JPS63138077A - Vibration control apparatus of structure - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a vibration suppressing device that suppresses vibrations caused in structures by earthquakes, lice, etc.

"Conventional technology and its problems" Due to factors such as the development of high-strength materials, progress in manufacturing technology, and development of structural analysis technology using computers, structures in recent years have become larger, more diverse in form, and lighter. As technology advances, structures are becoming more flexible. In addition, such lightweight and flexible structures tend to have low natural frequencies and low vibration damping, and as a result, various unpredictable vibrations occur due to the influence of external aerodynamic forces caused by wind. there is a possibility.

For this reason, for the purpose of cutting off this type of vibration source, aerodynamic measures can be taken into the external shape of the structure, but the external shape of the structure has a functional, L-bow, design aspect. Since there are various restrictions, it is difficult to rely solely on aerodynamic measures.

Therefore, in the specification of Japanese Patent Application No. 60-241045, the inventor of the present application stored a liquid that vibrates at a predetermined position of a structure at the same period as the natural vibration period of the structure, but with a phase difference. We have proposed a vibration suppression device that is equipped with a storage tank that suppresses the vibration of a structure by the vibration of this liquid, thereby solving the problems mentioned above.

One embodiment of the vibration suppressing device shown in the above-mentioned specification had a structure in which a cylindrical storage tank was provided on the roof of a structure and liquid was stored in this storage tank. By the way, it is necessary to ensure that the liquid stored in this storage tank has a vibration period that is the same as the natural vibration period of the structure and a predetermined amount that causes a predetermined phase shift. It is thought that the village may change due to water loss due to evaporation or water increase due to rainwater, and countermeasures are necessary.

In view of the above-mentioned problem, the present invention has been made by developing the vibration suppressing device previously proposed by the inventor of the present invention, and is capable of always securing a predetermined amount of liquid in the vibration suppressing storage tank. To provide a vibration suppressing device that always exhibits a reliable vibration suppressing effect.

"Means for Solving the Problems" In order to solve the above problems, the present invention provides a storage tank at a predetermined position of a structure, and inside this storage tank,
A liquid that vibrates at the same natural vibration period as the natural vibration period of the structure and with a required phase difference from the vibration unique to the structure is stored, and an auxiliary tank is attached to the storage tank, A liquid drain device η and a liquid supply device for transferring liquid between the storage tank and the auxiliary tank are attached to the storage tank.

"Effect" When a structure is vibrated by wind, etc., the liquid stored in the storage tank vibrates at the same frequency as the structure's vibration frequency and with a required phase shift, causing the structure to oscillate around the horizontal motion. suppresses vibrations caused by The liquid in the storage tank is always maintained at a predetermined level by operating the liquid supply and drainage devices in response to increases in water due to mountains and decreases due to evaporation.

"Embodiment" Figures 1 to 5 show a structure such as a high-rise structure equipped with a vibration suppression and control device according to an embodiment of the present invention.
In the structure I of this embodiment, a storage tank 3 for suppressing vibrations is installed on the roof, which is assumed to be most effective against vibrations caused by wind. Note that when installing the storage tank 3, the storage tank 3 can also be installed on the rooftop via a flexible structure support stand made of a laminated structure of an elastic body such as rubber and a steel plate.

The storage tank 3 is a cylindrical storage tank used for purposes such as storing drinking water or fire prevention water in the structure I, or a cylindrical storage tank installed separately from these purposes. By storing the liquid W under conditions such that the vibration period is the same as that of the structure 1, vibrations of the structure caused by wind or the like are suppressed. In addition,
If necessary, the storage tank 3 may be divided into a plurality of parts.

Further, on the roof of the structure 1, on both sides of the storage tank 3, auxiliary tanks IO, 10 are provided.

and a storage tank 3 adjacent to the auxiliary tank 10.10.
A liquid suction/drainage pipe 12 is formed on the side wall of the liquid W at a position slightly higher than the required level of the liquid W. This liquid suction/drainage pipe 12 is connected to the liquid W in the storage tank 3 and the auxiliary tank IO.
and the pump I6 is connected to each of the suction and drainage pipes 12 and 12.
is included. Moreover, inside the storage tank 3,
A liquid level detector 17 is installed to detect a required liquid level. The liquid level detector 17 is connected to the operation control section of the pump 16, and the pump 16 is activated by a signal output from the liquid level detector 17 to supply and drain liquid W from the auxiliary tank 10 to the liquid supply pipe 12. The water can be supplied to the storage tank 3 via. That is, the liquid supply/drainage pipe 12, the pump 16, and the liquid detector 17 constitute a liquid supply/drainage device 20.

Next, the operation of the vibration suppressing device configured as described above will be explained.

The liquid W in the storage tank 3 is stored at a depth that has the same vibration period as the vibration period of the structure 1, so that it vibrates with a phase shift of 172 cycles from the vibration of the structure 1 caused by the wind. 4", the vibration of structure I is suppressed.

Additionally, if the liquid in the storage tank 3 increases due to rain or other causes, or if the liquid in the storage tank 3 decreases due to evaporation, etc., the liquid level detector 17 detects this and the pump 16
is activated to supply liquid W from the auxiliary tank IO to the required height. As described above, the liquid level detector I7 operates to adjust the liquid ~Vffi in the storage tank 3 to the required depth. As a result, a certain amount of liquid W can always be stored in the storage tank 3, and the vibration suppressing device always exhibits a predetermined vibration suppressing effect. Note that while the liquid ~V is vibrating, the trough portion of the wave formed by the liquid W may temporarily reach the bottom of the liquid level detector 17. Second, this problem can be solved if the pump 16 is operated only when a decrease in the liquid level of the liquid W is continuously detected.

By the way, the amount of liquid W stored in the auxiliary tank 10 provided on the roof of the structure 1 is the liquid stored in the storage tank 3~■
The amount should be set so as not to inhibit the vibration suppression effect.

In addition, the vibration analysis of Structure I and the storage tank conducted in Japanese Patent Application No. 60-241045-1 will be described below.

First, the storage tank 3 and the structure I exhibit vibration characteristics similar to the vibration model shown in FIG.

The vibration model shown in Figure 3 has a spring constant K. Spring 4 A
Suppose that the object 5A of quality M~io is supported by the attenuation rate. Vibration system A (vibration model of a structure) to which Dashbot 6A is added, and spring constant ri! 1. It is composed of a vibration system B (vibration model in a storage tank) in which an object 5B with a mass M1 is supported by a spring 4B of 1, and a dashpot 6B with a damping rate of 1 is added.

In such a vibration model, when vibration system A starts to vibrate due to an external force applied to object 4A, vibration system B starts to vibrate with a phase difference of 1/2 period. By matching the vibration periods of -H, the vibration of the vibration system A can be suppressed.

Here, the vibration period of the vibration system is and the vibration period T of the construct l.

is the mass M determined from the viewpoint of structural design. , and spring constant K. Since it is uniquely determined by, the vibration period T of the liquid W stored in the storage tank 3.

The above T. The dimensions and capacity of the storage tank 3 are set to match the two.

That is, according to the Hausner theory that holds true regarding the behavior of the stored liquid in the storage tank, as shown in the example shown in the figure, there is a free water effective particle (a particle I that acts as a vibrating body) M that can move within the storage tank 3. , , are given by the following equation (2).

However, l]...Distance R from the bottom of the storage tank 3 to the water surface...Radius M of the storage tank 3...Actually stored in the storage tank 3 The mass of the liquid Also, the natural vibration ω (so-called natural frequency of sloshing) of the stored liquid W is determined by the following equation (3). The period T is found.

If, for example, R=15m f-2m M=1·114 t (M=812t from equation 2) is substituted into each of the above parameters, T=11.7 seconds.

Then, the two vibration periods of the liquid in the storage tank and the vibration period T of the structure are obtained from the above equation. Between, T,=T,
. . . Each dimension and storage amount of the storage tank 3 are set so that equation (5) holds true.

As a result of the simulation of the change in the vibration suppression effect with respect to the change in the vibration frequency, the characteristics shown in FIGS. 4 and 5 were obtained. FIG. 4 shows the results of a simulation performed with liquid (water) stored in the storage tank, and FIG. 5 shows the results of a simulation performed with the storage tank empty.

That is, by providing a storage tank in a structure having a large amplitude at a frequency close to the natural frequency as shown in FIG. 4 and storing the liquid, vibrations can be suppressed as shown in FIG. 5.

Furthermore, as a result of the simulation, the effective mass M of the liquid W,
The ratio of mass M of structure l to M 1/ M = 1/
50~l/100・・・・・・・・・・・・(6)
The vibration suppression effect was effectively achieved when the equation was set as follows. Here, if the effective mass is less than 1/100, a sufficient vibration damping effect cannot be obtained, and if it is more than 1750, the influence of the mass of the liquid on the structural design of the structure becomes large, and the structural design of the structure must be re-designed. Because it is necessary to do this, it is necessary to set the ratio of M and Ml as shown in equation (6) above.

Furthermore, if it is necessary to keep the liquid in the storage tank in a fixed state (in a tightly packed state in a closed storage tank) due to various factors, instead of the above formula (2), the following is adopted: However, the volume of the storage tank and the type B values can be determined from the results obtained using equation (2).

Note that the shape of the storage tank 3 is not limited to the cylindrical shape shown in the above embodiment, and may be changed to various shapes depending on the installation conditions, such as a square planar shape, a spherical shape, and a planar elliptical shape.

In this case, it is sufficient to apply Hausner's theory and set the vibration period and mass based on a formula depending on the shape.

"Effects of the Invention" As explained above, the present invention has a structure in which a liquid that vibrates with the same period as the structure and a phase difference is stored in a storage tank provided at a predetermined position of a structure. In order to suppress the vibration of a structure, it is possible to obtain a vibration suppressing effect against wind that causes vibrations different from the frequency of an earthquake, mainly in a structure whose strength against earthquakes is increased.

In addition, the liquid in the storage tank can be maintained at a predetermined level by using a liquid suction and draining device to drain the liquid from the storage tank into the auxiliary tank or by supplying the liquid from the auxiliary tank to the storage tank.
There is an effect that the vibration of the structure can be suppressed by always exhibiting a predetermined vibration suppression effect.

Furthermore, if the supply liquid storage tank or fire prevention water storage tank provided in the structure is used as the vibration suppression storage tank, there is no need to specially install a storage tank, which has an advantageous effect in terms of equipment costs. be.

[Brief explanation of the drawing]

Figures 1 and 2 show one embodiment of the present invention, and Figure 1 is a front view of a +1 structure equipped with a vibration suppression device;
Figure 3 is a cross-sectional view of the storage tank, Figure 3 is a front view of a vibration model of the structure, Figure 4 is a cross-sectional view showing the vibration damping situation with the vibration damping device of the present invention, and Figure 5 is an empty storage tank. FIG. W...Liquid, 1...Structure, 2...Support stand,
3...Storage tank, 10...Auxiliary tank, 12...Liquid supply and drainage pipe, 16...Pump, 17...
...Liquid detector.

Claims (1)

[Claims] A storage tank is provided at a predetermined position of the structure, and inside this storage tank, vibration is caused to vibrate at the same vibration period as the vibration period unique to the structure and with a required phase difference from the vibration unique to the structure. The liquid is stored, and an auxiliary tank is attached to the storage tank, and a liquid supply/drainage device is attached to the storage tank for supplying and discharging liquid between the auxiliary tank and the storage tank. Vibration suppression device for structures.