Adjustable impact acoustic black hole periodic shock mitigation device

Abstract

The application discloses an adjustable collision acoustic black hole periodic damping shock absorbing device, comprising a plurality of identical damping shock absorbing units arranged periodically on the surface of a structure to be damped; the damping shock absorbing unit comprises a U-shaped cavity wall and a mass block-acoustic black hole beam combined structure arranged in the U-shaped cavity wall; the adjustable collision acoustic black hole periodic damping shock absorbing device has periodicity in the direction perpendicular to the U-shaped cavity wall; the U-shaped cavity wall comprises an upper cavity and a top ventilation hole arranged at the top end of the upper cavity; the mass block-acoustic black hole beam combined structure comprises an acoustic black hole beam, a mass block and a cavity perpendicular to the structure to be damped; the end of the acoustic black hole beam is provided with a damping layer, the mass block moves up and down in the cavity, collides with the acoustic black hole beam arranged below to transfer vibration energy and is absorbed and dissipated by the damping layer. The application realizes a broadband damping effect by arranging the damping shock absorbing units periodically on the surface of the structure to be damped.

Description

Technical Field

[0001] This invention relates to the field of vibration reduction and shock resistance technology for large structures, and in particular to an adjustable collision acoustic black hole periodic vibration reduction and shock resistance device. Background Technology

[0002] With the development of modern equipment towards larger and lighter sizes, the problem of low-frequency vibration is becoming increasingly serious. In addition, equipment is inevitably subjected to external impacts during use, and harmful vibrations and impacts seriously affect the normal operation of the equipment and the physical and mental health of the staff.

[0003] Acoustic metamaterials are a novel method for vibration reduction and noise reduction proposed in recent years. They block the propagation of elastic waves in specific frequency bands by periodically arranging artificially designed unit structures. Compared to traditional passive control methods, acoustic metamaterials can achieve lightweight vibration reduction devices in suppressing low-frequency broadband vibrations. However, most acoustic metamaterials have fixed bandgap frequencies and cannot be adjusted according to changes in the vibration frequency of the environment.

[0004] The acoustic black hole effect is achieved by adjusting the thickness of the structure according to a power law or setting the material parameters according to a power law, so that the propagation speed of bending waves in the acoustic black hole structure gradually decreases until it approaches zero. This is further enhanced by attaching damping layers at the ends of the structure, thus achieving efficient absorption and dissipation of vibrational energy. However, traditional acoustic black hole structures are primarily effective in the mid-to-high frequency range and are not suitable for low-frequency vibration reduction in large structures. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings and defects of the prior art and provide an adjustable collision acoustic black hole periodic vibration reduction and shock-resistant device with a simple overall structure, easy processing, and good theoretical and practical performance. It aims to achieve good low-frequency broadband vibration reduction and shock resistance, and can be flexibly adapted to different operating frequency bands through simple adjustment.

[0006] An adjustable impact acoustic black hole periodic vibration damping and shock-resistant device includes several identical vibration damping and shock-resistant units periodically arranged on the surface of the structure to be damped; each vibration damping and shock-resistant unit includes a zigzag cavity wall and a mass block-acoustic black hole beam combination structure arranged inside it; the adjustable impact acoustic black hole periodic vibration damping and shock-resistant device is periodic in the zigzag direction perpendicular to the zigzag cavity wall; the zigzag cavity wall includes an upper chamber and a top vent at the top of the upper chamber; the mass block-acoustic black hole beam combination structure includes an acoustic black hole beam, a mass block, and a cavity perpendicular to the structure to be damped; a damping layer is arranged at the end of the acoustic black hole beam, and the mass block moves up and down in the cavity, transmitting vibration energy through collisions with the acoustic black hole beam arranged below, which is then absorbed and dissipated by the damping layer.

[0007] The zigzag cavity wall includes a metal base with bottom mounting holes. The metal base is fixed to the vibration damping structure through the bottom mounting holes.

[0008] The zigzag cavity wall is a closed structure, and the thickness of the upper cavity is greater than the thickness of the base.

[0009] The mass block is a spherical mass block.

[0010] The cavity is a cylindrical cavity.

[0011] The diameter of the cavity is slightly larger than the diameter of the mass block.

[0012] The bottom of the mass block has a predetermined gap with the acoustic black hole beam. During operation, it collides with the acoustic black hole beam, transmits vibration energy, and dissipates it through the damping layer.

[0013] The mass of the mass block, the parameters of the acoustic black hole beam, the thickness and material of the damping layer are flexibly designed according to the required frequency band to adapt to vibration reduction in different operating frequency bands.

[0014] The structure being damped is a planar structure.

[0015] The mass blocks of different vibration damping and shock-resistant units have different mass sizes; by adjusting the mass blocks of different vibration damping and shock-resistant units, low-frequency broadband vibration reduction of large structures can be achieved.

[0016] The adjustable impact acoustic black hole periodic vibration damping and shock-resistant device provided by this invention achieves broadband vibration damping by periodically arranging vibration damping and shock-resistant units on the surface of the structure being damped. The design of the vibration damping and shock-resistant units incorporates contact collisions to transfer low-frequency vibration energy, improving the vibration damping performance of acoustic black holes in the low-frequency range.

[0017] The adjustable collision acoustic black hole periodic vibration reduction and shock-resistant device provided by the present invention can achieve flexible adjustment of vibration reduction in different frequency bands by replacing the substructures within the unit. It is a novel passive vibration reduction and shock-resistant technology, suitable for vibration reduction and shock-resistant of large structures. Moreover, the entire device is easy to process and simple to assemble. Attached Figure Description

[0018] Figure 1 This is a three-dimensional structural diagram of the present invention;

[0019] Figure 2 This is a schematic diagram of the vibration damping and shock-resistant unit in this invention;

[0020] Figure 3 This is a front view of the mass block-acoustic black hole beam composite structure of the vibration damping and shock-resistant unit in this invention;

[0021] Figure 4 This is a front view of the acoustic black hole beam in this invention;

[0022] Figure 5 This is a schematic diagram of the vibration reduction structure of the present invention;

[0023] Explanation of reference numerals in the attached figures:

[0024] 1-1. Metal base; 1-2. Upper chamber; 1-3. Mounting hole; 1-4. Vent hole; 2-1. Acoustic black hole beam; 2-2. Damping layer; 3-1. Cavity; 3-2. Mass block. Detailed Implementation

[0025] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0026] The adjustable collision acoustic black hole periodic vibration reduction and shock-resistant device of this invention improves the vibration reduction performance of acoustic black holes in the low-frequency band by introducing contact collision to transfer vibration energy; through periodic design, it achieves a wide-band vibration reduction effect on large structures; and through simple adjustment, it can flexibly adapt to different vibration reduction working frequency bands.

[0027] The adjustable impact acoustic black hole periodic vibration reduction and shock-resistant device of this invention consists of several identical vibration reduction and shock-resistant units arranged periodically. Each vibration reduction and shock-resistant unit transfers vibration energy through contact and collision between a mass block and the acoustic black hole beam, which is then absorbed and dissipated by a damping layer. By adjusting the mass blocks of different units, low-frequency broadband vibration reduction of large structures can be flexibly achieved.

[0028] like Figure 1 As shown, the present invention provides an adjustable periodic vibration damping and shock-resistant device for impact acoustic black holes, comprising several identical vibration damping and shock-resistant units arranged periodically on the surface of the structure to be damped; in use, the vibration damping and shock-resistant units can be easily adjusted to flexibly adapt to changes in environmental vibration frequency, and have good low-frequency broadband vibration damping and shock resistance effects.

[0029] like Figure 2 As shown, the vibration damping and shock-resistant unit consists of a U-shaped cavity wall and an internal mass block-acoustic black hole beam combination structure. The U-shaped cavity wall is composed of a metal base 1-1 and an upper chamber 1-2. The metal base has several symmetrical mounting holes 1-3, which, along with screws, allow the metal base of the U-shaped cavity wall to be fixed to the structure being damped. The upper chamber has several symmetrical ventilation holes 1-4 at its top. The mass block-acoustic black hole beam combination structure consists of an acoustic black hole beam 2-1, a damping layer 2-2 located at the end of the acoustic black hole beam 2-1, a cavity 3-1, and a mass block 3-2.

[0030] The upper end of the cavity 3-1 is fixed to the inner top of the upper chamber of the zigzag cavity wall, perpendicular to the base. The acoustic black hole beam 2-1 and the damping layer 2-2 are fixed in the upper chamber of the zigzag cavity wall. The bottom is separated from the metal base 1-1 and does not contact it. The end with the same thickness is fixed to the side wall of the upper chamber of the zigzag cavity wall.

[0031] In some embodiments, the U-shaped cavity wall is a closed structure formed by connecting a metal base 1-1 (which is a flat plate structure) and an upper cavity 1-2, and the thickness of the upper cavity is greater than the thickness of the base, so as to protect the inner top when the mass block collides with the inner top of the upper cavity.

[0032] Preferably, the mass block is a spherical mass block, and the cavity is a cylindrical cavity. The diameter of the cavity is slightly larger than the diameter of the mass block, that is, there is a gap between the inner wall of the cavity and the mass block. The gap ranges from 1 / 150 to 1 / 100 of the radius of the mass block, so as to facilitate the up and down movement of the mass block and to reduce vibration.

[0033] The bottom of the mass block has a predetermined gap with the acoustic black hole beam, which is 1 / 5 to 1 / 2 of the mass block's radius. This prevents the mass block from falling out of the cavity and affecting the normal operation of the device. At the same time, by reserving a certain gap, the energy transfer efficiency during the collision can be adjusted, avoiding excessive increase in the system's stiffness when the collision occurs, and ensuring that the collision occurs at an appropriate time.

[0034] The mass of the mass block, the parameters of the acoustic black hole beam, the thickness and material of the damping layer are flexibly designed according to the required frequency band to adapt to vibration reduction in different operating frequency bands.

[0035] In some embodiments, the damped structure is a planar structure, which is fixed to the vibration damping and shock-resistant unit by screws.

[0036] In a preferred embodiment, the acoustic black hole beam is composed of a first part with a uniform cross-section and a second part with a variable cross-section. The maximum thickness of the second part is consistent with the uniform thickness of the first part, and is 15-20 times the minimum thickness of the second part. This allows the wave velocity to gradually decrease during the transmission of vibrational energy from the collision point to the end of the acoustic black hole beam, thereby concentrating it near the minimum thickness.

[0037] Preferably, a damping layer of equal thickness is adhered to the end of the acoustic black hole beam. The damping layer is adhered below the end of the acoustic black hole beam with varying thickness. The right end face of the damping layer is aligned with the end face of the acoustic black hole beam with the minimum thickness, and the thickness of the damping layer is consistent with the minimum thickness of the acoustic black hole beam.

[0038] Preferably, the damping layer is made of a viscoelastic material, which can effectively dissipate the accumulated vibration energy, reduce reflection, and thus enhance the vibration reduction effect.

[0039] like Figure 3 As shown, the mass block 3-2 can move up and down within the cylindrical cavity 3-1. During operation, it collides with the acoustic black hole beam 2-1 to transfer vibrational energy, which is absorbed and dissipated by the damping layer 2-2.

[0040] like Figure 4 As shown, the thickness h of the acoustic black hole structure 2-1 satisfies the following relationship:

[0041]

[0042] Where x is the distance from the left end of the acoustic black hole beam; x1 is the length of the uniformly thick portion of the acoustic black hole beam; L is the total length of the acoustic black hole beam; h0 is the uniform thickness of the acoustic black hole beam; h1 is the minimum thickness of the acoustic black hole beam; ε is the slope of the acoustic black hole profile, ε>0; and m is the order of the acoustic black hole.

[0043] like Figure 5 As shown, the vibration damping and shock-resistant units are arranged periodically along the direction perpendicular to the zigzag surface. During operation, they are fixed to the structure to be damped through the mounting holes 1-2 of the metal base. The mass block 3-2 contacts and collides with the acoustic black hole beam 2-1, transmitting vibration energy which is absorbed and dissipated by the damping layer 2-2.

[0044] This invention improves the vibration reduction performance of acoustic black holes in the low-frequency range by introducing contact collisions into the vibration reduction and shock-resistant unit; it achieves broadband vibration reduction for large structures by combining the concept of acoustic metamaterials (the structure obtained by periodically arranging the structure of a unit is called a metamaterial / acoustic metamaterial) for periodic design; and it allows the frequency band in which the overall structure is effective to be flexibly adjusted according to changes in the environmental vibration frequency by simply adjusting the collision mass.

[0045] In this embodiment of the invention, each vibration damping and shock-resistant unit transfers vibrational energy through the collision between a mass block and an acoustic black hole beam, which is then absorbed and dissipated through a damping layer. This invention incorporates the concept of metamaterials, arranging the vibration damping and shock-resistant units periodically to achieve a broadband vibration reduction effect. When the environmental vibration frequency changes, the mass block can be adjusted to meet the vibration reduction requirements of different operating frequency bands.

[0046] The device in this embodiment of the invention has a simple structure, is easy to manufacture, and is easy to implement while having good vibration reduction and impact resistance performance, thus possessing good theoretical and practical performance.

[0047] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention.

[0048] Therefore, the embodiments should be regarded as exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of the equivalents of the claims be included within the invention.

[0049] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. An adjustable impact acoustic black hole periodic vibration damping and shock-resistant device, characterized in that, The device comprises several identical vibration damping and impact-resistant units arranged periodically on the surface of the structure to be damped; each vibration damping and impact-resistant unit includes a zigzag cavity wall and a mass block-acoustic black hole beam combination structure arranged inside it; the adjustable impact acoustic black hole periodic vibration damping and impact-resistant device is periodic in a zigzag direction perpendicular to the zigzag cavity wall; the zigzag cavity wall includes an upper chamber and a top vent at the top of the upper chamber; the mass block-acoustic black hole beam combination structure includes an acoustic black hole beam, a mass block, and a cavity perpendicular to the structure to be damped; the ends of the acoustic black hole beam are arranged with... The acoustic black hole beam, which is equipped with a damping layer, consists of a first part with a uniform cross-section and a second part with a variable cross-section. The maximum thickness of the second part is consistent with the uniform thickness of the first part and is 15-20 times the minimum thickness of the second part. The damping layer is attached to the underside of the variable-thickness end of the acoustic black hole beam. The mass block moves up and down in the cavity and transmits vibration energy by colliding with the acoustic black hole beam arranged below. The vibration energy is absorbed and dissipated by the damping layer, so that the wave speed gradually decreases during the transmission of vibration energy from the collision point to the end of the acoustic black hole beam and accumulates near the minimum thickness.

2. The adjustable impact acoustic black hole periodic vibration damping and shock-resistant device according to claim 1, characterized in that, The zigzag cavity wall includes a metal base with bottom mounting holes. The metal base is fixed to the vibration damping structure through the bottom mounting holes.

3. The adjustable impact acoustic black hole periodic vibration damping and shock-resistant device according to claim 1, characterized in that, The zigzag cavity wall is a closed structure, and the thickness of the upper cavity is greater than the thickness of the base.

4. The adjustable impact acoustic black hole periodic vibration damping and shock-resistant device according to claim 1, characterized in that, The mass block is a spherical mass block.

5. The adjustable impact acoustic black hole periodic vibration damping and shock-resistant device according to claim 4, characterized in that, The cavity is a cylindrical cavity.

6. The adjustable impact acoustic black hole periodic vibration damping and shock-resistant device according to claim 5, characterized in that, The diameter of the cavity is slightly larger than the diameter of the mass block.

7. The adjustable impact acoustic black hole periodic vibration damping and shock-resistant device according to claim 1, characterized in that, The bottom of the mass block has a predetermined gap with the acoustic black hole beam. When working, it collides with the acoustic black hole beam, transmits vibration energy, and dissipates it through the damping layer.

8. The adjustable impact acoustic black hole periodic vibration damping and shock-resistant device according to claim 1, characterized in that, The mass of the mass block, the parameters of the acoustic black hole beam, the thickness and material of the damping layer are flexibly designed according to the required frequency band to adapt to vibration reduction in different operating frequency bands.

9. The adjustable impact acoustic black hole periodic vibration damping and shock-resistant device according to claim 1, characterized in that, The thickness h of the acoustic black hole beam satisfies the following relationship: ； Where x is the distance from the left end of the acoustic black hole beam; x1 is the length of the uniformly thick portion of the acoustic black hole beam; L is the total length of the acoustic black hole beam; h0 is the uniform thickness of the acoustic black hole beam; h1 is the minimum thickness of the acoustic black hole beam; ε is the slope of the acoustic black hole profile, ε>0; and m is the order of the acoustic black hole.

10. The adjustable impact acoustic black hole periodic vibration damping and shock-resistant device according to claim 1, characterized in that, The structure being damped is a planar structure, and the mass blocks of different damping and shock-resistant units have different mass sizes; by adjusting the mass blocks of different damping and shock-resistant units, low-frequency broadband vibration reduction of large structures can be achieved.

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