JP2024119302A - Vibration control device - Google Patents

Abstract

A pendulum type vibration damping device is provided that allows easy adjustment of the natural frequency for each movable direction.
[Solution] The first and second hanging members 11, 12 are both attached to a structure 81 that is the vibration control target, and suspend a mass body 2 in the vertical direction so that the mass body 2 can passively sway in response to vibration of the structure 81. The first and second elastic members 31, 32 are both arranged so as to be inclined with respect to the vertical direction, and are arranged so as to connect between the structure 81 and the mass body 2, or between the structure 81 and the first and second hanging members 11, 12. The first and second elastic members 31, 23 are both arranged in a vertical plane, and are arranged so as to be symmetrical with respect to a vertical imaginary axis of symmetry.
[Selection] Figure 13

Description

The present invention relates to a vibration control device for controlling horizontal vibrations that occur in structures such as buildings and bridges. More specifically, the present invention relates to a pendulum-type vibration control device that allows easy adjustment of the natural frequency for each moving direction.

When vibrations occur on structures such as buildings and bridges due to wind loads from typhoons or earthquake loads or traffic loads, these vibrations not only pose a safety issue for the structure, but also cause discomfort to users of the structure. For this reason, attempts are being made to suppress or minimize vibrations using vibration control devices.

A typical vibration control device for structures is the Tuned Mass Damper (TMD). A TMD has a movable mass and a damper that passively vibrates in response to vibrations in the structure, and vibrations can be controlled by installing a TMD in the structure.

Figure 1 shows a vibration dynamics model of a horizontally vibrating structure and TMD. The movable mass (mass m _T ) is about a few percent of the mass m _S of the structure. For example, when the structure vibrates due to wind load, earthquake load, etc., the TMD also vibrates in sync and operates. At this time, the vibration energy is absorbed by the damper C _T installed in the TMD, and the vibration of the structure is also suppressed. In order to efficiently exert such vibration control effect, it is necessary to set the natural frequencies of the structure and the TMD to be almost equal (for example, the frequency ratio is about 98% to 99%).

Damping devices are classified into vertical and horizontal vibration damping devices depending on the vibration direction of the structure, but the following describes horizontal vibration damping devices. Horizontal vibration damping devices are also classified into slide type and pendulum type, but the following describes a pendulum type vibration damping device with a structure in which a movable mass 200 is suspended by a hanging material 100 such as a wire so that it can passively vibrate, as shown in Figure 2.

In general, structures such as buildings and bridges have various natural frequencies depending on the direction of vibration. In other words, when a high-rise building vibrates horizontally, the natural frequency of the building when it sways back and forth is generally not equal to the natural frequency of the building when it sways left and right. Similarly, the natural frequency of a bridge tower is not the same when it sways in the direction of the bridge axis and when it sways perpendicular to the bridge axis.

As mentioned above, the natural frequency of the TMD is set to be approximately equal to the natural frequency of the structure. Therefore, the natural frequency of the pendulum-type vibration control device must also be set to be approximately equal to the natural frequency of the structure.

On the other hand, the natural frequency of the moving mass in a pendulum-type vibration control device, i.e. a pendulum TMD, depends on the length of the vibrating pendulum (specifically the length of the hanging member). In other words, the natural frequency decreases in proportion to the square root of the reciprocal of the pendulum length. In a pendulum TMD, one or more pendulums of the same length are used, which means that in the case of a pendulum TMD that operates horizontally, it has the same natural frequency regardless of the direction of operation.

However, as mentioned above, structures such as buildings and bridges generally have different natural frequencies depending on the direction of vibration. Therefore, in this case, the control effect of the pendulum-type vibration control device is significantly reduced depending on the vibration direction.

In order to solve the above problems, the technology shown in Figures 3 to 7 has been proposed. This technology allows the entire length of the pendulum in a pendulum-type vibration damping device that operates in the horizontal direction to move in one direction, and restricts a certain length of the pendulum from moving in the other direction, making it possible to set the natural frequency to be different depending on the vibration direction of the pendulum-type vibration damping device. That is, in a pendulum-type vibration damping device that operates horizontally in the X and Y directions by suspending the movable mass 200 from the hanging material 100 as shown in Figure 3, a frequency adjustment device shown by the symbol 400 in Figures 4 and 5 is installed in an appropriate position. Then, as shown in Figure 6, when the pendulum-type TMD operates in the X direction, the pendulum operates only a certain length (L2) due to the frequency adjustment device 400. On the other hand, as shown in Figure 7, when the pendulum-type TMD moves in the Y direction, the pendulum is not affected by the frequency adjustment device 400, so the entire length of the pendulum (L1 + L2) operates.

Therefore, the natural frequency of the movable mass 200 can be set differently depending on the direction of vibration. However, when adjusting the natural frequency of the pendulum using such a system, friction between the pendulum and the frequency adjustment device 400 becomes an issue. This friction is not large when the pendulum operates in the Y direction, but when the pendulum operates in the X and Y directions simultaneously (i.e., operates in a direction that has components in both directions), a large frictional force is generated. Even if a material with low friction is used for the frequency adjustment device 400, friction of at least a few percent is expected, and in this case, the pendulum-type TMD has the disadvantage of not functioning for small vibrations.

As another prior art, a pendulum-type TMD has been proposed in which a rigid body device 500 as shown in Figure 8 is placed between the hanging members 100 and operates in the horizontal direction. With this technology, the entire length of the pendulum is allowed to move in one direction, while a certain length of the pendulum is restrained from moving in the other direction, making it possible to set different natural frequencies depending on the vibration direction of the movable mass 200.

That is, in a pendulum type vibration damping device that operates horizontally in the X and Y directions as shown in FIG. 3, a rigid body device (specifically, for example, a rectangular iron plate) 500 shown in FIG. 8 and FIG. 9 is installed with an appropriate size. Then, a certain length (L1+L3) of the pendulum can be operated in the X direction as shown in FIG. 10. On the other hand, the entire length (L1+L2+L3) of the pendulum can be operated in the Y direction as shown in FIG. 11. In this way, the natural frequency of the movable mass 200 can be set differently depending on the direction of vibration. However, when adjusting the natural frequency of the movable mass 200 using such a system, the rigid body device 500 installed on the pendulum may perform independent motion such as buckling apart from the pendulum motion, thereby reducing the vibration damping performance. In addition, there is a disadvantage that it is very difficult to fine-tune the natural frequency in the X direction.

Furthermore, in the following Patent Document 1, the natural frequencies in the X and Y directions are adjusted by providing an inclined spring 601 and a damper 602 in the X and Y directions as shown in Figure 12. In this technology, the inclined spring is fixed to the center of gravity (G) or center of gravity line of the movable mass 200, and the hanging material 100 is fixed to the height of the center of gravity (P) of the movable mass.

If the inclined spring is not fixed to the center of gravity of the movable mass, when the pendulum-type TMD vibrates in the X and Y directions simultaneously, the movable mass 200 will move in the torsional direction, greatly reducing the vibration damping effect, but this problem is solved by the above configuration. In addition, since the springs are not arranged symmetrically in the X and Y directions, with spring 601 on one side and damper 602 on the other, if the spring is not fixed to the center of gravity (G) or center of gravity line of the movable mass 200, this will be another cause of torsional motion of the movable mass. Furthermore, with this technology, the frequency is set higher in both the X and Y directions than the frequency of the TMD due to the length of the pendulum, so the pendulum must be made longer, which has the disadvantage of requiring more space to install the TMD.

Japanese Patent Application Publication No. 7-238987

The present invention was made in consideration of the above-mentioned circumstances, and aims to provide a pendulum-type vibration control device that eliminates the above-mentioned shortcomings and makes it easy to adjust the natural frequency for each moving direction.

The means for solving the above problems can be described as follows:

(Item 1)
The device includes first and second suspension members, a mass body, and an elastic mechanism,
the first and second hanging members are both attached to a structure that is a vibration damping target, and are configured to suspend the mass body in a vertical direction so as to be passively swingable in response to vibration of the structure;
The elastic mechanism includes first and second elastic members,
the first and second elastic members are both arranged so as to be inclined with respect to the vertical direction, and are arranged so as to connect between the structure and the mass body, or between the structure and the first and second hanging members;
and wherein the first and second elastic members are both arranged in a vertical plane and are arranged symmetrically with respect to a vertical imaginary axis of symmetry.

(Item 2)
2. The pendulum type vibration damping device according to item 1, wherein the vertical surface is set along a direction in which a frequency is to be adjusted.

(Item 3)
3. The pendulum type vibration damping device according to item 1 or 2, wherein the structural body is a ceiling surface of a structure or a support body fixed to the structure and capable of supporting the first and second hanging members.

(Item 4)
The first and second hanging members are both arranged so as to be vertical in a stationary state.
3. The pendulum type vibration damping device according to item 1 or 2.

(Item 5)
2. A vibration control method for controlling vibration of a structure by using the pendulum type vibration control device according to claim 1.

(Item 6)
6. The vibration damping method according to item 5, further comprising a step of adjusting a natural frequency of the mass body oscillating within the vertical plane by adjusting an inclination angle and/or an elastic modulus of the first and second elastic members.

The present invention makes it possible to provide a pendulum-type vibration control device that allows easy adjustment of the natural frequency for each direction of movement.

FIG. 1 shows a mechanical model of a structure and TMD against horizontal vibration. FIG. 1 is a schematic explanatory diagram of a conventional pendulum type vibration damping device. FIG. 1 is a schematic explanatory diagram of a conventional pendulum type vibration damping device that operates in the X and Y directions. FIG. 1 is a schematic explanatory diagram of a conventional pendulum type vibration damping device using a vibration frequency adjustment device. FIG. 5 is an explanatory diagram showing FIG. 4 as viewed from the side. 5 is an explanatory diagram showing a state in which the device in FIG. 4 operates in the X direction. FIG. 5 is an explanatory diagram showing a state in which the device in FIG. 4 operates in the Y direction. FIG. FIG. 13 is a schematic explanatory diagram of a conventional pendulum type vibration damping device using another vibration frequency adjustment device. FIG. 9 is an explanatory diagram showing FIG. 8 as viewed from the side. 9 is an explanatory diagram showing a state in which the device in FIG. 8 operates in the X direction. 9 is an explanatory diagram showing a state in which the device in FIG. 8 operates in the Y direction. FIG. 13 is a schematic explanatory diagram of a conventional pendulum type vibration damping device using yet another vibration frequency adjustment device. FIG. 2 is an explanatory diagram in which parameters are added to a schematic front view of the pendulum type vibration damping device according to the first embodiment of the present invention. FIG. 14 is a schematic perspective view for explaining the arrangement of the hanging material in the device of FIG. 13 . FIG. 14 is an explanatory diagram with parameters added, showing a state in which the device in FIG. 13 is operated in the X direction. FIG. 14 is a schematic explanatory diagram in which the description of parameters is omitted from FIG. 13 . FIG. 14 is a schematic explanatory diagram of the device of FIG. 13 as viewed from the side. FIG. 17 is an explanatory diagram showing a state in which the device in FIG. 16 is operated in the X direction. FIG. 17 is an explanatory diagram showing a state in which the device in FIG. 16 is operated in the Y direction. FIG. 11 is a schematic explanatory diagram of a pendulum type vibration damping device according to a second embodiment of the present invention, as viewed from the front. FIG. 21 is a schematic explanatory diagram of the device of FIG. 20 as viewed from the side. FIG. 11 is a schematic explanatory diagram of a pendulum type vibration damping device according to a third embodiment of the present invention, as viewed from the front. FIG. 13 is a schematic explanatory diagram of a pendulum type vibration damping device according to a fourth embodiment of the present invention, as viewed from the front. FIG. 13 is a schematic explanatory diagram of a pendulum type vibration damping device according to a fifth embodiment of the present invention, as viewed from the front. FIG. 13 is a schematic explanatory diagram of a pendulum type vibration damping device according to a sixth embodiment of the present invention, as viewed from the front. FIG. 13 is a schematic explanatory diagram of a pendulum type vibration damping device according to a seventh embodiment of the present invention, as viewed from the front. FIG. 23 is a schematic explanatory diagram of a pendulum type vibration damping device according to an eighth embodiment of the present invention, as viewed from the front.

The following describes the pendulum-type vibration damping device (hereinafter simply referred to as the "vibration damping device" or "device") according to the first embodiment of the present invention, with reference to Figures 13 to 19.

(Configuration of this embodiment)
The vibration damping device of this embodiment has a pendulum mechanism 1, a mass body 2, and an elastic mechanism 3 as main components.

Specifically, the pendulum mechanism 1 of this embodiment is composed of first to fourth hanging members 11 to 14 (see FIG. 14). Note that in FIG. 14, the elastic mechanism 3 is omitted for ease of viewing.

(Pendulum mechanism)
The first to fourth hanging members 11 to 14 are all attached to a structure 81 that is the target of vibration control, and are configured to suspend the mass body 2 in the vertical direction so that it can passively swing in accordance with the vibration of the structure 81. Here, the structure 81 is, for example, a support (so-called frame) that is fixed to a structure 8 such as a building or the ground and is capable of supporting the hanging members, but is not limited to this and may be any object that is the target of vibration control, such as the ceiling surface of a building or the underside of a bridge.

The first to fourth hanging members 11 to 14 are all arranged so that they are vertical when stationary. These hanging members 11 to 14 are made of, for example, wires or rods, but the same hanging members as those used in various ordinary pendulum mechanisms can be used.

(Mass)
The mass body 2 may be any suitable weight. The mass body 2 functions as a so-called movable mass in the TMD. The operation of the mass body 2 based on a dynamic model will be described later.

(Elastic mechanism)
The elastic mechanism 3 of this embodiment has first and second elastic members 31 and 32. The first and second elastic members 31 and 32 are both arranged so as to be inclined with respect to the vertical direction and to connect between the structure 81 and the mass body 2. Furthermore, the first and second elastic members 31 and 32 are both arranged in an imaginary vertical plane and are arranged so as to be symmetrical with respect to a vertical imaginary symmetric axis 5 (see FIG. 13). This imaginary vertical plane is set along the direction in which the natural frequency is to be adjusted (the X direction in this example). As the first and second elastic members 31 and 32 in this embodiment, for example, springs and rubber can be used, but they are not limited to these, and various mechanisms having the required elastic coefficient and strength can be used.

(Theoretical background of the vibration damping device of this embodiment)
Here, the theoretical background of the vibration damping device of this embodiment will be described with reference to FIGS.

As shown in FIG. 13, the parameters of the vibration control device are set as follows:
Mass of mass body (movable mass): m
The elastic coefficient of the first and second elastic members is k
Angle between one elastic member and the vertical direction (virtual axis of symmetry): φ ₀
Length of one elastic member: _L0
Distance between both ends of the elastic member (horizontal distance): b
Let us assume that.

For example, when the mass body 2 of the vibration damping device of this embodiment moves horizontally (in the x direction) by an angle θ as shown in FIG. 15, the increment ΔL in the length of the elastic member (first elastic member 31 in the illustrated example) can be expressed as follows:

Since equation (1-3) is a nonlinear equation, if we apply the following Taylor Series to it to derive a linear equation, ΔL can be expressed as follows:

Based on the above formula, the equation of motion and natural frequency f of the mass 2 shown in the figure can be derived as follows. Here, g represents the gravitational acceleration.

As can be seen from equation (3-4), in a pendulum-type vibration damping device having a pendulum length l and a movable mass m, the natural frequency of the mass body 2 can be increased by appropriately adjusting the elastic coefficient k of the elastic member and its length _L0 . In other words, it becomes possible to adjust the natural frequency. Here, the distance b is determined according to the position of the bottom end of the elastic member. In Figure 15, an example is shown in which the mass body 2 moves to the right in the figure, but in principle, the operation is the same when it moves to the left in the figure, except that the left and right are reversed.

In conclusion, the natural frequency of the mass body 2 of this embodiment increases in proportion to the square root of the elastic coefficient k. It can also be seen that the natural frequency increases as b/L ₀ , that is, the inclination angle of the elastic members 31 and 32, increases.

(Operation of this embodiment)
Based on the above theoretical background, the operation of the vibration damping device of this embodiment will be described with further reference to FIGS.

First, regarding the vibration in the x direction shown in Figures 16 and 18, as explained in the theoretical background, the natural frequency can be increased depending on parameters such as the elastic coefficient of the elastic member and the inclination angle.

On the other hand, for vibration in the y direction shown in Figures 17 and 19, the elastic members 31 and 32 remain parallel to the hanging material and no change in length occurs, so the effect of the elastic members 31 and 32 can be almost ignored. Therefore, the mass body 2 operates at a natural frequency in the y direction that is determined by the length of the hanging material.

In other words, as described above, the vibration control device of this embodiment can achieve different natural frequencies in the x and y directions. Therefore, if the natural frequency of the structure to be controlled is high in the x direction and low in the y direction, the vibration control device of this embodiment can be installed to match this, thereby achieving good vibration control effects in both directions.

Furthermore, with the vibration damping device of this embodiment, the elastic coefficient k of the first and second elastic members 31 and 32 can be adjusted by a very simple method, such as replacing the springs. In addition, the angles of the first and second elastic members 31 and 32 with respect to the vertical can also be easily adjusted.

The vibration damping device of this embodiment does not generate frictional resistance as in the conventional vibration damping device shown in Figures 4 to 7, so it can be expected to have a sufficient vibration control effect even for small vibrations. In addition, since it does not require a rigid body device as in the conventional vibration damping device shown in Figures 8 to 11, it is possible to prevent unstable phenomena such as buckling. Furthermore, in this embodiment, since the pair of elastic members 31 and 32 are arranged symmetrically, abnormal phenomena such as torsional behavior can be prevented even if the elastic members 31 and 32 are not fixed to the center of gravity of the mass body 2, and a high vibration damping effect can be obtained.

Second Embodiment
Next, a vibration device according to a second embodiment of the present invention will be described with reference to Fig. 20 and Fig. 21. In the description of this second embodiment, the same reference numerals are used for components that are basically the same as those in the first embodiment described above, thereby avoiding duplication of description.

In this second embodiment, multiple elastic mechanisms 3 are provided parallel to each other (see FIG. 21). The configuration of each elastic mechanism 3 is the same as in the first embodiment (see FIG. 20).

In the vibration device of the second embodiment, as in the first embodiment, the natural frequency in the x direction (see FIG. 20) can be increased. The natural frequency in the y direction (see FIG. 21) remains almost unchanged.

The device of the second embodiment has the advantage that, because multiple elastic mechanisms 3 are provided, it is possible to reliably prevent the occurrence of twisting in the mass body 2. This makes it possible to reliably adjust the natural frequency.

The other configurations and advantages of the vibration device of the second embodiment are basically the same as those of the first embodiment described above, so further detailed explanation will be omitted.

Third Embodiment
Next, a vibration device according to a third embodiment of the present invention will be described with reference to Fig. 22. In the description of this third embodiment, the same reference numerals are used for components that are basically the same as those in the first embodiment described above, thereby avoiding duplication of description.

In this third embodiment, the distance between the ends (lower ends) of the first and second elastic members 31 and 32 is narrowed and they are attached to the upper surface of the mass body 2. In the device of the third embodiment, the inclination angle of the first and second elastic members 31 and 32 is smaller than that of the device of the first embodiment, so that, other conditions being the same, the natural frequency of the mass body 2 in the x direction is lower than that of the device of the first embodiment.

The other configurations and advantages of the vibration device of the third embodiment are basically the same as those of the first embodiment described above, so further detailed explanation will be omitted.

Fourth Embodiment
Next, a vibration device according to a fourth embodiment of the present invention will be described with reference to Fig. 23. In the description of the fourth embodiment, the same reference numerals are used for components that are basically the same as those in the first embodiment described above, thereby avoiding duplication of description.

In this fourth embodiment, the upper ends of the first and second elastic members 31 and 32 are spaced apart. In this example, the upper ends of the first and second elastic members 31 and 32 are positioned outboard of the upper ends of the hanging members 11 and 12. However, it is possible to position the upper ends of the first and second elastic members 31 and 32 inboard of the upper ends of the hanging members 11 and 12.

The vibration control device of this fourth embodiment has the advantage that it is easy to install even if a storage space is created between the hanging materials or if there is a protrusion on the ceiling surface. Another advantage is that there are fewer restrictions on the inclination angle of the elastic members 31 and 32.

The other configurations and advantages of the vibration device of the fourth embodiment are basically the same as those of the first embodiment described above, so further detailed explanation will be omitted.

Fifth Embodiment
Next, a vibration device according to a fifth embodiment of the present invention will be described with reference to Fig. 24. In the description of the fifth embodiment, the same reference numerals are used for components that are basically the same as those in the first embodiment described above, thereby avoiding duplication of description.

In this fifth embodiment, the first and second elastic members 31 and 32 are arranged to cross each other. It is preferable that the first and second elastic members 31 and 32 are made of a material or have a structure that does not interfere with each other's elasticity.

The other configurations and advantages of the vibration device of the fifth embodiment are basically the same as those of the first embodiment described above, so further detailed explanation will be omitted.

Sixth Embodiment
Next, a vibration device according to a sixth embodiment of the present invention will be described with reference to Fig. 25. In the description of the sixth embodiment, the same reference numerals are used for components that are basically the same as those in the first embodiment described above, thereby avoiding duplication of description.

In this sixth embodiment, the lower ends of the first and second elastic members 31 and 32 are attached to the middle positions of the hanging materials 11 and 12. As a result, in the sixth embodiment, the first and second elastic members 31 and 32 connect the structure 81 and the hanging materials. In addition, the upper ends of the first and second elastic members 31 and 32 are attached to the structure 81 in a mutually spaced state. The sixth embodiment can provide the same advantages as the fourth embodiment described above.

The other configurations and advantages of the vibration device of the sixth embodiment are basically the same as those of the first embodiment described above, so further detailed explanation will be omitted.

Seventh Embodiment
Next, a vibration device according to a seventh embodiment of the present invention will be described with reference to Fig. 26. In the description of the seventh embodiment, the same reference numerals are used for components that are basically the same as those in the first embodiment described above, thereby avoiding duplication of description.

In this seventh embodiment, the lower ends of the first and second elastic members 31 and 32 are attached to the midpoint of the hanging members 11 and 12.

The other configurations and advantages of the vibration device of the seventh embodiment are basically the same as those of the first embodiment described above, so further detailed explanation will be omitted.

Eighth embodiment
Next, a vibration device according to an eighth embodiment of the present invention will be described with reference to Fig. 27. In the description of this eighth embodiment, the same reference numerals are used for components that are basically the same as those in the first embodiment described above, thereby avoiding duplication of description.

In this eighth embodiment, the upper ends of the first and second elastic members 31 and 32 are attached to the lower end of a protrusion 82 that protrudes downward from the structure 81.

The other configurations and advantages of the vibration device of the eighth embodiment are basically the same as those of the first embodiment described above, so further detailed explanation will be omitted.

The present invention is not limited to the above-described embodiments. Various modifications may be made to the specific configuration of the present invention within the scope of the claims.

For example, in each of the above-mentioned embodiments, four hanging members are used as shown in FIG. 3, but two or more hanging members are sufficient. However, it is necessary that the mass body 2 can swing at least in the X and Y directions. When two hanging members are used, the first and second elastic members 31 and 32 are arranged in a vertical plane that includes any two of the hanging members.

1 Pendulum mechanism 11 to 14 First to fourth hanging members 2 Mass body 3 Elastic mechanism 31, 32 First and second elastic members 5 Virtual axis of symmetry 8 Structure 81 Structure 82 Protrusion

(Elastic mechanism)
The elastic mechanism 3 of this embodiment has first and second elastic members 31 and 32. The first and second elastic members 31 and 32 are both arranged so as to be inclined with respect to the vertical direction and to connect between the structure 81 and the mass body 2. Furthermore, the first and second elastic members 31 and 32 are both arranged in an imaginary vertical plane and are arranged so as to be symmetrical with respect to a vertical imaginary symmetry axis 5 (see FIG. 13). This imaginary vertical plane is set along the direction in which the natural frequency is to be adjusted ( the x direction in this example). As the first and second elastic members 31 and 32 in this embodiment, for example, springs and rubber can be used, but they are not limited to these, and various mechanisms having the required elastic coefficient and strength can be used.

Claims (6)

The device includes first and second suspension members, a mass body, and an elastic mechanism,
the first and second hanging members are both attached to a structure that is a vibration damping target, and are configured to suspend the mass body in a vertical direction so as to be passively swingable in response to vibration of the structure;
The elastic mechanism includes first and second elastic members,
the first and second elastic members are both arranged so as to be inclined with respect to the vertical direction, and are arranged so as to connect between the structure and the mass body, or between the structure and the first and second hanging members;
and wherein the first and second elastic members are both arranged in a vertical plane and are arranged symmetrically with respect to a vertical imaginary axis of symmetry. The pendulum type vibration damping device according to claim 1 , wherein the vertical surface is set so as to be aligned with a direction in which a frequency is to be adjusted. 3. The pendulum type vibration damping device according to claim 1, wherein the structural body is a ceiling surface of a structure, or a support body fixed to the structure and capable of supporting the first and second hanging members. The first and second hanging members are both arranged so as to be vertical in a stationary state.
3. A pendulum type vibration damping device according to claim 1 or 2. A vibration control method comprising: controlling vibration of the structure using the pendulum type vibration control device described in claim 1. The vibration damping method according to claim 5 , further comprising the step of adjusting the natural frequency of the mass body oscillating within the vertical plane by adjusting an inclination angle and/or an elastic modulus of the first and second elastic members.

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