JP2740879B2 - Vibration suppression device for structures - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure vibration suppressing device capable of effectively suppressing vibrations caused by an external force such as an earthquake or a strong wind. .

[Prior art] In recent years, architectural and civil engineering structures have become larger, more diversified, and lighter due to factors such as the development of high-strength materials, dramatic progress in machining technology, and the development of structural analysis technology using computers. The structure has become more flexible with respect to external forces. In such a lightweight and flexible structure, the natural frequency tends to be low and the vibration damping tends to be small. For this reason, when an external force such as an earthquake or a strong wind acts on the structure, various unexpected vibrations may occur.

For this reason, it is conceivable to take aerodynamic measures against the outer shape of the structure for the purpose of cutting off these vibration sources, but there are various restrictions on the outer shape of the structure from a functional and design perspective. It is difficult to rely on this aerodynamic measure alone.

Therefore, in order to suppress the above-described vibration, a water tank for storing a liquid at a required position of the structure is provided, and various vibration suppression methods capable of suppressing the vibration of the structure by the vibration of the liquid have been proposed. It is adopted for various structures. Representative of these systems are the following three systems. First
In this method, a water tank is provided at a required position of a structure, and a liquid that vibrates with the same cycle as the inherent vibration cycle of the structure and with a phase difference is stored in the water tank, and is generated by the vibration of the liquid. This is a TLD (Tuned Liquid Damper) system that uses the reaction force to suppress the vibration of the structure. A typical example of this method is a sloshing damper method.

The second method is to suspend the water tank at a required position on the structure with a wire or the like so that the water tank can vibrate in the direction in which the vibration of the structure is desired to be suppressed, and the water tank vibrates like a pendulum. It is a TMD (Tuned Mass Damper) system that suppresses vibration.

In the third method, the water tank is mounted at a required position on the structure so as to be able to vibrate in a direction in which the vibration of the structure is to be suppressed, and the external force is forcibly applied to the water tank by mechanical force or magnetic force of an actuator or the like. The active mass damper (AMD) system moves the water tank horizontally by adding water and suppresses the vibration of the structure due to the generated reaction force.

[Problems to be Solved by the Invention] The first TLD method has an advantage that there is no need to apply energy from the outside, but the generated reaction force is relatively small, and the inherent period of the structure is long. On the contrary, the effective reaction force is reduced to a small extent, and the water tank needs to be enlarged. In the above-mentioned second TMD method, the longer the inherent cycle of the structure, the longer the cycle of the water tank, and it is necessary to sufficiently increase the length of the wire for suspending the water tank. Therefore, there is a disadvantage that it is difficult to secure a three-dimensional space in the structure corresponding to the length of the wire or the like. In the third AMD method,
Since the water tank is moved in the horizontal direction by forcibly applying an external force to the water tank, there is a structural disadvantage that a long stroke slide mechanism and a large driving force are required.

An object of the present invention is to provide a vibration suppression device for a structure which can effectively solve the above problems and simplify the entire device, and has a vibration suppression effect superior to the conventional system. .

[Means for Solving the Problems] In order to solve the above problems, the present invention employs the following structure vibration suppression device. That is, the vibration control device for a structure is provided at a predetermined position of the structure, and is capable of suppressing vibration excited in the structure due to an external force due to an earthquake, wind, or the like. The vibration suppression device includes a water tank for storing a liquid, a column supporting a central portion of a bottom surface of the water tank, and a plurality of actuators supporting both ends of the bottom surface of the water tank so as to be vertically movable.

[Operation] In the present invention, when vibration is excited in the structure by an external force due to an earthquake, wind, or the like, the plurality of actuators are moved in the vertical direction, and the water tank is centered on the bottom and both ends of the bottom are in a vertical plane. Move up and down with. This movement causes the center of gravity of the liquid in the water tank to move outward in the horizontal direction, and generates a reaction force. Vibration can be suppressed by digging this reaction force into vibration centered on the lateral swing of the structure.

[Embodiment] FIGS. 1 to 7 show an embodiment of the present invention. In these drawings, reference numeral 1 denotes a structure vibration suppression device (hereinafter, simply referred to as a vibration suppression device) according to the present invention.

As shown in FIG. 1, this vibration suppression device 1 is a floor near the rooftop of a high-rise building A that can be assumed to be most effective against vibrations caused by the earthquake or strong wind on the high-rise building (structure) A. Mounted on planes E and F. The vibration suppressing device 1 includes a support 2, an elevated water tank (water tank) 3, an actuator
4, 4, the control device 5, the sensors 6, 6, and the sensor 7 as constituent elements.

The support column 2 supports the elevated water tank 3 from below, and serves as a fulcrum when the elevated water tank 3 vibrates. The shape is almost a truncated cone, and a pin 8 having a spherical tip is attached upward in the center of the upper bottom surface 2a, and the lower bottom surface 2b
Are fixed on the floor surface E in close contact with each other. Pin 8
Is in contact with the center of the bottom surface 3a of the elevated water tank 3.

The elevated water tank 3 is a long box-shaped water tank having a rectangular cross section in the longitudinal direction.
Are stored about half of the internal volume. Sensors 6 and 6 for measuring the vibration of the elevated water tank 3 are attached to the center of both longitudinal ends of the bottom surface 3b above the elevated water tank 3. Similarly, actuators 4 and 4 are connected to the center of both longitudinal ends of the bottom surface 3a, respectively.

The actuator 4 has a rod shape whose center can be freely varied in length, and is installed substantially vertically on the floor surface E. The upper end 4a of the actuator 4 is the bottom of the elevated water tank 3.
It is connected to the center of one end in the longitudinal direction of 3a, and is rotatable in a vertical plane including these actuators. The lower end 4b is connected to the floor E and is rotatable in the same vertical plane as the upper end 4a.

On the other hand, a sensor 7 for measuring the vibration excited in the high-rise building A is attached to the roof 10 of the high-rise building A.

The control device 5 is installed on the floor F and the vibration suppressing device 1
It performs overall control, and includes a control unit 11, a drive unit 12, and a computer 13 as main components. The control unit 11
Input from the sensor 6 and the sensor 7, input and output of the computer 13,
The input and output of the drive unit 12 are performed uniformly and effectively. The drive unit 12 is for operating the actuators 4, 4 in the vertical direction according to the output from the control unit 11. The computer 13 calculates the amplitude, phase, period, and the like of the vibration based on the information on the vibration transmitted from the sensors 6, 6 and the sensor 7 to the control unit 11, calculates appropriate operating conditions of the actuators 4, 4, and calculates Is fed back to the control unit 11.

Next, a method of suppressing the vibration excited in the high-rise building A using the vibration suppressing device 1 having the above configuration will be described with reference to FIGS.

High-rise building A with vibration suppression device 1 installed near the roof
When an earthquake acts on the high-rise building A, since the high-rise building A is a long-period structure having a long natural period, sinusoidal vibration due to the long-period component included in the seismic motion is excited in the high-rise building A.
This vibration is sensed by the sensor 7 and information on the vibration is transmitted to the control unit 11. Upon receiving this information, the control unit 11 starts up the drive unit 12 and transmits the information to the computer 13. The computer 13 calculates the magnitude, phase, natural period, etc. of the vibration of the earthquake based on this information, calculates the magnitude, phase, period, etc. of the vibration, which are appropriate operating conditions of the actuator 4, and feeds it back to the control unit 11. I do. The control unit 11 operates the drive unit 12 based on the calculation result, and operates the actuators 4, 4 in an up-down direction under appropriate operation conditions. In this case, the actuators 4, 4 always operate in directions opposite to each other. The vertical movement distance (stroke) of the actuators 4, 4 is twice the vertical movement distance when the elevated water tank 3 is inclined from the rest position and the draft line reaches the bottom of the elevated water tank 3. The elevated water tank 3 oscillates in a vertical plane with the pin 8 as a fulcrum according to the movement of the actuators 4,4,
A series of movements (a) → (b) → (a) → (c) → (a) →... Are periodically repeated as shown in the figure (a schematic diagram of the vibration suppression device 1). Here, FIGS. 2 (a) to 2 (c)
(A): the stationary position of the elevated water tank 3; (b): the position when the elevated water tank 3 is inclined from the stationary position by θ = x / L; (c): the elevated water tank 3 from the stationary position (b) And in the opposite direction to θ
= Position when tilted by x / L.

Symbols in the figure are: 2L: length of elevated water tank 3 in the longitudinal direction, d: depth of elevated water tank 3, d / 2: depth of water 9 at rest, 2x: stroke of actuator 4, Go: : The center of gravity of the water 9 at rest, G: the center of gravity of the water 9 when the elevated water tank 3 is at the maximum inclination, r: the horizontal movement distance of the center of gravity G of the water 9. Here, when the elevated water tank 3 is tilted from the rest position by θ = x / L, the center of gravity of the water 9 in the elevated water tank 3 moves by r in the horizontal direction. Assuming that the mass of the water 9 is m, the generated reaction force is obtained by the following equation.

P = m · (d ² r / dt ² ) d ² r / dt ² : acceleration of movement of the center of gravity of water 9 This reaction force is used as a control force for the vibration of the high-rise building A. The magnitude, phase, and period of the control force are calculated by the computer 13 so that the force most effectively acts on the vibration control of the high-rise building A.

The movements of the actuators 4, 4 are constantly monitored by the sensors 6, 6, and information on their operation is transmitted to the control unit 11 moment by moment. The computer 13 calculates and corrects the operating condition of the actuator 4 again based on this information.

FIG. 3 schematically illustrates the above control.
These series of movements are continued until the vibration of the high-rise building A is damped within a certain limit.

Next, the results of a study of checking the effect of the vibration suppression device 1 of the present invention will be described with reference to FIGS. 4 to 7. FIG.

Fig. 4 (a) to (c) show a structure with a primary natural period of 10 seconds, an elevated water tank with a length of 10m, a depth of 5m, and a height of 2m, filled with water up to a depth of 1m. (Water weight 50ton)
FIG. 3 illustrates a response when the vibration suppression device is driven. Here, the vibration of the structure is converted into a harmonic sinusoidal wave (sinω
t). FIG. 4 (a) shows a harmonic sine wave (sin ω).
The vertical movement distance x of the actuator oscillating at t)
And x is represented by the following equation.

x = 0.96 sin ωt (≒ sin ωt) FIG. 12B is a diagram showing the horizontal movement distance r of the center of gravity of water caused by the vibration of the actuator.
Is represented by the following equation.

FIG. 3C is a diagram showing a reaction force P exerted by the elevated water tank on the structure due to horizontal movement of water, where P is expressed by the following equation.

As can be seen from these figures, it is understood that a large reaction force is generated by attaching the vibration suppressing device to the structure.

Fig. 5 shows that when the damping constant of the structure is 2.0%, the control force (kgf) generated per ton of the structure in a state where the response is reduced to the comfort study limit curve (steady state) (kgf)
FIG. 6 illustrates the relationship between the period and the cycle (second). here,
The control force generated when the top of a structure having a period of 10 seconds, a first-order damping constant of 2.0%, and a weight of 500,000 tons oscillates in a sinusoidal manner at 20 gal is obtained from the figure.
It becomes 4kgf. Therefore, in the case of the above structure, 200t
With the ON control force, the vibration can be reduced to a level that does not interfere with normal work and living. When the reaction force exerted on the structure by the water tank is obtained from FIG. 4 (c), a reaction force of 4.22 ton is obtained per one water tank (50 ton). Here, a water tank with a length of 20 m, a depth of 20 m, and a depth of 2 m is provided.
Assuming that the unit operates in this embodiment, It turns out that it can respond enough.

The above example is a study example for a skyscraper of about 100 stories, so in a building of about 50 stories, the size of the water tank is about 1/10 of the above.

Figure 6 is a reaction force P ₁ occurring case of driving the vibration suppression device of the present invention when it is installed the elevated tank to the structure,
A reaction force P ₂ that occurs when the elevated tank is moved in the horizontal direction at the same stroke attaching the actuator of the same vibration suppressing device to the side of the elevated tank, a comparison for the difference in shape of the tank. The ratio of P ₁ and P ₂ is expressed by the following equation.

_{P 1 / P 2 = (d} 2 r / dt 2) / (d 2 x / dt 2) = (2L / 3d) ^{[{2+ (1/2) (d /} L) 2} 2 + (1/2 ) (D / L) ² +3] In addition, the shape of the water tank is the ratio of the bottom length 2L to the height d (d / L).
2L). As can be seen from this figure, the reaction force generated by mounting the vibration suppressing device of the present invention.
P ₁ is seen to be much larger than the reaction force P ₂ generated by moving the actuator in a horizontal direction. As shown in the figure, the value of P ₁ / P ₂ takes the minimum value 6 when the value of d / 2L is about 0.5. Further, as the value of d / 2L becomes smaller than 0.5, that is, as the depth becomes smaller, a very large reaction force is generated. Similarly, it can be seen that the greater the value of d / 2L is greater than 0.5, that is, the greater the depth, the greater the reaction force.

In the above series of studies, it is assumed that water moves quietly.However, when the water tank is shallow or the cycle is short, water movement becomes dynamic, and in some cases, nonlinear movement such as breaking waves may occur. The behavior of The reaction force in this case is even greater than if the water were assumed to move quietly. Further, if the tank is further inclined after the water draft line reaches the bottom of the tank, the reaction force is further increased.

Furthermore, in the above study, the movement of the actuator is also sinusoidal, but if this movement is instantaneously pulsed in accordance with the vibration cycle of the structure as shown in FIG. As shown in FIG. 7 (b), the movement of the water becomes dynamic, and the horizontal movement distance r of the center of gravity of the water increases.
Therefore, the acceleration of the movement of the center of gravity becomes much larger, and the generated reaction force becomes considerably large. Also, the impact force when the water collides with the side wall of the aquarium becomes considerably large. In the above case, the time difference from before tilting the water tank until the reaction force is generated by the movement of water, that is, the phase difference of the reaction force is obtained by calculation, and if the phase is synchronized with the vibration phase of the structure, It will be effective.

As described above, the vibration excited in the high-rise building A can be suppressed by the vibration suppression device 1 of the present invention. Here, the vibration suppressing device 1 according to the present embodiment includes an elevated water tank 3
And a column 2 supporting a central portion of a bottom surface 3a of the elevated water tank 3;
Since two actuators that support both ends of the bottom surface 3a of the elevated water tank 3 so as to be able to move in the vertical direction are main components, the size is smaller than the conventional vibration suppression devices according to the first to third systems. A large vibration suppressing effect can be obtained even with the above device, and it is not necessary to increase the size of the water tank. Therefore, the device can be greatly simplified, downsized, and labor-saving. Further, since the water tank is not hung, there is no need to secure a wide space, and space can be saved. Further, since it is not necessary to forcibly apply a stress to the water tank and move the water tank in the horizontal direction, the length of the stroke can be shortened, and a slide mechanism having a long stroke and a large driving force are not required. Further, since there is no need to synchronize the water tank and the water amount with the cycle of vibration of the structure as in the sloshing damper method, the degree of freedom in design is increased. Accordingly, the present invention can be sufficiently applied to a general structure such as a hotel or a house where a person always lives or lives. Further, an effective vibration suppression effect can be obtained even with small vibrations such as wind.

The details of the structure vibration suppressing device of the present invention are not limited to the above-described embodiment, and various modifications are possible.
As an example, a configuration in which actuators are provided at four corners of the bottom surface of the water tank, respectively, may be used. Furthermore, by attaching the actuator and the control device of the present invention to each of two water tanks stacked and arranged so as to be orthogonal to each other, expansion in various directions on a horizontal plane becomes possible.

[Effects of the Invention] As described in detail above, according to the present invention, the vibration suppressing device includes a water tank for storing a liquid, a column supporting the center of the bottom of the water tank, and both ends of the bottom of the water tank. A vibration suppression device for a structure including a plurality of actuators that movably support the device in a vertical direction, so that a large vibration suppression effect can be obtained even with a small device as compared with a vibration suppression device using a conventional water tank. This eliminates the need to increase the size of the water tank. Therefore, the equipment is greatly simplified, downsized,
Labor saving can be achieved. Further, since the water tank is not hung, there is no need to secure a wide space, and space can be saved.
Further, since it is not necessary to forcibly apply a stress to the water tank and move the water tank in the horizontal direction, the length of the stroke can be shortened, and a slide mechanism having a long stroke and a large driving force are not required. Further, since there is no need to synchronize the water tank and the water amount with the cycle of the structure, the degree of freedom in design is increased. As a result, general structures, such as hotels and houses, in which humans always live or live, can be sufficiently collected. Further, an effective vibration suppression effect can be obtained even with small vibrations such as wind.

Therefore, it is possible to effectively suppress the vibration caused to the structure by an external force such as an earthquake or a strong wind, and the safety measures at the time of an earthquake or a strong wind are further improved.

[Brief description of the drawings]

1 to 7 are views showing an embodiment of the present invention. FIG. 1 is a schematic front view of a vibration suppressing device, FIG. 2 (a) is a schematic diagram showing a stationary position of an elevated water tank, FIG.
Is a schematic diagram showing the position when the elevated water tank is inclined by θ = x / L from the rest position, and FIG. (C) shows the elevated water tank from the rest position by θ = x / L in the opposite direction to FIG. FIG. 3 is a schematic diagram showing a position when the device is tilted, FIG. 3 is an explanatory diagram showing a state of control of the vibration suppressing device, FIG. 4 (a) is a diagram showing a moving distance of the actuator, and FIG. Fig. 5C shows the horizontal movement distance of the center of gravity of water caused by the horizontal movement, Fig. 5C shows the reaction force generated by the horizontal movement of the center of gravity of water, and Fig. 5 shows the state in which the response is reduced to the comfort study limit curve. FIG. 6 is a diagram showing the relationship between the control force and the cycle generated in the apparatus, and FIG. 6 shows the reaction force P ₁ generated by the vibration suppressing device of the present invention and the reaction force P ₂ generated when the elevated water tank is moved in the horizontal direction. graph showing the relationship between the ratio (P ₁ / P ₂₎ and a ratio of length 2L and the height d of the bottom surface of the aquarium (d / 2L) and, FIG. 7 (a) is an actuator FIG. 4B is a schematic view showing the movement of the water tank accompanying the pulse-like movement of the actuator. A ... high-rise building 1 ... structure vibration suppression device 2 ... support column 3 ... elevated water tank 4 ... actuator 5 ... control device 6 ...
Sensor 7, ... sensor.

Claims (1)

(57) [Claims] 1. A vibration suppression device for a structure which is installed at a predetermined position of a structure and suppresses vibration excited by the structure by an external force such as an earthquake or a wind.
A structure comprising: a water tank for storing liquid; a column supporting a central portion of a bottom surface of the water tank; and a plurality of actuators supporting both ends of the bottom surface of the water tank in a vertically movable manner. Vibration suppression device.