Light super-structure mechanical function element and low-frequency broadband vibration and noise reduction composite super-structure

Abstract

The invention discloses a lightweight metamaterial mechanical functional element and a low-frequency broadband vibration and noise reduction composite superstructure, the functional element comprises a harmonic element, a support element and at least one excitation element, and the support element is fixedly connected to the harmonic element; the excitation element comprises a cantilever and a balancing weight, one end of the cantilever is fixedly connected with the supporting element, and the balancing weight is arranged at the other end of the cantilever so as to increase the dynamic mass of the balancing weight under the action of the cantilever; an overshoot gap is formed between the balancing weight and the wall surface of the harmonizing element, and when the functional element is excited to generate resonance motion, the cantilever drives the balancing weight to move, so that the balancing weight enters the overshoot gap and intermittently rubs with the inner wall of the harmonizing element, and therefore, the overdamping characteristic of the functional element is excited, and the energy of the functional element is dissipated. The method is applied to the field of vibration and noise control, and the low-frequency broadband vibration noise suppression effect can be remarkably improved.

Description

Technical Field

[0001] The present invention relates to the field of vibration and noise control technology, specifically a lightweight metamechanical functional element and a low-frequency, broadband vibration and noise reduction composite metastructure, 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), 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, piping 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 features. The resulting vibration and noise issues are becoming increasingly prominent. Mechanical structural vibration can cause surface damage and loosening at the mildest, while at the most severe, it can lead to structural fatigue, fracture, and even serious accidents such as system failure. Furthermore, excessive vibration radiates noise, reducing ride comfort and contributing to 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 conventional damping materials can achieve good vibration and noise reduction effects. However, for low-frequency vibration noise (100-1000Hz), traditional structures can only suppress low-frequency vibration noise by increasing 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 metamaterial / metastructure technology has brought new approaches to equipment vibration and noise reduction design. Existing research shows that acoustic metastructures designed using acoustic metamaterial principles (such as locally resonant plate-shaped metamaterials and thin-film metamaterials) can partially overcome mass and spatial size limitations in the low-frequency band, but their control frequency band is relatively narrow. Series / parallel structural connections or complex supercell designs can broaden the bandwidth to a certain extent, but this also comes with the disadvantages of increased mass and size. Furthermore, existing acoustic metastructures suffer from poor control effectiveness in the high-frequency band. A major challenge facing equipment vibration and noise control is how to achieve low-frequency broadband (low-frequency to high-frequency) vibration noise suppression while maintaining high stiffness while maintaining lightweight and compact size. Summary of the Invention

[0005] In response to the above-mentioned deficiencies in the prior art, the present invention provides a lightweight superstructure mechanical functional element and a low-frequency broadband vibration and noise reduction composite superstructure, which can significantly improve the low-frequency broadband (low frequency to high frequency) vibration and noise suppression effect.

[0006] To achieve the above-mentioned object, the present invention provides a lightweight metamechanical functional element, comprising a harmonizing element, a supporting element, and at least one excitation element, wherein the supporting element is fixedly connected to the harmonizing element; The excitation element includes a cantilever and a counterweight, one end of the cantilever is fixedly connected to the supporting element, and the counterweight is provided at the other end of the cantilever to amplify the dynamic mass of the counterweight under the action of the cantilever; There is an overshoot gap between the counterweight block and the wall surface of the harmonizing element. When the functional element is excited to resonate, the cantilever drives the counterweight block to move, causing the counterweight block to enter the overshoot gap and intermittently rub against the inner wall of the harmonizing element, thereby stimulating the super-damping characteristics of the functional element and dissipating the energy of the functional element.

[0007] In one embodiment, the gap size of the overshoot gap when the functional element is not excited to produce resonant motion is Lr, and the amplitude when the functional element is excited to produce resonant motion is Ht, wherein 0.05×Ht≤Lr≤1×Ht. For example, the gap size of the overshoot gap when the functional element is not excited to produce resonant motion can be set to 0.7mm, 0.2mm or 1.03mm according to different situations.

[0008] In one embodiment, when there are more than two excitation elements, each of the cantilevers is connected to the supporting element in a ring array of one or more layers, or each of the cantilevers is connected to the supporting element in a linear array or a rectangular array.

[0009] In one embodiment, the counterweights on the cantilevers are not connected to each other; or The counterweight blocks on some of the cantilevers are connected as one; or The counterweight blocks on all the cantilevers are connected as one.

[0010] In one embodiment, the cantilever is a rectangular beam, a fan-shaped beam or a rod-shaped structure.

[0011] In one embodiment, a through hole is provided on the cantilever.

[0012] In one embodiment, the supporting element is a cylinder, a rectangular beam, a C-beam or an I-beam.

[0013] In one embodiment, the counterweight block and the cantilever, the cantilever and the supporting element, and the supporting element and the harmonizing element are fixed by snap connection, riveting, welding, gluing, screw connection or pin connection.

[0014] In one embodiment, the harmonizing element is a cylindrical structure, a boxed structure, a curved plate structure, a folded plate structure or a flat plate structure.

[0015] To achieve the above object, the present invention further provides a low-frequency, broadband, vibration-damping and noise-reducing composite superstructure, comprising a matrix and the above-mentioned lightweight superstructure mechanical functional element, wherein the matrix is ​​a beam structure or a plate structure; The lightweight metamechanical functional element is connected to the surface of the substrate, and the harmonizing element in the lightweight metamechanical functional element is integrally formed with the substrate or is independent of each other; or The lightweight metamechanical functional element is connected to the interior of the matrix, and the harmonizing element in the lightweight metamechanical functional element is integrally formed with the matrix or is independent of each other.

[0016] Compared with the prior art, the present invention has the following beneficial technical effects: 1. The present invention provides an overshoot gap between the counterweight and the wall surface of the harmonic element. By setting the gap size of the overshoot gap, the counterweight and the harmonic element are not in contact when the functional element is not excited to resonate. When the functional element is excited to resonate, it induces and drives the counterweight to move violently, allowing it to enter the overshoot gap and intermittently rub against the inner wall of the harmonic element, thereby stimulating the nonlinear enhancement of the damping of the functional element, inducing super-damping characteristics, achieving mass amplification, dissipating the energy of the functional element, and significantly improving the low-frequency broadband (low-frequency to high-frequency) vibration noise suppression effect. 2. The present invention connects the counterweight to the supporting element by providing a cantilever, thereby amplifying its motion amplitude under the action of the cantilever, thereby driving the supporting element to move violently, achieving dynamic mass amplification of the counterweight and enhancing its ability to suppress low-frequency elastic waves; 3. Based on acoustic superlattice theory, a subwavelength, lightweight metamechanical functional element is innovatively constructed. The coupling of the elastic wavelength traveling wave characteristics in the matrix with the periodic localized resonant cells, combined with the placement of the counterweight away from the support, the opening of holes in the cantilever, and the compression of the thin layer, effectively suppress the propagation of low-frequency, broadband vibration waves, achieving an ultra-low frequency band gap in a lightweight and compact size, improving space utilization, reducing weight, and mitigating the negative impact of size effects. 4. Through the ingenious design of the harmonizing elements, synergistic coupling and efficient protection of the excitation elements are achieved, improving the structure's anti-interference capability and environmental adaptability. Furthermore, through a fully functional material matching design, an all-metal configuration scheme is achieved for each component of the lightweight metamechanical functional element, further enhancing its overall stiffness, strength, and environmental adaptability. The structure of the present invention exhibits extraordinary low-frequency, broadband (from low to medium and high frequencies) acoustic vibration suppression performance, and is highly reliable, highly anti-interference, and highly robust. 5. The present invention has a simple structure, can be assembled in a modular manner, is easy to use, and can realize the design of basic elements of the same material system. It is economical and has strong market competitiveness. It is easy to promote and apply in large-scale engineering projects, providing users with excellent vibration and noise reduction solutions. This invention can be used for vibration and noise reduction control in modern transportation equipment and high-end precision equipment. It can effectively suppress vibration and noise problems caused by equipment operation, significantly improving the stability and reliability of equipment operation, and protecting the physical and mental health of workers from the intrusion of machine vibration and noise. This invention achieves the multifunctional integrated design requirements of light weight, high rigidity, strong anti-interference properties, excellent weather resistance, and low-frequency, broadband, and efficient vibration and noise reduction, offering broad design space and application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] 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.

[0018] Figure 1 Schematic diagram of the structure of the lightweight metamechanical functional element in Example 1 of the present invention; Figure 2 Schematic diagram of the explosion of the lightweight metamechanical functional element in Example 1 of the present invention; Figure 3 Schematic diagrams of the structures of the excitation unit in Example 1 of the present invention, wherein: (a) is a schematic diagram of a first embodiment of the excitation unit, (b) is a schematic diagram of a second embodiment of the excitation unit, (c) is a schematic diagram of a third embodiment of the excitation unit, and (d) is a schematic diagram of a fourth embodiment of the excitation unit; Figure 4Schematic diagrams of the structure of the cantilever in Example 1 of the present invention, wherein: (a) is a schematic diagram of a first embodiment of the cantilever, (b) is a schematic diagram of a second embodiment of the cantilever, (c) is a schematic diagram of a third embodiment of the cantilever, (d) is a schematic diagram of a fourth embodiment of the cantilever, (e) is a schematic diagram of a fifth embodiment of the cantilever, (f) is a schematic diagram of a sixth embodiment of the cantilever, (g) is a schematic diagram of a seventh embodiment of the cantilever, and (h) is a schematic diagram of an eighth embodiment of the cantilever; Figure 5 Schematic diagrams of the distribution of counterweights in Example 1 of the present invention, wherein: (a) is a schematic diagram of a first embodiment of the distribution of counterweights, (b) is a schematic diagram of a second embodiment of the distribution of counterweights, (c) is a schematic diagram of a third embodiment of the distribution of counterweights, (d) is a schematic diagram of a fourth embodiment of the distribution of counterweights, (e) is a schematic diagram of a fifth embodiment of the distribution of counterweights, and (f) is a schematic diagram of a sixth embodiment of the distribution of counterweights; Figure 6 Schematic diagrams of the structure of the support element in Example 1 of the present invention, wherein: (a) is a schematic diagram of a first embodiment of the support element, (b) is a schematic diagram of a second embodiment of the support element, (c) is a schematic diagram of a third embodiment of the support element, (d) is a schematic diagram of a fourth embodiment of the support element, and (e) is a schematic diagram of a fifth embodiment of the support element; Figure 7 Schematic diagrams of the structure of the harmonic primitive in Example 1 of the present invention, wherein: (a) is a schematic diagram of a first embodiment of the harmonic primitive, (b) is a schematic diagram of a second embodiment of the harmonic primitive, and (c) is a schematic diagram of a third embodiment of the harmonic primitive; Figure 8 This is a schematic diagram of a second implementation structure of the lightweight metamechanical functional element in Example 1 of the present invention; Figure 9 This is a schematic diagram of the third implementation structure of the lightweight metamechanical functional element in Example 1 of the present invention; Figure 10 Schematic diagrams of the structure of the substrate in Example 2 of the present invention, wherein: (a) is a schematic diagram of a first embodiment of the substrate, (b) is a schematic diagram of a second embodiment of the substrate, (c) is a schematic diagram of a third embodiment of the substrate, (d) is a schematic diagram of a fourth embodiment of the substrate, and (e) is a schematic diagram of a fifth embodiment of the substrate; Figure 11 This is a schematic diagram of the first implementation structure of the low-frequency broadband vibration and noise reduction composite superstructure in Example 2 of the present invention; Figure 12 This is a schematic diagram of a second implementation structure of the low-frequency broadband vibration and noise reduction composite superstructure in Example 2 of the present invention; Figure 12This is a schematic diagram of a third implementation structure of the low-frequency broadband vibration and noise reduction composite superstructure in Example 2 of the present invention; Figure 13 This is a schematic diagram of a fourth implementation structure of the low-frequency broadband vibration and noise reduction composite superstructure in Example 2 of the present invention; Figure 14 This is a schematic diagram of a low-frequency, broadband, vibration and noise reduction composite superstructure according to Example 2 of the present invention; Figure 15 This is a comparison chart of the vibration reduction effect test results of the low-frequency broadband vibration and noise reduction composite superstructure in Example 2 of the present invention.

[0019] Figure numbers: harmonizing element 1, supporting element 2, cantilever 3, counterweight block 4, end cover 5, base 6, lightweight metamechanical functional element 7.

[0020] 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

[0021] 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.

[0022] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0023] In addition, the terms "first," "second," and so on, used in this disclosure are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referenced. Thus, a feature specified as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of this disclosure, "plurality" means at least two, such as two or three, unless otherwise specifically defined.

[0024] 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.

[0025] 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.

[0026] Example 1 like Figure 1 、 Figure 2 The present embodiment shows a lightweight metamechanical functional element disclosed in this embodiment, which primarily comprises a harmonic element 1, a supporting element 2, and at least one excitation element. The supporting element 2 is fixedly connected to the harmonic element 1, and the excitation element comprises a cantilever 3 and a counterweight 4. One end of the cantilever 3 is fixedly connected to the supporting element 2, and the counterweight 4 is disposed at the other end of the cantilever 3, thereby amplifying the dynamic mass of the counterweight 4 under the action of the cantilever 3. An overshoot gap exists between the counterweight 4 and the wall of the harmonic element 1. When the functional element is not excited into resonant motion, the counterweight 4 and the wall of the harmonic element 1 form a clearance fit. When the functional element is excited into resonant motion, the cantilever 3 drives the counterweight 4 to move, causing the counterweight 4 to enter the overshoot gap and intermittently rub against the inner wall of the harmonic element 1, thereby stimulating the super-damping characteristics of the functional element and dissipating its energy.

[0027] In this embodiment, when the functional unit is not excited to resonate, the gap size of the overshoot gap is recorded as Lr, and the amplitude of the functional unit during resonant motion is recorded as Ht, and 0.05×Ht≤Lr≤1×Ht. Preferably, 0.2×Ht≤Lr≤0.9×Ht, so that when the functional unit is excited to resonate, the counterweight block 4 can generate friction motion with the wall surface of the functional unit, stimulating the super-damping characteristics of the structure, thereby dissipating the energy of the functional unit and significantly improving the low-frequency broadband (low-frequency to high-frequency) vibration noise suppression effect.

[0028] As a preferred embodiment, at least one of the two contact surfaces between the counterweight block 4 and the harmonizing element 1 is rough, for example, a number of bumps, grooves or threaded protrusions are arranged on the contact surface of the counterweight block 4 and / or the harmonizing element 1, so as to enhance the excitation effect of the structural super-damping characteristics when the counterweight block 4 and the harmonizing element 1 generate friction motion.

[0029] In a specific implementation process, when there are more than two excitation units, each cantilever 3 is connected to the supporting unit 2 in a ring array of one or more layers, for example Figure 3 (a) shows that multiple cantilevers 3 are connected to the support element 2 in a ring array. Alternatively, the cantilevers 3 can be connected to the support element 2 in a linear array, for example Figure 3 (b) As shown. The cantilevers 3 can also be connected to the supporting element 2 in a rectangular array, for example Figure 3 (c) When the cantilevers 3 are arranged in a linear array or a rectangular array, multiple supporting elements 2 can be provided for joint support, for example Figure 3 (d) shown.

[0030] In this embodiment, the cantilever 3 is a rectangular beam, a fan-shaped beam or a rod-shaped structure. When there are more than two excitation elements, each cantilever 3 can be formed as one piece, or arranged separately or connected and fixed by a connector. At the same time, a through hole can be opened on the cantilever 3 to achieve the effect of weight reduction. For example Figure 4 (a)~ Figure 4 (b) shows a structure in which multiple fan-shaped beam cantilevers 3 are integrally formed. Figure 4 (e)~ Figure 4 (f) shows the structure in which the rectangular beam cantilever 3 is arranged separately and has a through hole. Figure 4 (h) shows a structure in which a plurality of rectangular beam cantilevers 3 are connected and fixed by connecting members.

[0031] In the specific implementation process, the counterweights 4 on each cantilever 3 can be unconnected, or the counterweights 4 on some cantilever 3 can be connected as one, or the counterweights 4 on all cantilever 3 can be connected as one. Figure 5 (a)~ Figure 5 (d) shows an implementation structure in which the counterweights 4 on each cantilever 3 are not connected to each other. Figure 5 (e) Figure 5 (f) shows the structure in which the counterweight blocks 4 on each cantilever 3 are connected as one.

[0032] In a specific implementation process, the supporting element 2 can be configured as a cylinder, a rectangular beam, a C-beam or an I-beam. Figure 6 (a) shows the supporting element 2 of the cylindrical structure. Figure 6 (b) shows the supporting element 2 of the solid rectangular beam structure. Figure 6(c) shows the supporting element 2 of the hollow rectangular beam structure. Figure 6 (d) shows the supporting element 2 of the I-beam structure. Figure 6 (e) shows the supporting element 2 of the C-beam structure.

[0033] In the specific implementation process, the harmonizing element 1 is a cylindrical structure, a boxed structure, an arc plate structure, a folded plate structure or a flat plate structure, for example Figure 7 (a) shows a harmonic primitive 1 with a cylindrical structure and an end cap 5, that is, the corresponding functional primitive is as follows Figure 1 As shown; Figure 7 (b) shows the harmonic primitive 1 of the boxed structure, that is, the corresponding functional primitive is as follows Figure 8 As shown; Figure 7 (c) shows the harmonic primitive 1 of the folded plate structure, that is, the corresponding functional primitive is as follows Figure 9 shown.

[0034] In this embodiment, the counterweight 4 and the cantilever 3, the cantilever 3 and the supporting element 2, and the supporting element 2 and the harmonizing element 1 are fixed by snap connection, riveting, welding, gluing, screw connection or pin connection.

[0035] Example 2 Based on the lightweight metamechanical functional element in Example 1, this embodiment discloses a low-frequency broadband vibration and noise reduction composite superstructure, which mainly includes a matrix 6 and at least two lightweight metamechanical functional elements 7 of Example 1. The matrix 6 is an engineering beam structure such as a rectangular beam, an I-beam, or a U-beam, or the matrix 6 is a plate structure such as a flat plate, a multi-layer composite plate, a stiffened plate, a corrugated plate, or a honeycomb sandwich plate. For example Figure 10 (a) Figure 10 (b) shows the base plate of the beam structure. Figure 10 (c)~ Figure 10 (e) shows the substrate of the plate structure.

[0036] In this embodiment, the lightweight metamechanical functional element 7 can be directly connected to the surface of the base 6, or the lightweight metamechanical functional element 7 can be set inside the base 6. Figure 11 As shown, multiple lightweight metamechanical functional elements 7 are distributed in a linear array on the base 6 of the I-beam structure. Figure 12 As shown, multiple lightweight metamechanical functional elements 7 are distributed in a rectangular array on a flat plate structure substrate 6. Figure 13 What is shown is that a plurality of lightweight metamechanical functional elements 7 are distributed in the matrix 6 of the plate structure.

[0037] In the specific implementation process, the harmonizing elements in the lightweight metamechanical functional element 7 can be formed as one piece with the matrix 6 or can be independent of each other.

[0038] The vibration and noise reduction effects of the low-frequency, broadband vibration and noise reduction composite superstructure in this embodiment will be further described below with reference to specific examples.

[0039] In this example, the low-frequency broadband vibration and noise reduction composite superstructure is composed of 10 lightweight metamechanical functional units periodically arranged on a substrate. The substrate is a light beam made of aluminum alloy, with a length, width and thickness of 1000mm×30mm×3mm and an arrangement lattice spacing of 95mm. The cantilever of the lightweight metamechanical functional unit is a rectangular beam with four circular holes. The cantilever counterweight is square and made of stainless steel. The supporting unit is a rectangular beam made of aluminum alloy. The harmonic unit is a small flat plate structure with an overshoot gap of 0.4mm. A sample was made and a vibration reduction test of the low-frequency broadband vibration and noise reduction composite superstructure was carried out ( Figure 14 is a sample photo), and compared with the traditional local resonance metamaterial noise reduction structure. The two comparison samples have the same substrate, arrangement number and gap, and total weight.

[0040] Figure 15 A comparison chart of the measured vibration reduction effects is presented. According to the experimental test results, within the low-frequency broadband range of 100Hz-2000Hz, the low-frequency broadband vibration and noise reduction composite superstructure of the present invention exhibits extraordinary super-damping and dynamic mass amplification characteristics. Its vibration reduction performance is far superior to that of the traditional local resonance metamaterial noise reduction structure (referred to as the comparison structure), verifying the efficient elastic wave suppression capability of the structure of the present invention (100Hz-2000Hz, the vibration transmissibility of the structure of the present invention is 10dB lower on average than that of the comparison structure, and is more than 20dB lower at the maximum frequency).

[0041] 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 lightweight supermechanical functional element, characterized in that: It includes a harmonizing element, a supporting element and at least one exciting element, wherein the supporting element is fixedly connected to the harmonizing element; The excitation element includes a cantilever and a counterweight, one end of the cantilever is fixedly connected to the supporting element, and the counterweight is provided at the other end of the cantilever to amplify the dynamic mass of the counterweight under the action of the cantilever; There is an overshoot gap between the counterweight block and the wall surface of the harmonizing element. When the functional element is excited to resonate, the cantilever drives the counterweight block to move, causing the counterweight block to enter the overshoot gap and intermittently rub against the inner wall of the harmonizing element, thereby stimulating the super-damping characteristics of the functional element and dissipating the energy of the functional element.

2. The lightweight metamechanical functional element according to claim 1, characterized in that: The gap size of the overshoot gap when the functional element is not excited to resonate is Lr, and the amplitude when the functional element is excited to resonate is Ht, wherein 0.05×Ht≤Lr≤1×Ht.

3. The lightweight metamechanical functional element according to claim 1 or 2, characterized in that: When there are more than two excitation units, each of the cantilevers is connected to the supporting unit in a ring array of one layer or more than two layers, or each of the cantilevers is connected to the supporting unit in a linear array or a rectangular array.

4. The lightweight metamechanical functional element according to claim 3, characterized in that: The counterweights on the cantilevers are not connected to each other; or The counterweight blocks on some of the cantilevers are connected as one; or The counterweight blocks on all the cantilevers are connected as one.

5. The lightweight metamechanical functional element according to claim 1 or 2, characterized in that: The cantilever is a rectangular beam piece, a fan-shaped beam piece or a rod-shaped structure.

6. The lightweight metamechanical functional element according to claim 1 or 2, characterized in that: A through hole is provided on the cantilever.

7. The lightweight metamechanical functional element according to claim 1 or 2, characterized in that: The supporting element is a cylinder, a rectangular beam, a C-beam or an I-beam.

8. The lightweight metamechanical functional element according to claim 1 or 2, characterized in that: The counterweight block and the cantilever, the cantilever and the supporting element, and the supporting element and the harmonizing element are fixed by snap connection, riveting, welding, gluing, screw connection or pin connection.

9. The lightweight metamechanical functional element according to claim 1 or 2, characterized in that: The harmonizing element is a cylindrical structure, a boxed structure, an arc-shaped plate structure, a folded plate structure or a flat plate structure.

10. A low-frequency, broadband, vibration and noise reduction composite superstructure, characterized in that: It comprises a base body and at least two lightweight metamechanical functional elements according to any one of claims 1 to 9, wherein the base body is a beam structure or a plate structure; The lightweight metamechanical functional element is connected to the surface of the substrate, and the harmonizing element in the lightweight metamechanical functional element is integrally formed with the substrate or is independent of each other; or The lightweight metamechanical functional element is connected to the interior of the matrix, and the harmonizing element in the lightweight metamechanical functional element is integrally formed with the matrix or is independent of each other.

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