JP2621731B2 - Damping structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration control structure for passively reducing vibration of a structure during an earthquake or the like.

[0002]

At present, a vibration damping method for passively reducing the vibration of a structure during an earthquake or the like is currently used to insulate the structure from the ground with a spring bearing, and at the same time to reduce the spring constant of the bearing and damping of the damper. The seismic isolation method that avoids resonance with the disturbance of the structure by adjusting the vibration, and the vibrating body (mass) that resonates with the disturbance is added to the structure to generate vibration in the vibrating body, thereby consuming the energy of the structure In addition to the method of damping the vibration with a damper, there is a method of installing a damper in an appropriate place in a structure and absorbing energy to the damper by using relative displacement such as interlayer displacement during vibration. In the damping method, where the absorption of energy depends only on the damper to reduce the vibration of the structure, the displacement generated between the layers is transmitted to the damper and the energy is absorbed by the damper. Is Damper since it is necessary to attenuate the absorption of energy between units installed in each layer, have resulted to be used a number.

[0003] The present invention has been made in view of the actual situation of the method of damping by the above-described damper, and aims to newly propose a structure for reducing the number of used dampers.

[0004]

According to the present invention, only the intermediate layer (including a plurality of continuous intermediate layers) in a structure composed of a plurality of layers has a relative level between the lower floor and the upper floor sandwiching the intermediate layer. A damper that generates damping force when displaced is installed, and the entire structure is made up of a lower floor and an upper floor in which the intermediate layer and the damper are connected between the lower floor and the upper floor due to the presence of the damper of only the intermediate floor. The vibrations of the lower and upper floors are made independent by dividing them into mass points, and at the same time, the natural frequencies of both the upper and lower floors are matched or approached, and the number of dampers is reduced by making the structure itself a dynamic vibration absorber. Effectively reduce the vibration of the structure.

[0005] The damper is installed only in the middle layer, and the damping is added thereto, so that the whole structure is roughly divided into two mass points of a lower floor and an upper floor where mass is concentrated above and below the middle layer. As a result, the structure in which the lower floor and the upper floor are connected via the intermediate layer and the damper is modeled as a two-mass vibration system in which the upper mass is connected to the lower mass by a spring and a dashpot, and both masses are connected. The horizontal stiffness of the middle layer, which is the spring constant of the spring to be adjusted, and the weight of the upper floor, which is the mass of the upper mass point, are adjusted according to the horizontal stiffness and weight of the lower floor, which corresponds to the spring connected to the ground and the lower mass point. The structure itself functions as a dynamic vibration absorber that attenuates vibration while consuming energy at the upper mass point by setting the natural frequency of the upper floor to a constant ratio to the natural frequency of the lower floor However, the vibration of the structure is effectively reduced by the damper having only the intermediate layer.

A dynamic vibration absorber in a structure is composed of a structure of a main vibration system and a mass of a vibration absorber system which is added to the top and connected to the structure by a spring and a damper. The vibration of the mass is attenuated by the damper while consuming the vibration energy transferred from the structure by causing the mass to resonate at the time of the vibration of the structure by being set to or near the frequency of the structure. However, in the structure of the present invention in which the damper is installed only in the middle layer, the lower floor is a main vibration system, the upper floor is a vibration absorber system, and the middle layer together with the damper connects the main vibration system and the vibration absorber system. It has the same vibration system as the dynamic vibration absorber by having both functions of damping and vibration.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings showing one embodiment.

[0008] Seismic structure (including a plurality of successive intermediate layer) The intermediate layer of the structure B composed of a plurality of layers as shown in FIG. 1 b ₂ only, the lower layer sandwiching the intermediate layer b ₂ of the present invention the damping force damper D placed occurring during the relative horizontal displacement between the floors b ₁ and the upper floors b _3, the intermediate layer b ₂ and the damper during the whole structure B, the lower floor b ₁ and the upper floors b ₃ D is connected, divided into two mass consisting of lower floors b ₁ and the upper floors b _3, and at the same time produce independently the vibration of the lower floor b ₁ and the upper floors b _3, upper floor b ₃ and the lower floor b _By adjusting both natural frequencies of ₁ so as to have a certain ratio, the structure B itself behaves as a dynamic vibration absorber, thereby
Is to reduce vibration.

[0009] As described above, if the damper D is disposed only in the intermediate layer b ₂ of the multilayer, the whole structure B shown in FIG. 1, as shown schematically in FIG. 2, the intermediate layer b ₂ Lower floor sandwiched
b ₁ and the upper floor b ₃ are divided into two mass points, the lower floor b ₁ is a spring having a spring constant k ₁ between the mass of the mass m ₁ and the ground, the upper floor b ₃ is a mass of the mass m ₃ , Further the spring of spring constant k ₂ of the intermediate layer b ₂ is connected to both mass points m _1, m _3, the damper D is replaced each dashpot damping coefficient c _2, structure B constitutes a two-mass vibration system .

[0010] The two-mass system model shown in FIG. 2 are identical to the vibration model of the dynamic vibration reducer that additional mass on top of the structure is installed, the intermediate layer b ₂ This vibration system is equivalent to the spring constant k ₂
The horizontal stiffness and mass m ₃ of the upper floor b ₃
k ₁ is adjusted in accordance with the horizontal stiffness and the weight of the lower floor b ₁ corresponding to the mass m _1, the upper floors b ₃ and the lower floor b both natural frequency of ₁ (angular frequency) is properly adjusted Accordingly, the structure B itself functions as a dynamic vibration absorber.

In the dynamic vibration absorber, the respective natural angular frequencies of the main vibration system and the vibration absorber system are determined by the spring constant and mass of each system. In the present invention, the lower floor b ₁ (m ₁ of mass point) and the upper floor Each natural angular frequency ω ₁ and ω ₃ of the floor b ₃ (m ₃ mass point) is ω ₁ =
(K ₁ / m ₁ ) ^1/2 , ω ₃ = (k ₂ / m ₃ ) ^1/2 , so the weight (m ₁ ), horizontal stiffness (k ₁ ), and upper layer of the lower floor b ₁ both natural angular frequency omega _1, omega ₃ ratio ω ₁ / ω ₃ is adjusted by the floor b ₃ weight (m ₃₎ and horizontal stiffness of the intermediate layer b ₂ (k ₂₎ is properly adjusted .

[0012] By natural angular frequency ratio of the lower floor b ₁ and the upper floors b ₃ are adjusted, the structure B has the higher floors b ₃ vibrates in accordance with the same vibration Lower floor b ₁ and dynamic vibration absorber while consuming vibration energy to be input to the lower floors b ₁ by resonating with lower floor b _1, a structure for attenuating the vibration by the damper D.

The damping ratio h of the vibration damper system in the dynamic vibration damper is determined by the ratio of its mass to the mass of the main vibration system (mass ratio μ) (damping ratio h = [3μ / 8 (1 + μ)] ^1/2 ). Normally, the mass is designed so that the mass of the additional mass does not affect the weight of the structure, that is, the mass ratio μ is in the range of about 1% to 10%. the weight of the upper floors b ₃ of B itself from be utilized as the mass of the vibration absorber system, the mass ratio _{(μ = m 3 / m 1} ) is greater, also rises attenuation factor.

[0014] The damper D is the intermediate layer b _2, and between the upper floors b ₃ side of the skeleton and the lower floor b ₁ side of the skeleton, such as a portion of the brace assembled axially so as to be relatively displaceable, upper floors b ₃ and lower floor b ₁
It is installed in a certain plane at the time of relative horizontal displacement between them, or at a place where relative displacement occurs in one direction.

[0015] The damper D when the vibration of the upper floors b _3, i.e. may be a form damping vibrations in operation at the time of relative horizontal displacement with respect to the lower floor b ₁ of the upper floors b _3, a damper D to be used in the present invention Does not matter in any form.

[0016]

According to the present invention, a damper which generates a damping force when a relative horizontal displacement between a lower story and an upper story sandwiching the intermediate story is provided only in the middle story of the plurality of structures, and the whole structure is constructed as a lower story. The upper and lower floors are connected to an intermediate layer and a damper. The lower floor and the upper floor are divided into two mass points to separate the vibration of the lower and upper floors, and at the same time, the upper floor with respect to the natural frequency of the lower floor. The lower floor is the main vibration system, the upper floor is the vibration absorber, and the middle layer including the damper connects the main vibration system and the vibration absorber system. The structure itself functions as a damper with the spring, and the structure itself forms the same vibration system as the dynamic vibration absorber.As a result, the structure vibrates while consuming vibration energy by the same mechanism as the dynamic vibration absorber by the damper of the intermediate layer only. And the use of a small number of dampers Effectively it is possible to reduce the vibration of the structure.

In particular, since the vibration absorber system is different from the additional mass and is on the upper floor which is a part of the structure, the mass ratio to the main vibration system is large, and the vibration reduction effect is also large.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing an outline of a structure according to the present invention.

FIG. 2 is a model diagram in which FIG. 1 is replaced with a vibration system.

[Explanation of symbols]

B ...... structure, D ...... damper, b ₁ ...... lower floor, b ₂ ...... intermediate layer, b ₃ ...... upper floors.

Claims (1)

(57) [Claims] An attenuator is formed only in an intermediate layer in a structure having a plurality of layers or in a plurality of continuous intermediate layers at the time of relative horizontal displacement between a lower layer and an upper layer sandwiching the intermediate layer or the plurality of intermediate layers. A damper that generates force is installed, and the whole structure is divided into two masses consisting of a lower floor and an upper floor, in which an intermediate layer or a plurality of intermediate layers and dampers are connected between a lower floor and an upper floor. The vibration of the lower floor and the upper floor are made independent, and the weight and horizontal rigidity of the lower floor, and the weight of the upper floor and the horizontal rigidity of the middle floor are adjusted, and the natural frequency of the upper floor is constant with respect to the natural frequency of the lower floor. Damping structure set to have the following ratio.