JP2020117269A - Damping device - Google Patents

Abstract

To provide a damping device capable of improving earthquake resistance and safety of a liquid storage tank against a bulging phenomenon.SOLUTION: This damping device disposed in a liquid storage tank comprises: first and second support plates 2, 3 made of hard resins; and a damping plate 4 including an elastic body. The first support plate 2 is fixed to the surface of the damping plate 4, the second support plate 3 is fixed to the backside of the damping plate 4, one end 22 of the first support plate 2 is located outside one end 33 of the second support plate 3 in the longitudinal direction of the device, and the other end 32 of the second support plate 3 is located outside the other end 23 of the first support plate 2.SELECTED DRAWING: Figure 1

Description

The present invention relates to a damping device arranged in a liquid storage tank.

A sloshing phenomenon is known as a phenomenon in which a liquid storage tank such as a water storage tank is destroyed by an earthquake motion. The sloshing phenomenon is a phenomenon in which the vibration of the liquid in the tank coincides with the natural frequency of the liquid, and the liquid vibrates significantly due to resonance, whereby the panel on the ceiling or the upper side surface of the tank is mainly damaged. Various countermeasures have been proposed for this sloshing phenomenon. For example, a method of disposing a vibration damping device as described in Patent Document 1 below in a liquid storage tank has been considered. There is.

JP, 2005-147590, A

However, analysis of the state of tank destruction due to recent earthquakes has revealed that the tank is destroyed not only by the sloshing phenomenon described above, but also by the phenomenon of bulging. The bulging phenomenon is a phenomenon in which the liquid in the tank vibrates as a lump (mass body) in a coupled manner with a panel on the side surface of the tank due to an earthquake motion. Since the hydrostatic pressure of the liquid in the tank is proportional to its depth, it becomes higher toward the bottom of the tank. Therefore, when the bulging phenomenon occurs, stress is likely to be concentrated in the lower portion of the tank, and there is a high possibility that the side panel and the corner portion in the lower portion of the tank are damaged.

In the current design standard of liquid storage tanks, although the sloshing phenomenon is dealt with, the bulging phenomenon is not always sufficiently dealt with. For example, in order to prevent the tank panel from bulging outward during the bulging phenomenon, it is conceivable to provide a tension material or the like on the outside of the panel to reinforce it. Even if it is possible, it is not possible to suppress the denting operation of the panel, and the effect of suppressing the bulging phenomenon is not so high.

It is an object of the present invention to provide a damping device that improves the earthquake resistance and safety of a liquid storage tank against the bulging phenomenon.

The damping device of the present invention is a damping device disposed in a liquid storage tank,
A first support plate and a second support plate made of hard resin, and a damping plate made of an elastic body,
The first support plate is fixed to the front surface of the damping plate, and the second support plate is fixed to the back surface of the damping plate,
In the device longitudinal direction, one end of the first support plate is located outside one end of the second support plate, and the other end of the second support plate is located outside the other end of the first support plate. It is characterized by doing.

According to this configuration, when kinetic energy such as earthquake motion is applied to the first support plate and/or the second support plate, the damping plate undergoes shear deformation in the longitudinal direction of the device. When the damping plate undergoes shear deformation, resistance is generated and kinetic energy due to earthquake motion or the like is converted into thermal energy, so that vibration due to earthquake motion or the like can be damped.

In the present invention, it is preferable to include a plurality of the first support plates and/or the second support plates and a plurality of the attenuation plates.

According to this configuration, since the damping device including more damping plates is configured, the damping effect is further enhanced.

In the present invention, it is preferable that the elastic body is made of a thermosetting elastomer or a thermoplastic elastomer.

Since the elastic body is made of a thermosetting elastomer or a thermoplastic elastomer as in the present configuration, the damping plate is easily sheared and deformed, and vibration due to seismic motion or the like can be damped more efficiently.

In the present invention, the hard resin is preferably a thermoplastic resin.

According to this configuration, since the thermoplastic resin is used as the hard resin, it is possible to manufacture the damping device that is easy to process and has excellent strength.

In the present invention, it is preferable that each of the first support plate and the second support plate and the damping plate be fixed by an adhesive.

According to this configuration, each of the first support plate and the second support plate and the damping plate can be fixed in close contact with each other by the adhesive, so that the first support plate and/or the second support plate can be fixed. The kinetic energy due to earthquake motion or the like applied to the damping plate is easily transmitted by the damping plate and can be further efficiently damped.

In the present invention, it is preferable that each of the first support plate and the second support plate and the damping plate are fixed so that their relative positions in the device longitudinal direction can be changed.

According to this configuration, since the length of the damping device in the longitudinal direction can be changed, the length can be adjusted according to the environment in which the damping device is installed, which is convenient for use.

In the present invention, it is preferable that the liquid storage tank is arranged at a corner portion.

According to this configuration, when an earthquake occurs, the damping plate undergoes shear deformation, so that vibration due to earthquake motion or the like in the liquid storage tank can be attenuated and the bulging phenomenon can be suppressed. As a result, it is possible to suppress the deformation and damage of the panel, frame and the like in the liquid storage tank. Moreover, since the existing liquid storage tank can be easily installed, the installation cost is excellent.

It is a perspective view of a damping device. It is a side view of a damping device. It is a side view of the damping device concerning another embodiment. It is a top view of the storage tank for liquids which provided the damping device. It is a perspective view of another embodiment of a damping device. FIG. 8 is a side view of another embodiment of the damping device. It is a perspective view of another embodiment of a damping device. FIG. 8 is a side view of another embodiment of the damping device. It is a perspective view of another embodiment of a damping device. FIG. 8 is a side view of another embodiment of the damping device. It is a perspective view of another embodiment of a damping device. It is a graph which shows the measurement result of each side plate displacement of the liquid storage tank (Example) which provided the damping device, and the liquid storage tank (Comparative example) which does not provide the damping device in various frequencies.

[Embodiment]
An embodiment of a damping device 1 according to the present invention will be described with reference to the drawings.
(Liquid storage tank)
The liquid storage tank in the present invention means a tank that stores and stores a storage liquid such as water, fuel, and chemical liquid.

A liquid storage tank to which the damping device according to the present invention can be applied includes, for example, a general box-shaped tank having a rectangular (square or rectangular) cross-sectional shape. The size of the tank is not particularly limited, and may be, for example, a general water receiving tank having a height of 3 m, a width of 3 m, and a depth of 3 m, or a large-sized tank having an effective water depth of more than 7 m. It can be widely applied to tanks.

(Attenuator)
As shown in FIG. 1, the damping device 1 according to the present embodiment includes a first support plate 2 and a second support plate 3 made of hard resin, and a damping plate 4 made of an elastic body. ..

The first support plate 2 and the second support plate 3 in this embodiment are members having the same size and shape (trapezoid). The first support plate 2 includes an upper bottom portion 20, a lower bottom portion 21, an inclined portion 22 inclined from the end of the upper bottom portion 20 to the end of the lower bottom portion 21, and from the other end of the upper bottom portion 20 to the other end of the lower bottom portion 21. A straight line portion 23 that extends over and extends at a right angle to both the upper bottom portion 20 and the lower bottom portion 21 is provided. Similarly to the first support plate 2, the second support plate 3 also includes an upper bottom portion 30, a lower bottom portion 31, an inclined portion 32 inclined from the end of the upper bottom portion 30 to the end of the lower bottom portion 31, and the other of the upper bottom portion 30. A straight portion 33 extending from the end to the other end of the lower bottom portion 31 and forming a right angle with both the upper bottom portion 30 and the lower bottom portion 31 is provided.

The inclined portion 22 of the first support plate 2 in the present embodiment is inclined from the end of the lower bottom portion 21 at an angle of approximately 45°, and the inclined portion 32 of the second support plate 3 is similarly formed at the end of the lower bottom portion 31. It is inclined at an angle of about 45° from.

Examples of the hard resin forming the first support plate 2 and the second support plate 3 include, but are not limited to, thermoplastic resins such as polyethylene, polypropylene, and ABS resin. However, for example, when the damping device 1 of the present invention is applied to a water receiving tank that stores tap water, it is necessary to use a material that does not adversely affect the quality of tap water.

The first support plate 2 and the second support plate 3 are manufactured by using the above-mentioned hard resin as a material, for example, by molding into a slender plate shape by a known extrusion molding method, and then cutting into a predetermined size and shape. can do.

The damping plate 4 in this embodiment is a rectangular member, the length of which is smaller than the lengths of the first support plate 2 and the second support plate 3, and the width thereof is the first support plate 2 and the second support plate. It has the same size as the plate 3.

Examples of the elastic body that constitutes the damping plate 4 include thermosetting elastomers such as rubber, and thermoplastic elastomers such as olefin elastomers, styrene elastomers, and vinyl chloride resin elastomers, but are not limited thereto. It is not something that will be done. However, for example, when the damping device 1 of the present invention is applied to a water receiving tank that stores tap water, it is necessary to use a material that does not adversely affect the quality of tap water.

The damping plate 4 can be manufactured by using the above-mentioned elastic body as a material, for example, by molding it into a slender plate shape by a known extrusion molding method, and then cutting it into a predetermined size and shape.

In the damping device 1 according to the present embodiment, the first support plate 2 is attached to the surface of the damping plate 4 such that the linear portion of the first support plate 2 is flush with the end of the damping plate 4 in the longitudinal direction. It is fixed. Further, the second support plate 3 is fixed to the back surface of the damping plate 4 so that the linear portion of the second support plate 3 is flush with the other end of the damping plate 4 in the longitudinal direction. That is, the damping device 1 has a three-layer structure in which the damping plate 4 is sandwiched between the first support plate 2 and the second support plate 3.

Regarding the method of fixing each of the first support plate 2 and the second support plate 3 and the damping plate 4, for example, as shown in FIG. Alternatively, as shown in FIG. 3, the bolts 6 or the like may be used to fix them in close contact with each other.

Further, as shown in FIGS. 1 to 3, in the damping device 1 according to the present embodiment, in the longitudinal direction, the inclined portion 22 which is one end of the first support plate 2 is a straight line which is one end of the second support plate 3. The inclined portion 32, which is located outside the portion 33 and is the other end of the second support plate 3, is located outside the linear portion 23, which is the other end of the first support plate 2. That is, the damping device 1 in a plan view has an isosceles trapezoidal shape.

In the damping device 1 described above, when the kinetic energy due to earthquake motion or the like is applied to the first support plate 2 and/or the second support plate 3, the damping plate 4 is sheared and deformed in the longitudinal direction of the device. Is configured. According to this configuration, resistance is generated when the damping plate 4 undergoes shear deformation, and kinetic energy due to earthquake motion or the like is converted into thermal energy, so that vibration due to earthquake motion or the like can be damped.

The damping device 1 according to the present invention is not limited to the above-described isosceles trapezoidal shape, and may have any shape based on the shape of the liquid storage tank T to be applied and the like without departing from the scope of the present invention. You can change it.

(How to use the damping device)
Next, a method of using the damping device 1 according to this embodiment will be described. Here, an example in which a liquid storage tank T configured as a general box-shaped body having a rectangular cross-sectional shape is used, and the above-described damping device 1 of the present embodiment is applied to the liquid storage tank T is used. explain.

As shown in FIG. 4, the liquid storage tank T includes a plurality of vertical frames F1 installed at regular intervals in the front-rear direction and the left-right direction along the vertical direction, and in the front-back direction along the horizontal direction. And a plurality of horizontal frames F2 installed at regular intervals in the left-right direction in combination with the outer periphery of a cage-like structure that is assembled like a jungle gym, and is made of, for example, fiber reinforced plastic (FRP) or the like. The assembled panel P is attached and configured.

The damping device 1 is attached so as to be substantially horizontal at the four corners of the liquid storage tank T. At this time, each of the inclined portion 22 of the first support plate 2 and the inclined portion 32 of the second support plate 3 in the damping device 1 is fixed to each of the two horizontal frames F2 forming the corners by bolts and nuts or the like. To be done.

The damping device 1 may be attached not only to the corners of the four corners of the liquid storage tank T, but also to other corners formed by the horizontal frames F2 orthogonal to each other and along the outer peripheral panel P, for example. .. Further, it is desirable that the damping device 1 be attached at a position where the panel P is expected to have a large amplitude due to bulging. For example, it is preferable that the liquid storage tank T is attached below the middle of the liquid storage tank T in the vertical direction, and not only one stage but also a plurality of stages in the vertical direction.

According to the above-described configuration, when an earthquake occurs, the damping plate 4 of the damping device 1 is sheared and deformed, so that vibration due to earthquake motion or the like in the liquid storage tank T can be damped and the bulging phenomenon can be suppressed. As a result, it is possible to suppress deformation and damage of the panel, frame, etc. in the liquid storage tank T.

[Other Embodiments]
1. As shown in FIG. 5, when fixing each of the first support plate 2 and the second support plate 3 and the damping plate 4 with the bolt 6, each of the first support plate 2 and the second support plate 3 is fixed. A recess 8 having a diameter larger than that of the bolt hole 7 may be formed in the periphery of the bolt hole 7 to accommodate the washer member 9.

2. As shown in FIG. 6 and FIG. 7, when fixing the first support plate 2 and the second support plate 3 and the damping plate 4 with bolts, the first support plate 2, the second support plate 3, By providing a plurality of bolt holes 7 along the device longitudinal direction in each of the damping plate 4 and the damping plate 4, each of the first supporting plate 2 and the second supporting plate 3 and the damping plate 4 are relatively arranged in the device longitudinal direction. The position may be fixed so that it can be changed. It should be noted that the bolt hole 7 may be provided with a recess 8 for accommodating a washer member, as in the case of FIG. 5, if necessary.

3. The damping device 1 may be configured by combining a plurality of configurations including the first support plate 2, the second support plate 3, and the damping plate 4 in the above-described embodiment as illustrated in FIGS. 8 to 11. For example, in the embodiment shown in FIGS. 8 and 9, by using two first support plates 2, one second support plate 3 and two damping plates 4, a five-layer structure is obtained. The damping device 1 is configured. Further, in the embodiment shown in FIGS. 10 and 11, the four first support plates 2, the one second support plate 3, and the four damping plates 4 are used, and the second support plate 3 is used. The damping device 1 has a five-layer structure on both the left and right sides in the longitudinal direction. Regarding the method of fixing each of the first support plate 2 and the second support plate 3 and the damping plate 4 in the present embodiment, as in the above-described embodiment, they are fixed using an adhesive, bolts, or the like. Good. In addition, the structure of the damping device is not limited to the above-described form, and the damping device is provided with a larger number of the first support plate 2, the second support plate 3, and the damping plate as needed, such as a stepwise configuration. May be configured.

4. The first support plate, the second support plate, and the damping plate in the above-described embodiment may have uneven surfaces formed by a plurality of grooves extending in the longitudinal direction on both surfaces thereof. At this time, the uneven surfaces of the first support plate and the second support plate are configured to mesh with the uneven surfaces of the front and back of the damping plate. According to this configuration, the contact area between the first support plate and the damping plate and the contact area between the second support plate and the damping plate are large, respectively, so that they are fixed more firmly.

5. For the liquid storage tank, the damping device according to the present invention and a known sloshing damper (vibration damping device) for suppressing the sloshing phenomenon may be used in combination.

[Demonstration test]
A verification experiment was conducted to confirm the effect of the damping device of the present invention.
As the damping device of the present invention, a damping device including a damping plate made of an olefin elastomer resin and a first supporting plate and a second supporting plate made of special polyethylene was used. Further, as the liquid storage tank, a 3 m×3 m×3 m FRP tank was used.

With respect to the FRP tank, a damping device was installed at each of four corners at positions of 1000 mm and 2000 mm from the bottom, as shown in FIG. 4, and the damping device had a two-stage structure. The thing was made into the Example. A comparative example was prepared under the same conditions except that no damping device was installed for the FRP tank.

In order to confirm the response of the FRP tank when bulging occurred, a sine wave vibration experiment was conducted with the water depth of the FRP tank set to 2700 mm (normal water depth). The acceleration was set to 0.35 m/s, and vibration was applied at 1.9 to 2.5 Hz which is considered to be the bulging frequency range of the FRP tank. The vibration was applied so as to be orthogonal to the measurement surface of the FRP tank (the wall surface at a position 1500 mm from the bottom).

Using a laser displacement meter (IL-600 manufactured by KEYENCE CO., LTD.), the wall surface displacement of the measurement surface was measured and the displacements were compared in each of the examples and comparative examples. Results are shown in FIG.

As shown by the white arrow in FIG. 12, the displacement amount of 10 mm when the damping device of the present invention was used (Example) at the bulging natural frequency (2 Hz) of the FRP tank used in this demonstration experiment. On the other hand, when the damping device of the present invention was not used (Comparative Example), the displacement amount was 26.4 mm, and it was confirmed that the deformation was suppressed by 16.4 mm.

INDUSTRIAL APPLICABILITY The damping device of the present invention can be used for a wide range of liquid storage tanks, from small tanks such as water receiving tanks for storing clean water to large tanks such as contaminated water storage tanks. ..

1 Damping Device 2 First Support Plate 20 Upper Bottom 21 Lower Bottom 22 Inclined Part (One End of First Support Plate)
23 Straight part (the other end of the first support plate)
3 2nd support plate 30 Upper bottom part 31 Lower bottom part 32 Inclined part (other end of a 2nd support plate)
33 Straight part (one end of the second support plate)
4 Damping Plate 5 Adhesive 6 Bolt 7 Bolt Hole 8 Recess 9 Washer Member T Liquid Storage Tank F1 Vertical Frame F2 Horizontal Frame P Panel

Claims (7)

In the damping device arranged in the liquid storage tank,
A first support plate and a second support plate made of hard resin, and a damping plate made of an elastic body,
The first support plate is fixed to the front surface of the damping plate, and the second support plate is fixed to the back surface of the damping plate,
In the device longitudinal direction, one end of the first support plate is located outside one end of the second support plate, and the other end of the second support plate is located outside the other end of the first support plate. A damping device characterized by: The damping device according to claim 1, comprising a plurality of the first support plates and/or the second support plates, and a plurality of the damping plates. The damping device according to claim 1 or 2, wherein the elastic body is made of a thermosetting elastomer or a thermoplastic elastomer. The damping device according to claim 1, wherein the hard resin is a thermoplastic resin. The damping device according to any one of claims 1 to 4, wherein each of the first support plate and the second support plate and the damping plate are fixed by an adhesive. Each of said 1st support plate and said 2nd support plate, and said damping plate are being fixed so that a relative position in a device longitudinal direction can be changed, The claim 1 characterized by the above-mentioned. The damping device according to the item. The damping device according to any one of claims 1 to 6, wherein the damping device is arranged at a corner portion in the liquid storage tank.

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