Low-frequency multi-spectrum wave resistance superstructure, vibration isolation device and design method

Abstract

The application belongs to the technical field of mechanical engineering, ship engineering and structural vibration control, and relates to a low-frequency multi-spectrum wave resistance superstructure, a vibration isolation device and a design method.The low-frequency multi-spectrum wave resistance superstructure comprises a plate-shaped unit and a plurality of elastic bodies.The elastic bodies have deformation force and restoring force under the action of external load, and the plurality of elastic bodies are arranged at the outer side of the plate-shaped unit to generate a plurality of low-frequency resonance modes.The elastic body comprises a top plate, a bottom plate and a connecting piece.The top plate is arranged on the top surface of the plate-shaped unit, the bottom plate is arranged on the bottom surface of the plate-shaped unit, and the connecting piece connects the top plate and the bottom plate.The connecting piece comprises a cylindrical coil spring, a disc spring, a leaf spring, a plate spring, a rubber spring or a cantilever beam type elastic bearing structure.When the connecting piece is the cylindrical coil spring, the elastic body further comprises two anti-shearing struts arranged at intervals and arranged at the bottom of the top plate and the top of the bottom plate respectively.The application can provide a multi-spectrum isolation effect of low frequency.

Description

Technical Field

[0001] This application relates to the fields of mechanical engineering, marine engineering, and structural vibration control technology, and in particular to low-frequency multi-line spectrum wave-damping superstructures, vibration isolation devices, and design methods. Background Technology

[0002] Structural vibration and noise are widespread in military equipment, ships, naval vessels, and civilian machinery. Vibration and noise not only directly affect crew comfort and reduce the acoustic stealth performance of submarines and helicopters, but can also lead to serious accidents such as loss of control, structural fatigue failure, fracture, and explosive disintegration.

[0003] Vibration isolators effectively prevent the transmission of vibration energy from the vibration excitation source to other equipment, thereby protecting important equipment and reducing vibration sound radiation. Therefore, vibration isolators are widely used in various systems. Many devices, such as pumps, motors, engines, and other moving parts, operate at a given frequency, generating fundamental and harmonic spectrum lines. Currently, there is an urgent need for vibration isolation devices that can effectively isolate multiple low-frequency spectrum lines while simultaneously supporting high loads at low frequencies.

[0004] Traditional passive vibration isolators, such as those based on single-degree-of-freedom isolation theory, including springs, rubber, steel wire, and metal-rubber, possess good overall performance, but their low-frequency isolation and line spectrum control capabilities are insufficient. A crucial approach to improving vibration isolation is reducing the isolator stiffness. Advanced airbag isolators can achieve natural frequencies below 3Hz, but their line spectrum suppression capabilities remain inadequate. Anti-resonance isolators combine the advantages of wideband and narrow-band line spectrum isolation, achieving high isolation efficiency near certain specific frequencies. However, traditional anti-resonance isolators have only one anti-mode, a very narrow operating bandwidth, and weak line spectrum isolation capabilities in real-world scenarios.

[0005] Metamaterial structures with band gaps exhibit excellent vibration isolation properties. However, due to practical engineering limitations in size and weight, existing metamaterial structure design methods struggle to generate broadband band gaps below 100Hz, thus failing to suppress low-frequency line spectra. This is a major obstacle restricting the application of metamaterial theory in vibration reduction and noise reduction. Summary of the Invention

[0006] Therefore, it is necessary to provide low-frequency multi-line spectrum wave impedance superstructures, vibration isolation devices, and design methods to address the aforementioned technical problems, which can provide multiple, low-frequency, high-efficiency, wide-bandwidth, and robust line spectrum isolation effects under the premise of appropriate fundamental frequency.

[0007] The low-frequency multi-line spectrum wave-damping superstructure includes: plate-like units and multiple elastic bodies; The elastomer has deformation force and restoring force under external load. Multiple elastomers are spaced apart on the outside of the plate-shaped unit to generate multiple low-frequency resonance modes.

[0008] In one embodiment, the elastomer includes: a top plate, a bottom plate, and a connector; The top plate is disposed on the top surface of the plate-shaped unit, the bottom plate is disposed on the bottom surface of the plate-shaped unit, and the connector connects the top plate and the bottom plate.

[0009] In one embodiment, the connector includes: a cylindrical helical spring, a disc spring, a leaf spring, a plate spring, a rubber spring, or a cantilever beam elastic load-bearing structure.

[0010] In one embodiment, when the connector is a cylindrical helical spring, the elastic body further includes: two shear-resistant struts; Two shear-resistant supports are spaced apart, one shear-resistant support is located at the bottom of the top plate and the other shear-resistant support is located at the top of the bottom plate; The shear-resistant support is cylindrical and is fitted inside the cylindrical helical spring.

[0011] In one embodiment, the plate-shaped unit is a rectangular, circular, or irregularly shaped thin plate structure. In one embodiment, the plate-shaped unit is provided with a plurality of through holes, the axial direction of which is consistent with the thickness direction of the plate-shaped unit.

[0012] In one embodiment, the plate-shaped unit has a plurality of reinforcing ribs on its top and / or bottom surfaces.

[0013] Vibration isolation device, including: multiple low-frequency multi-line spectrum wave impedance superstructures; Multiple low-frequency multi-line spectrum wave-damping superstructures are stacked and arrayed along the bearing direction of the low-frequency multi-line spectrum wave-damping superstructure, and adjacent low-frequency multi-line spectrum wave-damping superstructures are connected by the elastic body so that there is a gap between adjacent plate-like structures.

[0014] The design method for vibration isolation devices, when the plate unit is a square structure, includes: Obtain the design specifications and the starting frequency of the vibration isolation band; The thickness of the plate element is obtained based on the starting frequency of the vibration isolation band, the size characteristics of the plate element, and the material properties of the plate element.

[0015] In one embodiment, when the connector is a cylindrical helical spring, it further includes: Obtain design parameters, including the mass of the object to be vibration-damped and the system fundamental frequency; The stiffness of the spring is obtained based on the mass of the object being damped and the fundamental frequency of the system. Based on the mass of the object being damped, the stiffness of the spring, and the characteristics of the spring, the dimensional information of the spring is obtained; Based on the dimensional characteristics of the plate-shaped unit and the dimensional information of the spring, the dimensional information of the top plate or bottom plate is obtained; Based on the spring's dimensions, the dimensions of the shear-resistant support are obtained.

[0016] The aforementioned low-frequency multi-line spectrum wave-damping metastructure, vibration isolation device, and design method address the lack of low-frequency, broadband, multi-line spectrum, and robust vibration isolation devices. Based on the principle of local resonance metamaterials, it combines corner support plates with the theory of periodic metamaterial structures. It utilizes elastic thin plates with multi-corner supports as local resonance units of the metamaterial, generating multiple low-frequency local resonance modes. This creates band gaps that suppress multiple low-frequency line spectra, forming a multi-line spectrum local resonance structure. Through periodic stacking, a wave-damping vibration isolation device is constructed to expand the bandwidth and enhance the band gap effect. Under the premise of appropriate fundamental frequency and maintaining moderate load-bearing stiffness, it achieves comprehensive line spectrum vibration isolation performance characterized by low frequency, high efficiency, small size, large bandwidth, multi-line spectrum, and strong robustness. It is particularly suitable for mechanical engineering, vibration and noise control, shipbuilding and marine engineering, and metamaterial structures. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of a low-frequency multi-line spectrum wave impedance superstructure in one embodiment, wherein (a) is a rectangular plate-shaped unit, (b) is a rectangular plate-shaped unit with multiple through holes, (c) is a rectangular plate-shaped unit with reinforcing ribs, and (d) is a circular plate-shaped unit. Figure 2 This is a schematic diagram of an elastic body in a low-frequency multi-line spectrum wave impedance superstructure in one embodiment, wherein (a) is an elastic body with a cylindrical compression spring as the connector, (b) is an elastic body with a rubber elastic material as the connector, (c) is a schematic diagram of an elastic body with a cantilever beam type elastic load-bearing structure as the connector from one perspective, and (d) is a schematic diagram of an elastic body with a cantilever beam type elastic load-bearing structure from another perspective. Figure 3 This is a schematic diagram of a wave-blocking vibration isolation device in one embodiment, wherein (a) is a wave-blocking vibration isolation device with rectangular plate units, and (b) is a wave-blocking vibration isolation device with rectangular plate units and multiple through holes. Figure 4 Here is an equivalent principle diagram of a wave-blocking vibration isolation device in one embodiment, where (a) is an equivalent principle diagram of the vibration isolator, (b) is a simplified boundary diagram of a rectangular thin plate, and (c) is an equivalent principle diagram of a multi-line spectrum local resonance structure. Figure 5 The analytical calculation of a wave-damping vibration isolation device in one embodiment is shown, where (a) is an infinite periodic dispersion curve, (b) is a multilayer structure transmissivity curve, and (c) is an analytical fitting curve of the equivalent model. Figure 6The following is a simulation result of a wave-blocking vibration isolation device in one embodiment, where (a) is the dispersion curve of the multi-line spectrum local resonance structure, and (b) is the transmissivity curve of the vibration isolator. Figure 7 This is a robust simulation result of bandgap for different vibration modes under complex excitation conditions in one embodiment.

[0018] Figure label: Plate-shaped unit 1; 2. Elastomer, 21. Top plate, 22. Bottom plate, 23. Connector, 24. Shear-resistant support. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this application.

[0020] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in the embodiments of this application are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0021] Furthermore, the use of terms such as "first" and "second" in this application is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of those features. In the description of this application, "multiple sets" means at least two sets, such as two sets, three sets, etc., unless otherwise explicitly specified.

[0022] In this application, unless otherwise expressly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection, an electrical connection, a physical connection, or a wireless communication connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two elements or the interaction between two elements, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0023] Furthermore, the technical solutions of the various embodiments of this application can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by this application.

[0024] This application provides a low-frequency multi-line spectrum wave impedance superstructure, such as Figure 1 and Figure 2 As shown, in one embodiment, it includes: a plate-like unit and a plurality of elastomers. The plate-shaped unit is a thin plate structure that acts as a scatterer, providing multiple low-frequency vibration modes. Its specific shape can be rectangular (including rectangles and squares), circular, or irregular.

[0025] Preferably, the plate-shaped unit is provided with multiple through holes, and the axial direction of the through holes is consistent with the thickness direction of the plate-shaped unit.

[0026] More preferably, the plate-shaped unit has multiple reinforcing ribs on its top and / or bottom surfaces.

[0027] The elastomer has deformation force and recovery force under external load (i.e., it can undergo linear deformation and recover). Multiple elastomers are spaced apart on the outside of the plate-shaped unit to generate multiple low-frequency resonance modes.

[0028] The elastomer includes a top plate, a bottom plate, and a connector; the top plate is located on the top surface of the plate-shaped unit, the bottom plate is located on the bottom surface of the plate-shaped unit, and the connector connects the top plate and the bottom plate, and the connector is located on the plate-shaped unit.

[0029] Preferably, the connector is an elastic structure, including: a cylindrical helical spring, a disc spring, a leaf spring, a plate spring, a rubber spring, or a cantilever beam type elastic load-bearing structure.

[0030] More preferably, when the connector is a cylindrical helical spring, the elastic body further includes: two shear-resistant supports; the two shear-resistant supports are spaced apart, one shear-resistant support is located at the bottom of the top plate and the other shear-resistant support is located at the top of the bottom plate; the shear-resistant supports are cylindrical and are sleeved inside the cylindrical helical spring.

[0031] This application also provides a vibration isolation device (i.e., a wave damping vibration isolation device), such as Figure 3 As shown, in one embodiment, it includes: a plurality of low-frequency multi-line spectrum wave impedance superstructures.

[0032] Multiple low-frequency multi-line spectrum wave-damping superstructures are stacked and arrayed along the bearing direction of the low-frequency multi-line spectrum wave-damping superstructure, and adjacent low-frequency multi-line spectrum wave-damping superstructures are connected by the elastic body so that there is a gap between adjacent plate units.

[0033] The aforementioned wave-blocking vibration isolation device expands the bandwidth and enhances the bandgap effect through periodicity.

[0034] This application also provides a design method for a vibration isolation device. In one embodiment, when the plate-shaped unit is a square structure and the connecting member is a cylindrical helical spring, it includes: Step 1: Obtain design parameters, including the starting frequency of the vibration isolation band, the mass of the object being vibration damped, and the system fundamental frequency; Step 2: Based on the starting frequency of the vibration isolation band, the dimensional characteristics of the plate unit, and the material properties of the plate unit, obtain the thickness of the plate unit; Step 3: Based on the mass of the object being damped, the system fundamental frequency, the characteristics of the spring, and the dimensional characteristics of the plate unit, obtain the spring stiffness, spring dimensions, top or bottom plate dimensions, and shear support dimensions.

[0035] Specifically: Obtain design parameters, including the mass of the object to be vibration-damped, the system fundamental frequency, and the starting frequency of the vibration isolation band; When the plate element is a square structure, the thickness of the plate element is obtained based on the starting frequency of the vibration isolation band, the dimensional characteristics of the plate element, and the material properties of the plate element:

[0036] In the formula, The thickness of the plate-shaped unit. ω mn The starting frequency of the vibration isolation band is the starting frequency of the vibration isolation band. Let be the side length of the plate-shaped unit. The material density of the plate-shaped unit. The Poisson's ratio of the material of the plate-shaped unit. The Young's modulus of the plate-shaped unit material; These are the eigenvalue coefficients. According to Table 1 below, the thickness can be calculated simply by substituting the first bandgap initiation frequency. h .

[0037] When the connecting component is a spring, the spring stiffness is obtained based on the mass of the object being damped and the system fundamental frequency:

[0038] In the formula, For the stiffness of the spring, For the system's base frequency, The mass of the object being damped; When the connecting component is a cylindrical helical spring, the dimensional information of the cylindrical helical spring is obtained based on the mass of the object being damped, the stiffness of the spring, and the characteristics of the spring:

[0039]

[0040]

[0041] In the formula, The mean diameter of the spring. , For the stiffness of the spring, The wire diameter ratio can be 5-8. The number of turns of the spring can be 2 (for a cylindrical compression spring, tighten both ends with 1.25 turns and grind them flat). The shear modulus of the spring material. The wire diameter of the spring. Let P be the spring pitch. For coefficients, , For the mass of the object being vibration damped, It is the acceleration due to gravity; When the connector is a cylindrical helical spring, the dimensional information of the top or bottom plate is obtained based on the dimensional characteristics of the plate unit and the dimensional information of the cylindrical helical spring:

[0042] In the formula, The mean diameter of the spring. The wire diameter of the spring. This refers to the side length of the top or bottom plate. Let be the side length of the plate-shaped unit; When the connector is a cylindrical helical spring, the dimensional information of the shear-resistant support is obtained based on the dimensional information of the cylindrical helical spring:

[0043] In the formula, The diameter of the shear-resistant support. The mean diameter of the spring. The wire diameter of the spring. The height of the shear-resistant support.

[0044] like Figure 4 As shown, the equivalent principle of the wave-blocking vibration isolation device (i.e., the multi-line spectrum local resonance structure) is as follows: like Figure 4 (a) By Bloch's theorem, the displacement of the upper and lower surfaces of the nth cell can be expressed by the following formula:

[0045] From the boundary continuity, we can know that

[0046] When the wave vector κ=0

[0047] The above equation shows that the upper and lower surfaces of the multi-line spectrum local resonance structure remain relatively stationary, and the elastic body as a whole does not undergo stretching or compression, but only translational motion. Therefore, the stiffness coefficient of the equivalent transverse constraint spring is... .

[0048] From the above equation, we can see that when the wave vector hour

[0049] The above equation shows that the displacements of the upper and lower surfaces of the multi-line spectrum local resonance structure are equal in magnitude and opposite in direction, and the load-bearing structure as a whole undergoes tension and compression. Therefore, the stiffness coefficient of the equivalent transverse constraint spring is:

[0050] Where a1 is the length of the elastic body. K t For equivalent boundary constraint stiffness, such as Figure 4 As shown in (b).

[0051] like Figure 4 (c) As a continuous body, the rectangular thin plate has multiple natural frequencies. Simply equating it to a spring-mass system does not adequately describe its physical characteristics. Therefore, it can be equating to multiple parallel spring-mass systems. Due to the high-frequency attenuation effect, the wave impedance effect of the first two low-frequency band gaps is usually considered.

[0052] like Figure 5 (a) Figure 5 As shown in (b), since the infinite periodic arrangement of mechanical metamaterials is difficult to achieve in reality, the simulation of band gap by stacking 1, 2, and 4 layers was compared. Through comparison, the 4-layer stack can fit the band gap law better.

[0053] like Figure 5 As shown in (c), the working principle of the multi-line spectrum wave blocking vibrator can be well approximated by using a spring-mass system in parallel. For k1 in 8*10... 4 -2*10 5 Within the N / m range, the start and end frequencies of its low-frequency bandgap can be obtained directly analytically.

[0054] The bandgap initiation frequency corresponds to the boundary condition of a multi-line spectrum local resonance structure with fixed support at its four corners; the bandgap termination frequency corresponds to the boundary condition of a multi-line spectrum local resonance structure undergoing free vibration. Define the normalized eigenvalue coefficients of the natural frequencies of a rectangular plate. :

[0055] m and n Let represent the wave number on the x and y axes, respectively, where 'a' is the length of the thin plate and 'D' is the bending stiffness of the plate. For the material density and thickness of the thin plate, the eigenvalue coefficient This can be directly obtained from Table 1. Among them, , The Young's modulus of the plate-shaped unit material. Given the Poisson's ratio of the plate-like unit material, therefore... .

[0056] Table 1: Eigenvalue Coefficients

[0057] In Table 1, the relative width of the band gap refers to the ratio of the band gap width to the midpoint of the band gap.

[0058] like Figure 6 As shown, the dispersion curve of the multi-line spectrum local resonance structure and the transmissivity curve of the multi-line spectrum wave-drag superstructure vibration isolator can fit very well. This indicates that by designing the multi-line spectrum local resonance structure, wave-drag vibration isolation can be achieved through periodic stacking.

[0059] Due to the symmetrical structure and periodic stacking of multi-line spectrum local resonance structures, efficient vibration isolation under complex loads can be achieved. For example... Figure 7 As shown, the first bandgap remains effective even when the torque is more than 1000 times the force load, demonstrating strong robustness; the second bandgap remains effective even when the torque is less than 10 times the force load, demonstrating weak robustness.

[0060] The aforementioned low-frequency multi-line spectrum wave-damping superstructure, vibration isolation device, and design method address the lack of vibration isolation devices with low frequency, wide bandwidth, multi-line spectrum, and strong robustness. Based on the principle of local resonance metamaterials, it combines corner support plates with the theory of periodic metamaterial structures. It uses elastic thin plates with multi-corner supports as local resonance units of the metamaterial, generating multiple low-frequency local resonance modes, thereby creating band gaps that suppress multiple low-frequency line spectra. By periodically stacking these layers to form a wave-damping vibration isolation device, it expands the bandwidth and improves the band gap effect. While maintaining appropriate load-bearing stiffness, it can produce comprehensive line spectrum vibration isolation performance with low frequency, high efficiency, small size, large bandwidth, multi-line spectrum, and strong robustness.

[0061] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0062] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A low-frequency multi-line spectrum wave impedance superstructure, characterized in that, include: Plate-shaped units and multiple elastic bodies, the plate-shaped units being thin plate structures to act as scatterers; The elastic body has deformation force and restoring force under external load. Multiple elastic bodies are spaced apart on the outside of the plate-shaped unit to generate multiple low-frequency resonance modes. When the plate-shaped unit is a square structure, the design methods for the vibration isolation device include: Obtain the design specifications and the starting frequency of the vibration isolation band; The thickness of the plate element is obtained based on the starting frequency of the vibration isolation band, the dimensional characteristics of the plate element, and the material properties of the plate element. When the connecting component is a cylindrical helical spring, the design method for the vibration isolation device also includes: Obtain design parameters, including the mass of the object to be vibration-damped and the system fundamental frequency; The stiffness of the spring is obtained based on the mass of the object being damped and the fundamental frequency of the system. Based on the mass of the object being damped, the stiffness of the spring, and the characteristics of the spring, the size information of the spring is obtained.

2. The low-frequency multi-line spectrum wave impedance superstructure according to claim 1, characterized in that, The elastomer includes: a top plate, a bottom plate, and a connector; The top plate is disposed on the top surface of the plate-shaped unit, the bottom plate is disposed on the bottom surface of the plate-shaped unit, and the connector connects the top plate and the bottom plate.

3. The low-frequency multi-line spectrum wave impedance superstructure according to claim 2, characterized in that, The connecting components include: cylindrical helical springs, disc springs, leaf springs, plate springs, rubber springs, or cantilever beam elastic load-bearing structures.

4. The low-frequency multi-line spectrum wave impedance superstructure according to claim 3, characterized in that, When the connector is a cylindrical helical spring, the elastic body further includes: two shear-resistant supports; Two shear-resistant supports are spaced apart, one shear-resistant support is located at the bottom of the top plate and the other shear-resistant support is located at the top of the bottom plate; The shear-resistant support is cylindrical and is fitted inside the cylindrical helical spring.

5. The low-frequency multi-line spectrum wave impedance superstructure according to claim 4, characterized in that, Based on the spring's dimensions, the dimensions of the shear-resistant support are obtained.

6. The low-frequency multi-line spectrum wave impedance superstructure according to claim 1, characterized in that, The plate-shaped unit is provided with multiple through holes, and the axial direction of the through holes is consistent with the thickness direction of the plate-shaped unit.

7. The low-frequency multi-line spectrum wave impedance superstructure according to claim 6, characterized in that, The plate-shaped unit is provided with multiple reinforcing ribs on its top and / or bottom surfaces.

8. A vibration isolation device, characterized in that, include: The low-frequency multi-line spectrum wave impedance superstructure according to any one of claims 1 to 7; Multiple low-frequency multi-line spectrum wave-damping superstructures are stacked and arrayed along the bearing direction of the low-frequency multi-line spectrum wave-damping superstructure, and adjacent low-frequency multi-line spectrum wave-damping superstructures are connected by the elastic body so that there is a gap between adjacent plate-like structures.

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