JPH08334147A - Sloshing damper for reduction of vibration - Google Patents

Abstract

PURPOSE: To easily regulate a sloshing damper and to efficiently reduce vibration of a structure. CONSTITUTION: This sloshing damper is furnished with a tank 5 storing liquid 6 inside of it and set on a structure 1, a piping 10 connected to both side walls of the tank 5 and communicated to the inside of the tank 5 and a pump 11 provided on the piping 10, and it is devised to measure vibration of the structure 1 on which the tank 5 is set and a flow rate of liquid flowing in the piping 10 by an accelometer 14 and a flow meter 12, control the pump 11 by a control device 16 in accordance with this measured value and control a flow rate of liquid circulating in the tank 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sloshing damper applied to reduce vibration of structures such as buildings, bridges, and steel towers, and more particularly to a sloshing damper suitable for reducing vibration of large structures.

[0002]

2. Description of the Related Art In order to reduce the vibration of a structure, there is a vibration absorbing device which attaches an auxiliary substructure to the conventional structure and utilizes the energy absorption of the substructure.

An example of a conventional vibration absorbing device will be described with reference to FIG. 3. In this device, a mass 4 is mounted on a structure 1 via a spring 2 and a damper 3.

When the structure 1 vibrates, the spring 2 and the damper 3
The mass 4 vibrates via the, and the vibration of the structure is reduced by the energy absorbed by the damper 3. The weight of mass 4 is
Normally set to a few percent of the mass of the vibrating part of the structure, the spring 2
Is set so that the natural frequency of the subsystem composed of the mass-spring matches the natural frequency of the structure. The strength of the damper 3 is set so that the vibration of the structure can be absorbed most efficiently, and this setting has been formulated for a long time.

In order to simplify the structure of the subsystem as shown in FIG. 3, as shown in FIG. 4 (a), the liquid 6 is stored in a tank 5 mounted on a structure (not shown). There is a sloshing damper that uses the inserted system. In this sloshing damper, the mass of the vibrating portion of the liquid 6 in the tank is set to be several% of the mass of the structure. The depth of the liquid in the tank 5 is set so that the natural frequency of this system matches the natural frequency of the structure.

Although this system does not have a damper equivalent to the system shown in FIG. 3, it absorbs energy due to the friction of the fluid generated by the flow 7 of the liquid in the tank 5 during rocking. To do.

Since the amount of energy absorbed is small only by the friction of the fluid in the flow 7, in order to realize a more efficient subsystem, a large number of rods 8 are included in the liquid in the tank as shown in FIG. 4 (b). Insert the net 9 as shown in Fig. 4 (c).
There is one that adjusts the friction energy of the liquid and reduces the vibration of the structure by inserting the liquid into the liquid in the tank.

The vibration absorbing device disclosed in Japanese Patent Laid-Open No. 05-118380 will be described with reference to FIG. In this device, a plurality of + electrodes 18 and − electrodes 19 are installed side by side in a tank 5 in which an electrorheological fluid 17 is placed and which is mounted on a structure not shown, and applied to the electrodes 18 and 19 via a voltage controller not shown. The applied voltage is increased or decreased to increase or decrease the viscosity of the liquid 17 to generate a wave in an optimum viscous state and reduce the vibration of the structure.

[0009]

The above-mentioned conventional FIG.
In the sloshing damper shown in (b) and FIG. 4 (c),
Optimal values such as the positions of rods and nets and the number of rods must be relied on experience, and it is necessary to change them manually. In addition, the structure needs to be vibrating for optimal adjustment, and adjustment is performed by selecting a windy day. Further, when the vibration characteristics of a structure such as a structure under construction change, it is necessary to adjust each time, and the adjustment may be troublesome and a problem may occur.

Further, in the conventional apparatus using the electrorheological fluid shown in FIG. 5, the electrorheological fluid is considerably expensive as compared with the water generally used for the sloshing damper, and in order to change the viscosity. Generally, it is necessary to apply a high voltage of several kilovolts or more, and the voltage control device becomes expensive.

The present invention is intended to provide a sloshing damper for vibration reduction which can solve the above problems.

[0012]

A sloshing damper for vibration reduction according to the present invention is a tank that accommodates a liquid therein and is installed in a structure, a pipe that is connected to both side walls of the tank and communicates with the inside of the tank, A pump provided in the pipe, and a control device that controls the pump based on the vibration of the structure in which the tank is installed and the flow rate of the liquid flowing through the pipe are provided.

[0013]

In the present invention, the liquid flowing out of the pump flows into the tank from the side surface of the tank through the pipe and flows in the tank. Further, the liquid flowing out from the side surface of the opposite tank is returned to the pump through the pipe and circulates. Therefore, by forcibly creating a flow in the liquid in the tank, the fluctuation of the liquid surface, that is, the friction of the fluid due to sloshing absorbs energy.

The energy absorption amount generated by the friction of the fluid due to the sloshing is determined by the flow rate of the liquid flowing in the tank. In the present invention, this energy absorption amount is easily adjusted by the rotational speed of the pump. can do. That is, the acceleration of vibration of the structure and the flow rate of the liquid flowing through the pipe are measured and input to the control device, and the pump is controlled so that the vibration of the structure is minimized.
Set the flow rate of the liquid flowing in the pipe. by this,
The flow rate of the liquid flowing in the tank is controlled to be optimum for the vibration of the structure, and the vibration of the structure can be effectively absorbed.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, on opposite side walls of the tank 5 installed on the structure 1 and containing the liquid 6 therein,
One pipe 10 is connected via a diffuser 13, and the pipe 10 communicates with the inside of the tank 5. A pump 11 is provided in the middle of the pipe 10, and a flow meter 12 is provided at a portion of the pipe 10 on the outlet side of the pump 11.

Reference numeral 14 denotes an accelerometer installed on the structure 1.
Reference numeral 15 is a wave height meter provided in the tank 5 for measuring the wave height of the liquid 6 in the tank 5, and the signals of the flow meter 12, the accelerometer 14, and the wave height meter 15 are installed on the structure 1. The controller 16 controls the voltage based on these signals and outputs the voltage to the pump 11.

In this embodiment, the liquid discharged from the pump 11 flows into the tank 5 through the flow meter 12 and the diffuser 13 to mix with the liquid 6 in the tank, and then flows out from the side wall of the tank on the opposite side. And passes through the pipe 10 and returns to the pump 11 for circulation.

The vibration acceleration of the structure 1 is measured by using the accelerometer 14, the flow rate of the liquid in the pipe 10 is measured by the flow meter 12, and the wave height of the liquid in the tank is measured by the wave height meter 15. To be done. These measured values are input to the control device 16, and the control device 1 is based on these measured values.
6 controls the voltage input to the pump 11,
The liquid flowing through is adjusted to have an optimum flow rate.

The control flow of the controller 16 will be described with reference to FIG. Structure 1 to be controlled subject to wind force
The output acceleration is determined by its characteristics. Output acceleration of the structure 1 measured by the accelerometer 14 and the flow meter 1
The signal of the flow rate flowing through the pipe 10 measured in 2 is input to the control device 16, and the voltage input to the pump 11 is determined based on these signals. This voltage determines the number of revolutions of the pump 11, and thus the flow rate of the liquid flowing through the pipe 10,
The characteristics of the structure 1 to be controlled change and the output acceleration changes.

In the control device 16, the above-mentioned control loop is repeated until the rate of change in the output acceleration of the structure 1 due to the change in the flow rate of the liquid flowing through the pipe 10 becomes 0, and the voltage at which the output acceleration becomes the minimum is obtained. This can be done and thus the adjustment can be automatically made to minimize the vibration of the structure 1.

In the present embodiment, the flow rate of the liquid flowing in the tank 5 is controlled by controlling the flow rate of the liquid flowing in the pipe 10 as described above, and the fluctuation of the liquid level in the tank 5, that is, the liquid caused by sloshing The vibration of the structure 1 can be effectively absorbed by setting the friction to the optimum value.

[0022]

According to the present invention, pipes are connected to both side walls of a tank that contains a liquid therein so that the tank communicates with the inside of the tank, and a pump provided in the pipe is used to prevent vibration and vibration of a structure in which the tank is installed. Since the control is performed on the basis of the flow rate of the flowing liquid, the pump, and thus the automatic damper, and the pump, and therefore the automatic damper, can easily and efficiently increase the energy absorption amount by the liquid flow in the tank. It has the effect that the flow rate of the liquid flowing through the pipe can be adjusted.

Therefore, without performing empirical work, the cost after installation is greatly reduced, and
It is possible to obtain a vibration damping effect that responds quickly to the structure.

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment of the present invention.

FIG. 2 is a control flow chart of the embodiment.

FIG. 3 is a conceptual diagram of an example of a conventional vibration absorber.

4 (a), 4 (b) and 4 (c) are perspective views showing examples of conventional sloshing dampers for vibration reduction.

FIG. 5 is a perspective view of a vibration absorbing device using a conventional electrorheological fluid.

[Explanation of symbols]

 1 Structure 2 Spring 3 Damper 4 Mass 5 Tank 6 Liquid 7 Liquid Flow 8 Bar 9 Net 10 Piping 11 Pump 12 Flowmeter 13 Diffuser 14 Accelerometer 15 Wave Height Meter 16 Controller 17 Electrorheological Fluid 18 + Electrode 19-Electrode

Claims (1)

[Claims] 1. A tank that contains a liquid inside and is installed in a structure, a pipe connected to both side walls of the tank and communicating with the inside of the tank, a pump provided in the pipe, and the structure in which the tank is installed. A sloshing damper for vibration reduction, comprising a control device for controlling a pump based on vibration of an object and a flow rate of a liquid flowing through the pipe.