Full-band vibration reduction structure and method based on acoustic black hole effect and resonance principle

Abstract

The present invention discloses a full-band vibration reduction structure and method based on the acoustic black hole effect and resonance principle, including an acoustic black hole structure connected to a uniform beam and a damping layer element arranged on the upper surface of the acoustic black hole structure; a plurality of array-distributed through holes are distributed on the uniform beam, and a damping resonator is arranged in the through hole; the acoustic black hole structure includes an arc-shaped plate composed of a tapered arc surface on the upper surface and a horizontal surface on the lower surface, and the damping resonator includes a mass block and a damping beam arranged on the periphery of the mass block, and the low-frequency band frequency that the vibration reduction structure needs to attenuate is selected by adjusting the thickness of the damping beam. The present invention concentrates the bending wave energy on the structure onto the acoustic black hole component, and utilizes the damping layer attached to the surface of the acoustic black hole structure to realize the absorption and dissipation of the medium and high frequency bending wave vibration energy, and concentrates the low-frequency vibration energy onto the damping resonator to realize the attenuation of the low-frequency bending wave vibration energy, thereby achieving a good effect of vibration reduction and noise reduction of the structure in the full frequency band.

Description

Technical Field

[0001] The present invention relates to the field of structural vibration reduction and noise reduction and acoustic vibration technology, and in particular to a full-band vibration reduction structure based on acoustic black hole effect and resonance principle. Background Art

[0002] The concept of acoustic black hole can be compared to the concept of black hole in astrophysics. The acoustic black hole effect gradually reduces the phase velocity and group velocity of the bending wave to zero by power-law trimming the thickness of the beam or thin plate structure or by gradient modification of the material properties, thereby achieving the bending wave aggregation effect at the end of the bending wave and forming a high energy density area. By adding damping material to the high energy area at the tip of the acoustic black hole, good energy absorption and vibration reduction and noise reduction effects can be achieved.

[0003] Therefore, the acoustic black hole effect has broad application prospects in vibration reduction, noise reduction, fluctuation control and energy recovery. In the process of structural vibration reduction and noise reduction, the acoustic black hole has certain advantages in practical application because of its single structure and material.

[0004] The thickness variation law of the ideal acoustic black hole structure obeys the power law distribution h(x) = εx m (where ε is the profile slope and m is the black hole order). Ideally, the thickness of the acoustic black hole structure is clipped to zero along the direction in which x decreases.

[0005] However, the traditional acoustic black hole structure mainly attenuates the vibration of the main structure in the medium and high frequency bands, and has a poor vibration reduction effect on the low frequency band. At the same time, the acoustic black hole effect is mainly achieved by trimming the thickness of the main structure, which will weaken the thickness of the main structure and reduce its stiffness and strength, which will affect the performance of the actual engineering structure.

[0006] Therefore, in the process of structural vibration and noise reduction, it is very important to design a full-band vibration reduction device that can compensate for the poor vibration reduction effect of the acoustic black hole effect in the low frequency band without destroying the strength of the main structure. Summary of the invention

[0007] In order to solve the above-mentioned defects existing in the prior art, the purpose of the present invention is to provide a full-band vibration reduction structure based on the acoustic black hole effect and the resonance principle. By connecting a damping resonator to the middle through hole of the uniform beam, connecting the acoustic black hole structure to the side of the uniform beam, and finally applying the vibration reduction structure to other main structures, the purpose of better full-band vibration reduction and noise reduction is achieved while avoiding reducing the strength of the main structure.

[0008] The object of the present invention is achieved through the following technical solutions.

[0009] The present invention provides a full-band vibration reduction structure based on the acoustic black hole effect and resonance principle, comprising a uniform beam, an acoustic black hole structure connected to the uniform beam, and a damping layer element arranged on the upper surface of the acoustic black hole structure; a plurality of array-distributed through holes are distributed on the uniform beam, and a damping resonator is arranged in the through hole;

[0010] The acoustic black hole structure comprises an arc-shaped plate with a tapered arc-shaped upper surface and a horizontal lower surface, wherein the end with a larger thickness is connected to a uniform beam, and the end with a smaller thickness is attached to a damping layer element;

[0011] The damping resonator comprises a mass block and a damping beam arranged on the periphery of the mass block. The low-frequency band frequency that the vibration reduction structure needs to attenuate is selected by adjusting the thickness of the damping beam.

[0012] Preferably, the uniform beam is a plate-like rectangular parallelepiped, the distance between the upper and lower surfaces is equal, a plurality of rectangular through holes are hollowed out in the middle of the uniform beam, and the damping resonator is arranged in the rectangular through holes of the uniform beam.

[0013] Preferably, the damping resonator mass block is a rectangular structure, and the thickness of the mass block is the same as the thickness of the uniform beam; the damping beam is a pair of rectangular frame beams, and the pair of damping beams are symmetrically arranged at both ends of the mass block, and the two ends of the damping beam are connected to the side walls of the middle through hole of the uniform beam.

[0014] Preferably, a pair of damping beams are provided with bending portions at opposite ends, and the bending direction of each damping beam is the same, one bending portion is connected to the mass block, and the other bending portion is bent outward; the bending directions of the oppositely arranged damping beams are opposite.

[0015] Preferably, the acoustic black hole structure is rigidly connected to the side surface of the uniform beam; the maximum thickness of the acoustic black hole structure is the same as the thickness of the uniform beam.

[0016] Preferably, the edge thickness of the acoustic black hole structure is 0.05-0.1 times its maximum thickness.

[0017] Preferably, the damping layer is applied to the edge of the upper surface of the acoustic black hole structure; the thickness of the damping layer is 1-4 times the thickness of the edge of the acoustic black hole structure.

[0018] Preferably, the uniform beam structure, the acoustic black hole structure and the mass block are made of Q235A3 steel; the damping layer and the damping beam are made of high damping alloy, rubber or foam plastic.

[0019] The present invention further provides a low-frequency band frequency screening method of the structure, comprising the following steps:

[0020] According to the geometric parameters of the vibration reduction structure, the damping resonator unit model is established in Comsol Mutiphysics6.0;

[0021] Determine the material parameters and material properties of the mass block and the damping beam respectively;

[0022] Select the characteristic frequency and set the thickness variation region of the damping beam of the damping resonator unit;

[0023] Perform parametric scanning calculation on the damping beam in the selected thickness variation area to obtain the modal frequency corresponding to the thickness of each damping beam in the set area;

[0024] The data processing software origin is used to draw the relationship curve between each thickness of the damping beam in the set area and the corresponding modal frequency value.

[0025] The present invention adopts the above technical solution, which has the following beneficial effects:

[0026] 1. The full-band vibration reduction structure based on the acoustic black hole effect and the resonance principle provided by the present invention has a plurality of rectangular through holes hollowed out in the uniform beam region of the vibration reduction structure, and a plurality of damping resonators are connected in the middle of the hollowed-out uniform beam through holes. Through the resonance principle, low-frequency vibration energy can be concentrated on the damping beam of the damping resonator, thereby attenuating the low-frequency vibration energy; and a plurality of damping resonators are arranged to enhance the attenuation effect of the selected frequency peak in the low-frequency band.

[0027] 2. The acoustic black hole structure connected to the side of the uniform beam utilizes the acoustic black hole effect to concentrate the bending wave energy transmitted from the uniform beam to the end of the acoustic black hole structure, and utilizes the damping layer applied to the surface of the acoustic black hole structure to realize the absorption and dissipation of the bending wave vibration energy in the medium and high frequency bands.

[0028] 3. The vibration reduction structure is applied to the main structure without cutting the main structure. Through the acoustic black hole effect, the acoustic black hole structure is used to absorb and dissipate the medium and high frequency vibration energy. At the same time, according to the resonance principle, the damping resonator is used to attenuate the low frequency vibration energy, which can achieve the excellent effect of vibration reduction and noise reduction of the main structure in the whole frequency band. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The drawings described herein are used to provide a further understanding of the present invention, constitute a part of the present application, and do not constitute an improper limitation of the present invention. In the drawings:

[0030] Figure 1 It is a three-dimensional structural schematic diagram of the vibration reduction structure of the present invention;

[0031] Figure 2 A three-dimensional schematic diagram of the acoustic black hole structure of the vibration reduction structure of the present invention;

[0032] Figure 3 It is a schematic diagram of the three-dimensional structure of the damping layer of the vibration reduction structure of the present invention;

[0033] Figure 4 It is a schematic diagram of the body structure of the damping resonator of the vibration reduction structure of the present invention;

[0034] Figure 5 A schematic diagram of the cross-sectional thickness variation of the vibration reduction structure of the present invention;

[0035] Figure 6 is a frequency selection curve of the damping resonator of the vibration reduction structure of the present invention in the low frequency band;

[0036] Figure 7 is a vibration characteristic response diagram of the vibration reduction structure of the present invention;

[0037] The marks in the attached drawings are: 1-uniform beam; 2-acoustic black hole structure; 3-damping layer; 4-damping resonator structure. DETAILED DESCRIPTION

[0038] The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments. The exemplary embodiments and descriptions of the present invention are used to explain the present invention but are not intended to limit the present invention.

[0039] like Figure 1 As shown, the present invention provides a full-band vibration reduction structure that combines the acoustic black hole effect with the resonator principle, which includes a uniform beam 1, an acoustic black hole structure 2 connected to the uniform beam 1, and a damping layer 3 arranged on the upper surface of the acoustic black hole structure, and a plurality of array-distributed through holes are distributed on the uniform beam, and a damping resonator 4 is provided in the through hole.

[0040] The uniform beam structure is a plate-like rectangular parallelepiped, the distance between the upper and lower surfaces of the uniform beam structure is equal, a plurality of rectangular through holes are hollowed out in the middle of the uniform beam, and a plurality of damping resonators are connected in the middle of the hollowed-out uniform beam through holes. Through the resonance principle, low-frequency vibration energy can be concentrated on the damping beam of the damping resonator, thereby attenuating the low-frequency vibration energy. A plurality of damping resonators are arranged to enhance the attenuation effect of the selected frequency peak in the low-frequency band.

[0041] like Figure 2 As shown, the upper surface of the acoustic black hole structure 2 is an arcuate surface, and the lower surface is a plane. In the present embodiment, the edge thickness of the acoustic black hole structure is 0.05 times the maximum thickness of the acoustic black hole structure. A damping layer 3 is attached to the end of the arcuate surface. In the present embodiment, the thickness of the damping layer is 4 times the edge thickness of the acoustic black hole structure. The acoustic black hole structure is rigidly connected to the side of the uniform beam, and the maximum thickness of the acoustic black hole structure is the same as the thickness of the uniform beam. The vibration energy transmitted from the uniform beam is absorbed and attenuated through the acoustic black hole effect. The surface height of the arcuate surface at the connection end with the uniform beam 1 is higher than the height of the outer end surface. The vibration energy is transmitted to the connection between the acoustic black hole and the uniform beam, and is concentrated to the tip of the acoustic black hole through the acoustic black hole effect. The thickness between the upper and lower surfaces of the arcuate surface of the acoustic black hole structure satisfies. Figure 5 The relationship shown.

[0042] The distance H between the upper surface and the lower surface of the vibration reduction structure satisfies the following relationship:

[0043]

[0044] Among them, x represents the distance from the edge of the acoustic black hole structure; x1 is the distance from the edge of the acoustic black hole structure to the maximum thickness of the acoustic black hole structure; x2 is the distance from the edge of the acoustic black hole structure to the edge of the uniform beam; h1 is the edge thickness of the acoustic black hole structure; h2 is the thickness of the uniform beam; ε is the slope of the acoustic black hole profile, ε>0; m is the order of the acoustic black hole, 2≤m≤3.

[0045] like Figure 3 As shown, the damping layer 3 is a uniform thin layer plane, and the damping layer is applied to the edge of the upper surface of the acoustic black hole structure. The energy concentrated to the tip of the acoustic black hole through the acoustic black hole effect is attenuated and dissipated by the damping layer.

[0046] like Figure 4 As shown, the damping resonator 4 is composed of a mass block 4-1 and a damping beam 4-2. The mass block 4-1 is a rectangular structure, and the damping beam 4-2 is a pair of rectangular frame beams. The pair of damping beams 4-2 are symmetrically arranged at both ends of the mass block 4-1. The opposite ends of the pair of damping beams 4-2 are provided with bending portions, and the bending directions of the bending portions of each damping beam 4-2 are the same, one of the bending portions is connected to the mass block 4-1, and the other bending portion is bent outward; the bending directions of the oppositely arranged damping beams 4-2 are opposite. The two ends of the damping beam 4-2 are connected to the side walls of the middle through hole of the uniform beam 1. The thickness of the mass block is the same as the thickness of the uniform beam.

[0047] The damping resonator 4 composed of the mass block 4-1 and the damping beam 4-2 corresponds to a resonant mode frequency. By adjusting the thickness of the damping beam 4-2, the resonant mode frequency of the damping resonator 4 can be changed. When the vibration is transmitted to the damping beam 4-2 connected to the side wall of the uniform beam through hole, the peak value of the resonant mode frequency can be consumed and attenuated through the resonance principle. By adjusting the thickness of the damping beam 4-2, the low-frequency band frequency that the vibration reduction structure needs to attenuate can be selected.

[0048] In this embodiment, the uniform beam structure, the acoustic black hole structure and the mass block are made of Q235A3 steel; the damping layer and the damping beam are made of high damping alloy, rubber and foam plastic.

[0049] The effectiveness of this vibration reduction structure is verified by the finite element simulation software Comsol Mutiphysics6.0.

[0050] 1. Simulation calculation model

[0051] In one embodiment of the present invention, the uniform beam 1 of the vibration reduction structure is selected to have a length of 200 mm, a width of 100 mm, and a thickness of 8 mm.

[0052] The mass block 4 - 1 in the damping resonator 4 is selected to have a length of 60 mm, a width of 40 mm, and a thickness of 8 mm.

[0053] The length of the damping layer 3 is selected to be 140 mm, the width is 100 mm, and the thickness is 3.2 mm.

[0054] In order to ensure the accuracy of low-frequency frequency screening of the calculation model and improve the specific frequency vibration reduction effect, this embodiment uses three damping resonator arrays connected to the uniform beam through holes.

[0055] When only the acoustic black hole structure and the damping layer are connected to the uniform beam, a frequency peak of 73 Hz is obtained in the low-frequency band of the vibration-damping structure through simulation.

[0056] Furthermore, the low-frequency band of the full-band vibration reduction structure is screened through the following steps:

[0057] Step 1: First, a damping resonator unit model with the same geometric parameters as the vibration reduction structure in Example 1 is established in Comsol Mutiphysics 6.0;

[0058] Step 2, then setting the mass block in the damping resonator to steel material parameters and setting the damping beam to rubber material properties;

[0059] Step 3, then select the characteristic frequency study and set the thickness variation range of the damping beam of the damping resonator unit to 0.0005m-0.002m.

[0060] Step 4, then perform parametric scanning calculation on the damping beam in the selected thickness variation area to obtain the modal frequency corresponding to the thickness of each damping beam in the set area, and select the low-frequency band frequency of the full-band vibration reduction structure to be 73 Hz.

[0061] Specifically, the parametric scanning calculation of the damping beam in the thickness variation area is carried out according to the following steps:

[0062] (1) First, in the Parameter column under the Global Definition node in the software model builder window, set the damping beam thickness variable parameter to k. x ;

[0063] (2) Then, in the Geometry column under the Component node in the Model Builder window, enter the variable parameter k of the damping beam thickness in step (1). x , a damping beam component model is established according to geometric parameters;

[0064] (3) Then, in the Study node of the Model Builder window, select the Parametric Sweep function bar. In its Settings window, locate the Study Settings bar. In the Parameter Name bar below, select the damping beam thickness variable parameter k defined in step (1). x , enter the required thickness variation range of the damping beam as range(0,0.002 / 100,0.002) in the parameter value list column, and finally return to the setting window and click the calculation icon to solve the parametric scanning results.

[0065] Step 5. Finally, use the data processing software origin to draw the relationship curve between each thickness of the damping beam in the set area and the corresponding modal frequency value.

[0066] like Figure 6 As shown, when the thickness of the damping beam 4-2 in the damping resonator 4 is adjusted to 1.04 mm through the above steps, the frequency peak at 73 Hz in the low frequency band can be resonantly attenuated.

[0067] 2. Model vibration characteristics

[0068] Depend on Figure 7 It can be seen that the acoustic black hole vibration reduction structure with a damping resonator added in the embodiment of the present invention can reduce the low-frequency band mean square vibration velocity frequency peak by nearly 20dB compared to the acoustic black hole vibration reduction structure without a damping resonator, thereby having an outstanding vibration reduction effect in the entire frequency band.

[0069] The present invention provides a full-band vibration reduction structure that combines the acoustic black hole effect and the resonator principle, which effectively solves the problem that the current acoustic black hole structure has poor effect in the low frequency band. This vibration reduction structure can be applied to the main structure to achieve absorption and dissipation of full-band vibration energy without destroying the strength of the main structure. It has the technical advantages of simple structure and wide vibration reduction frequency band.

[0070] The present invention is not limited to the above-mentioned embodiments. On the basis of the technical solution disclosed in the present invention, technicians in this field can make some substitutions and deformations to some technical features therein according to the disclosed technical content without creative labor, and these substitutions and deformations are all within the protection scope of the present invention.

Claims

1. A full-band vibration reduction structure based on acoustic black hole effect and resonance principle, characterized in that: It comprises a uniform beam, an acoustic black hole structure connected to the uniform beam, and a damping layer element arranged on the upper surface of the acoustic black hole structure; a plurality of array-distributed through holes are distributed on the uniform beam, and a damping resonator is arranged in the through hole; The acoustic black hole structure comprises an arc-shaped plate with a tapered arc-shaped upper surface and a horizontal lower surface, wherein the end with a larger thickness is connected to a uniform beam, and the end with a smaller thickness is attached to a damping layer element; The damping resonator comprises a mass block and a damping beam arranged on the periphery of the mass block. The low-frequency band frequency that the vibration reduction structure needs to attenuate is selected by adjusting the thickness of the damping beam.

2. The full-band vibration reduction structure based on the acoustic black hole effect and resonance principle according to claim 1 is characterized in that: The uniform beam is a plate-shaped rectangular parallelepiped, with an equal distance between the upper and lower surfaces, a plurality of rectangular through holes are hollowed out in the middle of the uniform beam, and the damping resonator is arranged in the rectangular through holes of the uniform beam.

3. The full-band vibration reduction structure based on acoustic black hole effect and resonance principle according to claim 1 is characterized in that: The damping resonator mass block is a rectangular structure, and the thickness of the mass block is the same as the thickness of the uniform beam; the damping beam is a pair of rectangular frame beams, a pair of damping beams are symmetrically arranged at both ends of the mass block, and the two ends of the damping beam are connected to the side walls of the middle through hole of the uniform beam.

4. The full-band vibration reduction structure based on the acoustic black hole effect and resonance principle according to claim 3 is characterized in that: A pair of damping beams are provided with bending parts at opposite ends, and the bending direction of each damping beam is the same, one bending part is connected to the mass block, and the other bending part is bent outward; the bending directions of the damping beams arranged oppositely are opposite.

5. The full-band vibration reduction structure based on acoustic black hole effect and resonance principle according to claim 1 is characterized in that: The acoustic black hole structure is rigidly connected to the side surface of the uniform beam; the maximum thickness of the acoustic black hole structure is the same as the thickness of the uniform beam.

6. The full-band vibration reduction structure based on acoustic black hole effect and resonance principle according to claim 1 is characterized in that: The maximum thickness H of the acoustic black hole structure satisfies the following relationship: Among them, x represents the distance from the edge of the acoustic black hole structure; x1 is the distance from the edge of the acoustic black hole structure to the maximum thickness of the acoustic black hole structure; x2 is the distance from the edge of the acoustic black hole structure to the edge of the uniform beam; h1 is the edge thickness of the acoustic black hole structure; h2 is the thickness of the uniform beam; ε is the slope of the acoustic black hole profile, ε>0; m is the order of the acoustic black hole.

7. The full-band vibration reduction structure based on acoustic black hole effect and resonance principle according to claim 1 is characterized in that: The edge thickness of the acoustic black hole structure is 0.05-0.1 times of its maximum thickness.

8. The full-band vibration reduction structure based on acoustic black hole effect and resonance principle according to claim 1 is characterized in that: The damping layer is applied to the edge of the upper surface of the acoustic black hole structure; the thickness of the damping layer is 1-4 times the thickness of the edge of the acoustic black hole structure.

9. The full-band vibration reduction structure based on acoustic black hole effect and resonance principle according to claim 1 is characterized in that: The uniform beam structure, the acoustic black hole structure and the mass block are made of Q235A3 steel; the damping layer and the damping beam are made of high damping alloy, rubber or foam plastic.

10. The low frequency band frequency screening method according to any one of claims 1 to 9, characterized in that: The following steps are involved: According to the geometric parameters of the vibration reduction structure, the damping resonator unit model is established in Comsol Mutiphysics6.0; Determine the material parameters and material properties of the mass block and the damping beam respectively; Select the characteristic frequency and set the thickness variation region of the damping beam of the damping resonator unit; A parametric scanning calculation is performed on the damping beam in the selected thickness variation area to obtain the modal frequency corresponding to the thickness of each damping beam in the set area.

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