CN212694826U - Additional eccentric acoustic black hole vibration reduction structure - Google Patents
Additional eccentric acoustic black hole vibration reduction structure Download PDFInfo
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- CN212694826U CN212694826U CN202021857338.6U CN202021857338U CN212694826U CN 212694826 U CN212694826 U CN 212694826U CN 202021857338 U CN202021857338 U CN 202021857338U CN 212694826 U CN212694826 U CN 212694826U
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- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 4
- 229910052782 aluminium Inorganic materials 0.000 claims description 4
- 229920005549 butyl rubber Polymers 0.000 claims description 4
- 230000007423 decrease Effects 0.000 claims description 3
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- 238000005452 bending Methods 0.000 abstract description 9
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Abstract
The utility model relates to an eccentric acoustics of additional formula black hole damping structure, in damping structure's even region be the cylinder region, the wave propagation speed and the wavelength of certain frequency are all unchangeable. In the acoustic black hole part, the wave propagation speed is reduced along with the reduction of the thickness, the wavelength is reduced, the vibration amplitude of the wave is increased and is gathered to the area with the reduced thickness, when the vibration reduction structure reaches the cut-off part, the vibration reduction structure is provided with an acoustic black hole extension part, namely a first annular part, the bending wave is continuously propagated at a small wave speed, the weak part of the structure is arranged at the outermost end of the structure, the outer end of the structure is easier to deform, the acoustic black hole effect is easier to occur, and the high-efficiency broadband vibration reduction and noise reduction are realized.
Description
Technical Field
The utility model relates to a technical field of making an uproar falls in the damping, especially relates to an eccentric acoustics of additional formula black hole damping structure.
Background
The vibration is standing wave generated by multiple reflections of the boundary in the structure, and the noise is fluctuation energy radiated to the air by the structure vibration, so that the control of the fluctuation behavior in the structure is an effective means for realizing the vibration and noise reduction of the structure. The manipulation of waves, which is now more common, is mainly divided into two methods, active and passive. The active method generally requires external energy supply, and the design system is very complicated, so that the active method is not popularized in a large scale at present. In addition, for passive methods, the most basic form is the addition of damping materials, some viscoelastic materials are effective at absorbing vibrational energy. However, for some heavy equipment, a large amount of damping materials are required to be adhered on the surface of the equipment for vibration reduction, so that the effect of vibration reduction and noise reduction can be achieved, but the light weight of the structure is not beneficial, the economic cost is increased, and excessive additional mass is added.
The proposal of the concept of Acoustic Black Hole (ABH) effect has opened a new chapter for the realization of artificial control of the propagation of bending waves in elastic media and structures. As a novel passive control method, the acoustic black hole controls the wave propagation by designing and optimizing the shape of the structure, has the advantages of simple and flexible realization and small quality, and has strong potential and wide application prospect in a thin-wall structure. The main way to achieve the acoustic black hole effect by changing the impedance of the structure is to change the thickness of the structure. By utilizing the propagation characteristics of the bending wave in the variable-thickness structure, when the thickness of the structure is reduced in the form of a certain exponential function, the phase velocity and the group velocity of the bending wave are correspondingly reduced. Ideally, when the thickness is reduced to zero, the wave velocity at the edge of the structure can be reduced to zero, so that zero reflection of the wave is achieved, all wave energy is concentrated at the tip of the structure, and the purposes of energy absorption or vibration reduction and noise reduction are achieved through damping of the structure and damping materials attached to the structure.
However, the traditional acoustic black hole structure achieves the purpose of vibration reduction and noise reduction by cutting a controlled object, so that the rigidity and the strength of the structure are inevitably reduced, and the design is not applicable in some key structural designs.
SUMMERY OF THE UTILITY MODEL
Based on this, the utility model aims at providing an eccentric acoustics of additional formula black hole damping structure, at acoustics black hole part, acoustics black hole effect takes place more easily, improves the damping effect.
In order to achieve the above object, the utility model provides a following scheme:
an add-on off-center acoustic black hole damping structure, the damping structure comprising: the eccentric disc and the first ring extending from the edge of the eccentric disc;
the eccentric disc comprises a cylinder and an acoustic black hole part coated on the side surface of the cylinder;
the upper end surface of the eccentric disc is a first circle, the lower end surface of the eccentric disc is a second circle, the plane of the first circle is parallel to the plane of the second circle, and a connecting line of the circle center of the first circle and the circle center of the second circle is not perpendicular to the plane of the first circle;
the thickness of the acoustic black hole part decreases exponentially from the side surface of the cylinder to the outside; the thickness of the acoustic black hole part is the thickness in the axial direction of the cylinder;
the first annular thickness is equal to a minimum thickness of the acoustic black hole portion.
Optionally, the expression of the index is h (r) armWherein h (r) represents the thickness of the acoustic black hole part, r represents the distance from any point on the first circle to the center of the upper surface of the cylinder minus the radius of the cylinder, a represents a coefficient, and m is greater than or equal to 2.
Optionally, the vibration damping structure further comprises: a second ring of a damping material adhered to the underside of the edge of the eccentric disc, the second ring having the same outer diameter as the first ring.
Optionally, the second annular damping material is a butyl rubber material.
Optionally, the eccentric disc and the first ring are aluminum.
Optionally, the first circular diameter of the eccentric disc is 120mm, and the diameter of the cylinder is 30 mm;
the circle of the upper end surface of the cylinder and the first circle form a third ring shape; the minimum width of the third ring is 30mm, and the maximum width of the third ring is 60 mm; the maximum thickness of the acoustic black hole part is 3mm, and the minimum thickness of the acoustic black hole part is 0.2 mm; the width of the first ring shape is 6 mm.
Optionally, the second ring has an outer diameter of 132mm, a width of 30mm and a thickness of 2 mm.
According to the utility model provides a concrete embodiment, the utility model discloses a following technological effect:
the utility model discloses an eccentric acoustics of additional formula black hole damping structure, it is regional that the cylinder is in the even region of damping structure, the wave propagation speed and the wavelength of certain frequency are all unchangeable. In the acoustic black hole part, the wave propagation speed is reduced along with the reduction of the thickness, the wavelength is reduced, the vibration amplitude of the wave is increased and is gathered to the area with the reduced thickness, when the vibration reduction structure reaches the cut-off part, the vibration reduction structure is provided with an acoustic black hole extension part, namely a first annular part, the bending wave is continuously propagated at a small wave speed, the weak part of the structure is arranged at the outermost end of the structure, the outer end of the structure is easier to deform, the acoustic black hole effect is easier to occur, and the high-efficiency broadband vibration reduction and noise reduction are realized.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without inventive labor.
Fig. 1 is a cross-sectional view of an additional eccentric acoustic black hole damping structure according to an embodiment of the present invention;
fig. 2 is a top view of an additional eccentric acoustic black hole damping structure according to an embodiment of the present invention;
fig. 3 is a schematic view illustrating propagation of an elastic wave in an acoustic black hole damping structure according to an embodiment of the present invention;
fig. 4 is a perspective view of an additional eccentric acoustic black hole damping structure according to an embodiment of the present invention;
FIG. 5 is a diagram showing the comparison of the damping characteristics between the leveling plates and the damping structure system of the present invention and the additional control group structure system;
fig. 6 is the embodiment of the present invention, i.e. the leveling plate and the leveling plate are attached to the vibration characteristic comparison diagram of the damping structure system and the additional contrast group structure system.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.
The utility model aims at providing an eccentric acoustics of additional formula black hole damping structure realizes a plurality of modals of single device control controlled object, improves the damping effect.
In order to make the above objects, features and advantages of the present invention more comprehensible, the present invention is described in detail with reference to the accompanying drawings and the detailed description.
As shown in fig. 1-2, the utility model discloses an eccentric acoustics of additional formula black hole damping structure, damping structure A2 includes: the eccentric disc and the first ring 3 extending from the edge of the eccentric disc, the damping structure A2 is arranged on the controlled structure A1.
The eccentric disc comprises a cylinder 1 and an acoustic black hole part 2 coated on the side surface of the cylinder;
the upper end face of the eccentric disc is a first circle 21, the lower end face of the eccentric disc is a second circle 22, the plane of the first circle 21 is parallel to the plane of the second circle 22, and a connecting line of the circle center of the first circle and the circle center of the second circle is not perpendicular to the plane of the first circle 21.
The damping structure A2 is in communication with the controlled structure A1 through the second circle 22.
The circle of the upper end surface of the cylinder 1 and the first circle 21 form a third ring shape, and the minimum width of the third ring shape is rABH1Maximum width of rABH2(ii) a The radial length of the acoustic black hole region 2 is uniformly changed along the circumferential direction from the minimum radial length rABH1Gradually increasing to a maximum radial length r in a circumferential direction of the eccentric disc-shaped structureABH2。
The thickness of the acoustic black hole part 2 decreases exponentially from the side surface of the cylinder 1 to the outside; the thickness of the acoustic black hole portion 2 is the thickness in the axial direction of the cylinder 1.
The expression of the index is h (r) armWherein h (r) represents the thickness of the acoustic black hole part 2, r represents the distance from any point on the first circle 21 to the center of the upper surface of the cylinder 1 minus the radius of the cylinder 1, a represents a coefficient, and m is greater than or equal to 2.
The vibration damping structure further includes: a second ring 4, the second ring 4 being a damping material, the second ring 4 being adhered under the edge of the eccentric disk, the second ring 4 having the same outer diameter as the first ring 3.
The damping material of the second ring 4 is butyl rubber material.
The first ring 3 has a thickness equal to the minimum thickness of the acoustic black hole part 2.
The eccentric disc and the first ring 3 are made of aluminum.
The utility model discloses an acoustics black hole damping structure is based on the bending wave in the solid medium and reduces along with structure thickness according to certain power function, and its corresponding phase velocity and group velocity also reduce to gather the bending wave of broadband in the region of structure thickness attenuation on certain space yardstick, as shown in figure 3. The wave energy on the controlled structure a1 can be transferred to the acoustic black hole damping structure a2 through the connecting portion central cylinder 1. In the uniform region of the vibration damping structure a2, i.e., the cylinder 1, the wave propagation speed and wavelength of a certain frequency are constant. And at acoustics black hole region 2, the propagation velocity of wave reduces along with the reduction of thickness, and the wavelength reduces, and the vibration amplitude of wave increases, to the regional gathering that thickness diminishes, when reacing the truncation department, because the utility model discloses an acoustics black hole damping structure has acoustics black hole extension part 3, and the bending wave continues to propagate with little wave speed, and the place that the structure is weak takes place again and warp at the outermost end of structure and outer end more easily, and acoustics black hole effect takes place more easily. In addition, most of bending wave energy is consumed by combining the circular damping material 4, so that the aims of high-efficiency energy absorption or vibration and noise reduction are fulfilled.
Fig. 4 is a perspective view of an additional eccentric acoustic black hole damping structure of the present invention, as shown in fig. 4, a uniform plate with a length of 300mm, a width of 240mm, and a thickness of 6mm is selected as a controlled object a 1. With the center of the uniformity plate as the origin, 1 additional eccentric acoustic black hole vibration reduction structure was attached at (-120, -90) mm of the uniformity plate. The damping structure comprises an eccentric disc with a first circular diameter of 120mm, a central cylinder 1 with a diameter of 30mm, and an acoustic black hole area part 2 with a minimum radial length rABH130mm, maximum radial length r ABH260 mm. Width r of the eccentric disc rim extension, i.e. the first ring 336 mm. The maximum thickness of the eccentric disc is 3mm, and the minimum thickness of the edge is 0.2 mm. The uniform plate, the eccentric disc and the first ring 3 are made of aluminum materials. Still include second ring 4 on the damping structure, second ring 4 is damping material, and the external diameter is 132mm, and wide 30mm, thickness are 2mm, select butyl rubber material for use to arrange, and the material loss factor sets up to 0.1. Meanwhile, for comparative study, a completely symmetrical acoustic black hole disc-shaped structure with the same size is designed as a control group.
The outer diameter of the annular damping material is the same as that of the first ring, and the thickness of the annular damping material is 2mm determined according to the thickness of the damping material which is common in practice. StickingThe width of the second ring is less than rABH1+r3) And choose to paste more damping material without adding too much extra mass.
A model is established in ABAQUS by a finite element method, and the damping level and the vibration response of the structure are calculated by a steady-state dynamics analysis and a modal superposition method.
Analysis of calculation results
1) Damping characteristic analysis
As shown in FIG. 5, the acoustic black hole vibration damping structure of the present invention can greatly improve the inherent damping of the structure, and the system damping ratio is improved by 5-80 times in the full frequency band. Compared with a completely symmetrical control group, the damping level of the structure can still be increased, particularly in the range of 1000Hz-2500Hz, the system damping is improved by 5-14 times compared with the control group, and the damping characteristic is slightly poor only at three modes near 3200 Hz. In general, the additional eccentric acoustic black hole vibration reduction structure can greatly improve the damping characteristic of the uniform plate, and is more superior to a completely symmetrical structure, so that the vibration reduction of the elastic structure is potentially beneficial, and meanwhile, the controlled object cannot be damaged.
2) Vibration control characteristic analysis
As shown in fig. 6, to evaluate the vibration level of the system, the origin response of the system was selected as an index study. It can be found from fig. 6, has attached the utility model discloses an behind the acoustics black hole damping structure, compare the whole broadband within range of structure before the control all frequencies all have 10-35 dB's vibration level to reduce, this is because the utility model discloses an acoustics black hole damping structure has very high modal damping ratio because acoustics black hole effect and dynamic vibration absorption effect to performance its characteristic that can to a great extent absorbs the structural fluctuation energy of being controlled, the vibration level of reduction system. In addition, compare in the even board system of the contrast acoustics black hole structure that has attached complete symmetry, add the utility model discloses an after the eccentric acoustics black hole structure, except that the effect at the formant department of 3096Hz, 3309Hz, 3476Hz three frequency is slightly poor, all there is 2-22 dB's vibration reduction in all other frequencies department. The reason for the improvement is that the complete symmetry of the previous disc-shaped structure is destroyed to a certain extent by designing the additional acoustic black hole structure in an eccentric mode, so that the additional structure can be more easily strongly coupled with a controlled object, the wave energy is better transferred to the additional structure and consumed, and the advantage of the acoustic black hole energy accumulation effect is fully played.
The utility model discloses an eccentric acoustics of additional formula black hole damping structure has ingeniously combined the characteristics of acoustics black hole and dynamic vibration absorber, has avoided the limitation in traditional acoustics black hole to destroy the inherent complete symmetry of disc type structure, can realize a plurality of modals of single device control controlled object, reached efficient damping effect. The utility model discloses can carry out the parameter design according to frequency characteristic etc. of controlled object, can further improve the wide band characteristic.
The utility model discloses an eccentric acoustics of additional formula black hole damping structure additional mass is little, satisfies the engineering application easily, has efficient characteristics simultaneously.
The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other.
The principle and the implementation of the present invention are explained herein by using specific examples, and the above description of the embodiments is only used to help understand the core idea of the present invention; meanwhile, for the general technical personnel in the field, according to the idea of the present invention, there are changes in the concrete implementation and the application scope. In summary, the content of the present specification should not be construed as a limitation of the present invention.
Claims (7)
1. An add-on eccentric acoustic black hole damping structure, the damping structure comprising: the eccentric disc and a first ring (3) extending from the edge of the eccentric disc;
the eccentric disc comprises a cylinder (1) and an acoustic black hole part (2) coated on the side surface of the cylinder;
the upper end surface of the eccentric disc is a first circle (21), the lower end surface of the eccentric disc is a second circle (22), the plane of the first circle (21) is parallel to the plane of the second circle (22), and the connecting line of the circle center of the first circle and the circle center of the second circle is not vertical to the plane of the first circle (21);
the thickness of the acoustic black hole part (2) decreases exponentially from the side surface of the cylinder (1) to the outside; the thickness of the acoustic black hole part (2) is the thickness of the cylinder (1) in the axial direction;
the first ring shape (3) has a thickness equal to the minimum thickness of the acoustic black hole portion (2).
2. The additional eccentric acoustic black hole damping structure according to claim 1, wherein the expression of the index is h (r) armWherein h (r) represents the thickness of the acoustic black hole part (2), r represents the distance from any point on the first circle (21) to the center of the upper surface of the cylinder (1) minus the radius of the cylinder (1), a represents a coefficient, and m is greater than or equal to 2.
3. The add-on eccentric acoustic black hole damping structure according to claim 1, further comprising: a second ring (4), the second ring (4) being a damping material, the second ring (4) being adhered to the underside of the edge of the eccentric disc, the second ring (4) having the same outer diameter as the first ring (3).
4. Additional eccentric acoustic black hole damping structure according to claim 3, characterized in that the second annular (4) damping material is butyl rubber material.
5. Additional eccentric acoustic black hole damping structure according to claim 1, characterized in that the eccentric disc and the first ring (3) are of aluminium.
6. Additional eccentric acoustic black hole damping structure according to claim 1, characterized in that the first circle (21) of the eccentric disc has a diameter of 120mm and the cylinder (1) has a diameter of 30 mm;
the circle of the upper end surface of the cylinder (1) and the first circle (21) form a third ring shape; the minimum width of the third ring is 30mm, and the maximum width of the third ring is 60 mm; the maximum thickness of the acoustic black hole part (2) is 3mm, and the minimum thickness is 0.2 mm; the width of the first ring (3) is 6 mm.
7. Additional eccentric acoustic black hole damping structure according to claim 3, characterized in that the second ring (4) has an outer diameter of 132mm, a width of 30mm and a thickness of 2 mm.
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111862921A (en) * | 2020-08-31 | 2020-10-30 | 裘天政 | Additional eccentric acoustic black hole vibration reduction structure |
| CN114822467A (en) * | 2022-04-25 | 2022-07-29 | 清华大学 | Phononic crystal based on gradient sound black hole structure band gap regulation and control |
| EP4270376A1 (en) * | 2022-04-27 | 2023-11-01 | BAE SYSTEMS plc | Acoustic black hole, structural damper, structurally damped structure |
| EP4270377A1 (en) * | 2022-04-27 | 2023-11-01 | BAE SYSTEMS plc | Acoustic black hole, structural damper, structurally damped structure, and method |
| WO2023209338A1 (en) * | 2022-04-27 | 2023-11-02 | Bae Systems Plc | Acoustic black hole, structure damper structurally damped structure and method |
| WO2023209339A1 (en) * | 2022-04-27 | 2023-11-02 | Bae Systems Plc | Acoustic black hole, structural damper, structurally damped structure, and method |
-
2020
- 2020-08-31 CN CN202021857338.6U patent/CN212694826U/en active Active
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111862921A (en) * | 2020-08-31 | 2020-10-30 | 裘天政 | Additional eccentric acoustic black hole vibration reduction structure |
| CN114822467A (en) * | 2022-04-25 | 2022-07-29 | 清华大学 | Phononic crystal based on gradient sound black hole structure band gap regulation and control |
| EP4270376A1 (en) * | 2022-04-27 | 2023-11-01 | BAE SYSTEMS plc | Acoustic black hole, structural damper, structurally damped structure |
| EP4270377A1 (en) * | 2022-04-27 | 2023-11-01 | BAE SYSTEMS plc | Acoustic black hole, structural damper, structurally damped structure, and method |
| WO2023209338A1 (en) * | 2022-04-27 | 2023-11-02 | Bae Systems Plc | Acoustic black hole, structure damper structurally damped structure and method |
| WO2023209339A1 (en) * | 2022-04-27 | 2023-11-02 | Bae Systems Plc | Acoustic black hole, structural damper, structurally damped structure, and method |
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