Offset acoustic metamaterial function element and vibration and noise reduction superstructure preparation method thereof
Through the tuning gap design and local resonance effect of the biased acoustic metamaterial functional element, the problems of increased mass, larger size and poor robustness in low-frequency broadband vibration noise control are solved, and a lightweight, high-rigidity broadband vibration and noise reduction effect is achieved.
Patent Information
- Application Number
- CN202511002730.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-21
- Publication Date
- 2025-09-09
AI Technical Summary
Existing acoustic superstructures have problems in low-frequency broadband vibration noise control, such as increased mass, larger size, weak load-bearing capacity, and poor robustness. It is difficult to achieve effective low-frequency broadband vibration noise suppression under light weight and small size conditions.
A biased acoustic metamaterial functional element is adopted. By setting a tuning gap area between the main mass element and the auxiliary mass element, the local resonance and collision effect are coupled to release the elastic wave energy and dissipate it in the form of heat energy. The bias element is designed in combination with nonlinear theory to provide resonant stiffness and main mass.
It maintains light weight and small size in ultra-low frequency design, and has high rigidity, so as to effectively suppress the transmission of vibration waves and reduce sound radiation in a wide frequency range, solving the shortcomings of existing technologies and having good robustness and vibration and noise reduction effects.
Smart Images
Figure CN120612913A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the field of vibration and noise control technology, specifically a biased acoustic metamaterial functional element and a method for preparing a vibration and noise reduction superstructure thereof, which can be applied to vibration and noise control in modern transportation vehicles (rail vehicles, aircraft, spacecraft, ships, automobiles, engineering transport / unloading vehicles), construction venues / rooms (waiting halls, recording / studios, conference venues, multi-functional classrooms, anechoic rooms, stadiums, airports), electronic equipment (air conditioners, refrigerators, washing machines, fresh air systems, computers, headphones, mobile phones, communication base stations, data centers), industrial fields (transformers, generator sets, fans, water pumps, natural gas units, pipeline systems and other equipment in places such as substations, power plants, water storage and supply stations, and natural gas plants), and roads and bridges (tracks, sound barriers, bridges, tunnels). Background Art
[0002] In recent years, modern transportation equipment, represented by high-speed trains, aircraft, and ships, has been developing towards higher speeds, heavier loads, lighter weight, and smarter technologies. The resulting vibration and noise issues are becoming increasingly prominent. Mechanical structural vibration can cause surface damage and loosening at the mildest, and even lead to structural fatigue, fractures, and even serious accidents such as system failure. Furthermore, excessive vibration radiates noise, reducing ride comfort and causing environmental noise pollution. Effective vibration and noise reduction measures are urgently needed to control vibration and noise.
[0003] For high-frequency vibration noise, due to its short wavelength and weak transmission capacity, the use of common damping materials can achieve good vibration and noise reduction effects. However, for low-frequency vibration noise, traditional structures can only suppress it by increasing the structural mass and space. However, increasing mass and space runs counter to the development philosophy of modern equipment and cannot effectively meet the needs of actual engineering applications.
[0004] In recent years, the development of acoustic metamaterials and metastructures has brought new approaches to the design of vibration and noise reduction in equipment. Acoustic metastructures are novel composite structures composed of specially designed artificial microstructure units (such as local resonance units, or oscillators) attached to a base structure in a specific manner. These structures exhibit extraordinary physical properties (such as negative equivalent mass density and negative equivalent modulus) not possessed by traditional materials and structures. They can achieve extraordinary manipulation of low-frequency elastic and acoustic waves, making them promising for low-frequency vibration and noise reduction. Existing research has shown that acoustic metastructures designed using acoustic metamaterial principles (such as local resonance plate-shaped metamaterials and thin-film metamaterials) can partially overcome mass and spatial size limitations at low frequencies, but their control frequency band is relatively narrow. While bandwidth can be broadened to some extent through series / parallel structural connections or complex supercell designs, this also comes with the disadvantages of increased mass and size. In addition, most existing acoustic superstructure units have shortcomings such as weak load-bearing capacity, poor robustness, and poor spatial integration when designed at ultra-low frequencies (below 200 Hz); how to achieve low-frequency broadband (low-frequency to high-frequency) vibration noise suppression while maintaining both high stiffness and good robustness under lightweight and small size conditions is a major challenge facing equipment vibration and noise control. Summary of the Invention
[0005] In response to the above-mentioned deficiencies in the prior art, the present invention provides a biased acoustic metamaterial functional element and a method for preparing a vibration-damping and noise-reducing superstructure thereof, which can significantly improve the low-frequency broadband (low-frequency to high-frequency) vibration noise suppression effect while also taking into account greater stiffness and good robustness.
[0006] To achieve the above objectives, the present invention provides a biased acoustic metamaterial functional element, comprising at least one cell, wherein the cell comprises a supporting element and at least one biasing component, wherein the supporting element is used to provide support and play a secondary regulation role in resonant stiffness; The biasing assembly comprises: A biasing element connected to the supporting element and configured to provide a resonant primary stiffness; A main mass primitive, provided on the bias primitive, for providing a resonant main mass; The auxiliary mass primitive is provided on the main mass primitive and is used to provide a resonant auxiliary mass.
[0007] In one embodiment, a tuning gap region is provided between the primary mass element and the secondary mass element; The cell has a local resonant wave mode at the resonant frequency. When the local resonant wave mode is excited, the bias element drives the main mass element and the auxiliary mass element to move violently, and the main mass element and / or the auxiliary mass element intermittently enter the tuning gap area, so that the auxiliary mass element intermittently collides with the main mass element, releasing elastic wave energy and dissipating it in the form of heat energy. In one embodiment, the main mass element is provided with a hole and / or a groove, and a portion of the auxiliary mass element is placed in the hole and / or the groove of the main mass element; There is a clearance fit between the auxiliary mass element and the inner wall of the hole and / or slot on the main mass element, that is, the tuning gap area is formed.
[0008] In one embodiment, the minimum gap size of the tuning gap region is L min , the resonance amplitude of the cell is H, where 0.01×H≤L min .
[0009] In one embodiment, the offset element is a straight rod, a curved rod, a straight thin beam or a curved thin beam.
[0010] In one embodiment, when the number of the cells is more than two, the supporting elements of two adjacent cells are connected via a connecting portion.
[0011] To achieve the above objectives, the present invention also provides a vibration and noise reduction superstructure, comprising a base portion and a plurality of the above-mentioned offset acoustic metamaterial functional elements, wherein each of the offset acoustic metamaterial functional elements is arranged on the surface or inside of the base portion in a predetermined manner.
[0012] In one embodiment, the base is a flat plate structure, a laminate structure, a sandwich structure, a stiffened plate structure, a rod structure, a beam structure, a lattice structure, or a perforated plate. Obviously, in practical engineering, the base can also be used for structures requiring vibration and noise reduction, such as cabin siding, tracks, train floors, pipelines, engine casings, doors and windows, air conditioner casings, and integrated tubs in robot vacuums.
[0013] To achieve the above object, the present invention further provides a method for preparing the above vibration and noise reduction superstructure, which is characterized by comprising the following steps: Step 1, obtaining basic information of the vibration and noise reduction superstructure; Step 2, based on the basic information, prepare the offset primitive, the main mass primitive, the auxiliary mass primitive, the support primitive and the base part by machining or 3D printing; Step 3: first assemble the bias element, the main mass element, the auxiliary mass element, and the support element to form a biased acoustic metamaterial functional element, and then connect the biased acoustic metamaterial functional element to the base part to form a vibration reduction and noise reduction metastructure prototype; Step 4: Inspect the appearance and connection of the vibration and noise reduction superstructure prototype, measure the outline, size, and weight parameters of the vibration and noise reduction superstructure prototype, test the local resonant frequency of the biased acoustic metamaterial functional element, and test the vibration and noise reduction performance of the vibration and noise reduction superstructure prototype; Step 5, iteratively feedback the design parameters of the vibration and noise reduction superstructure until the vibration and noise reduction performance of the initial prototype of the vibration and noise reduction superstructure meets the design requirements, thereby obtaining the final prototype of the vibration and noise reduction superstructure, wherein the design parameters include the local resonant frequency and arrangement quantity of the biased acoustic metamaterial functional unit, the mass of the main mass unit, the stiffness of the bias unit, the tuning gap, and the layout of the vibration and noise reduction superstructure.
[0014] In one embodiment, the basic information includes the composition form of the biased acoustic metamaterial functional unit, the composition form of the cell, the connection method between the biased acoustic metamaterial functional unit and the base part, and the material and processing accuracy requirements of each component.
[0015] Compared with the prior art, the present invention has the following beneficial technical effects: 1. Based on nonlinear theory and local resonance effects, the present invention proposes a biased acoustic metamaterial functional element. By setting a tuning gap region between the main mass element and the auxiliary mass element, when the local resonance fluctuation mode of the biased acoustic metamaterial functional element is excited, the bias element drives the main mass element and the auxiliary mass element into violent motion. The main mass element and / or the auxiliary mass element enter the tuning gap region, causing the auxiliary mass element to intermittently collide with the inner wall of the main mass element's hole or slot, releasing elastic wave energy, which is dissipated as heat. Through the coupling of the local resonance effect and the collision effect, the generation of structural vibration and radiated noise can be effectively suppressed. 2. The present invention maintains light weight and small size in ultra-low frequency designs, while also offering high stiffness and good robustness in the face of external disturbances. This effectively suppresses the transmission of vibration waves and reduces sound radiation efficiency over an ultra-low frequency and wide frequency range, thus effectively resolving key issues of existing technologies, such as weak low-frequency and broadband capabilities, large size (poor spatial integration), low stiffness, and poor robustness. 3. The present invention has a simple structure, is easy to process and assemble, has strong reliability, is easy to process, has good economy, and is conducive to large-scale production and promotion. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] 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 or the description of the prior art. 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 the structures shown in these drawings without paying any creative work.
[0017] Figure 1 Schematic diagram of the first embodiment of the cell in the embodiment of the present invention, wherein: Figure 1 (a) is a schematic diagram of the first configuration of the cell in the first embodiment, Figure 1 (b) is a schematic diagram of the second configuration of the cell under the first embodiment, Figure 1 (c) is a schematic diagram of the third configuration of the cell under the first embodiment, Figure 1 (d) is a schematic diagram of the fourth configuration of the cell under the first embodiment; Figure 2 This is a schematic diagram of a second embodiment of a cell in an embodiment of the present invention, wherein: Figure 2 (a) is a schematic diagram of the first configuration of the cell under the second embodiment, Figure 2 (b) is a schematic diagram of the second configuration of the cell under the second embodiment, Figure 2 (c) is a schematic diagram of the third configuration of the cell under the second embodiment; Figure 3 Schematic diagram of a third implementation of a cell in an embodiment of the present invention; Figure 4 Schematic diagram of a fourth implementation of a cell in an embodiment of the present invention; Figure 5 Schematic diagram of the structure of the bias primitive in an embodiment of the present invention, wherein: Figure 5 (a) is a schematic diagram of a first embodiment of a bias primitive, Figure 5 (b) is a schematic diagram of a second embodiment of the bias primitive, Figure 5 (c) is a schematic diagram of a third embodiment of the bias primitive, Figure 5 (d) is a schematic diagram of a fourth embodiment of the bias primitive, Figure 5 (e) is a schematic diagram of a fifth embodiment of the bias primitive, Figure 5 (f) is a schematic diagram of a sixth embodiment of the biasing primitive; Figure 6 Schematic diagram of the structure of the biased acoustic metamaterial functional unit in an embodiment of the present invention; Figure 7 FIG. 5 is another schematic diagram of another implementation of a biased acoustic metamaterial functional unit in an embodiment of the present invention, wherein: Figure 7 (a) is a schematic diagram of the first configuration. Figure 7 (b) is a schematic diagram of the second configuration. Figure 7 (c) is a schematic diagram of the third configuration; Figure 8 Schematic diagram of a first embodiment of a vibration and noise reduction superstructure in an embodiment of the present invention; Figure 9 Schematic diagram of a second embodiment of the vibration and noise reduction superstructure in an embodiment of the present invention; Figure 10 Schematic diagram of a third embodiment of the vibration and noise reduction superstructure in an embodiment of the present invention; Figure 11 Schematic diagram of a fourth embodiment of the vibration and noise reduction superstructure in an embodiment of the present invention; Figure 12 Schematic diagram of a fifth embodiment of the vibration and noise reduction superstructure in an embodiment of the present invention; Figure 13 Schematic diagram of a sixth embodiment of the vibration and noise reduction superstructure in an embodiment of the present invention; Figure 14 Schematic diagram of a seventh embodiment of the vibration and noise reduction superstructure in an embodiment of the present invention; Figure 15 2. Exploded view of a seventh embodiment of the vibration and noise reduction superstructure according to an embodiment of the present invention; Figure 16 Schematic diagram of a first embodiment of a vibration and noise reduction superstructure using a perforated plate as a base portion in an embodiment of the present invention; Figure 17 Schematic diagram of a second embodiment of a vibration and noise reduction superstructure using a perforated plate as a base portion in an embodiment of the present invention; Figure 18 Schematic diagram of a third embodiment of a vibration and noise reduction superstructure using a perforated plate as a base portion in an embodiment of the present invention; Figure 19 Schematic diagram of an eighth embodiment of the vibration and noise reduction superstructure according to an embodiment of the present invention; Figure 20 Schematic diagram of a perforated plate according to an embodiment of the present invention, wherein: Figure 20 (a) is a schematic diagram of the first configuration of the perforated plate. Figure 20 (b) is a schematic diagram of the second configuration of the perforated plate. Figure 20 (c) is a schematic diagram of the third configuration of the perforated plate. Figure 20 (d) is a schematic diagram of the fourth configuration of the perforated plate. Figure 20 (e) is a schematic diagram of the fifth configuration of the perforated plate. Figure 20 (f) is a schematic diagram of the sixth configuration of the perforated plate.
[0018] Figure numerals: support element 1, bias element 2, main mass element 3, auxiliary mass element 4, tuning gap region 5, connection part 6, base part 7, flat plate 701, perforated plate 702.
[0019] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION
[0020] 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. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.
[0021] In the present invention, unless otherwise specified or limited, the terms "connection" and "fixation" should be understood in a broad sense. For example, "fixation" can mean fixed connection, detachable connection, or integration; it can mean mechanical connection, electrical connection, physical connection, or wireless communication connection; it can mean direct connection or indirect connection through an intermediate medium; it can mean internal communication between two elements or interaction between two elements, unless otherwise specified. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.
[0022] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in this field can implement it. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.
[0023] Example 1 This embodiment discloses a biased acoustic metamaterial functional element, comprising at least one cell, which includes a support element 1 and at least one biasing component. The support element 1 is used to provide support and play a secondary role in regulating the resonant stiffness. The biasing component includes a biasing element 2, a main mass element 3, and an auxiliary mass element 4. The biasing element 2 is connected to the support element 1 and is used to provide the resonant primary stiffness; the main mass element 3 is provided on the biasing element 2 and is used to provide the resonant primary mass; and the auxiliary mass element 4 is provided on the main mass element 3 and is used to provide the resonant auxiliary mass.
[0024] There is a tuning gap area 5 between the main mass element 3 and the auxiliary mass element 4, and there is a local resonant fluctuation mode in the cell at the resonant frequency. When the local resonant fluctuation mode is excited, the bias element 2 drives the main mass element 3 and the auxiliary mass element 4 to move violently, and the main mass element 3 and / or the auxiliary mass element 4 intermittently enter the tuning gap area 5, so that the auxiliary mass element 4 intermittently collides with the main mass element 3, releasing elastic wave energy and dissipating it in the form of heat energy. Through the coupling of local resonance effect and collision effect, the generation of structural vibration and radiation noise can be effectively suppressed.
[0025] In a specific implementation, a hole and / or a slot is provided on the main mass element 3, and a portion of the auxiliary mass element 4 is placed in the hole and / or the slot of the main mass element 3. A clearance fit is formed between the auxiliary mass element 4 and the inner wall of the hole and / or the slot on the main mass element 3, thus forming a tuning gap region 5. For example, one or more through holes can be provided on the main mass element 3, and the same number of mass rods as the through holes can be used as the auxiliary mass element 4. The auxiliary mass element 4 is then inserted into the through holes, and pins or threaded connection caps (the size of the caps is larger than the size of the through holes on the main mass element 3) are provided at both ends of the auxiliary mass element 4 to prevent the auxiliary mass element 4 from slipping. The maximum gap size of the tuning gap region 5 is L max , the resonance amplitude of the cell is H, where L max ≤2×H.
[0026] In this embodiment, the cell has various implementation forms, and the number of bias components thereon can be set to one or more according to requirements.
[0027] Figure 1 (a) shows a schematic diagram of the first embodiment of the cell, in which the cell includes a bias component, the support element 1 is a polyhedron structure, the bias element 2 is a straight rod, one end of the bias element 2 is plugged into one surface of the support element 1, and the main mass element 3 is arranged at the other end of the bias element 2. In addition to plug-in fixation, the bias element 2 and the support element 1 and the main mass element 3 can also be fixed by threaded connection, welding or gluing. In addition, plug-in holes can also be provided on other surfaces of the support element 1 for installing other bias components, so that the cell has two, three or four bias components, for example Figure 1 (b) Figure 1 (c) Figure 1 (d) shown.
[0028] Figure 2(a) shows a schematic diagram of the second embodiment of the cell, in which the cell includes a biasing component, the supporting element 1 is a rectangular block structure, the biasing element 2 is a straight thin beam, the bottom surface of one end of the biasing element 2 is fixed to the top of the supporting element 1 by welding or gluing, and the main mass element 3 is fixed to the top surface of the other end of the biasing element 2 by welding or gluing; when there are multiple biasing components, each biasing component can be arranged side by side on the supporting element 1, for example Figure 2 (b) As shown. In addition, a hollow groove can be set on the bias element 2, that is, Figure 2 (c) shown.
[0029] Figure 3 The diagram shows a third embodiment of a cell. In this case, the cell includes two symmetrically arranged biasing components. Support element 1 is a rectangular block structure, and biasing element 2 is a straight thin beam with a hollowed-out slot. The bottom surface of one end of biasing element 2 is fixed to the top of support element 1 by welding or gluing, while the main mass element 3 is fixed to the top surface of the other end of biasing element 2 by welding or gluing. When a cell has multiple sets of symmetrically arranged biasing components, each biasing component can be arranged side by side in two columns on top of support element 1.
[0030] Figure 4 The diagram shows a fourth embodiment of a cell. In this case, the cell includes a biasing assembly. Support element 1 is a two-rectangular block structure, and biasing element 2 is a straight thin beam with a hollowed-out slot. The bottom surfaces of biasing element 2 are fixed to the tops of the two rectangular blocks by welding or gluing. The main mass element 3 is also fixed to the center of the top of biasing element 2 by welding or gluing. When a cell has multiple biasing assemblies, each biasing assembly can also be arranged side by side on the tops of the two rectangular blocks.
[0031] In this embodiment, the biasing element 2 has various structural forms, and can be a straight rod, a curved rod, a straight thin beam or a curved thin beam. Figure 5 (a) shows an embodiment in which a straight thin beam with hollow grooves is used as the biasing element 2. Figure 5 (b) shows an embodiment in which a spiral bending rod is used as the biasing element 2. Figure 5 (c) shows an embodiment in which a straight rod is used as the biasing element 2. Figure 5 (d) Figure 5 (e) shows an embodiment in which a zigzag beam is used as the biasing element 2. Figure 5 (f) shows an embodiment in which a bending rod is used as the biasing element 2 .
[0032] In a specific implementation, when the number of cells is more than two, the supporting elements 1 of two adjacent cells are connected by a connecting portion 6, and the connecting portion 6 can be a beam structure, a tube structure or a rod structure. Preferably, when the number of cells is more than three, the biased acoustic metamaterial functional elements can be combined into a polygonal frame structure through multiple connecting portions 6, and on the polygonal frame structure, some supporting elements 1 can be provided with bias components, while other supporting elements 1 are not provided with bias components. For example Figure 6 What is shown is a biased acoustic metamaterial functional unit of a hexagonal frame structure, wherein bias components are provided on three mutually spaced support units 1, while the other three support units 1 are not provided with bias components. Figure 7 The figure shows a quadrilateral frame structure biased acoustic metamaterial functional unit, where Figure 7 (a) shows a support element 1 provided with a biasing component, while the other three support elements 1 are not provided with a biasing component; Figure 7 (b) shows three support elements 1 provided with biasing components, while another support element 1 is not provided with a biasing component; Figure 7 The four supporting elements 1 shown in (c) are all provided with biasing components.
[0033] Example 2 This embodiment discloses a vibration and noise reduction metastructure, comprising a base portion 7 and several offset acoustic metamaterial functional elements of Example 1, each offset acoustic metamaterial functional element being arranged in a predetermined manner on the surface or within the base portion 7. The base portion 7 may be a flat plate structure, a laminate structure, a sandwich plate structure, a stiffened plate structure, a rod-shaped structure, a lattice structure, or a perforated plate.
[0034] refer to Figure 8 This is a schematic diagram of the first embodiment of the vibration-damping and noise-reducing superstructure in this embodiment. In this case, the base portion 7 is a rod-shaped structure. At the same time, the base portion 7 also serves as the supporting element 1 of the cell on the biased acoustic metamaterial functional element, and the biased components are spaced apart and distributed on both sides of the base portion 7.
[0035] refer to Figure 9 Schematic diagram of the second embodiment of the vibration and noise reduction superstructure in this embodiment, in which the base portion 7 is a rod-shaped structure, and the offset acoustic metamaterial functional elements are arranged on the base portion 7 at intervals along a straight line; refer to Figure 10 This is a schematic diagram of the third embodiment of the vibration and noise reduction superstructure in this embodiment. In this case, the base portion 7 is a lattice structure distributed in a linear array. At the same time, the base portion 7 also serves as the connecting portion 6 on the biased acoustic metamaterial functional element.
[0036] refer to Figure 11 This is a schematic diagram of the fourth embodiment of the vibration reduction and noise reduction superstructure in this embodiment. In this case, the vibration reduction and noise reduction superstructure consists of several Figure 6 The offset acoustic metamaterial functional element array shown is arranged, and adjacent vibration and noise reduction superstructures share a common connection part. In addition, all the connection parts 6 directly constitute the base part 7, that is, the base part 7 is a lattice structure composed of several connection parts 6.
[0037] refer to Figure 12 This is a schematic diagram of the fifth embodiment of the vibration reduction and noise reduction superstructure in this embodiment. In this case, the vibration reduction and noise reduction superstructure consists of several Figure 7 The offset acoustic metamaterial functional element array shown in (c) is arranged, and adjacent vibration and noise reduction metastructures share a common connection part. In addition, all the connection parts 6 directly constitute the base part 7, that is, the base part 7 is a lattice structure composed of several connection parts 6.
[0038] refer to Figure 13 This is a schematic diagram of the sixth embodiment of the vibration and noise reduction superstructure in this embodiment. In this case, the base portion is a flat plate 701, and several Figure 7 (c) The offset acoustic metamaterial functional elements are arranged in a rectangular array at intervals on the base.
[0039] refer to Figure 14 、 Figure 15 Schematic diagram of the seventh implementation of the vibration and noise reduction superstructure in this embodiment. In this embodiment, the vibration and noise reduction superstructure is formed by stacking multiple layers of offset acoustic metamaterial functional element arrays.
[0040] refer to Figures 16 to 18 This is a schematic diagram of an embodiment of a vibration and noise reduction superstructure using a perforated plate 702 as a base portion. Figure 7 (c) The offset acoustic metamaterial functional elements are arranged in a rectangular array at intervals on the base.
[0041] refer to Figure 19 This is a schematic diagram of the eighth embodiment of the vibration and noise reduction superstructure in this embodiment. In this case, the base portion includes a flat plate 701 and a perforated plate 702. Figure 7 The offset-type acoustic metamaterial functional unit rectangular array shown in (c) is distributed between the flat plate 701 and the perforated plate 702 at intervals.
[0042] refer to Figure 20 The schematic diagram of the structure of the perforated plate in this embodiment is shown. The perforations on the perforated plate can be evenly distributed, for example Figure 20 (a) Figure 20 (b) It can also be divided into regions where some regions are evenly distributed and other regions are array distributed, for example Figure 20 (c) to Figure 20 (f) shown.
[0043] Example 3 This embodiment discloses a method for preparing the vibration and noise reduction superstructure of embodiment 2, which mainly includes the following steps: Step 1: Obtain basic information about the vibration and noise reduction metastructure, including the composition of the biased acoustic metamaterial functional unit, the composition of the unit cell, the connection method between the biased acoustic metamaterial functional unit and the base, and the material and processing accuracy requirements of each component; Step 2: Based on the basic information, the bias element 2, the main mass element 3, the auxiliary mass element 4, the support element 1, the connection part and the base part are prepared by machining or 3D printing. The support element 1, the connection part and the base part can be assembled after separate machining according to the requirements of the basic information, or can be processed in an integrated manner; Step 3: first assemble the bias element 2, the main mass element 3, the auxiliary mass element 4, and the support element 1 to form a biased acoustic metamaterial functional element, and then connect the biased acoustic metamaterial functional element to the base part to form a vibration reduction and noise reduction metastructure prototype; Step 4: Inspect the appearance and connection of the vibration and noise reduction superstructure prototype, measure the outline, size, and weight parameters of the vibration and noise reduction superstructure prototype, test the local resonant frequency of the biased acoustic metamaterial functional element, and test the vibration and noise reduction performance of the vibration and noise reduction superstructure prototype; Step 5, iteratively feedback the design parameters of the vibration and noise reduction superstructure until the vibration and noise reduction performance of the initial prototype of the vibration and noise reduction superstructure meets the design requirements, thereby obtaining the final prototype of the vibration and noise reduction superstructure, wherein the design parameters include the local resonant frequency and arrangement quantity of the biased acoustic metamaterial functional unit, the mass of the main mass unit, the stiffness of the bias unit, the tuning gap, and the layout of the vibration and noise reduction superstructure.
[0044] The above description is only a preferred embodiment of the present invention and does not limit the scope of protection of the present invention. All equivalent structural transformations made by using the contents of the present invention description and drawings under the inventive concept of the present invention, or direct / indirect application in other related technical fields are included in the scope of protection of the present invention.
Claims
1. A biased acoustic metamaterial functional element, characterized in that: The device comprises at least one cell, wherein the cell comprises a supporting element and at least one biasing component, wherein the supporting element is used to provide support and play a secondary adjustment role of resonant stiffness; The biasing assembly comprises: A biasing element connected to the supporting element and configured to provide a resonant primary stiffness; A main mass primitive, provided on the bias primitive, for providing a resonant main mass; The auxiliary mass primitive is provided on the main mass primitive and is used to provide a resonant auxiliary mass.
2. The biased acoustic metamaterial functional element according to claim 1, characterized in that: There is a tuning gap region between the main mass element and the auxiliary mass element; The cell has a local resonant fluctuation mode at the resonant frequency. When the local resonant fluctuation mode is excited, the bias element drives the main mass element and the auxiliary mass element to move violently, and the main mass element and / or the auxiliary mass element intermittently enter the tuning gap region, so that the auxiliary mass element intermittently collides with the main mass element, releasing elastic wave energy and dissipating it in the form of heat energy.
3. The biased acoustic metamaterial functional element according to claim 2, characterized in that: The main mass element is provided with a hole and / or a groove, and a portion of the auxiliary mass element is placed in the hole and / or the groove of the main mass element; There is a clearance fit between the auxiliary mass element and the inner wall of the hole and / or slot on the main mass element, that is, the tuning gap area is formed.
4. The biased acoustic metamaterial functional element according to claim 3, characterized in that: The minimum gap size of the tuning gap region is L max , the resonance amplitude of the cell is H, where L max ≤2×H.
5. The biased acoustic metamaterial functional element according to claim 1, 2, 3 or 4, characterized in that: The offset element is a straight rod, a curved rod, a straight thin beam or a curved thin beam.
6. The biased acoustic metamaterial functional element according to claim 1, 2, 3 or 4, characterized in that: When the number of the cells is more than two, the supporting elements of two adjacent cells are connected via a connecting portion.
7. A vibration and noise reduction superstructure, characterized in that: The invention comprises a base part and several biased acoustic metamaterial functional elements according to any one of claims 1 to 6, wherein each biased acoustic metamaterial functional element is arranged on the surface or inside of the base part in a predetermined manner.
8. The vibration and noise reduction superstructure according to claim 7, characterized in that: The base part is a flat plate structure, a laminated plate structure, a sandwich plate structure, a stiffened plate structure, a rod-shaped structure, a beam structure, a lattice structure or a perforated plate.
9. A method for preparing the vibration and noise reduction superstructure according to claim 7 or 8, characterized in that: The steps include: Step 1, obtaining basic information of the vibration and noise reduction superstructure; Step 2, based on the basic information, prepare the offset primitive, the main mass primitive, the auxiliary mass primitive, the support primitive and the base part by machining or 3D printing; Step 3: first assemble the bias element, the main mass element, the auxiliary mass element, and the support element to form a biased acoustic metamaterial functional element, and then connect the biased acoustic metamaterial functional element to the base part to form a vibration reduction and noise reduction metastructure prototype; Step 4: Inspect the appearance and connection of the vibration and noise reduction superstructure prototype, measure the outline, size, and weight parameters of the vibration and noise reduction superstructure prototype, test the local resonant frequency of the biased acoustic metamaterial functional element, and test the vibration and noise reduction performance of the vibration and noise reduction superstructure prototype; Step 5, iteratively feedback the design parameters of the vibration and noise reduction superstructure until the vibration and noise reduction performance of the initial prototype of the vibration and noise reduction superstructure meets the design requirements, thereby obtaining the final prototype of the vibration and noise reduction superstructure, wherein the design parameters include the local resonant frequency and arrangement quantity of the biased acoustic metamaterial functional unit, the mass of the main mass unit, the stiffness of the bias unit, the tuning gap, and the layout of the vibration and noise reduction superstructure.
10. The preparation method according to claim 9, characterized in that The basic information includes the composition form of the biased acoustic metamaterial functional unit, the composition form of the cell, the connection method between the biased acoustic metamaterial functional unit and the base part, and the material and processing accuracy requirements of each component.