JP2555204B2 - Vibration suppression method for structures - Google Patents

Description

The present invention relates to a method for suppressing vibration of a structure using a sloshing damper.

[Conventional technology]

Conventionally, the dynamic vibration absorbers (dynamic dampers) that have been mainly used in the field of machinery for countermeasures against mechanical vibration are also applied to the field of construction for the purpose of suppressing the vibration of buildings due to wind and earthquakes. In addition to a basic dynamic vibration absorber consisting of a weight, a spring and a damper as an additional mass, a sloshing damper (see JP-A-62-101764) and a pendulum-type dynamic vibration absorber (JP-A-63-254247) Various types of vibration suppression devices have been developed.

[Problems to be Solved by the Invention]

By the way, although the sloshing damper is an effective device for damping a tower-like structure, its rising characteristics are not good. Therefore, if the wave is not excited to some extent,
Damping effect cannot be obtained.

The present invention is intended to solve the problem of rising characteristics in such a sloshing damper as a vibration suppressing device.

[Means for solving the problem]

In the present invention, as a vibration suppressing device for suppressing the vibration of the structure that is the main vibration system, a sloshing damper consisting of a container having a predetermined size and a predetermined amount of liquid injected into the container is used, and this sloshing damper, that is, An initial displacement is given to the vibration absorbing system in advance, or an initial displacement is given at the time of control to create an artificial vibration or wave, thereby improving the rising characteristics of the sloshing damper.

The initial displacement is obtained, for example, by supporting the container constituting the sloshing damper in an inclined state and keeping the liquid surface inclined. In this case, the wave of the liquid in the container is excited by returning the inclination of the container during control, and a large amplitude is obtained even in the initial stage of vibration of the structure.

The initial displacement does not always have to be given at all times, and the initial displacement may be given when control is required, such as during strong wind.

Also, instead of tilting the container, applying a horizontal force to the container by a force device such as an actuator can excite the wave of the liquid in the container, and similar to the case where the container is tilted to give the initial displacement, A large amplitude can be given at the initial stage of vibration of the object, and the vibration of the structure, which is the main vibration system, can be effectively suppressed.

[Action]

Figure 10 shows an example of observation of a dynamic damper installed at the Chiba Port Tower (see 1988 Architectural Institute of Japan Conference Abstracts No.2288). Even with such a dynamic damper, it takes about 0 to 15 seconds. Until the effect is hardly seen.

This is because a dynamic damper (same as sloshing damper) excites the amplitude of the damper due to the vibration of the building, and the effect is exhibited only when the amplitude exceeds a certain level.

11 to 14 show the vibration suppressing effect as a model. In the model of the structure a and the vibration suppressing device b of FIG. 11, the seismic motion or the wind external force is input as shown in FIG. Then, the structure a, which is the main vibration system, starts to vibrate.
Since the amplitude h of the vibration absorbing system is small at the beginning of this vibration,
There is little damping energy. As shown in FIG. 13, as the amplitude h gradually increases in the middle of vibration, the damping energy also increases. In the latter stage of vibration, as shown in FIG. 14, the vibration of the structure a is reduced by the energy absorption on the side of the vibration suppressing device b. Depending on the type of the damper, when the amplitude is small, the damper may not vibrate due to a loss such as friction and may not be effective at all.

Therefore, when the sloshing damper according to the present invention vibrates with an appropriate amplitude from the beginning, the rising characteristics are improved and the vibration suppressing effect on the structure is further enhanced. That is, the vibration suppressing effect as shown in FIG. 15 is obtained.

〔Example〕

 Next, the illustrated embodiment will be described.

1 and 2 show an embodiment corresponding to the invention described in claim 1 of the present application, and show a sloshing damper composed of a water tank 1 as a container and water 2 as a liquid in FIG. As shown, the water tank 2 is tilted in advance, and when the wind is strong, the water tank 1 is returned horizontally as shown in FIG. 2 to create a wave in the water 2 in the water tank 1.

That is, one end of the lower surface of the water tank 1 is used as the pin support 3, and the upper end of the water tank 1 on the opposite side is suspended by a suspending member such as a wire 4. When starting the control, the wire fixing device 5 can be released and the aquarium 1 can be returned to the horizontal position, thereby generating a large wave.

3 and 4 also show another embodiment corresponding to the invention described in claim 1, in which the water tank 1 is hung in the above-mentioned example, while the opposite side of the pin bearing 3 is an actuator. It is configured to be lifted by 6 or the like. Also in this case, by lowering the rod of the actuator 6 at the time of control, the water tank 1 can be returned to the horizontal position and waves can be generated.

Note that the water tank 1 does not always need to be tilted regardless of whether it is a hanging type or a lifting type, and a system may be used in which the water tank 1 is hoisted or lifted for control when the wind is strong.

5 and 6 show an example of a horizontal force type as an embodiment corresponding to the invention of claim 2 of the present application, in which a force applying device such as an actuator 7 is attached to the side of the water tank 1. By applying horizontal reciprocating force in strong wind,
It creates waves. After the wave is excited, the actuator 7 is stopped and fixed by a stopper or the like. In the figure, 8 is a rail.

FIGS. 7 to 9 cite three examples as specific examples of the wire fixing device 5 in the embodiments of FIGS. 1 and 2 described above.

The wire fixing device shown in FIG. 7 is an example of the wedge stopper type fixing device 21, and the wire is set in the cylindrical body.
The fixed end portion 22a of 22 is inserted, and the electromagnet 23
When the fixation due to is released, the wedge 24 rotates and the wire 22 moves.

The wire fixing device shown in FIG. 8 is a brake type fixing device 31.
The wire 32 in the cylindrical body is an example of
The fixed end 32a of the friction brake 33 is electromagnetic or hydraulic.
It has been fixed by the
32 is configured to move freely.

The wire fixing device shown in FIG. 9 is an example of a variable stroke type fixing device 41, and is configured to generate a vibration stroke necessary for vibration control by winding and rewinding the wire 42 with a motor and a pulley 43. It is a thing.

〔The invention's effect〕

The structure vibration suppression method of the present invention is to create an artificial wave by applying an initial displacement to a container of a sloshing damper in which a liquid is injected, or by applying a horizontal force during control. An amplitude is provided that sufficiently exerts a vibration suppressing effect even in the initial stage of vibration of an object. That is, the rising characteristic of the sloshing damper, which has been a problem in the past, is significantly improved, and disturbances such as earthquakes and winds can be immediately and efficiently dealt with, and a good vibration suppressing effect can be obtained.

Further, the method of the present invention is basically a passive vibration suppressing method, and does not require constant energy supply, and secures energy for giving initial displacement even when external energy is required for initial displacement. By doing so, it can function reliably.

[Brief description of drawings]

1 and 2 are elevation views showing an embodiment corresponding to the invention described in claim 1 of the present application, and FIGS. 3 and 4 are other embodiments corresponding to the invention described in claim 1. 5 and 6 are elevation views showing a horizontal force type embodiment corresponding to the invention of claim 2 of the present application, and FIGS. 7 to 9 are views of a wire fixing device. Sectional view showing a specific example, FIG. 10 is a graph showing a control example of a conventional dynamic damper,
11 to 14 are model diagrams for explaining the control effect, and FIG. 15 is a graph showing the control effect when the present invention is applied. 1 ... water tank, 2 ... water, 3 ... support, 4 ... wire,
5: Wire fixing device, 6 ... Actuator, 7
...... Actuator, 8 …… Rail

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-2-300541 (JP, A) JP-A 63-53332 (JP, A) JP-A 59-161566 (JP, A) JP-A 61- 274134 (JP, A) JP-A-60-85164 (JP, A)

Claims (2)

(57) [Claims] 1. A method for suppressing vibration of a structure, which is a main vibration system, wherein a vibration suppressing device that constitutes a vibration absorbing system having a predetermined mass and a natural frequency is provided to suppress the vibration of the main vibration system. As the vibration suppressing device, a sloshing damper consisting of a container having a predetermined size and a predetermined amount of liquid injected into the container is used, and the container is preliminarily tilted and supported to give an initial displacement to the liquid surface. Every other time, when controlling the vibration of the main vibration system, the wave of the liquid in the container is excited by returning the inclination of the container, and a predetermined large vibration corresponding to the initial displacement is given to the liquid of the sloshing damper to cause the vibration of the main vibration system. A method for suppressing vibration of a structure, which comprises suppressing vibration. 2. A method for suppressing vibration of a structure, which comprises a vibration suppressing device constituting a vibration absorbing system having a predetermined mass and a natural frequency for a structure which is a main vibration system to suppress the vibration of the main vibration system. As the vibration suppressing device, a sloshing damper composed of a container having a predetermined size and a predetermined amount of liquid injected into the container is used, and a horizontal force is applied to the container by a force applying device at the time of controlling the vibration of the main vibration system. A method for suppressing vibration of a structure, which comprises exciting a wave of a liquid in a container and giving a predetermined large vibration to the liquid of a sloshing damper to suppress vibration of a main vibration system.