Additional acoustic black hole and nonlinear arc beam combined vibration absorption and isolation device
By combining nonlinear arc beams and a vibration isolator of the acoustic black hole, the ship vibration problem is solved, broadband vibration reduction and low-frequency vibration isolation are achieved, the structure's load-bearing capacity is enhanced, and the acoustic black hole structure is protected.
Patent Information
- Application Number
- CN202510619631.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-14
- Publication Date
- 2025-08-01
AI Technical Summary
The lack of combining arc beams and acoustic black holes to absorb vibration isolation in the prior art makes it difficult to effectively solve the vibration problem of ships in the marine environment.
A vibration isolator with an additional acoustic black hole combined with a nonlinear arc beam is designed. By using a nonlinear arc beam assembly and an additional acoustic black hole structure in the vibration isolation assembly, the energy aggregation effect and dynamic vibration absorption characteristics of the acoustic black hole are used to reduce structural vibration.
The broadband vibration-absorbing and noise reduction effect of the ship structure is achieved, the low-frequency vibration isolation performance is improved, the bearing capacity of the structure is enhanced, and the acoustic black hole structure is protected from external interference.
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Figure CN120402570A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of vibration and noise reduction, and particularly to a vibration absorption and isolation device combining an additional acoustic black hole and a nonlinear circular arc beam. Background Art
[0002] When a ship sails in a marine environment, it will suffer various forms of vibrations, which mainly come from factors such as engine operation, wave impact, and resonance of the hull structure. Vibration not only affects the comfort of the ship, but also poses serious hazards to the structural integrity and equipment functions of the ship. Long-term vibration will cause fatigue of the hull material, loosening of welded joints, and wear and damage of equipment, thereby reducing the service life and reliability of the ship. In addition, electronic devices and instruments on the ship are also prone to failure under strong vibration, which may affect key functions such as navigation, safety, and communication. In order to ensure the safety and performance of the ship, it is particularly important to study effective vibration reduction measures.
[0003] The Acoustic Black Hole (ABH) effect changes the thickness of the structure, making it change according to a certain power law, thereby changing the structural impedance, and causing the propagation speed of elastic waves in the structure to gradually decrease. In an ideal situation, when the thickness decreases to zero, the wave speed also correspondingly decreases to zero, resulting in zero reflection and energy concentration of the wave. In actual processing, due to the existence of truncation, the thickness cannot be reduced to zero, but the energy is still concentrated in the area of the minimum thickness of the structure. Therefore, by combining a small amount of damping material in the energy concentration area, the structural loss factor can be effectively enhanced, energy can be absorbed, and the vibration of the structure can be reduced.
[0004] The quasi-zero stiffness isolator is a combined isolator that combines positive and negative stiffness elastic elements in the static equilibrium position to obtain zero stiffness. By reasonably optimizing the geometric and stiffness parameters of the negative stiffness mechanism, it is possible to achieve excellent low-frequency vibration isolation performance while having a large bearing capacity for the vibration isolation system. The slender circular arc beam exhibits high bearing capacity during initial buckling and low stiffness after being loaded for a period of time. Its high bearing capacity enables the structure to have good load-bearing performance, and its low stiffness makes the natural frequency of the structure lower, thus widening the vibration isolation frequency band. These properties of the circular arc beam structure make it an ideal choice for mechanical isolators. Compared with other vibration isolation structures, the circular arc beam structure can have a lower stiffness after loading, so it has a lower structural frequency and is more effective for the low-frequency vibration isolation of the structure. However, there is a lack of research on combining circular arc beams and acoustic black holes for vibration absorption and isolation in the prior art. Summary of the Invention
[0005] The purpose of the present invention is to provide a vibration absorption and isolation device combining an additional acoustic black hole and a nonlinear circular arc beam to solve the problems existing in the above prior art and reduce the vibration problem of the structure.
[0006] To achieve the above object, the present invention provides the following solutions:
[0007] The present invention provides a vibration isolation and absorption device combining an additional acoustic black hole and a non-linear circular arc beam, which includes a vibration isolation component and an absorption component. The vibration isolation component is used to be placed between an excitation source and a controlled structure, and includes a first cover body, a second cover body, and a plurality of non-linear circular arc beam components that are circumferentially distributed and supported between the first cover body and the second cover body. The first cover body and the second cover body are used to be fixedly connected to the excitation source and the controlled structure respectively; the absorption component includes at least one additional acoustic black hole structure, and the additional acoustic black hole structure can be fixedly placed between the first cover body and the second cover body, and the additional acoustic black hole structure is surrounded by a plurality of the non-linear circular arc beam components.
[0008] Preferably, each of the non-linear circular arc beam components includes a first connecting plate, a second connecting plate, and a plurality of non-linear circular arc beam cells arranged between the first connecting plate and the second connecting plate. Each of the non-linear circular arc beam cells is connected to the first connecting plate and the second connecting plate; the first connecting plate and the second connecting plate are respectively fixedly connected to the first cover body and the second cover body.
[0009] Preferably, each of the non-linear circular arc beam cells includes two acoustic black hole beams that are bent and symmetrically arranged. Both ends of each acoustic black hole beam are thin ends, and the middle is a thick end; the thickness of the acoustic black hole beam decreases exponentially from the middle to both ends.
[0010] Preferably, the expression of the thickness decreasing exponent of the acoustic black hole beam is h(x) = εx m + h0; where 0 ≤ x ≤ l, x represents the distance from a point on the acoustic black hole beam to the thick end, h(x) is the thickness of the acoustic black hole beam; ε represents a coefficient; l is the length of the acoustic black hole beam; m is a constant and m ≥ 2; h0 is the thickness of the thick end of the acoustic black hole beam.
[0011] Preferably, the bending directions of the two acoustic black hole beams of each non-linear circular arc beam cell are opposite to each other.
[0012] Preferably, adjacent non-linear circular arc beam cells are arranged at intervals.
[0013] Preferably, the absorption component includes a plurality of the additional acoustic black hole structures, and the plurality of additional acoustic black hole structures are stacked and fixedly connected.
[0014] Preferably, each of the additional acoustic black hole structures includes an eccentric disc, a first connecting ring, and a second connecting ring. The eccentric disc includes a connecting column and a damping disc surrounding the circumference of the connecting column. The connecting column is connected to the first cover body, and the thickness of the longitudinal section of the damping disc decreases exponentially from the side attached to the connecting column along the direction away from the connecting column; the first connecting ring is fixedly arranged at the circumferential edge of the eccentric disc, and the second connecting ring is fixedly arranged on the side of the first connecting ring away from the first cover body.
[0015] Preferably, the connecting column is arranged as a rectangular column, the damping disc is arranged as a rectangular disc, and both the first connecting ring and the second connecting ring are arranged as rectangular rings.
[0016] Preferably, the expression of the thickness decreasing exponent of the longitudinal section of the damping disc is h(w i ) = h1 + aw i n , i = 1, 2, 3, 4, where h(w i ) represents the thickness of the damping disc, w i , i = 1, 2, 3, 4 respectively represent the distance from any point on the four sides of the damping disc to the corresponding parallel side of the upper surface of the connecting column, h1 represents the thickness of the thick end of the damping disc, a represents a coefficient, and n ≥ 2.
[0017] The present invention has achieved the following technical effects compared with the prior art:
[0018] The vibration isolation and absorption device with an additional acoustic black hole combined with a non - linear circular arc beam provided by the present invention forms a support structure through the non - linear circular arc beam assembly, and is respectively connected to the excitation source and the controlled structure through the first cover body and the second cover body. The circular arc beam support structure has a large stiffness when the load is low, and the stiffness rapidly decreases as the load increases until the stiffness decreases to the minimum and then starts to increase. Therefore, it can use its high static - low dynamic characteristics for vibration isolation; at the same time, an absorption component is arranged inside the vibration isolation component, which includes an additional acoustic black hole structure. Waves with a certain frequency emitted by the excitation source are transmitted to the additional acoustic black hole structure through the non - linear circular arc beam assembly. Utilizing the acoustic black hole effect and the characteristics of dynamic absorption of the additional acoustic black hole structure, broadband vibration reduction and noise reduction are carried out on the controlled structure; in addition, since the additional acoustic black hole structure is arranged inside the non - linear circular arc beam assembly, while the non - linear circular arc beam assembly plays a supporting role, it can also protect the additional acoustic black hole structure from external interference and damage, affecting the vibration reduction effect. Description of the Drawings
[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.
[0020] Figure 1 Structural diagram of the additional acoustic black hole combined with a non-linear circular arc beam isolator provided for Embodiment 1;
[0021] Figure 2 Unilateral structural diagram of the non-linear circular arc beam assembly provided for Embodiment 1;
[0022] Figure 3 Schematic diagram of the non-linear circular arc beam cell provided for Embodiment 1;
[0023] Figure 4 Schematic diagram of the mechanical loading of the acoustic black hole beam provided for Embodiment 1;
[0024] Figure 5 Front view schematic diagram of the vibration absorber assembly provided for Embodiment 1;
[0025] Figure 6 Top view schematic diagram of a single additional acoustic black hole structure provided for Embodiment 1;
[0026] Figure 7 For Figure 6 Cross-sectional schematic diagram in the A-A direction;
[0027] Figure 8 For Figure 6 Cross-sectional schematic diagram in the B-B direction;
[0028] Figure 9 Schematic diagram of the vibration energy propagation and aggregation of the vibration damping disc provided for Embodiment 1;
[0029] Figure 10 Schematic diagram of the displacement load curve and the curve of the structural stiffness changing with displacement of the additional acoustic black hole combined with a non-linear circular arc beam isolator provided for Embodiment 1;
[0030] Figure 11 Schematic diagram of the transmissibility curve of the additional acoustic black hole combined with a non-linear circular arc beam isolator after being subjected to a pre-pressure provided for Embodiment 1.
[0031] In the figure: 1 - vibration isolation component; 11 - first cover; 12 - second cover; 13 - non-linear circular arc beam component; 131 - first connecting plate; 132 - second connecting plate; 133 - non-linear circular arc beam cell; 134 - acoustic black hole beam; 2 - vibration absorption component; 21 - additional acoustic black hole structure; 211 - eccentric disc; 212 - first connecting ring; 213 - second connecting ring; 214 - connecting column; 215 - vibration damping disc. Specific embodiments
[0032] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.
[0033] The purpose of the present invention is to provide a vibration isolation and absorption device combining an additional acoustic black hole and a non-linear circular arc beam to solve the problems existing in the above-mentioned prior art. A part of the vibration energy is isolated by the non-linear circular arc beam, and then a part of the vibration energy is dissipated through the energy aggregation effect of the additional acoustic black hole and the principle of dynamic vibration absorption, reducing the vibration problem of the structure.
[0034] To make the above objects, features and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.
[0035] Embodiment 1
[0036] This embodiment provides a vibration isolation and absorption device combining an additional acoustic black hole and a non-linear circular arc beam. Please refer to Figure 1 , which includes a vibration isolation component 1 and a vibration absorption component 2; the vibration isolation component 1 is used to be placed between the excitation source and the controlled structure, and includes a first cover 11, a second cover 12, and a plurality of non-linear circular arc beam components 13 that are circumferentially distributed and supported between the first cover 11 and the second cover 12. The first cover 11 and the second cover 12 are used to be fixedly connected to the excitation source and the controlled structure respectively; the vibration absorption component 2 includes at least one additional acoustic black hole structure 21. The additional acoustic black hole structure 21 can be fixedly placed between the first cover 11 and the second cover 12, and the additional acoustic black hole structure 21 is surrounded by a plurality of non-linear circular arc beam components 13.
[0037] In an alternative solution of this embodiment, preferably, please refer to Figure 2, each non - linear circular arc beam assembly 13 includes a first connecting plate 131, a second connecting plate 132, and a plurality of non - linear circular arc beam cells 133 disposed between the first connecting plate 131 and the second connecting plate 132. Each non - linear circular arc beam cell 133 is connected to the first connecting plate 131 and the second connecting plate 132; the first connecting plate 131 and the second connecting plate 132 are respectively fixedly connected to the first cover 11 and the second cover 12; by providing the first connecting plate 131 and the second connecting plate 132, it is convenient for the non - linear circular arc beam cells 133 to be relatively fixed to the first cover plate 11 and the second cover plate 12, and the plurality of non - linear circular arc beam cells 133 can all play a vibration isolation role; wherein, the connection methods between the first connecting plate 131 and the second connecting plate 132 and the first cover plate 11 and the second cover plate 12, and the connection methods between the non - linear circular arc beam cells 133 and the first connecting plate 131 and the second connecting plate 132 can be fixedly connected by corresponding fixing methods such as welding or printing and forming integrally according to the selected materials. The first connecting plate 131 and the second connecting plate 132 can also be bolt - connected by appropriately punching holes on the contact surfaces. The first connecting plate 131 and the second connecting plate 132 can be obtained by 3D printing using photosensitive resin.
[0038] In an alternative embodiment of the present invention, more preferably, please refer to Figure 3 , each non - linear circular arc beam cell 133 includes two acoustic black hole beams 134 that are bent and symmetrically arranged. The two ends of each acoustic black hole beam 134 are thin ends, and the middle is a thick end. The two thin ends of the acoustic black hole beam 134 are respectively connected to the first connecting plate 131 and the second connecting plate 132 and can undergo relative torsion under a load; the thickness of the acoustic black hole beam 134 decreases exponentially from the middle to the two ends; the acoustic black hole beam 134 is designed into a non - linear circular arc beam cell 133 by bending a one - dimensional acoustic black hole beam around a circular arc. When the non - linear circular arc beam cells 133 are assembled in an array to form a non - linear circular arc beam assembly 13, it has a relatively large stiffness when the load is low, and as the load increases, the stiffness rapidly decreases until the stiffness reaches the minimum and then starts to increase. Therefore, it can utilize its high static - low dynamic characteristics for vibration isolation.
[0039] Furthermore, the expression of the thickness decreasing exponent of the acoustic black hole beam 134 is h(x) = εx m + h0; where 0 ≤ x ≤ l, x represents the distance from a point on the acoustic black hole beam 134 to the thick end, h(x) is the thickness of the acoustic black hole beam 134; ε represents a coefficient and is a negative number; l is the length of the acoustic black hole beam 134; m is a constant and m ≥ 2; h0 is the thickness of the thick end of the acoustic black hole beam 134.
[0040] In an alternative embodiment of the present invention, more preferably, the bending directions of the two acoustic black hole beams 134 of each non - linear circular arc beam cell 133 are opposite. By setting them in opposite directions, interference during the bending process of the two acoustic black hole beams 134 is avoided.
[0041] In an optional solution of this embodiment, it is more preferred that adjacent nonlinear arc beam cells 133 are spaced apart to avoid interference in the bending processes of adjacent nonlinear arc beam cells 133 .
[0042] The nonlinear arc beam assembly 13 provided in this embodiment is formed by an array of multiple nonlinear arc beam cells 133, ensuring that the properties of the structural nonlinear arc beam cells 133 remain unchanged. The nonlinear arc beam assembly 13 of this embodiment is stacked in a single layer, and can be stacked in multiple layers as needed during actual application. If multi-layer stacking is performed, additional cross beams can be added between layers to avoid direct connection of the nonlinear arc beam cells 133 between the multiple layers. Direct connection can easily lead to changes in the properties of the nonlinear arc beam cells 133; the nonlinear arc beam cells 133 have excellent nonlinear performance, and the structural stiffness can drop sharply as the applied load increases. It has a lower modal frequency and is more effective for low-frequency vibration reduction.
[0043] Among the optional solutions of this embodiment, it is more preferred to refer to Figure 8 The vibration absorbing component 2 includes multiple additional acoustic black hole structures 21, which are stacked and fixedly connected. By stacking multiple additional acoustic black hole structures 21, the vibration reduction and noise reduction effects are improved.
[0044] Among the optional solutions of this embodiment, it is more preferred to refer to Figures 5 - 8 Each additional acoustic black hole structure 21 includes an eccentric disk 211, a first connecting ring 212 and a second connecting ring 213. The eccentric disk 211 includes a connecting column 214 and a vibration-damping disk 215 arranged around the connecting column 214. The connecting column 214 is connected to the first cover 11. The thickness of the longitudinal section of the vibration-damping disk 215 decreases exponentially from the side that is in contact with the connecting column 214 in the direction away from the connecting column 214; the first connecting ring 212 is fixedly arranged on the circumferential edge of the eccentric disk 211, and the second connecting ring 213 is fixedly arranged on the side of the first connecting ring 212 away from the first cover 11; the wave of a certain frequency emitted by the excitation source is transmitted to the additional acoustic black hole structure 21 through the nonlinear arc beam component. Since the thickness of the vibration-damping disk 215 decreases exponentially, the propagation speed of the wave decreases as the thickness decreases, the wavelength decreases, the vibration amplitude of the wave increases, and it gathers in the area with smaller thickness, such as Figure 9 As shown, the acoustic black hole effect and the characteristics of dynamic vibration absorption are used to perform broadband vibration and noise reduction on the controlled structure; wherein the connecting column 214 can be detachably connected to the first cover body 11, such as by bolts, so as to achieve wave transmission.
[0045] Among them, when the flexural wave propagates in the acoustic black hole region (variable thickness region) of the vibration damping disc 215, the propagation speed of the elastic wave decreases as the structural thickness decreases. When the structural thickness is 0, the wave speed decreases to 0 and thus no reflection occurs. However, in actual processing, the structural thickness cannot be 0, so a truncation is provided. When the wave reaches the truncation of the vibration damping disc 215, due to the presence of the first connecting ring 212, the wave continues to propagate at a small wave speed, thereby concentrating the flexural wave energy in the thinner part at the edge of the structure; the outer edge of the circumferential direction of the second connecting ring 213 is flush with the outer edge of the circumferential direction of the first connecting ring 212. The second connecting ring 213 can be set as an annular damping gasket, which can consume the flexural wave energy concentrated at the edge, thereby achieving the purpose of high-efficiency energy absorption or vibration reduction and noise reduction. The annular damping gasket can be made of butyl rubber material, and the thickness can be specifically determined according to different materials.
[0046] Specifically, the eccentric disc 211 and the first connecting ring 212 can be integrally formed to improve stability, and the second connecting ring 21 can be bonded to the first connecting ring 212.
[0047] Further preferably, the connecting column 214 and the vibration damping disc 215 are eccentrically arranged to form the eccentric disc 211, that is, the line connecting the center of the connecting column 214 and the center of the upper surface of the vibration damping disc 215 is not perpendicular to the upper surface of the vibration damping disc 215. The entire additional acoustic black hole structure 21 is eccentrically arranged. Designing it in an eccentric form, compared with a symmetric structure, enables the additional acoustic black hole structure 21 to be more easily and strongly coupled with the controlled structure, better transfer the wave energy to the additional acoustic black hole structure 21 and consume it, and fully utilize the advantage of the energy concentration effect of the acoustic black hole.
[0048] In an alternative solution of this embodiment, more preferably, the connecting column 214 is set as a rectangular column, the vibration damping disc 215 is set as a rectangular disc, and both the first connecting ring 212 and the second connecting ring 213 are set as rectangular rings. Further, the expression of the thickness decreasing exponent of the longitudinal section of the vibration damping disc 215 is h(w i ) = h1 + aw i n , i = 1, 2, 3, 4, where h(w i ) represents the thickness of the vibration damping disc 215, w i , i = 1, 2, 3, 4 respectively represent the distance from any point on the four sides of the vibration damping disc 215 to the corresponding parallel side of the upper surface of the connecting column 214, h1 represents the thickness of the thick end of the vibration damping disc 215, a represents a coefficient, which is negative, n ≥ 2, specifically, n takes 2.
[0049] It should be noted that in the actual application process, the specific structure of the additional acoustic black hole structure 21 is not limited to the additional acoustic black hole structure 21 provided in this embodiment, and other types of additional acoustic black hole components can be selected according to actual needs.
[0050] The vibration isolation and absorption device combining an additional acoustic black hole and a nonlinear circular arc beam provided in this embodiment has the following specific working principle: The first cover plate 11 is connected to the excitation source, and the second cover plate 12 is connected to the controlled structure. The one-dimensional acoustic black hole beam 134 is designed as a nonlinear circular arc beam cell 133 by bending around a circular arc. The nonlinear circular arc beam components 13 are formed by assembling the nonlinear circular arc beam cells 133 in an array. The nonlinear circular arc beam components 13 have a large stiffness when the load is low, and the stiffness rapidly decreases as the load increases until the stiffness reaches the minimum and then starts to increase. Therefore, it can utilize its high-static-low-dynamic characteristics for vibration isolation. At the same time, an additional acoustic black hole structure 21 is arranged inside the nonlinear circular arc beam component 13. Waves of a certain frequency emitted by the excitation source are transmitted to the additional acoustic black hole structure 21 through the nonlinear circular arc beam component 13. Since the thickness of the damping disc 215 decreases exponentially, the propagation speed of the wave decreases as the thickness decreases, the wavelength decreases, and the vibration amplitude of the wave increases, gathering towards the region with a smaller thickness. Utilizing the acoustic black hole effect and the characteristics of dynamic vibration absorption, broadband vibration reduction and noise reduction are performed on the controlled structure. In addition, since the additional acoustic black hole structure 21 is arranged inside the nonlinear circular arc beam component 13, the nonlinear circular arc beam component 13 can support and protect the additional acoustic black hole structure 21 at the same time, avoiding external interference and damage to the additional acoustic black hole structure 21 and affecting the vibration reduction effect of the vibration reduction structure. That is, by combining the low selectivity of the nonlinear structure for frequency and the effective energy aggregation and dissipation characteristics of the acoustic black hole, the disadvantages that the traditional additional dynamic vibration absorber can only effectively play a role at a specific frequency can be effectively avoided, and its advantages can be efficiently exerted in structural vibration isolation.
[0051] The dimensions of each part of the vibration isolation and absorption device combining an additional acoustic black hole and a nonlinear circular arc beam provided in this embodiment are determined according to actual needs. Specifically, the following dimensions can be adopted in this embodiment. The additional acoustic black hole structures 21 are fixedly stacked together through connecting columns 214, such as by welding or integrally formed, as Figure 5 shown. The symbol "***" in the figure represents multiple additional acoustic black hole structures 21. In this embodiment, a total of 5 additional acoustic black hole structures 21 are stacked. The dimensions of each additional acoustic black hole structure 21 are the same, and the widths of each damping disc 215 are w ABH1 = 80 mm, w ABH2 = 35 mm, w ABH3 = 60 mm, w ABH4 = 70 mm, the maximum thickness is 10 mm, the minimum thickness is 1 mm, and the damping disc 215 structure is made of aluminum. In this embodiment, the maximum thickness at the center of each one-dimensional acoustic black hole beam 134 is 1 mm, and the minimum thickness at both ends is 0.2 mm. Please refer to Figure 3, the length b1 of the arc beam is 60 mm, and the height b2 is 10 mm. A symmetric non-linear arc beam cell 133 is established. Each first connecting plate 131 is connected to 7 non-linear arc beam cells 133, and the distance between each cell is 10 mm. Both the first connecting plate 131 and the second connecting plate 132 adopt a strip structure with a length * width * height of 240 mm * 20 mm * 1 mm respectively, and the materials of the first connecting plate 131 and the second connecting plate 132 are aluminum. Both the first cover plate 11 and the second cover plate 12 adopt a rectangular plate structure with a length * width * height of 240 mm * 240 mm * 4 mm respectively, and both the first cover plate 11 and the second cover plate 12 are made of metal materials, steel or aluminum.
[0052] As Figure 4 shown, it is a schematic diagram of an acoustic black hole beam 134 with both ends hinged under axial load, where L is the original length of the beam, x is the axial displacement, F is the axial load, w is the transverse displacement, and the relationship between the axial displacement x and the load F is:
[0053]
[0054] where represents the critical load at which the acoustic black hole beam 134 with both ends hinged yields, where E is the elastic modulus and I is the section moment of inertia. From the above equation, the relationship between the axial displacement and the structural stiffness can be obtained as follows:
[0055]
[0056] Figure 10 shows that the change of the structural stiffness with displacement in this embodiment is consistent with the result of the above formula; the load is applied to the second cover plate 12 on the upper side, and the relationship between the displacement and the load of the second cover plate 12 after the first cover plate 11 on the lower side is fixed and constrained, and the change of the structural stiffness is obtained from the displacement-load curve; it can be seen from its stiffness curve that when the structure initially deforms, the structural stiffness reaches 175 N / mm. As the amount of compressive deformation increases, the structural stiffness rapidly decreases in the initial deformation stage. After compressing 4 mm, the structural stiffness decreases to 50 N / mm. As the load continues to increase, the structural stiffness can further decrease and finally decrease to zero or even a negative number; therefore, the large stiffness in the early stage can be used to provide a strong bearing capacity for the system, and as the stiffness decreases, the natural frequency of the structure also decreases, so its low stiffness can be used for vibration isolation; where Figure 10 is only the curve measured for the structure of this embodiment, and curves with the same properties but different numerical values can be obtained by changing the structural parameters and materials.
[0057] As Figure 11As shown, when exciting the first cover plate 11 on the lower side, the mean square vibration velocity of the first cover plate 11 and the second cover plate 12 is extracted, and the transmissibility between the first cover plate 11 and the second cover plate 12 is obtained through the difference in the mean square velocity of the first cover plate 11 and the second cover plate 12. The calculation formula for the mean square vibration velocity of the plate surface is as follows, where a i v_i(f) is the velocity value of the i-th node at a certain frequency, a ms v(f) is the mean square vibration velocity of the corresponding frequency to be obtained, and n is the total number of nodes on the plate surface;
[0058]
[0059] Figure 11 In this embodiment, the transmissibility curve of the structure after being subjected to a pre-pressure of 700 N is calculated. The structural stiffness of the structure is 178.8 N / mm under the condition of not bearing pre-pressure, and the structural stiffness is 18.7 N / mm after applying a pre-pressure of 700 N, and the stiffness is almost reduced by 10 times. The structural stiffness can be obtained from the slope of the load curve, that is Figure 10 . When the load is 0 (i.e., the origin), the slope of the curve is 178.8, and when the load is 700 N, the slope is 18.7; from the definition of its transmissibility, when the transmissibility is less than 0, it indicates that the vibration transmitted from the excitation end (the first cover plate 11) to the output end (the second cover plate 12) decreases, indicating that the vibration isolation structure has a certain vibration isolation effect. From the transmissibility results, the transmissibility is less than 0 in all frequency bands, indicating that the structure of this embodiment has a good vibration isolation effect. This is because the circular arc beam structure has a relatively small structural frequency at low stiffness and can play a good role in isolating low-frequency vibrations. At the same time, the additional acoustic black hole structure inside the structure can absorb vibration energy, thereby further reducing the vibration energy transmitted to the upper plate surface.
[0060] In the present invention, specific examples are used to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present invention.
Claims
1. An additional acoustic black hole combined with a non-linear circular arc beam vibration absorber, characterized in that: Comprising: A vibration isolation component (1), which is used to be placed between an excitation source and a controlled structure, and includes a first cover body (11), a second cover body (12), and a plurality of non-linear circular arc beam components (13) that are circumferentially distributed and supported between the first cover body (11) and the second cover body (12). The first cover body (11) and the second cover body (12) are used to be fixedly connected to the excitation source and the controlled structure respectively; A vibration absorption component (2), which includes at least one additional acoustic black hole structure (21). The additional acoustic black hole structure (21) can be fixedly placed between the first cover body (11) and the second cover body (12), and the additional acoustic black hole structure (21) is surrounded by a plurality of the non-linear circular arc beam components (13).
2. The vibration absorption and isolation device of the additional acoustic black hole combined with the nonlinear circular arc beam according to claim 1, characterized in that: Each of the non-linear circular arc beam components (13) includes a first connecting plate (131), a second connecting plate (132), and a plurality of non-linear circular arc beam cells (133) arranged between the first connecting plate (131) and the second connecting plate (132). Each of the non-linear circular arc beam cells (133) is connected to the first connecting plate (131) and the second connecting plate (132); the first connecting plate (131) and the second connecting plate (132) are fixedly connected to the first cover body (11) and the second cover body (12) respectively.
3. The additional acoustic black hole combined with a non-linear circular arc beam vibration absorber according to claim 2, characterized in that: Each of the non-linear circular arc beam cells (133) includes two acoustic black hole beams (134) that are bent and symmetrically arranged. Both ends of each of the acoustic black hole beams (134) are thin ends, and the middle is a thick end; the thickness of the acoustic black hole beam (134) decreases exponentially from the middle to both ends.
4. The additional type acoustic black hole combined with a non-linear circular arc beam vibration absorber according to claim 3, wherein: The expression for the thickness decreasing exponent of the acoustic black hole beam (134) is h(x) = εx m + h0; Where 0≤x≤l, x represents the distance from a point on the acoustic black hole beam (134) to the thick end, h(x) is the thickness of the acoustic black hole beam (134); ε represents a coefficient; l is the length of the acoustic black hole beam (134); m is a constant, and m≥2; h0 is the thickness of the thick end of the acoustic black hole beam (134).
5. The additional type acoustic black hole combined with a non-linear circular arc beam vibration absorber according to claim 3, characterized in that: The bending directions of the two acoustic black hole beams (134) of each of the non-linear circular arc beam cells (133) are opposite to each other.
6. The additional acoustic black hole combined with the non-linear circular arc beam vibration absorber according to claim 2, characterized in that: Adjacent non-linear circular arc beam cells (133) are arranged at intervals.
7. The vibration absorption and isolation device of an additional acoustic black hole combined with a non-linear circular arc beam according to claim 1, characterized in that: The vibration absorption component (2) includes a plurality of the additional acoustic black hole structures (21), and the plurality of the additional acoustic black hole structures (21) are stacked and fixedly connected.
8. The additional acoustic black hole combined with the nonlinear circular arc beam vibration absorber according to claim 7, characterized in that: Each of the additional acoustic black hole structures (21) includes an eccentric disk (211), a first connecting ring (212) and a second connecting ring (213). The eccentric disk (211) includes a connecting column (214) and a damping disk (215) surrounding the circumferential side of the connecting column (214). The connecting column (214) is connected to the first cover body (11). The thickness of the longitudinal section of the damping disk (215) decreases exponentially from the side attached to the connecting column (214) along the direction away from the connecting column (214). The first connecting ring (212) is fixedly arranged at the circumferential edge of the eccentric disk (211), and the second connecting ring (213) is fixedly arranged on the side of the first connecting ring (212) away from the first cover body (11).
9. The vibration absorption and isolation device of an additional acoustic black hole combined with a non-linear circular arc beam according to claim 8, characterized in that: The connecting column (214) is arranged as a rectangular column, the damping disk (215) is arranged as a rectangular disk, and both the first connecting ring (212) and the second connecting ring (213) are arranged as rectangular rings.
10. The vibration absorption and isolation device of an additional acoustic black hole combined with a non-linear circular arc beam according to claim 9, characterized in that: The expression of the thickness decreasing exponent of the longitudinal section of the damping disc (215) is h(w i ) = h1 + aw i n , i = 1, 2, 3, 4, where h(w i ) represents the thickness of the damping disc (215), w i , i = 1, 2, 3, 4 respectively represent the distances from any point on the four sides of the damping disc (215) to the corresponding parallel sides of the upper surface of the connecting column (214), h1 represents the thickness of the thick end of the damping disc (215), a represents the coefficient, and n ≥ 2.