KR20230017021A - Helix acoustic black hole module and noise and vibration reduction system using the same - Google Patents

Abstract

The present invention is to provide a spiral acoustic black hole structure for assembling more acoustic black hole beams into a modular acoustic black hole structure. Embodiments include a beam coupling module mounted on a structure to reduce vibration and noise; and a plurality of spiral acoustic black hole beams coupled to the beam coupling module, wherein the plurality of spiral acoustic black hole beams are radially positioned around the beam coupling module, and at least a partial region of the plurality of spiral acoustic black hole beams is twisted based on a longitudinal axis.

Description

Helix acoustic black hole module and noise and vibration reduction system using the same

The present invention relates to a spiral acoustic black hole module and a noise and vibration reduction system using the same.

Reducing unwanted vibration is important for structural comfort and durability in industrial applications. The two main techniques for controlling unwanted vibrations are active and passive.

Active vibration control devices require high input energy and very complex electromechanical designs. Sometimes it is not easy or desirable to use an active device. Another technique is a passive method of attaching a damping layer to a structure. This additional damping layer always increases the weight of the structure, which can be problematic for ecological and economic reasons, especially in the aerospace or automotive industries. It is of great interest that new vibration suppression technologies are envisioned using lightweight construction designs. Acoustic black hole (ABH), a passive vibration control approach, has generated great interest that new vibration suppression technologies will be envisioned using lightweight structural designs. Acoustic black holes, a passive vibration control approach, were developed in 1988. A power-law taper profile is built on the beam and plate, and the vibrational energy is concentrated. This rigid structure reduces the wave speed. As the thickness decreases, the propagation speed of flexural waves in the structure decreases because the wave speed slows down. And, the wave eventually takes an infinite amount of time to reach the end of the structure. ABH applications are introduced into beam and plate structures to generate large amounts of wave energy focus. To analyze vibrational and acoustic radiation, the ABH effect was applied through numerical and experimental work in thin plates. Mobility is experimentally compared between a bare ABH embedded in a plate and a plate with an adhesive damping layer. It has been shown that the ABH plate with an absorber layer significantly suppresses resonant vibration peaks. Many researchers have studied the ABH effect for structural vibration control, acoustic emission control, and vibration energy harvesting.

Additive manufacturing (AM) technology has been adopted to overcome the limitations of traditional manufacturing methods such as the use of milling machines. The dynamic response of the ABH feature beam fabricated by the AM technique was experimentally and numerically analyzed, and some differences were found in the response between smooth and cascaded ABH beams, especially at higher frequencies.

It is well known that when a flexural wave propagates into the ABH region, the wave speed slows down and the amplitude increases as it approaches the end of the structure. Theoretically, the incident vibration wave cannot be reflected when the thickness becomes zero. However, the end of the structure cannot be zero. A real structure must have a finite thickness (truncated area). Since the well-in region exists in the real state, the flexural wave is reflected at the edge. Mironov (Mironov M (1988) Propagation of a flexural wave in a plate whose thickness decreases smoothly to zero in a finite interval. Soviet Physics: Acoustics 34: 318-319.) argues that the theoretical reflection for an ABH beam with clipped regions coefficients were presented. The reflection coefficient is always far from zero because the cut-out region exists in the actual fabricated structure. Applying a thin damping layer to the surface of the ABH structure can significantly reduce the reflection coefficient, which has been experimentally demonstrated. Recently, we compared the reflection coefficients of the geometrical acoustic approach with an analytically derived exact solution using the Euler-Bernoulli equation. The approach mentioned above may only be suitable for very simple beam structures. Both methods are very difficult to apply to real 3D structures because of their geometric complexity. Therefore, a new approach is required to obtain the reflection coefficient of a 3D structure. Denis et al. (Denis V, Gautier F, Pelat A, et al. (2015) Measurement and modeling of the reflection coefficient of an acoustic black hole termination. Journal of Sound and Vibration 349: 67.) ABH termination was used to experimentally measure . The far-field assumption is introduced for the measurement of the reflection coefficient. This assumption can be used when the excitation point and boundary are far from the measuring point. Recently, Ouisse et al. (Ouisse M, Renault D, Butaud P, et al. (2019) Damping control for improvement of acoustic black hole effect. Journal of Sound and Vibration 454: 63.) compares the reflection coefficient with the far-field assumptions for environmental temperature-dependent damping. effect was estimated.

Although many studies have been published, there have been few studies on the feasibility of applying ABH technology to real structures. Zhou and Cheng (Zhou T. and Cheng L. (2018) A resonant beam damper tailored with acoustic black hole features for broadband vibration reduction. Journal of Sound and Vibration 430: 174-184.) act as a dynamic vibration absorber (DVA). published an ABH structure. The DVA consists of an Oberst cantilever beam (Jones DIG (2001) Handbook of Viscoelastic Vibration Damping. Baffins Lane, Chichester, West Sussex, England: John Wiley & Sons Ltd.) with a tuning mass at the beam end. An ABH-shaped cantilever beam was adopted to suppress the broadband resonant frequency of the host structure, called an ABH-featured resonant beam damper (ABH-RBD). Another practical example of ABH is presented to reduce noise emissions from engine covers. An average reduction of 6.5 dB compared to the reference sample was reported (Zhao C and Prasad M (2019) Acoustic black holes in structural design for vibration and noise control. Acoustics. 1: 220-251.). However, in terms of durability and stress concentration, it is impractical to reduce engine cover thickness to control unwanted vibration. Recently Lee and Park (Lee DH and Park YY (2018) Vibration analysis of Modular acoustic black hole on a plate. In: Congr. Korea Soc. Mech. Eng. Dyn. Control. Div., Kangwon Land, S. Korea, 12 -15 December, 2018, 2119-2121.) proposed a modular ABH structure composed of a 4-ABH beam and a base as shown in FIG.

The main idea behind the modular ABH structure is to attach it to the structural surface. Oscillating waves can be collected by a modular ABH structure. The trapped vibrating waves are then damped by the damping material. Modular ABH structures can also be applied to existing on-site structures. Obtaining the ABH effect on field structures requires cutting the material with the power-law profile of conventional methods, which are not recommended due to manufacturability and safety concerns. However, the modular ABH structure can be easily applied to real structures by attaching materials instead of cutting them.

27 in the existing modular ABH structure, the 4-ABH beam is attached to the base to collect vibrational energy and serves as a DVA. In modular ABH, the wave propagation in the plate-like base excites the base and the beam is accelerated in the transverse direction.

Although a modular ABH structure has been proposed, there is still a need to improve its performance in terms of absorbing unwanted vibrations. There are several ways to improve performance, such as adding high-damping materials or increasing the number of ABH beams. One effective and easy way is to increase the number of ABH beams. However, due to space constraints, up to 8 or up to 10 ABH beams can be assembled into the base in the current model. Vertical assembling of ABH beams has been proposed to overcome the spatial constraints. A conventional ABH beam rotated 90 degrees is used. Since the thickness of vertically assembled ABH beams is much smaller than their width, more ABH beams can be assembled into the base, which can collect more wave energy at the tip of the ABH beam. Vertically assembled ABH beams are expected to perform better in terms of damping and durability because more ABH beams are assembled. Therefore, since the excitation direction is vertical rather than horizontal, it is necessary to investigate the dynamic characteristics of vertically assembled ABH beams. However, since the thickness of the conventional ABH beam rotated by 90 degrees does not decrease smoothly, side wave propagation may be reflected from the end of the ABH beam, so there is a limit in which the ABH effect is not expected.

Korean Patent Publication No. 10-2020-0119985 Japanese Patent Laid-Open No. 2012-47190

(Paper 001) Vibration Characteristics of Acoustic Black Hole Flat Plates with Confined Damping Layers (Joint Academic Conference in 2017, Korean Society of Noise and Vibration Engineering, Lee Doo-ho and 2 others) (Thesis 002) Numerical analysis of wave energy dissipation by damping treatments in a plate with acoustic black holes (Journal of Mechanical Science and Technology 32 (8) (2018) 3547~3555, Duho Lee et al.) (Thesis 003) Vibration Reduction Analysis of Flat Structure Using Modular Acoustic Black Hole (Paper 004) Effective Damping for Reduction of Vibration of Acoustic Black Holes (Spring Conference on Dynamics and Control in 2018, Duho Lee et al.) (Dissertation 005) A study on the reflection coefficient of helix acoustic black holes (2019 Korean Society of Sound and Vibration Engineering Chewage Conference, Lee Doo-ho and 1 other person) (Thesis 006) Experimental verification of the noise/vibration reduction performance of modular simple acoustic black holes (Korea Society for Noise and Vibration Engineering 2019 Chuge Conference, Lee Doo-ho and one other person)

The present invention proposes a spiral acoustic black hole structure capable of assembling more acoustic black hole beams into a modular acoustic black hole structure.

The present invention provides a spiral acoustic black hole module capable of increasing the number of assembled h-ABH beams by numerically representing the characteristics of h-ABH beams in a modular ABH structure, and a method and system for reducing noise and vibration using the same.

The present invention proposes a new concept for an ABH beam structure to overcome the spatial limitations and the loss of the ABH effect.

Although the direction of the excitation wave is vertical, it provides a spiral acoustic black hole beam in which the wave can be converted to a transverse wave in order to be captured as a propagation in the ABH region.

The present invention provides a spiral acoustic black hole module capable of increasing performance by combining a larger number of beams.

Embodiments include a beam coupling module mounted on a structure to reduce vibration and noise; A plurality of spiral acoustic black hole beams coupled to the beam combining module, wherein the plurality of spiral acoustic black hole beams are radially positioned around the beam combining module, and the plurality of spiral acoustic black hole beams are based on an axis in a longitudinal direction. As a result, a spiral acoustic black hole module having at least a partial area twisted can be provided.

In another aspect, each of the plurality of spiral acoustic black hole beams may provide a spiral acoustic black hole module whose thickness gradually decreases in a direction away from the beam combining module.

In another aspect, the beam combining module may provide a spiral acoustic black hole module in which a structure insertion hole is formed in a central region in a direction perpendicular to the spiral acoustic black hole beam.

In another aspect, each of the plurality of spiral acoustic black hole beams is divided into a beam area and a fastening area fastened to the beam combining module, wherein the beam area includes one flat area and another flat area, and the one side flat area and the other flat area. It is possible to provide a spiral acoustic black hole module composed of torsion regions between

In another aspect, the beam combining module may provide a spiral acoustic black hole module in which a plurality of beam fastening grooves extending from an upper surface to a side surface are formed, and the fastening area is coupled to the plurality of beam fastening grooves.

In another aspect, the beam combining module may provide a spiral acoustic black hole module including a torsion adjusting device for adjusting a degree of twist of the spiral acoustic black hole beam.

On another aspect, It includes a beam combining module mounted on a structure to reduce vibration and noise, and a plurality of spiral acoustic black hole beams coupled to the beam combining module, wherein the plurality of spiral acoustic black hole beams are radially positioned around the beam combining module. , A spiral acoustic black hole module in which the plurality of spiral acoustic black hole beams have a shape in which at least some regions are twisted with respect to an axis in a longitudinal direction; and a sensing unit attached to a plurality of regions of interest of a device including the structure to sense the vibration and noise information. A computing device for analyzing a transmission path of the vibration and noise based on the sensing information of the sensing unit; and displaying an installation position of the spiral acoustic black hole module in the area of the structure based on the analysis result of the computing device A noise and vibration reduction system using a spiral acoustic black hole module may be provided.

In another aspect, the beam combining module includes a torsion adjusting device for adjusting the degree of twist of the spiral acoustic black hole beam, and the computing device controls the structure based on vibration and noise information of the structure to which the spiral acoustic black hole module is attached. It is possible to provide a noise and vibration reduction system using a spiral acoustic black hole module that adjusts the torsion degree of a spiral acoustic black hole beam of a spiral acoustic black hole module attached thereto through the torsion adjusting device.

Since the modular ABH structure according to the embodiment efficiently controls unwanted vibration and overcomes spatial limitations, there is an advantage in that it can be applied to actual structures.

Embodiments allow assembling more ABH beams into a modular ABH structure to collect and emit vibrational waves with a damping material.

The embodiment provides a spiral acoustic black hole module in which the effect of ABH is exhibited even though the excitation direction is a binormal direction.

Embodiments may provide a spiral acoustic black hole module capable of effectively and efficiently controlling wave propagation.

The embodiment may provide a system capable of analyzing the proper installation position of the spiral acoustic black hole module in a structure by analyzing transmission paths of vibration and noise in a plurality of areas of the device.

The embodiment is in the form of attaching to a structure in which vibration/structure-induced noise is a problem. 1) It has a reduction effect in all frequency regions above the cutoff frequency whose frequency range is determined according to the length of the acoustic black hole beam of the module, 2 ) There is an effect that can be installed by changing the number of acoustic black hole beams variably according to the vibration energy.

In addition, the spiral acoustic black hole module can be attached to a flat part on a structure to reduce the magnitude of vibration in a direction perpendicular to the surface in a region of a specific frequency or higher, and when mounted on a shaft, torsional vibration of the shaft can be reduced.

1 and 2 are perspective views of a spiral acoustic black hole module according to an embodiment of the present invention, and FIG. 3 is a perspective view of a spiral acoustic black hole module from which a cap is separated.
4 to 6 are views of the cap-separated beam coupling module from various angles.
7 to 9 are views of a spiral acoustic black hole beam from various angles.
10 is for explaining in detail how a spiral acoustic black hole beam is coupled to a beam combining module.
In FIG. 11, (a) shows the shape of an acoustic black hole beam for transient analysis, and (b) is a graph of excitation force time history for transient analysis.
12 shows structures of an acoustic black hole beam (a) without twisting, an acoustic black hole beam (b) rotated by 90 degrees, and an h-ABH beam.
13 is for explaining another response node for comparing the travel time of the transient analysis.
14 is a graph showing the displacement of a designated position for an acoustic black hole beam of a comparative example.
15 is a graph showing displacement at a designated position for an h-ABH beam.
16 is for explaining excitation and response nodes for estimating the reflection coefficient of h-ABH.
Figure 17 shows three additional models of h-ABH for reflection coefficients.
18 is a graph showing reflection coefficients for four different h-acoustic black hole beams with binormal excitation.
19 is a graph comparing the reflection coefficients and normal excitation for a conventional acoustic black hole beam and four other acoustic black hole beams.
20 is a graph showing normalized wavenumber change for H-ABH.
21 is a state diagram in which one spiral acoustic black hole beam is separated from a spiral acoustic black hole module according to another embodiment of the present invention.
22 shows a spiral acoustic black hole module having a torsion adjusting device provided in a beam combining module.
23 shows a part of the torsion adjustment device in detail.
24 is for explaining the twisting of a spiral acoustic black hole beam according to the driving of the torsion adjusting device.
25 is a block diagram of a noise and vibration reduction system using a spiral acoustic black hole module according to an embodiment of the present invention.
26 is a graph showing the effect of reducing vibration of a structure to which an embodiment of the present invention is applied.
27 shows a conventional modular ABH structure.

Since the present invention can apply various transformations and have various embodiments, specific embodiments will be illustrated in the drawings and described in detail in the detailed description. Effects and features of the present invention, and methods for achieving them will become clear with reference to the embodiments described later in detail together with the drawings. However, the present invention is not limited to the embodiments disclosed below and may be implemented in various forms. In the following embodiments, terms such as first and second are used for the purpose of distinguishing one component from another component without limiting meaning. Also, expressions in the singular number include plural expressions unless the context clearly dictates otherwise. In addition, terms such as include or have mean that features or elements described in the specification exist, and do not preclude the possibility that one or more other features or elements may be added. In addition, in the drawings, the size of components may be exaggerated or reduced for convenience of description. For example, since the size and thickness of each component shown in the drawings are arbitrarily shown for convenience of description, the present invention is not necessarily limited to the illustrated bar.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, and when describing with reference to the drawings, the same or corresponding components are assigned the same reference numerals, and overlapping descriptions thereof will be omitted. .

- Spiral acoustic black hole module

1 and 2 are perspective views of a spiral acoustic black hole module according to an embodiment of the present invention, and FIG. 3 is a perspective view of a spiral acoustic black hole module from which a cap is separated.

1 and 2, the helix acoustic black hole module according to an embodiment of the present invention may be composed of a beam combining module 100 and a helix-acoustic black hole (h-ABH) beam 200. there is.

The spiral acoustic black hole beam 200 may be configured in plurality. For example, the number of spiral acoustic black hole beams 200 is 12, and a large number of beams may be mounted in the beam combining module 100. The higher the number of ABH beams assembled in the modular ABH structure, the better the performance as higher wave energy is captured and then dissipated by the damping material.

A plurality of spiral acoustic black hole beams 200 may be coupled to the beam combining module 100 in a radial form with the beam combining module 100 as the center. Each of the plurality of spiral acoustic black hole beams 200 may be spaced apart from each other at the same distance in a state of being coupled to the beam combining module 100, and when the embodiment is viewed from the top, the beam combining module 100 is centered. As a result, it may have a left-right and up-down symmetrical shape.

In addition, the spiral acoustic black hole beams 200 may have the same length as each other.

- Beam combination module

4 to 6 are views of the cap-separated beam coupling module from various angles.

Referring to FIGS. 3 to 6 , the beam combining module 100 may have a circular shape as a whole. The beam combining module 100 may have a circular shape in order to minimize the effect on the structure as the center of gravity is biased in a specific direction and fastened to the structure. In addition, it is preferable to have a circular shape in order to prevent problems that interfere with providing a uniform centrifugal force according to the bias of the weight of the beam coupling module 100 coupled to the rotating structure in a specific direction.

A plurality of beam fastening grooves 110 extending from the upper surface to the side of the beam combining module 100 may be formed. The plurality of beam coupling grooves 110 may be formed on the upper surface of the beam coupling module 100 to correspond to the number of spiral acoustic black hole beams coupled to the beam coupling module 100 . Each of the plurality of beam coupling grooves 110 is spaced apart from the center of the beam coupling module 100 by the same distance from each other, and each of the plurality of beam coupling grooves 110 is spaced apart by the same distance from each other to form the beam coupling module 100. It shows a left-right and top-down symmetrical shape centered on the center.

A structure insertion hole 120 may be formed in a central region of the beam combining module 100 . That is, a structure insertion hole 120 in a direction perpendicular to the spiral acoustic black hole beam 200 may be formed in the central region of the beam combining module 100 .

The structure insertion hole 120 is a hole connecting the upper and lower surfaces of the beam combining module 100 . Through the structure insertion hole 120 , the beam combining module 100 may be coupled to a structure (for example, a pipeline) requiring vibration or noise reduction.

A plurality of fastening holes 130 may be formed on an upper surface of the beam combining module 100 . Each of the plurality of fastening holes 130 may be formed on an area where the plurality of beam fastening grooves 110 are not formed on the upper surface of the beam combining module 100 .

When the beam coupling module 100 is attached to a structure (external surface of the device) through a plurality of fastening holes 130, for example, the beam coupling module 100 can be attached to the structure by screw coupling.

When a plurality of spiral acoustic black hole beams 200 are combined with the beam combining module 100, the shape is the same as in FIG. The module can be assembled.

- Spiral Acoustic Black Hole Beam

7 to 9 are views of a spiral acoustic black hole beam from various angles.

Referring to FIGS. 7 to 9 , the spiral acoustic black hole beam 200 may have a twisted shape based on a longitudinal axis. In detail, the spiral acoustic black hole beam 200 is composed of a gradient type in which the thickness decreases in the longitudinal direction according to a certain power law, and may gradually rotate in the longitudinal direction to form a vertical direction at an end portion. Accordingly, vibration in the direction of the attachment surface on the structure of the beam combining module 100 is effectively reduced.

In addition, a damping layer may be formed at an end of the spiral acoustic black hole beam 200 .

The spiral acoustic black hole beam 200 may be divided into a beam region (a) and a fastening region (b). The beam area (a) may be divided into a flat area 210 and a torsion area 220 .

The thickness of the spiral acoustic black hole beam 200 may gradually decrease along the length direction, and some areas may be twisted.

The beam area (a) and the fastening area (b) may be integrally formed with each other.

The fastening area (b) is an area corresponding to the fastening part 230 .

Each of one side and the other side of the beam region (a) may be a flat region 210, and a twist region 220 may be between the one side and the other flat region 210. The flat region 210 may be divided into a flat region 211 on one side and a flat region 212 on the other side. The other flat area 212 is an area connected to the fastening part 230 . In addition, the beam area (a) may have a shape in which the thickness gradually decreases in a direction away from the beam combining module 100 .

The twist region 220 may be a region twisted at a predetermined ratio compared to the flat region 210 in the entire area of the beam region (a).

The twist region 220 may be formed while being twisted along the Y-axis direction.

The fastening part 230 of the spiral acoustic black hole beam 200 is a part fastened to the beam combining module 100 . That is, the plurality of spiral acoustic black hole beams 200 may be coupled to the beam combining module 100 in a detachable manner rather than in a manner in which the plurality of spiral acoustic black hole beams 200 are coupled to the beam combining module 100 by welding or the like.

10 is for explaining in detail how a spiral acoustic black hole beam is coupled to a beam combining module.

Referring to FIG. 10 , a spiral acoustic black hole beam 200 may be coupled to the beam combining module 100 in a form of being inserted from an upper side to a lower side of the beam combining module 100 .

The beam fastening groove 110 is composed of a first fastening groove 111, a second fastening groove 112, and a third fastening groove 113, which may form one groove. The first fastening groove 111 is a groove formed from a portion of the outer surface of the beam combining module 100 to a predetermined depth toward the center of the beam combining module 100, and the second fastening groove 112 is the first fastening groove. It is a groove formed at a predetermined depth toward the center of the beam combining module 100, continuing from the groove 111, and the third fastening groove 113 continues from the second fastening groove 112 and forms the center of the beam combining module 100. It is a groove formed to a predetermined depth toward the The second fastening groove 112 has a narrower left and right width than the first fastening groove 111, and the third fastening groove 113 has a groove shape approximately circular as a whole and has a length of diameter of the second fastening groove 112. It can be longer than wide.

The fastening part 230 of the spiral acoustic black hole beam 200 may have a shape corresponding to the beam fastening groove 110 . Accordingly, the fastening part 230 includes a first part 231 having a shape corresponding to the first fastening groove 111, a second part 232 having a shape corresponding to the second fastening groove 112, and a third fastening groove. It may have a third portion 233 having a shape corresponding to (113). The third fastening groove 113 has a groove shape approximately circular as a whole, and as the length of the diameter is longer than the width of the second fastening groove 112, the fastening part 230 is coupled to the beam coupling module 100 It is fixed while being prevented from leaving in the left and right, front and rear directions. Then, while the cap (FIG. 2) is covered on the upper side, the fastening part 230 is fixed while being prevented from moving upward.

Hereinafter, in order to numerically investigate the characteristics of the h-ABH of the present invention, transient analysis and harmonic frequency analysis were performed. Through transient analysis, how well the wave propagation can be captured in the ABH region is determined by comparing the travel time between the uniform thickness portion and the ABH region. It is also known that the reflection coefficient is one of the most important performance in conventional ABH beams. Through harmonic frequency analysis, it is important to know how the reflection coefficient varies depending on how “sharpen” or “smooth” the ABH region is twisted. Therefore, four different models of h-ABH are proposed to analyze it. The reflection coefficient of the h-ABH beam is estimated and the result is compared with the conventional ABH beam.

Hereinafter, this will be described in detail.

In FIG. 11, (a) shows the shape of an acoustic black hole beam for transient analysis, and (b) is a graph of excitation force time history for transient analysis. 12 shows structures of an acoustic black hole beam (a) without twisting, an acoustic black hole beam (b) rotated by 90 degrees, and an h-ABH beam.

-ABH

In general, two items can be considered for torsion-free ABH beams. The two items are the uniform thickness area and the ABH area. Since the thickness of the ABH decreases, the thickness polynomial function of the ABH region satisfies Equation 1.

[Equation 1]

In Equation 1, the exponent m is a positive number and must be greater than 2.0, the coefficient is a constant value, and y is the distance from the end of the power law profile. As for the thickness h1, as shown in FIG. 11(a), since it is impossible to construct a structure having a thickness of 0 in practice, the ABH region truncated thickness is required. The oscillation of the incident wave shown in FIG. 11(b) generally occurs in the transverse direction in the ABH beam to which distortion is not applied, as shown in FIG. 12(a).

Under the Euler-Bernoulli assumption, one-dimensional wave propagation can be explained using the complex amplitude W(y) as shown in Equation 2. Then, the flexural wave propagates through the ABH region, and a power-law profile is used at this time.

[Equation 2]

In Equation 2, A(y) is the amplitude of the wave at position y, j is an imaginary unit, and θ(y) is the total cumulative phase as shown in Equation 3 below.

[Equation 3]

In Equation 3, kf(y) is the local flexural wave number. Assuming that the thickness changes according to Equation 1, the local flexural wave number satisfies Equation 4.

[Equation 4]

In Equation 4, ρ is the density, ω is the angular frequency, E = E (1 + jη) is the complex Young's modulus (E is the storage coefficient, η is the loss coefficient), and h (y) is the thickness. Since c = ω/kf, the phase velocity satisfies Equation 5.

[Equation 5]

For a uniform isotropic planar beam of constant thickness, the phase velocity is proportional to the square root of the frequency. When the thickness of the ABH section becomes zero, the frequency approaches infinity and the bending wave velocity approaches zero, resulting in the ABH effect.

- reflection coefficient

The basic concept of torsion-free ABH is based on "zero reflection" when the phase velocity approaches zero. A general solution for the displacement can be expressed as the sum of four waves as shown in Equation 6.

[Equation 6]

In Equation 6, the coefficients A, B, C, and D represent the magnitude of forward propagation and attenuation waves.

Assuming that the waves are far from the excitation point and the boundary, the damped waves can be neglected and the wavefield Denis et al. (2015), Ouissee et al. (2019) can be approximated as in Equation 7 as the sum of the two radio waves.

[Equation 7]

Therefore, the reflection coefficient can be defined as in Equation 8.

[Equation 8]

The reflection coefficient can be obtained by measuring the displacement at several locations.

Arrangement w(yi) is measured at n positions yi along the transverse beam (i = 1, ..., n; n ≥ 2). Then, the measured displacement satisfies the general solution of equation (7). Thus, the equation of Equation 9 is obtained at each frequency.

[Equation 9]

The coefficients A and B can be estimated by multiplying the pseudoinverse matrix as in Equation 10.

[Equation 10]

In Equation 10, the Moore-Penrose generalized inverse matrix M † = (MM) ^-1 , and M ^* is the conjugate transpose of M.

- spiral acoustic black hole

To assemble more ABH beams into modular ABH structures, new types of ABH beams are needed. In the assembled ABH beam, more unwanted wave energy can be collected and dissipated. However, it is not easy to assemble more ABH beams on the base due to space constraints. In order to overcome this spatial limitation, the ABH beam is vertically assembled as shown in FIG. 12(b), where the excitation wave of the base is lateral. In this case, since the dimension in the vertical direction of the thickness does not change at all, the ABH effect may not occur. One solution to overcome this problem is to simply twist the ABH region along the longitudinal axis h-ABH.

One) Coordinate rules for h-ABH

The torsion-free ABH and h-ABH structures consist of two parts: a uniform thickness part and an ABH beam area. In the h-ABH, the thickness of the ABH region decreases while being twisted along the longitudinal direction, as shown in FIG. 12(c). Since the ABH region is twisted along the longitudinal direction (Y axis), the normal direction is also different. X, Y, Z coordinates are defined. Directions should be clearly defined to avoid coordinate system ambiguity. In particular, in the case of the ABH portion of the h-ABH beam, the terms "normal" and "binormal" for the direction, respectively, are adopted instead of the terms "transverse" and "lateral". The normal is the direction pointing outward perpendicular to the bottom surface of the ABH region in the h-ABH beam. The "normal" direction is aligned with the Z axis and the "binormal" direction is aligned with the X axis at the interface point between the ABH region and the uniform thickness portion for h-ABH. However, the "normal" direction is aligned with the X-axis and the "bi-normal" direction coincides with the inverse of the Z-axis at the end of the h-ABH beam.

2) wave propagation simulation

[Table 1]

Transient analysis was performed to compare the bending wave propagation of the ABH and h-ABH beams of the comparative example. As shown in Fig. 11(b), the beam was excited at the edge of the uniform thickness part using a Hanning windowed pure tone burst force signal with a 5-period Hanning window. Table 1 shows the mechanical material properties and parameters for both the untwisted beam and the h-ABH beam.

In the modular ABH structure with four twist-free ABH beams shown in Fig. 27, vertical excitation is transmitted from the base structure. However, the excitation direction is lateral to the ABH beam rotated 90 degrees. Therefore, two different types of excitation waves were considered. (1) one of vertical excitation using an ABH beam without torsion and (2) one of vertical excitation using an ABH beam rotated by 90 degrees. In the case of the h-ABH beam, only binormal excitation is considered. The purpose of the wave propagation simulation is to compare the travel time between the uniform thickness section and the ABH region.

MSC Nastran, a commercial finite element analysis software, was used to perform the numerical simulations. A three-dimensional eight-node hexahedral second-order element was adopted and a minimum of eight elements per local wavelength was included to ensure numerical simulation accuracy. Three different location nodes were selected to estimate the travel time. One is the excitation point, the next point is the interface point between the uniform thickness and the ABH region, and the last node is at the end of the ABH region. It can also be seen that the uniform thickness portion and the length of the ABH region are the same.

13 is for explaining another response node for comparing the travel time of the transient analysis.

Wave propagation simulation was performed for the ABH without twisting applied. The black circle at the y2 position in FIG. 13 is the excitation point. The red triangle y1 is at the interface between the uniform thickness beam part and the ABH region. The blue rectangle y0 is at the end of the ABH region. The excitation direction is set to the Z axis (ie, vertical direction) in the case of an ABH beam without twisting or to the X axis (ie, lateral direction) in the case of an ABH beam rotated by 90 degrees. The spans between the locations selected in FIG. 13 are the same, and if waves propagate at a constant speed, they will pass through the area at equal time intervals. However, it is clear that the time interval changes as the number of waves changes. If the time interval of the ABH region is longer than that of the uniform region, the ABH effect of trapping waves in the ABH region is expected. Otherwise, no ABH effect is expected. Therefore, the travel time for the bending wave to pass through the two regions was compared.

14 is a graph showing the displacement of a designated position for an acoustic black hole beam of a comparative example.

The time interval between the black circle and the red triangle represents the time it takes for a wave to pass through a uniformly thick section. The time interval between the red triangle and blue square points represents the travel time through the ABH region. As can be seen in Fig. 13, the circled black line is the transverse displacement at the excitation point. As soon as the force excites the beam, the displacement also fluctuates. The red line with the triangle represents the displacement of the red triangle point, which is the boundary point between the uniform thickness part and the ABH region. It took 2.02 ms to move the uniform thickness part. The blue line with squares represents the displacement of the beam tip. The maximum displacement is displayed approximately 4.26 ms after the red line where the triangle fluctuates. Since the thickness decreases in the ABH region, the wave speed also slows down. Because of the ABH effect, the travel time is longer than for uniform thickness sections.

The displacements of the three points prescribed for lateral excitation using an ABH beam rotated by 90 degrees are shown in Fig. 14(b). In this case, the travel time through the two regions is approximately the same. It is 0.69 ms in the uniform thickness part and 0.70 ms in the ABH region. This means that the ABH effect does not occur in the ABH region. Since the thickness in the vertical direction does not change, the velocity of the vertical bending wave does not change during wave propagation. It should be noted that the time of lateral excitation (0.69 ms) is much faster than that of vertical excitation (2.02 ms) because the wave number of the ABH beam rotated by 90 degrees is much lower.

Numerical simulations of vertical and lateral excitation showed that the ABH beam rotated by 90 degrees did not experience the ABH effect.

Wave propagation simulations were performed for h-ABH. Wave propagation simulations were performed on h-ABH to confirm the ABH effect in binormal excitation. In the h-ABH beam, the thickness of the ABH region is twisted while decreasing along the vertical direction (Y axis) as shown in FIG. 12(c).

15 is a graph showing displacement at a designated position for an h-ABH beam.

In the case of the h-ABH beam, the transient response was also calculated with unsteady excitation as shown in FIGS. 15(a) and (b). The selected position is the same as that of the existing ABH model.

Fig. 15 (a) shows the displacement in the Z direction. The position of y0 mainly fluctuates. The displacements at the other points y1 and y2 are almost negligible. Since the excitation direction is the X axis, the displacement in the Z direction of the uniform thickness portion is almost zero. However, the binormal displacement at the end of the ABH region is highly biased because the thickness of this region is very thin. The round-trip travel time at the end of the ABH region is 2.79 ms, which is almost twice the total one-way travel time of the 90 degree rotated ABH beam case (1.39 ms). In the case of the X-direction displacement shown in Fig. 15(b), the time interval between the black circle and the red triangle (i.e., the travel time of the uniform thickness part) is 0.69 ms, which is almost the same as that of the ABH beam rotated by 90 degrees. Obvious. The time interval between the red triangle and the blue square (i.e., the travel time through the twisted ABH region) is 4.21 ms, which is similar to the untwisted ABH of the transverse excitation case (4.26 ms). It should be noted that the displacement in the X direction at the y1 position is binormal, as shown in Fig. 15(c). For the y1 position, the binormal directional wave propagates through the entire h-ABH beam and takes 1.41 ms to reflect at the end of the ABH region and 1.37 ms to return to the uniform thickness portion. The travel time through the uniform thickness part is slightly shorter than the other part due to the larger moment of inertia. Fig. 15 shows that although the excitation direction is binormal, the waves in normal and binormal directions moved the h-ABH beam simultaneously.

[Table 2]

Table 2 summarizes the travel times of (1) a conventional ABH beam without twisting, (2) a 90 degree rotated ABH beam, and (3) an h-ABH beam. Each beam has a uniform thickness section and an ABH region. For the conventional ABH beam, the travel times are 2.02 ms and 4.26 ms in the uniform thickness part and ABH region, respectively. When the wave speed slows down in the ABH region, the ABH effect occurs. However, in the case of the conventional ABH beam rotated by 90 degrees, the ABH effect does not occur because the travel time of the uniform thickness portion and the ABH area is almost the same. In the case of h-ABH, the movement took 0.69 ms in the uniform thickness part. In the ABH region, it took 4.21 ms. From these results, it is clear that the ABH effect occurs in the h-ABH beam.

3) Reflection coefficient estimation

[Table 3]

The reflection coefficient is the most important performance of an ABH beam. From now on, the reflection coefficient of the h-ABH beam structure is estimated using a finite element (FE) model. 16 shows the dimensions of the h-ABH beam and the FE model used for reflection coefficient estimation. Harmonic frequency analysis was performed to evaluate the reflection coefficient. The h-ABH beam and the attenuation layer of h-ABH were discretized to 18,000 and 2000 with second-order eight-node hexahedral elements, respectively. Table 3 shows the geometric dimensions of the h-ABH beam. The material properties are the same as those of the conventional ABH beam in Table 1.

16 is for explaining excitation and response nodes for estimating the reflection coefficient of h-ABH. And, Figure 17 shows three additional models of h-ABH for the reflection coefficient.

The reflection coefficient was estimated from the binormal displacement W(yi) at three different locations as shown in FIG. The sampling point should be located in the middle of the beam span and should be measured in two or more. The reflection coefficient estimation method at different points was verified by comparing the reflection coefficient for the conventional ABH beam with that of Ouisse et al. Under free-free boundary conditions, a unit force was applied along the binormal, X-axis direction at the green point 4 mm from the edge of the uniform thickness part. The binormal displacement was taken at three red points at y1 = 70 mm, y2 = 84 mm, and y3 = 122 mm at the edge of the uniform thickness beam.

The damping material plays a very important role in the reflection coefficient. For the h-ABH beam, the size and thickness of the attenuation layer are 20 mm × 20 mm. The loss factor of the damping material (ηv) is 0.8, the Young's modulus (Ev) is 1.8 MPa, and the density (ρv) is 968 kg/m ³ .

As shown in Fig. 16, the entire length of the ABH portion is progressively twisted along the Y axis. However, it is necessary to investigate the performance of some differently twisted h-ABH models. If the entire length of the ABH region is twisted, this is referred to as the “full proportion” h-ABH. Therefore, models with helix ratios of 2/3, 1/2 and 1/3, respectively, were used, as shown in Fig. 17(a)-(c). For example, twist only 2/3 ABH length. For the 2/3 model, the other length part is flat. The excitation and measurement points were identical to those of the h-ABH beam as shown in FIG. 16 .

The mesh quality of the twisted ABH region for the FE model was confirmed in terms of aspect ratio and distortion. For the 4 different h-ABH models, including the "full ratio" h-ABH beam, the maximum aspect ratio was 6 allowed. Large aspect ratio elements with values greater than 5 resulted in 1020 out of 18,000 (only 6%), most of which were located near the ends of the ABH beams. The maximum distortion allowed among all FE models is 29.03°.

18 is a graph showing the reflection coefficients for four different h-acoustic black hole beams with binormal excitation, and FIG. 19 compares the reflection coefficients and normal excitations for a conventional acoustic black hole beam and four different acoustic black hole beams. 20 is a graph showing normalized wavenumber change for H-ABH.

We compare the reflection coefficients and normal excitation for a normal acoustic black hole beam and four different acoustic black hole beams.

Normalized wavenumber shift for an H-acoustic black hole beam.

18 shows estimated reflection coefficients for the four h-ABH models described above. Regardless of the percentage of helices in the total reflection coefficient, the performance is almost the same. In the low frequency range (0-3,000 Hz), the reflection coefficient is close to unity. After that, significant changes in the reflection coefficient appeared near 3000 Hz, 5500 Hz and 7200 Hz. The reflection coefficient differed depending on the twist length of the ABH segment. Although the reflection coefficient is high at certain frequencies, the reflection coefficient tends to be low in the high frequency range. It should also be noted that the number of valleys increases as the spiral ratio decreases, as shown in FIG. 18 . In terms of the reflection coefficient, h-ABH can replace the existing ABH because the ABH effect is maintained.

19 also shows the reflection coefficients for the conventional ABH beam and the four different h-ABH models described above together with the stationary direction wave. The only difference from the previous estimate is the excitation direction and the reaction point, i.e. the normal direction rather than the binormal direction.

Compared to the conventional ABH, the h-ABH structure exhibited similar performance for reflection coefficient regardless of the helix ratio. The two are similar in that the number of valleys increases as the twist length decreases, as shown in FIG. For example, when the spiral ratio is 1, the number of valleys is 4 (near 1800, 4000, 7000 and 9700 Hz). However, it is 9 if we consider the 1/3 helix ratio model.

[Table 4]

A normalized wavenumber change was introduced into the smoothness of the geometrical acoustic approximation. It is difficult to discern the normalized wavenumber change of the h-ABH beam due to geometric complexity. Two-dimensional profile information is required to describe the geometric smoothness characteristics of h-ABH beams. The positional data of the central node along the widthwise X axis were retrieved in the YZ plane, which can indicate the smoothness of the h-ABH beam. Based on these coordinates, the difference between the two-dimensional profile data and the data obtained in Equation 1 was minimized to identify unknown variables, the coefficient ( ) and the exponent (m). At this time, h0 was regarded as 0. For the full ratio length of the h-ABH beam, the coefficient and exponent were 1.56 × 10 and 2.29, respectively. However, considering the 1/3 length of the h-ABH beam, the coefficient was 3.35 × 10 10 and the exponent was 5.15. The identified parameters of the four different h-ABH profiles are shown in Table 4. As expected, the slope is very drastic for the 1/3 h-ABH beam. The index value is greater than 5.0. A comparison of normalized wavenumber changes for four different h-ABH beam models using these parameters is shown in Fig. 20. By increasing the value of the exponent, the smoothness criterion is violated in the low frequency range such that for one-third the length of the h-ABH beam the criterion is violated below 2,000 Hz.

In the examples, the characterization of h-ABH beams was performed numerically to increase the number of assembled h-ABH beams in a modular ABH structure. Because the modular ABH structure efficiently controls unwanted vibrations, it has great potential for application in practical structures. The more ABH beams are assembled into the modular ABH structure, the more vibrational waves can be collected and emitted by the damping material. In order to understand the characteristics of the h-ABH beam according to the embodiment, (i) compare the travel time of the uniform thickness portion and the ABH region through transient analysis, and (ii) calculate the reflection coefficient of the h-ABH beam through harmonic frequency analysis. estimated. In the case of the existing ABH beam, the uniform thickness took 2.02 ms and the ABH area took 4.26 ms of travel time. This means that the wave speed slows down in the ABH region, and in this case, the ABH effect occurs. For the conventional ABH beam rotated by 90 degrees, it took 0.69 ms and 0.70 ms for the uniform thickness and ABH area, respectively. The arrival time is almost the same, which is different from the previous case. Since the thickness of the ABH portion does not change at all, the wavenumber change is very small. In the case of a conventional ABH beam case that rotates 90 degrees, the ABH effect cannot be expected. It should also be noted that the wave speed is much higher than in the previous case because the moment of inertia is much higher. It took 0.69 ms for the uniform thickness using the h-ABH beam and 4.21 ms for the excitation displacement in the ABH region. The travel time of 4.21 ms is almost identical to the conventional ABH case, and we can expect the ABH effect to exist even though the excitation direction is binormal.

In addition, the reflection coefficient was evaluated. For each of (1) full torsional ABH area, (2) 2-3 longitudinal twist ABH beam segments, (3) half length torsional ABH beam segments and (4) one-third torsional length of the ABH beam area of h-ABH. The reflection coefficient was evaluated. The reflection coefficient tended to be low in the high frequency range for both normal and binormal excitation. The total reflection coefficient is similar to the original value with normal excitation. It should be clear that the reflection coefficient differs for different lengths of the twisted ABH segments. However, there are local drop-off points in the reflection coefficient for the three different shapes. Short twist lengths tend to have more local drop points. In addition, normalized wavenumber changes according to four different h-ABH beam models were estimated. The shorter the length of the twist ratio, the higher the index value is identified. Numerical simulations show that the new h-ABH beam can effectively and efficiently control the wave propagation for modular ABH structures. The h-ABH beam can be assembled into a modular ABH structure that retains the ABH effect. Even considering the binormal excitation, a normal directional wave is generated from the h-ABH beam, so the ABH effect can be expected.

21 is a state diagram in which one spiral acoustic black hole beam is separated from a spiral acoustic black hole module according to another embodiment of the present invention. In addition, FIG. 22 shows a spiral acoustic black hole module having a torsion adjusting device provided in the beam combining module, FIG. 23 shows a part of the torsion adjusting device in detail, and FIG. 24 shows a spiral according to the driving of the torsion adjusting device. This is to explain the twisting of the acoustic black hole beam.

Referring to FIG. 21 , a spiral acoustic black hole module 10 according to another embodiment of the present invention may include a beam combining module 100 and a spiral acoustic black hole beam 200 . A plurality of beam insertion grooves 190 may be formed along the side circumference of the beam combining module 100 . One side of the plurality of acoustic black hole beams 200 may be inserted into the beam insertion groove 190 and combined. A structure insertion hole 120 into which structures may be coupled may be formed in a central region of the beam combining module 100 .

In some embodiments, the spiral acoustic black hole beam 200 may be made of a material having a predetermined elasticity.

Referring to FIGS. 22 to 24 , a torsion adjusting device 300 may be installed in the beam combining module 100 . The twist adjustment device 300 includes a first gear 310 rotating around the structure insertion hole 120 inside the beam coupling module 100 and a plurality of second gears 320 rotating in engagement with the first gear 310. ) may be included. The first and second gears 310 and 320 may be driven by a hypoid gear system, and a driving system (not shown) for rotating the second gear 320 is provided on the inner lower surface of the beam coupling module 100. ) can be installed. In addition, the second gear 320 may rotate about an axis in the longitudinal direction of the spiral acoustic black hole beam 200 . The second gear 320 may be installed as many as the number of spiral fornication black hole beams 200 . A beam axis 330 is coupled to the center of the second gear 320, and a pressing portion 340 may be formed at an end of the beam axis 330. That is, one end of the beam shaft 330 may be connected to the center of the second gear 320 and the other side may be connected to the pressing unit 340 . The beam axis 330 and the pressing part 340 may be integrally formed with each other.

In some embodiments, a beam axis 330 and a pressing portion 340 are formed inside the spiral acoustic black hole beam 200, and one end of the beam axis 330 is drawn out of the spiral acoustic black hole beam 200, When the spiral acoustic black hole beam 200 is coupled to the beam insertion groove 190 , one end of the beam shaft 330 may be connected to the second gear 320 . The beam axis 330 is installed inside the spiral acoustic black hole beam 200 along the longitudinal direction of the spiral acoustic black hole beam 200, and the pressing part 340 is connected to the axis of the spiral acoustic black hole beam 200 in the longitudinal direction. It may be installed at the end of the spiral acoustic black hole beam 200 in a vertical direction.

As the first gear 310 rotates by a predetermined angle, the plurality of second gears 320 engaged with the first gear 310 rotate correspondingly, and thus the beam axis 330 rotates while the beam axis ( The pressing part 340 connected to the end of 330) rotates. As the pressing unit 340 rotates, the end of the spiral acoustic black hole beam 200 receives a rotational force around the longitudinal axis of the spiral acoustic black hole beam 200, so that the spiral acoustic black hole beam 200 is twisted. do. In addition, since the plurality of second gears 320 meshed with the first gear 310 all rotate at the same angle, the torsion degree of all the spiral acoustic black hole beams 200 becomes the same.

25 is a block diagram of a noise and vibration reduction system using a spiral acoustic black hole module according to an embodiment of the present invention.

Referring to FIGS. 24 and 25 , a noise and vibration reduction system 1 using a spiral acoustic black hole module may include a computing device 400 , a display 500 , and a sensing unit 600 . The computing device 400 and the display 500 may be configured as one device. The computing device 400 may include at least one processor 410 and at least one memory 420 . Computing device 400 is intended to represent various forms of digital computers, such as laptop computers, convertible computers, tablet computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframes, and other suitable computers. Computing device 400 is intended to represent various forms of mobile devices such as personal digital assistants, cellular telephones, smart phones, and other similar computing devices. The components depicted herein, their connections and relationships, and their function are meant to be illustrative only and are not meant to limit implementations of the invention described and/or claimed herein. Additionally, computing device 400 may include a high-speed interface coupled to the storage device, memory, and high-speed expansion port, and a low-speed interface coupled to a low-speed bus and the storage device. Each of the components are interconnected using various buses and may be mounted on a common motherboard or in other ways suitable. Processor 410 processes instructions for execution within computing device 400, including instructions stored in memory 420 or storage devices, to display a GUI on an external input/output device such as a display connected to a high-speed interface. graphic information can be displayed. In another implementation, multiple processors and/or multiple buses may be used, as appropriate, along with multiple memories and types of memory. In addition, multiple computing devices 400 may be connected (eg, as a server bank, blade server group, or multi-processor system) with each device providing a portion of the required operation.

The sensing unit 600 may be installed in a device including a structure. The sensing unit 600 may be attached to a plurality of regions of the device. Based on the sensing information of the sensing unit 600, the computing device 400 determines between a plurality of areas to which the sensing unit 600 is attached? The transmission path of vibration and noise can be analyzed. Also, the computing device 400 may display a transmission path of vibration and noise through the display 500 based on the analysis result. In addition, the computing device 400 may display the installation position of the spiral acoustic black hole module 10 in the area of the structure based on the analysis result.

In various embodiments, the computing device 400 analyzes the degree of vibration and noise of the structure based on the sensing information of the sensing unit provided in the structure in which the spiral acoustic black hole module 10 is installed, and the torsion adjustment device 300 based on the analysis result. ) can be driven, and the twist degree of the spiral acoustic black hole beam 200 can be adjusted accordingly. In addition, the computing device 400 adjusts the rotational position of the second gear 320 of the torsion adjusting device 300 to the original position when the structure is not in operation (when vibration and noise are not generated) to spiral the spiral. The twisting of the acoustic black hole beam 200 can be released.

26 is a graph showing the vibration reduction effect of a structure to which an embodiment of the present invention is applied.

Referring to FIG. 26, comparing the case where the spiral acoustic black hole module 10 according to the embodiment is installed (red graph) and the case where it is not (black graph), vibration through the results of the frequency response function at several positions It can be seen that there is a reduction effect.

Embodiments according to the present invention described above may be implemented in the form of program instructions that can be executed through various computer components and recorded on a computer-readable recording medium. The computer readable recording medium may include program instructions, data files, data structures, etc. alone or in combination. Program instructions recorded on the computer-readable recording medium may be specially designed and configured for the present invention, or may be known and usable to those skilled in the art of computer software. Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks and magnetic tapes, optical recording media such as CD-ROMs and DVDs, and magneto-optical media such as floptical disks. medium), and hardware devices specially configured to store and execute program instructions, such as ROM, RAM, flash memory, and the like. Examples of program instructions include high-level language codes that can be executed by a computer using an interpreter or the like as well as machine language codes generated by a compiler. A hardware device may be modified with one or more software modules to perform processing according to the present invention and vice versa.

Specific implementations described in the present invention are examples and do not limit the scope of the present invention in any way. For brevity of the specification, description of conventional electronic components, control systems, software, and other functional aspects of the systems may be omitted. In addition, the connection of lines or connecting members between the components shown in the drawings are examples of functional connections and / or physical or circuit connections, which can be replaced in actual devices or additional various functional connections, physical connection, or circuit connections. In addition, if there is no specific reference such as “essential” or “important”, it may not be a component necessarily required for the application of the present invention.

In addition, the detailed description of the present invention described has been described with reference to preferred embodiments of the present invention, but those skilled in the art or those having ordinary knowledge in the art will find the spirit of the present invention described in the claims to be described later. And it will be understood that the present invention can be variously modified and changed without departing from the technical scope. Therefore, the technical scope of the present invention is not limited to the contents described in the detailed description of the specification, but should be defined by the claims.

Claims (8)

Beam coupling module mounted on the structure to reduce vibration and noise;
A plurality of spiral acoustic black hole beams coupled to the beam combining module;
The plurality of spiral acoustic black hole beams are radially positioned around the beam combining module,
The plurality of spiral acoustic black hole beams have a shape in which at least some regions are twisted with respect to an axis in the longitudinal direction.
Spiral acoustic black hole module. According to claim 1,
Each of the plurality of spiral acoustic black hole beams has a thickness that gradually decreases in a direction away from the beam combining module.
Spiral acoustic black hole module. According to claim 2,
The beam combining module has a structure insertion hole formed in a direction perpendicular to the spiral acoustic black hole beam in the central region.
Spiral acoustic black hole module. According to claim 3,
Each of the plurality of spiral acoustic black hole beams is divided into a beam area and a fastening area fastened to the beam combining module,
The beam area is composed of a flat area on one side, a flat area on the other side, and a torsion area between the flat area on one side and the other flat area.
Spiral acoustic black hole module. According to claim 4,
The beam coupling module is formed with a plurality of beam fastening grooves extending from the top surface to the side surface,
The fastening area is coupled to the plurality of beam fastening grooves to be coupled
Spiral acoustic black hole module. According to claim 3,
The beam combining module includes a torsion adjusting device for adjusting the degree of torsion of the spiral acoustic black hole beam.
Spiral acoustic black hole module. It includes a beam combining module mounted on a structure to reduce vibration and noise, and a plurality of spiral acoustic black hole beams coupled to the beam combining module, wherein the plurality of spiral acoustic black hole beams are radially positioned around the beam combining module. , A spiral acoustic black hole module in which the plurality of spiral acoustic black hole beams have a shape in which at least some regions are twisted with respect to an axis in a longitudinal direction; and
a sensing unit attached to a plurality of regions of interest of a device including the structure and sensing the vibration and noise information;
A computing device that analyzes a transmission path of the vibration and noise based on the sensing information of the sensing unit; includes,
Displaying the installation position of the spiral acoustic black hole module in the area of the structure based on the analysis result of the computing device
Noise and vibration reduction system using spiral acoustic black hole module. According to claim 7,
The beam combining module includes a torsion adjusting device for adjusting the degree of twist of the spiral acoustic black hole beam, and the computing device includes a spiral attached to the structure based on vibration and noise information of the structure to which the spiral acoustic black hole module is attached. Adjusting the twist degree of the spiral acoustic black hole beam of the acoustic black hole module through the torsion adjusting device
Noise and vibration reduction system using spiral acoustic black hole module.

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