KR20110039106A - Method for reducing vibration of slender structure and apparatus adopting the method - Google Patents

Abstract

PURPOSE: A method and an apparatus for reducing vibration of a slender structure are provided to absorb the vibration in a slender structure through a collision between a steel body and a wall body. CONSTITUTION: An apparatus for reducing vibration of a slender structure comprises a steel body(22), a vessel(21), and a shock absorbing member. The vessel is installed in a slender structure(10) and accepts the steel body. The vessel has a wall body(23) for restricting the moving area of the steel body, and multiple spaces. The shock absorbing member is made of a rubber material and is formed between the steel body and the wall body.

Description

Method for reducing vibration of Slender Structure and Apparatus adopting the method

The present invention relates to a vibration damping method of an elongated structure and a device using the same, and in detail, to a vibration damping method and apparatus using an impact damper.

The present invention is derived from a study conducted as a part of the new technology R & D support project of Korea Institute of Construction and Transportation Technology Evaluation Institute and Mokpo National University Industry-Academic Cooperation Group. [Task management number: 05 region characteristics B05-01, task name: cable bridge and flexible structure Wind resistance and vibration damping technology development]

The elongated structure is vibrated by horizontal loads such as earthquakes and wind loads. Such vibration is a hazard of stability and longevity of the elongated structure. Various types of vibration control devices and control algorithms for dissipating the energy of the elongated structure have been studied, and the characteristics and economics of the elongated structure are considered.

Multifaceted studies and efforts on the control of vibration caused by horizontal loads in elongated structures have led to the development of vibration suppression and vibration isolation mechanisms that can be applied in practice. Active, passive, and semi-active dampers are responded to this, which requires a rather complicated device to manufacture, install, and construct due to the increased damping ratio of the elongated structure.

According to various embodiments, a method of reducing vibration of an elongated structure having a simple structure and easy to manufacture and install and an apparatus using the same are provided.

In the embodiment, the vibration reduction method for an elongated structure includes a space having a wall in a portion of the elongated structure, and provides a rigid body that freely collides with the wall by vibrating the elongated structure in the space, thereby providing the rigid body. The vibration of the structure is absorbed by the collision between the rigid body and the wall.

According to a vibration reduction method according to another embodiment, energy absorption is induced by elastic deformation between the rigid body and the wall during the collision between the rigid body and the wall.

According to another embodiment, a plurality of the space is arranged around one axis and the mass is provided in each space to induce vibration absorption by a plurality of rigid bodies and walls.

According to another embodiment, the vibration absorption by one rigid body or a plurality of rigid bodies as described above is performed in each of a plurality of regions arranged in the longitudinal direction of the elongated structure.

Vibration reduction device according to an embodiment,

Rigid body;

And a container having a bottom portion in which the rigid body is rolled and a wall restricting an area of motion of the rigid body.

Elongated structure according to the embodiment,

An elongated body;

And a vibration reduction device provided in a portion of the elongated body,

The vibration reduction device:

Rigid body;

A container in which the rigid body is accommodated, the container having a bottom portion in which the rigid body rolls and a wall restricting a movement area of the rigid body; It has a structure to be provided.

An elongated structure according to another embodiment includes a plurality of vibration reducing devices spaced apart from each other in the longitudinal direction of the elongated body.

According to other embodiments of the vibration reduction device and the elongated structure,

The container includes a plurality of spaces arranged around one axis, and the rigid bodies are respectively provided in each space.

According to another embodiment of the vibration reduction device and the elongated structure,

An impact absorbing layer due to elastic deformation is formed on at least one side of the surface of the rigid body and the wall of the container.

Vibration reduction method and apparatus for an elongated structure according to the embodiment applies the impact damping effect (impact damping effect). That is, a rigid body that is moved by inertia, frictional force, etc. in the container vibrating together by the vibration of the elongated structure is used to utilize the collision between the rigid body and the wall of the container and thus energy dissipation.

As shown in FIG. 1, the impact damper 20 as a vibration damping device includes a container 21 located at a portion or one side of the main body 10 of the elongated structure, and a rigid body disposed in the container 21. (22) is provided. The rigid body 22 is basically a mass that collides with the wall 23 of the container 21 while moving against the movement of the main body 10 of the elongated structure. Rigid body 22 is accommodated in the container 21 additionally installed in some areas inside or outside the elongated structure body 10, the movement of the rigid body 22 between the wall 23 and the rigid body of the container 21 There is an allowable distance or working distance d on both sides. The rigid body 22 collides with the wall 23 of the container 21 while moving in the space in the container 21 when the elongated structure 10 vibrates. This collision: leads to the dissipation of the vibrational energy of the elongated structure 10; and the exchange of momentum to the rigid body 22; Here, the momentum exchange to the rigid body 22 is an important process of absorbing the kinetic energy of the elongated structure 10 to reduce vibration.

The impact damper is a vibration damping device for protecting the elongated structure from fatigue strength or fracture caused when an elongated structure such as a street lamp having a high degree of flexibility and a low damping force vibrates by an external load such as wind. to be. Here, by adjusting the impact period of the rigid body according to the natural frequency of the elongated structure to be reduced vibration, the operating distance (d) of the rigid body and the mass of the rigid body, the rigid body according to the progress of the elongated structure by the external load By vibrating the elongated structure (wall of the container), vibration of the elongated structure is reduced.

These impact dampers are relatively simple in structure and low in cost. Such impact dampers are easy to install on elongated structures, for example street lights. Impact dampers with this advantage can effectively absorb the vibration energy of the elongated structure due to external loads from various directions such as wind or earthquake.

In the vibration reduction method, which is a technical background of the vibration rewinding device described above, a space having a wall is provided in a partial region of the elongated structure, and a rigid body freely moved by the vibration of the elongated structure is provided in the space. The vibration of the elongated structure is to be absorbed by the collision between the rigid body and the wall due to the vibration of the elongated structure. The space may be provided by a container as described above, or in another embodiment may be provided by a cavity provided in the elongated structure itself. Such a vibration reduction method may induce an energy absorption due to elastic deformation within an operating section between the rigid body and the wall when the impact between the rigid body and the wall impacts. In such energy absorption, an elastic deformation body and an elastic deformation film (layer) that absorb impact energy by mechanical elastic deformation may be used. An example of the representative material is rubber. This will be described in a part related to FIGS. 5A and 5B in the accompanying drawings.

According to a vibration reduction method of another embodiment, by arranging a plurality of the space around one axis and by providing a rigid body in each space can be induced vibration absorption by the rigid bodies and the wall. This is advantageous for the effective vibration absorption for all vibration directions of the elongated structure, which will be described with reference to FIGS. 3 and 4A and 4B.

According to another embodiment, vibration absorption by one rigid body or a plurality of rigid bodies as described above may be performed for a plurality of regions disposed in the longitudinal direction of the elongated structure. This is advantageous for very long elongated structures, which can respond locally to various parts of the oscillation that differ in frequency or phase. This will be described with reference to FIGS. 2 and 3 described below.

Hereinafter, an embodiment of a specific vibration reduction device and an elongated structure for applying the same to the aforementioned vibration reduction method will be described with reference to the accompanying drawings.

2 illustrates a structure in which a plurality of impact dampers 20 of the type shown in FIG. 1 are disposed at regular intervals on the main body 10a of the elongated structure. Such a structure can be applied to street lamps, for example. As shown in FIG. 2, the impact damper 20 is provided in a portion of the elongated structure body 10, for example, inside the main body of the elongated structure. As such, when a plurality of impact dampers 20 are disposed in one elongated structure body 10, vibrations of locally different phases may be effectively reduced.

FIG. 3 illustrates an embodiment in which the impact damper is installed outside the elongated structure unlike the structure shown in FIG. 2. As shown in FIG. 3, the impact damper 20a is sewn to the outside of the main body 10a of the elongated structure. The impact damper 20a is ring-shaped and may include a plurality of rigid bodies 22 therein.

4A and 4B are cross-sectional and longitudinal cross-sectional views of the ring impact damper 20a applied to the embodiment of FIG. 3. As shown in FIGS. 4A and 4B, the impact damper 20a includes a cylindrical inner wall 23 that contacts the elongated structure body and an outer wall 24 that surrounds the elongated structure body to provide a space in which the rigid body 22 is located. . The space in which the rigid body 22 is located is sealed by the toroidal upper and lower plates 27 and 26. On the other hand, the space is divided by a plurality of partitions (25) arranged at equal angles in the radial direction, the rigid body 22 is provided in each partition space. As described above, the impact damper 20a having a plurality of divided spaces and a plurality of rigid bodies may be installed inside the main body of the elongated structure.

5A and 5B show a modification of the impact damper shown in FIG. 1.

5A is a longitudinal sectional view according to another embodiment, and FIG. 5B is a cross sectional view. As shown in FIGS. 5A and 5B, a container 21 and a rigid body 22 disposed in the container 21 are provided. Here, the elastic deformation layer 28 in which the rigid body 21 collides is provided on the inner surface of the wall 23. The elastic strained layer 28 may be formed of, for example, rubber, which absorbs kinetic energy upon collision with the rigid body 22. The elastic deformation layer 28 as described above may be formed on the surface of the rigid body 22 as well as the inner surface of the wall 23, it may be formed on at least one side of both.

Hereinafter, a numerical analysis method of an elongated structure in which an impact damper is installed, for example, a street lamp, as a theoretical background for deep understanding of vibration reduction by the impact damper as described above is as follows.

1) In order to simplify the movement of the street lamp, the elongated structure is a simple induction vibration system.

)로 하고 세장 구조물의 감쇠(

)는 가능한 무시한다.2) rigidity of the elongated structure (

) And damping of the elongated structure

) Ignore as much as possible.

)과 세장 구조물 사이의 상대운동에서의 마찰은 무시한다.3) free mass of a rigid body (

) And the friction in the relative motion between the elongated structure.

This assumption simplifies the equations of motion for elongated structures and rigid bodies.

충격력을 라 하고 이 시스템의 운동방정식은 다음과 같다.Occurs when a rigid body impacts an elongated structure

The impact force is called and the equation of motion of this system is

은 세장 구조물(예를 들어 가로등)의 질량행렬,

는 세장 구조물의 감쇠행렬,

는 세장 구조물의 강성행렬,

,

,

는 각각 세장 구조물의 가속도, 속도, 변위 응답이다.

는 바람이나 지진 등에 의한 외부 하중이며,

는 강체에 의한 충격이며,

은 강체의 질량이다.here

Is the mass matrix of the elongated structure (eg

Is the damping matrix of the elongated structure,

Is the stiffness matrix of the elongated structure,

,

,

Are the acceleration, velocity, and displacement responses of each elongated structure.

Is the external load caused by wind or earthquake,

Is the impact caused by the rigid body,

Is the mass of the body.

As understood through various embodiments of the above, the vibration reduction method and apparatus according to the present invention can effectively reduce the excessive vibration displacement in the resonance region of the elongated structure without the installation of a complex device. The effect on the control of these vibrations varies with changes in mass ratio and separation distance. As the mass ratio increases, the optimum spacing becomes smaller, and the amplitude of the elongated structure decreases, resulting in better control. In addition, the larger the mass ratio and the narrower the interval, the greater the momentum due to the mass of the ball, the smoother collisions occur between the narrower intervals, the smoother the damping action, and the smaller the peak in the resonance region appears. As the separation distance increases, the distance that the impactor moves increases gradually, and the momentum of the rigid body increases, but after some time, the momentum that the rigid body receives decreases, and the rigid body does not impact the elongated structure.

According to the present invention as described above, it is possible to effectively control the vibration of the elongated structure such as a street lamp with a relatively simple device and low cost.

Thus far, exemplary embodiments have been described and illustrated in the accompanying drawings in order to facilitate understanding of the present invention. However, it should be understood that these embodiments are merely illustrative of the invention and do not limit it. It is to be understood that the invention is not limited to the details shown and described. This is because various other modifications may occur to those skilled in the art.

1 is a schematic longitudinal cross-sectional view of an impact damper according to one embodiment.

2 is a schematic longitudinal cross-sectional view of an elongated structure to which a plurality of impact dampers are applied according to an embodiment.

3 is a schematic longitudinal cross-sectional view of an elongated structure to which a plurality of impact dampers are applied according to another embodiment.

4A and 4B are schematic cross-sectional and longitudinal cross-sectional views of the impact damper applied to the elongated structure shown in FIG. 3.

5A and 5B are schematic longitudinal cross-sectional and cross-sectional views of an impact damper according to another embodiment.

Claims (15)

In some regions of the elongated structure, a space having a wall is provided, and a rigid body freely moved by the vibration of the elongated structure is provided in the space, and the elongated body is caused by the collision between the rigid body and the wall caused by the vibration of the elongated structure. Vibration reduction method of the elongated structure, characterized in that to absorb the vibration of the structure. The method of claim 1, And an impact upon collision between the rigid body and the wall induces energy absorption by elastic deformation in the gap between the rigid body and the wall. The method according to claim 1 or 2, And arranging a plurality of the spaces around one axis and providing the rigid bodies in each space to induce vibration absorption by a plurality of rigid bodies and walls. The method of claim 3, wherein Vibration absorption method of the elongated structure is characterized in that for performing a plurality of areas arranged in the longitudinal direction of the elongated structure. The method according to claim 1 or 2, Vibration absorption method of the elongated structure is characterized in that for performing a plurality of areas arranged in the longitudinal direction of the elongated structure. Rigid body; And a container installed in the elongated structure and accommodating the rigid body therein and having a bottom portion in which the rigid body rolls and restricts the movement area of the rigid body. The method of claim 6, And a shock absorbing member for absorbing the impact force between the rigid body and the wall on at least one surface of the rigid body and the wall. The method of claim 7, wherein The shock absorbing member is a vibration reducing device, characterized in that the rubber. The method according to any one of claims 6 to 8, The vessel includes a plurality of spaces arranged around the axis about one axis, the vibration reduction device, characterized in that the rigid body is provided in each space. The method of claim 9, The container: An inner wall surrounding the shaft; An outer wall positioned outside of the inner wall by surrounding the axis; An upper plate and a lower plate for sealing between the inner wall and the outer wall; And And a plurality of separators provided between the inner separate body and the outer wall to provide the plurality of spaces. The vibration reduction device of Claims 6-8; Elongated structure having a. The method of claim 11, The container includes a plurality of spaces arranged around the axis around a single axis, characterized in that the rigid body is provided in each space. 13. The method of claim 12, The container: An inner wall surrounding the shaft; An outer wall positioned outside of the inner wall by surrounding the axis; An upper plate and a lower plate for sealing between the inner wall and the outer wall; And And a plurality of separators provided between the inner separate body and the outer wall to provide the plurality of spaces. The method of claim 11, The vibration reduction device is an elongated structure, characterized in that it is disposed in a plurality of areas of the elongated body. 13. The method of claim 12, The vibration reduction device is an elongated structure, characterized in that it is disposed in a plurality of areas of the elongated body.

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