JP2973763B2 - Fluid damping device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a passive fluid type vibration damping device which has a large mass damping effect with a small mass ratio (fluid weight / structure weight). .

[0002]

2. Description of the Related Art In a passive fluid type vibration damping device, a storage tank is provided at a predetermined position of a structure such as a roof of a high-rise building or the like, and the inside of the storage tank coincides with the inherent vibration period of the structure. be those liquid such as water which oscillates with a desired phase difference between the vibration of the structure at the vibration period is stored, when the structure is at rest, the structure as shown in phantom in FIG. 3 The liquid 2 in the storage tank 1 fixed on the floor 3 is stationary. When the structure vibrates, tank 1
The liquid 2 inside oscillates at a delay of 90 ° from the vibration phase of the building, the liquid moves in that direction, and the oscillating displacement ± x1 acts on the wall surface of the tank 1 as an inertial force F1 and is transmitted to the building, and as a result, This rocking energy acts as a damping force for the structure,
Prevents structures from continually shaking due to wind or earthquake.

[0003] Conventionally, a storage tank constituting this passive fluid type vibration damping device is either fixed to an upper part of a structure as shown in the figure or suspended from above. However, there were the following technical disadvantages.

[0004]

First, in the case of the fixed system, the center of gravity of the fluid in the storage tank moves slowly, the inertia force is small, and the vibration damping effect is small. Conversely, to provide a large damping force, a large capacity tank and fluid are required.

[0005] On the other hand, in the method of hanging from above, the structure itself swings due to the swing of the structure, so that the inertia force is large.
Since the tank is supported in a pendulum shape, the space occupied by the entire device becomes large, and the natural period of the pendulum and the natural period due to the movement of the liquid intersect, complicating the analysis. The relative movement between the tank and the tank is reduced, and there is a possibility that sloshing is reduced.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a large inertial force by allowing a tank to be slightly inclined with the swing of a liquid. It is intended to provide a fluid type vibration damping device as described above.

[0007]

In order to achieve the above object, the present invention provides a storage tank at a predetermined position of a structure, and a vibration tank having a vibration period corresponding to a natural vibration period of the structure inside the tank. In a vibration damping device in which a liquid that vibrates with a required phase difference from the vibration of the structure is stored, the tank bottom surface is formed as a downwardly convex arc surface.
In the structure, the tank bottom surface is swingably supported.
And is convex downward, and the curvature thereof is an arc surface of the tank bottom surface.
A pedestal with an arc surface smaller than the curvature of
More, the swing of the tank is obtained by holding always-on horizontal balance.

[0008]

[0009]

[0010]

According to the above arrangement, when the structure is in a stationary state, the fulcrum of the storage tank and the center of gravity of the fluid coincide with each other and are stationary. When the structure vibrates from this state, the liquid is rocked and displaced according to the strength of the vibration, and at the same time, the position of the center of gravity is changed and the storage tank is tilted so that the displacement direction side becomes lower around the fulcrum, Further, the fluid flow is accelerated, transmitting greater inertial forces to the structure through the tank walls. Since the cycle of the inclination of the tank always coincides with the swing cycle of the water, the analysis is simple. Moreover, the tank itself hardly moves horizontally, so there is no danger of reducing sloshing.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows an embodiment of the present invention. In the figure, for example, a rooftop floor 10 of a high-rise building or the like.
A pedestal 12 having a concave arcuate surface with a predetermined curvature is fixedly disposed on the upper side, and a U-tube-shaped storage tank 14 is installed on the pedestal 12, and a control water 16 is stored therein. I have. The water 16 has a vibration cycle that matches the vibration cycle inherent in the building, and vibrates with a required phase difference from the vibration of the structure. The phase difference gives a damping force.

The bottom surface 14a of the storage tank 14 is formed as a convex arcuate surface having a curvature higher than the curvature of the pedestal. .

In the above configuration, when the building is in a stationary state, the center of gravity G0 of the water 16 and the fulcrum O of the bottom surface 14a coincide with each other, and as shown by the imaginary line in FIG. I have.

[0015] When vibration is transmitted to the building from this state due to a strong wind or an earthquake, the swing displacement ± x1 acts on the wall surface of the tank 14 as an inertial force F1 and is transmitted to the building (see FIG. 5).
However, in the present invention, the center of gravity G0 is simultaneously moved in the displacement directions G1 and G2. As a result, the tank 14
, The water flow is accelerated by x2 (> x1: see FIG. 5), and a larger inertia force F2 (> F1: see FIG. 5) is generated. It effectively contributes as a damping force to the vehicle.

It should be noted that, although not shown, if means for regulating the maximum inclination of the tank 14 is provided, it is possible to prevent overturning and falling of the water 16. Further, the tank 14 can be tilted in all directions in accordance with the movement of the water 16 such as not only in the horizontal direction but also in the front-back direction perpendicular to the paper surface.

FIG. 2 shows an experimental example of the time history of the amplitude when a vibration is given to a certain structure model.
When an input wave of a specific amplitude is given to the structure model as shown in (a), and when control for vibration suppression is not performed, the structure model is sequentially changed as shown in (b). Vibration continues while damping.

On the other hand, when the tank is tilted only by the movement of the center of gravity of the water, the amplitude sharply attenuates as shown in FIG. confirmed.

[0019]

[0020]

[0021]

[0022]

[0023] It should be noted that, as the storage tank is in front of you施例U
Although a tubular shape is used, it is a matter of course that a rectangular tank or another shape advantageous for vibration suppression may be used.

[0024]

As described in detail in the above embodiments, in the fluid type vibration damping device according to the present invention, when the structure vibrates, the liquid is oscillatingly displaced in accordance with the vibration intensity. At the same time, by changing the position of the center of gravity and tilting the storage tank so that the displacement direction side is lower around its fulcrum, the fluid flow is further accelerated, and a larger inertial force is transmitted to the structure through the tank wall, A large vibration damping effect can be obtained with a small mass ratio as compared with the above, which is suitable for reducing the size and cost of the apparatus. Since the cycle of the inclination of the tank always coincides with the swing cycle of the water, the analysis is simple, and the design and the like can be easily performed. Moreover, since the tank itself hardly moves horizontally, there is no danger of reducing sloshing.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating the principle of a fluid-type vibration damping device according to an embodiment of the present invention.

FIGS. 2A to 2C are graphs showing experimental examples of the time history of amplitude when a vibration is applied to a structure model.

FIG. 3 illustrates the principle of a conventional passive fluid type vibration damping device.
FIG.

[Explanation of symbols]

10 Floor 1 4 storage tank 16 water (liquid) 14 a fulcrum (bottom)

Claims (1)

(57) [Claims] 1. A storage tank is provided at a predetermined position of a structure, and a vibration cycle corresponding to a natural vibration cycle of the structure is provided inside the tank. In the vibration damping device in which the liquid oscillating with is stored, the tank bottom surface is formed in a downwardly convex circular arc surface,
In the structure, the tank bottom surface is swingably supported,
It is convex downward and its curvature is the curvature of the arc surface on the bottom of the tank.
By placing a pedestal with an arc surface smaller than the ratio
Ri, fluid type vibration damping device, characterized in that the swing of the tank was kept always-on horizontal balance.