Vibration control device

Abstract

To provide a vibration control device capable of simultaneously controlling vibration by a plurality of vibration modes of a structure, having a low installation cost, and making an installation space small.SOLUTION: A vibration control device includes: an additional mass body 12; a support member 13 installed between a structure 11 and the additional mass body 12, and supporting the additional mass body 12 so as to make it displaceable in a horizontal direction; and a plurality of attenuation mechanisms 14, 14,...14 corresponding to the number of vibration modes of the structure 11, as the attenuation mechanism 14 which has a rotary inertia mass damper installed between the structure 11 and the additional mass body 12, and generating a rotary inertia mass by the displacement of the additional mass body 12, and a spring member extended / contracted by the displacement of the additional mass body, and restricts the displacement of the additional mass body 12. Among the plurality of attenuation mechanisms 14, 14,...14, at least one of the attenuation mechanisms 14 further has an attenuation member for attenuating the displacement of the additional mass body 12, and a natural period of the additional mass body 12 is set to be larger than a natural period of each of the vibration modes of the structure 11.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a vibration damping device, and more particularly to a vibration damping device that is mounted on a structure such as a building to reduce vibrations. [Background technology]

[0002] Tuned mass dampers (TMDs), which are added mass dampers that are connected to the building via springs or other mechanisms, are well known as response control technologies for buildings due to wind, earthquakes, etc.

[0003] However, this TMD has some problems, such as the difficulty of adjusting the natural period of the TMD because it requires adjusting springs, etc. to synchronize the natural period of the TMD with the natural period of the building; while it is an effective method for response control to steady waves (floor vibration, etc.), it is not effective for non-steady waves such as earthquake motion; and the need to adjust the TMD period as part of maintenance to prevent deterioration of the building over time (cracks in the structure, etc.).

[0004] To solve these problems, Patent Document 1 discloses a system in which the natural period of an added-mass type vibration damping device is set to 2 to 10 times the natural period of the building, thereby eliminating the need to synchronize the natural period of the added mass with the natural period of the building, thereby achieving vibration damping effects.However, this system has the problem that it cannot be expected to have much vibration damping effect unless the mass of the added mass is 10% or more of the mass of the building.

[0005] Against this background, the applicant of this application proposed a vibration control device in which the natural period of an additional mass is set to be greater than the natural period of a structure, the vibration control device comprising, as a damping mechanism connected to the additional mass, a rotational inertia mass damper that generates rotational inertia mass due to displacement of the additional mass, a spring member that expands and contracts due to displacement of the additional mass, and a damping member that damps the displacement of the additional mass (see Patent Document 2).The applicant then discovered that this vibration control device can achieve a significant vibration control effect even if the mass ratio of the additional mass to the structure is small.

[0006] When a building sways due to wind or an earthquake, the building sways in its own vibration modes, but depending on the building's height, scale, and type of structure, many buildings have multiple vibration modes, including the primary mode and those below.Of the various vibration modes, the secondary and lower vibration modes can have a large impact on the magnitude of the shaking.

[0007] Conventional TMD technology and the prior art described in Patent Document 2 are control technologies that reduce the influence of the first mode of a building's inherent vibration modes, but are unable to reduce the influence (displacement, acceleration) of building behavior caused by vibrations of the building's inherent second and lower vibration modes.

[0008] If conventional TMDs were to be used to reduce the impact of vibrations in the building's inherent second-order and lower modes, it would be necessary to install multiple individual units with adjusted added mass and rigidity so that they could control each vibration mode of the building, for each order to be controlled. This would not only increase installation costs but also require a large amount of installation space. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Publication No. 2022-107290 [Patent Document 2] Patent Application No. 2023-186137 Summary of the Invention [Problem to be solved by the invention]

[0010] The present invention has been made based on the above technical background and has the following objectives. An object of the present invention is to provide a vibration damping device that can simultaneously control vibrations due to a plurality of vibration modes of a structure, and that is inexpensive to install and requires a small installation space. [Means for solving the problem]

[0011] Unlike TMD, the prior art described in Patent Document 2 does not require the natural period of the added mass to be synchronized with the natural period of the building, but is premised on setting the natural period of the added mass to be greater than the natural period of the building. The inventors of this invention therefore discovered that, according to this prior art, a single vibration control device can be used to address multiple vibration modes of a building.

[0012] That is, the present invention provides a vibration damping device that is mounted on a structure having a plurality of vibration modes and reduces vibrations of the structure, comprising: an additional mass; a support member that is installed between the structure and the additional mass and that supports the additional mass so that the additional mass can be displaced in a horizontal direction; a damping mechanism that limits displacement of the additional mass, the damping mechanism including a rotary inertia mass damper that is installed between the structure and the additional mass and that generates a rotary inertia mass in response to displacement of the additional mass, and a spring member that expands and contracts in response to displacement of the additional mass, the damping mechanism comprising a plurality of damping mechanisms corresponding to the number of vibration modes of the structure; at least one of the plurality of damping mechanisms further includes a damping member that damps the displacement of the additional mass body; The vibration damping device is characterized in that the natural period of the additional mass body is set to be larger than the natural period of each vibration mode of the structure. [Effects of the Invention]

[0013] According to the present invention, vibrations of a structure due to a plurality of vibration modes can be controlled simultaneously, and further, the installation cost is low and the installation space is small. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a front view showing an embodiment of the present invention. [Figure 2] FIG. 2 is an enlarged front view showing the entire vibration damping device. [Figure 3]FIG. 1 is a front view showing an example of a damping mechanism incorporated in a vibration damping device. [Figure 4] FIG. 10 is a front view showing another example of a damping mechanism incorporated in a vibration damping device. DETAILED DESCRIPTION OF THE INVENTION

[0015] An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a front view showing a schematic overall view of an embodiment of the present invention. In this embodiment, a vibration damping device 10 is mounted on the top of a building 11, which is usually called the rooftop, in the same manner as a conventional TMD. The building 11 on which the vibration damping device 10 is to be installed may be made of steel, reinforced concrete, steel reinforced concrete, wood, or the like, and may be either an existing or new building. Furthermore, the structure on which the vibration damping device 10 is mounted is not limited to a building, and may be a tower-like structure, a tank structure, or other structures.

[0016] The vibration control device 10 comprises an added mass 12, a support member 13 installed on the top of the building and supporting the added mass 12 so that it can be displaced horizontally, and a damping mechanism train 30 consisting of a plurality of damping mechanisms 14, 14...14 (see Figure 2) that absorb the vibration energy of the building 11 and limit the displacement of the added mass 12.

[0017] 2 is an enlarged front view of the entire vibration damping device 10. The additional mass 12 is made of, for example, steel and has a rectangular shape with an appropriate thickness. A plurality of support members 13 that support the additional mass 12 are installed on the building 11.

[0018] In the illustrated embodiment, a sliding bearing is shown as the support member 13. This sliding bearing 13 includes a support column 15 provided on the underside of the additional mass body 12, a guide rail 16 provided on the building 11 to support the support column 15 so that it can move (slide) horizontally, and one or more spring members 31 provided between the additional mass body 12 and the building 11 to restore the additional mass body 12 that has been displaced in the horizontal direction.

[0019] This invention has been made to control vibrations of a building 11 having multiple vibration modes, and multiple damping mechanisms 14, 14, ... 14 corresponding to the multiple vibration modes are installed between the added mass 12 and the building 11. The letters "primary," "secondary," ... "jth order" attached to each damping mechanism 14 indicate that the respective damping mechanism 14 is for the "primary vibration mode," "secondary vibration mode," ... "jth order vibration mode" (j is a positive integer).

[0020] 3 is a front view showing an example of damping mechanism 14. Damping mechanism 14 includes a rotational inertia mass damper 17 that generates a rotational inertia mass in response to the displacement of added mass 12, a spring member 18 that expands and contracts in response to the displacement of added mass 12, and a damping member 19 consisting of an oil damper that damps the displacement of added mass 12. Rotational inertia mass damper 17 includes a rotary weight 20 and a rotational force transmission mechanism 21 that transmits the displacement of added mass 12 to rotary weight 20 as a rotational force. It is not necessary to provide damping member 19 in all of damping mechanisms 14, 14, ... 14; it is sufficient to incorporate damping member 19 into at least one damping mechanism. However, the more damping mechanisms that incorporate damping member 19, the better the damping performance will be.

[0021] The oscillating weight 20 is supported on a shaft so as to be rotatable horizontally relative to the building 11. The rotational force transmission mechanism 21 includes a rack 22 that is provided so as to be movable horizontally relative to the building 11, and a gear train 23 that includes a pinion that rotates in mesh with the rack 22. The rack 22 has teeth on both sides in the longitudinal direction, and therefore the gear train 23 and oscillating weight 20 are provided on both sides of the rack 22.

[0022] Displacement of additional mass 12 causes rack 22 to move horizontally, and this horizontal movement is transmitted as a rotational force to oscillating weight 20 by gear train 23. This causes oscillating weight 20 to rotate, generating a rotational inertia mass. The rotational inertia mass generated by rotational inertia mass damper 17 is calculated from the moment of inertia of each gear that makes up gear train 23, the moment of inertia of oscillating weight 20, etc.

[0023] 3 shows a gear train 23 (excluding the pinion) made up of spur gears as a component of the torque transmission mechanism 21, but a reducer can be used instead of such a gear train made up of spur gears. It is preferable to use a reducer incorporating a planetary gear mechanism using helical gears (for example, the "IB Series P2 Type" manufactured by Sumitomo Heavy Industries, Ltd.) as the reducer.

[0024] In this case, by connecting the shaft of the pinion that meshes with the rack to the output shaft of the reducer and connecting the shaft of the oscillating weight 20 to the input shaft, it is possible to increase the rotation speed of the oscillating weight 20. The helical gear used in the reducer is stronger than a spur gear, and furthermore, by using the reducer, it is possible to make the rotational force transmission mechanism 21 more compact.

[0025] 4 shows another example of the damping mechanism 14. In this example, a horizontally disposed ball screw 24 is used as the rotational force transmission mechanism 21 of the rotary inertia mass damper 17. An end of the ball screw 24 is connected to a housing 25 that is provided so as to be horizontally movable relative to the building 11.

[0026] Oscillating weight 20 is provided on the outer periphery of ball screw 24. A nut threaded onto ball screw 24 is housed in housing 26 fixed to building 11, and oscillating weight 20 is fixed to this nut. When ball screw 24 moves horizontally due to the displacement of additional mass body 12, the nut rotates, causing oscillating weight 20 to rotate, thereby generating a rotational inertial mass.

[0027] When designing a vibration damping device, the mass m of the added mass, the stiffness k of the added mass (the stiffness of the spring member 31 shown in FIG. 2), and the rotational inertia mass m d , the rotational inertia mass damper stiffness (the stiffness of the spring member 18 shown in FIGS. 3 and 4) k d , the damping coefficient of the damping member incorporated in each damping mechanism (hereinafter also referred to as additional damping) c d The calculation or determination of these items is required below.

[0028] (1) Set the mass ratio μ and calculate the mass m of the added mass The mass ratio μ is the ratio of the mass m of the added mass to the mass M of the structural material (μ=m / M), and the mass m of the added mass is calculated using this relational expression.

[0029] (2) Set the natural period T of the added mass and calculate the stiffness k of the added mass. The natural period T of the added mass is T = 2π(m / k) using the mass m and stiffness k of the added mass. 1 / 2 The stiffness k of the added mass is calculated from this relational expression. The natural period T of the added mass is set to be larger than the natural period of the structure (for example, three times the natural period of the structure).

[0030] (3) Set the DM ratio γ and the rotational inertia mass m d Calculate The DM ratio γ is the rotational inertia mass m d and the ratio of the additional mass m (γ=m d / m), and from this equation, the rotational inertia mass m d The DM ratio γ is selected from the range of 0.1 to 100 in accordance with the knowledge disclosed in Patent Document 2. The same value of γ may be set for each damping mechanism (each vibration mode), or different values ​​may be set.

[0031] (4) Rotational inertia mass damper stiffness k of the damping mechanism for the jth vibration mode d Decide In this setting method, the vibration mode mass ratio used in the optimal tuning formula and optimal damping formula for the jth vibration mode of the target structure is j gamma m can be expressed as a periodic relation as in Equation (1).

number

[0032]

number

[0033] (5) Additional damping c of the damping mechanism for the jth vibration mode d Decide Using equation (1), the optimal damping formula is expressed as equation (3).

number

[0034] According to the above embodiment, since multiple damping mechanisms corresponding to multiple vibration modes are incorporated into one vibration damping device, vibrations due to multiple vibration modes can be controlled simultaneously. Furthermore, since a vibration damping unit is not installed for each vibration mode, installation costs are low and installation space is small.

[0035] In the above embodiment, an example was shown in which the vibration damping device according to the present invention was mounted on the top of a building, but this is not limiting. The vibration damping device can also be installed on the middle floors of a building, and in this case, multiple floors may be used. Furthermore, other types of bearing members, such as spherical sliding bearings and laminated rubber bearings, can also be used. Furthermore, the number of bearing members can be either single or multiple, depending on the shape of the structure in which the vibration damping device is installed.

[0036] The damping mechanism 14 does not necessarily have to be provided for all vibration modes of the structure, but may be provided for appropriately selected modes among the vibration modes of the structure. [Explanation of symbols]

[0037] 10: Vibration control device 11: Buildings (structures) 12: Additional mass 13: Support member 14: Damping mechanism 17: Rotating inertial mass damper 18: Spring material 19: Damping member 20: Oscillating weight 21: Rotational force transmission mechanism 31: Spring member

Claims

[Claim 1] A vibration damping device mounted on a structure having a plurality of vibration modes to reduce vibration of the structure, comprising: an additional mass; a support member that is installed between the structure and the additional mass and that supports the additional mass so that the additional mass can be displaced in a horizontal direction; a damping mechanism that limits displacement of the additional mass, the damping mechanism including a rotary inertia mass damper that is installed between the structure and the additional mass and that generates a rotary inertia mass in response to displacement of the additional mass, and a spring member that expands and contracts in response to displacement of the additional mass, the damping mechanism comprising a plurality of damping mechanisms corresponding to the number of vibration modes of the structure; At least one of the plurality of damping mechanisms further includes a damping member that damps the displacement of the additional mass body, A vibration damping device, characterized in that the natural period of the additional mass is set to be greater than the natural period of the structure.

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