact stress (such as the form of arc surface to arc surface). If the elastic layer 5 is directly integrally formed with the suspension beam 3 or connected by gluing or other methods, it will cause significant stress concentration. Therefore, this embodiment adopts a structure in which the elastic layer 5 and the suspension beam 3 are in separate surface contact.

[0033] Figure 3 and Figure 4 The state diagram before and after the preset air pressure is filled into the air pressure chamber 201 is shown. Before the preset air pressure is filled into the chamber 201, the negative Poisson's ratio contact beam 2 is in a normal state and does not contact the suspension beam 3. After the preset air pressure is filled into the chamber 201, the negative Poisson's ratio contact beam 2 expands along the X-axis direction, and the contact section 202 extends toward the suspension beam 3 until it contacts the suspension beam 3, changing the structural dynamic characteristics of the resonant unit. The connecting section 203 also extends along the X-axis direction, and its bending degree is reduced, resulting in a stretching state tending to a horizontal state.

[0034] Figure 5 and Figure 6The diagram shows the stiffness of the air pressure chamber 201 before and after it is filled with a preset air pressure, where M1 and M2 represent the masses of the chiral outer frame 1 and the scatterer 4, respectively, K1 represents the shear stiffness of the suspension beam 3 along the X-axis, K2 represents the stiffness of the elastic layer 5, and K3 represents the equivalent stiffness of the elastic layer 5 after the negative Poisson's ratio contact element contacts the suspension beam 3. The chiral characteristics of the chiral outer frame 1 can ensure that the structure has a smaller X-direction stiffness under the premise of having sufficient Y-direction stiffness (ensuring that the scatterer 4 is reliably suspended in the middle), thereby widening the stiffness of K1 and K3 as much as possible. And after the air pressure chamber 201 is filled with a preset air pressure and contacts the suspension beam 3, the chiral characteristics of the chiral outer frame 1 have better low-frequency band gap characteristics.

[0035] 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.

[0036] 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 pressure-contact-controlled chirality-negative Poisson's ratio acoustic metamaterial structure, characterized in that: The device is composed of an array of multiple sub-units arranged adjacent to each other, wherein the sub-units include: Chiral outer framework (1); A resonance unit is arranged inside the chiral outer frame (1) and fixedly connected to the inner surface of the chiral outer frame (1) along the Y-axis direction; A negative Poisson's ratio contact element is arranged on the left and right sides of the resonance unit along the X-axis direction. When the negative Poisson's ratio contact element is filled with a preset air pressure, the negative Poisson's ratio contact element expands along the X-axis direction and comes into close contact with the resonance unit, thereby changing the structural dynamic characteristics of the resonance unit. When the negative Poisson's ratio contact element is not filled with the preset air pressure, it is away from the resonance unit.

2. The pressure-contact-controlled chirality-negative Poisson's ratio acoustic metamaterial structure according to claim 1, characterized in that: The negative Poisson's ratio contact element comprises: A negative Poisson's ratio contact beam (2) is made of a negative Poisson's ratio material and is fixedly arranged on the inner surface of a chiral outer frame (1) and forms an air pressure action cavity (201) with the chiral outer frame (1). The air pressure action cavity (201) is used to be filled with a preset air pressure. When the air pressure action cavity (201) is not filled with the preset air pressure, a gap exists between the negative Poisson's ratio contact beam (2) and the resonance unit.

3. The pressure-contact controllable chirality-negative Poisson's ratio acoustic metamaterial structure according to claim 2, characterized in that: The negative Poisson's ratio contact beam (2) comprises a contact section (202) and a connecting section (203), wherein the contact section (202) corresponds to the resonant unit and is adapted to the shape of its outer surface, and the connecting section (203) is used to connect the contact section (202) and the inner surface of the chiral outer frame (1), and the connecting section (203) is bent in the direction of the air pressure action chamber (201).

4. The pressure-contact controllable chirality-negative Poisson's ratio acoustic metamaterial structure according to claim 1, characterized in that: The resonance unit comprises: A suspension beam (3) defines an installation chamber inside, and its upper and lower ends extend outward along the Y-axis direction and are fixedly connected to the inner surface of the chiral outer frame (1); A scatterer (4) is embedded in the installation cavity, and an elastic layer (5) is provided between the scatterer (4) and the inner surface of the installation cavity.

5. The pressure-contact controllable chirality-negative Poisson's ratio acoustic metamaterial structure according to claim 4, characterized in that: The upper and lower ends of the suspension beam (3) extend outwards along the Y-axis direction to form an upper connecting beam (301) and a lower connecting beam (302), respectively; the upper connecting beam (301) and the lower connecting beam (302) are arc-shaped structures with opposite bending directions.

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