JP2970476B2 - Damping device and damping method - 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 damping device and a vibration damping method, and more particularly to a structure in which a tension member such as a cable is stretched between a structure to be damped and a damper fixed to the ground. The present invention relates to a vibration damping device and a vibration damping method in which vibration of an object is transmitted to a damper via a tension member to be damped.

[0002]

2. Description of the Related Art Conventionally, as a vibration damping device of this kind, there has been known a vibration damping device disclosed in Japanese Patent Application Laid-Open No. Hei 4-176974 (E04H 9/02, E04B 1/34). This device is generally
As shown in FIG. 6, as a vibration transmitting material, between a structure 2 such as a high-rise building or a super-high-rise building or a warehouse rack constructed on the ground 1 and a damper 3 fixed to the ground 1. A tension member 4a, 4b such as a wire that transmits only a tensile force and does not transmit a compressive force is stretched over, and horizontal vibration generated in the structure 2 due to an earthquake, wind, or the like, that is, horizontal vibration of the structure 2, Thus, the vibration is transmitted to the damper 3 via the tension members 4a and 4b to be attenuated to attenuate the vibration of the structure 2. In the illustrated example, one end of a pair of tensile members 4a and 4b is connected to each of two places on both left and right ends of the top of the structure 2 where the vibration displacement is most remarkable in the primary mode vibration. The pair of tension members 4a, 4b
Are crossed diagonally downward and led to the base of the structure 2, and are wrapped around pulleys 5 a and 5 b disposed in a pair at the left and right ends of the base of the structure 2. Guided to the center of the base. On the other hand, structure 2
In the center of the base portion, a laminated rubber type damper 3 is provided, which is fixed to the ground 1 separately from the structure 2 and absorbs energy by shearing deformation. , 4b are connected to each other. When the structure 2 vibrates in the horizontal direction, one of the tension members 4a is pulled between the structure 2 and the damper 3 in response to the vibration, causing the damper 3 to shear. At this time, the other tensile member 4b is pulled between the top of the structure 2 and the damper 3 that is sheared and deformed, and the vibration of the structure 2 is transmitted to the damper 3 and attenuated by such an action. It has become.

[0003]

By the way, in the conventional vibration damping device constituted by the tension members 4a and 4b and the damper 3 as described above, the tension members 4a and 4b transmit the deformation of the structure 2. The vibration energy of the structure 2 is absorbed by a damper 3 which takes a reaction force on the ground 1 side.

[0004] However, the energy absorption efficiency of the damper 3, that is, the damping performance of the damper 3 has a unique limit as described below, and the vibration damping that can be obtained by the above-described conventional vibration damping device. The effect was small.

[0005] To explain this point, a vibration transfer function of the above-mentioned conventional vibration damping device is formulated, and a case where the damping coefficient of the damper 3 of the damping term is made infinite and a case where the damping coefficient is set to 0 are described. By trial calculation, as shown in the graph of FIG.
These vibration transfer functions f1 and f2 intersect at only one point V. Then, no matter what value the damping coefficient of the damper 3 has, any fixed point theorem that all the vibration transfer functions pass through the intersection point V is established.

[0006] Briefly describing this graph, the horizontal axis is the vibration frequency, the vertical axis is the vibration transmissibility (x / y), x is the horizontal vibration displacement of the structure 2 at the vibration measurement point, and y is the vibration displacement at the time of the earthquake. Ground motion displacement. The vibration transfer function f1 is obtained when the damping coefficient of the damper 3 is set to zero. In this case, a damper 3 for connecting the other ends of the tensile members 4a and 4b in FIG.
Does not exist, that is, a function when the structure 2 is freely vibrated. Therefore, the vibration frequency fr1 that becomes the peak p1 of the vibration transfer function f1 is the natural vibration frequency of the structure 2. On the other hand, the vibration transfer function f2 is obtained when the damping coefficient of the damper 3 is infinite. This case corresponds to the case where the other ends of the tensile members 4a and 4b are directly connected to the ground 1 in FIG. Then, as a result of directly connecting the structure 2 and the ground 1 with the tensile members 4a and 4b, the vibration transfer function f2 at this time becomes the vibration transfer function f1
Shifts to the high frequency side as it is, and reaches a peak p2 at a natural vibration frequency fr2 higher than the natural vibration frequency fr1 of the structure 2. In determining the vibration transfer functions f1 and f2, the tensile members 4a and 4b are assumed to have the same considerable elastic coefficient.

Since all the vibration transfer functions pass through the intersection V of these vibration transfer functions f 1 and f 2,
When the largest vibration damping rate can be obtained, that is, when the vibration transmissibility becomes the smallest, the result is to select a damper 3 having a damping coefficient that gives a vibration transfer function fx with this intersection V as a peak px. . This is because, even if the damper 3 having any damping coefficient is used, there is no damper 3 having a vibration transmissibility smaller than the vibration transmissibility at the intersection V. Therefore, the damper 3 that gives the vibration transfer function fx that takes the peak px at the natural vibration frequency frx is the optimum damper. According to such an optimum damper, it can be said that the best damping effect can be obtained as far as it is concerned, however, the damping effect at that time is limited.

From the above, in order to improve the vibration damping performance of the conventional vibration damping device, it is necessary to study from other viewpoints, and a method for obtaining a sufficient vibration damping effect has been devised. Was desired.

Here, the inventor of the present application has proposed a tension member 4 such as a wire used as a vibration transmitting member in the above-mentioned conventional vibration damping device.
With respect to a and 4b, if the tension members 4a and 4b have a spring property,
That is, if the tensile stiffness can be made infinite, even in the conventional device, a better vibration damping effect can be obtained, but the actual tensile members 4a and 4b have considerable spring properties. By paying attention, by eliminating the influence of the tensile members 4a and 4b acting as the elastic member,
The present inventors have found that a better damping effect can be obtained, and have completed the present invention.

That is, as shown in FIG. 6, the tensile members 4a and 4b such as wires actually exhibit properties as elastic members. Therefore, the vibration damping force transmitted from the damper 3 to the structure 2 causes a phase delay with respect to the swing of the structure 2 due to the elastic action of the tension members 4a and 4b. This is because the natural vibration frequency frx when the optimum damper represented by the vibration transfer function fx is used in the graph of FIG. 7 calculated in consideration of the realistic elastic coefficients of the tensile members 4a and 4b.
Is deviated from the natural vibration frequency fr1 of the structure 2. It is said that due to the phase delay caused by the elasticity of the tensile members 4a and 4b, a part of the damping force input from the damper 3 to the structure 2 does not contribute to vibration absorption but acts rigidly. I found a problem.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and has as its object to stretch a tension member exhibiting an elastic action between a structure and a damper fixed to the ground. An object of the present invention is to provide a vibration damping device and a vibration damping method that can improve the vibration damping effect on the premise of the vibration damping device that has been used.

[0012]

According to the vibration damping device of the present invention, a tension member such as a cable is stretched between a structure and a damper fixed to the ground, and the damper is connected to the damper through the tension member. In a vibration damping device configured to transmit damping force to the structure to attenuate the vibration, in order to correct a phase delay of damping force transmission caused by elasticity of the tension member, the tension member and the damper are used. Is provided with an additional mass body which is installed on the ground and adjusts its natural vibration frequency.

Further, the additional mass body is connected to the tensile member via amplifying means for amplifying and transmitting the behavior of the tensile member.

Further, the damper is connected to the tensile member via amplifying means for amplifying and transmitting the behavior of the tensile member.

On the other hand, in the vibration damping method according to the present invention, a tension member such as a cable is stretched between a structure and a damper fixed to the ground, and the damping force of the damper is reduced via the tension member. In a vibration damping method for transmitting vibrations to a structure to attenuate the vibration, an additional mass body installed on the ground to adjust a natural vibration frequency of the vibration system formed by the tension member and the damper is provided. Is provided to correct the phase delay of the damping force transmission caused by the elasticity of the tensile member by the additional mass body.

Further, the additional mass body is connected to the tension member via an amplifying means, so that the behavior of the tension member is amplified and transmitted.

Further, the damper is connected to the tension member via amplifying means, so that the behavior of the tension member is amplified and transmitted.

The operation of the apparatus and method of the present invention will be described. An additional mass body for adjusting a natural vibration frequency is provided in a vibration system including a damper for attenuating vibration of a structure and a tensile member. In practice, the additional mass can correct for the phase lag that occurs when the damping force from the damper is transmitted to the structure due to the considerable elasticity of the tensile material. That is, by providing the additional mass body in the vibration system including the damper and the tension member, the natural vibration frequency can be made to match the natural vibration frequency of the structure itself, and the vibration of the structure is most remarkable. At the peak of the vibration transfer function, the damping force of the damper can be transmitted to the structure without phase delay, and an excellent vibration damping effect can be obtained.

Further, since the additional mass body is connected to the tensile member via the amplifying means for amplifying and transmitting the behavior of the additional mass body, the mechanical effect of the additional mass body can be amplified.
A large natural vibration frequency adjusting ability can be obtained with an additional mass having a small mass.

Since the damper is connected to the tensile member via amplifying means for amplifying and transmitting the behavior of the damper, the damping effect of the damper can be amplified. A large vibration damping effect can be obtained.

[0021]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 shows a schematic configuration of a vibration damping device according to the present invention. The device configuration is almost the same as the above-described conventional example, and includes a structure 12 such as a high-rise / super-high-rise building or a warehouse rack constructed on the ground 11,
As a vibration transmission material, tension members 14a and 14b such as cables that transmit only a tensile force and do not transmit a compressive force are stretched between a damper 13 fixedly provided on the ground 11 and an earthquake or wind. The horizontal vibration generated in the structure 12 by the vibration, that is, the horizontal vibration of the structure 12 is transmitted to the damper 13 via the tension members 14a and 14b which are pulled by the vibration, thereby damping the vibration of the structure 12. Have been.

In this embodiment as well, one end of a pair of tension members 14a and 14b is connected to each of the two right and left ends of the top of the structure where the vibration displacement is most remarkable in the vibration of the first mode. The pair of tension members 14a, 14
b is crossed diagonally downward and led to the base of the structure 12, and is wrapped around the pulleys 15 provided at the left and right ends of the base of the structure 12, respectively.
Guided to the center of the base.

On the other hand, a hydraulic cylinder type damper 13 is horizontally provided at the base of the structure 12 separately from the structure 12 and fixed to the ground 11. This damper 13
The cylinder 13a is connected to the ground 11, and has a general structure that absorbs energy by generating a pressure loss in the flow of hydraulic oil accompanying the reciprocating operation of the piston rod 13b.

The damper 13 fixed to the ground 11 and the tension member 14 stretched from the structure 12
a and 14b, an additional mass body 17 for adjusting the natural vibration frequency of the vibration system 16 is provided.
Is provided. Specifically, the additional mass body 17 is
1 is supported by a roller 18 slidably rolling on the running surface 11 a, and is movably provided at the center of the base of the structure 12, and its mass is supported by the ground 11. And this additional mass body 17 has a
The other ends of the pair of tension members 14a and 14b guided horizontally are connected to each other, and the tension members 14a and 14b are connected to each other.
The cylinder rod 13b of the damper 13 arranged horizontally in parallel with the cylinder b is connected.

When the structure 12 vibrates in the horizontal direction, one of the tension members 14a is pulled between the damper 13 and the additional mass body 17 while traveling on the ground 11 in response to the vibration. 13 piston rod 13b
To generate a flow in the hydraulic oil of the damper 13.
At this time, the other tensile member 14b is pulled between the top of the structure 12 and the additional mass body 17 traveling and moving. Such an action occurs alternately in the pair of tension members 14a and 14b in response to the vibration of the structure 12, and the pulling force drives the additional mass body 17 and drives the damper 13 to operate the structure. Twelve vibrations are attenuated.

The model of the conventional apparatus shown in FIG.
(A)) and a model of the device of the present invention (FIG. 2 (b)). Here, m is the mass of the structures 2 and 12 itself, k is the elasticity of the structures 2 and 12 itself, and c is the structures 2 and 1
2 itself. In the conventional device, the damper 3 is connected to the structure 2
It is installed on the ground 1 side of the base in a stationary state, and the reaction force of the damping force generated by the damper 3 can be applied to the ground 1, so that the damping force of the damper 3 can be effectively applied to the structure 2. Can be. If the elastic modulus of the tensile members 4a and 4b is extremely large, and if the damping force from the damper 3 can be transmitted to the structure 2 without a phase delay according to the deformation speed of the structure 2, a large vibration damping effect can be expected. However, in reality,
Since the tensile members 4a and 4b have the property of a spring, the damping force transmitted from the damper 3 to the structure 2 is less than that of the structure 2.
The phase is delayed with respect to the deformation speed.

According to the present invention, an additional mass body 17 is provided in a vibration system 16 composed of tension members 14a and 14b for damping the structure 12 and a damper 13. At 17, the natural vibration frequency of the vibration system 16 is adjusted, and by adjusting the natural vibration frequency, the phase delay of the damping force of the damper 13 transmitted to the structure 12 is corrected. By providing the additional mass body 17 in the vibration system 16 including the damper 13 and the tensile members 14a and 14b, the natural vibration frequency can be made to match the natural vibration frequency of the structure 12 itself, and The damping force of the damper 13 can be transmitted to the structure 12 with no phase delay at the peak of the vibration transfer function at which the swing of the vibration 12 is most remarkable, and an excellent vibration damping effect can be obtained.

As a similar technique for such phase adjustment, a so-called TMD method as shown by a model in FIG. 2C is known. This TMD method uses the structure 2
Is connected to an additional mass body 21 mounted on the structure 2 via a spring 20 so that the additional mass body 21 responds to the vibration of the structure 2. The inertial force generated by the vibration
The damping force of the damper 19 acts on the structure 2 to control the vibration. Then, the natural vibration frequency of the vibration system 22 including the damper 19, the spring 20, and the additional mass body 21 mounted on the structure 2 is made to coincide with the natural vibration frequency of the structure 2. The vibration damping effect is obtained at the peak of the vibration transfer function of No. 2. At this time, the natural vibration frequency of the vibration system 22 is adjusted by appropriately setting the mass of the additional mass body 21, and this plays a role of the additional mass body 21.

In the TMD method, the damper 19 is mounted on the structure 2.
The additional mass body 21 is employed from the viewpoint of how to obtain a reaction force for the function of the damper 19 installed in the vehicle. Is to utilize the inertial force of the additional mass body 21 vibrating with the vibration of the damper 19 as a reaction force of the damping force of the damper 19. Therefore, in the TMD method, it is essential that the entire vibration system 22 for attenuating the vibration of the structure 2 be mounted on the structure 2, and otherwise, the vibration damping effect is obtained. Can not. Therefore, the additional mass body 21 is necessarily mounted on the structure 2. As described above, the TMD method has a function of adjusting the natural vibration frequency of the vibration system 22 as a function of the additional mass body 21, but is inherently always mounted on the vibrating structure 2, and the inertial force of the vibration system 22 is reduced by the damper 19. Function is required.

On the other hand, in the vibration damping device of the present invention, the damper 13 is installed on the ground 11 and the reaction force of the damping force is applied to the ground 1.
Since the configuration is assumed to be 1, the vibration system is completely different from the vibration system 22 configured by the TMD method from the vibration equation. Therefore, the concept of the additional mass body 21 in the TMD method cannot be introduced as it is. And the additional mass body 1
7 is required to be configured so as to exhibit only the natural vibration frequency adjusting function of the vibration system 16, and therefore, the TMD utilizing the inertial force of the additional mass body 17 generated by the seismic motion.
Contrary to the law, the inertial force of the additional mass 17
2 must not be affected.

According to this aspect, according to the present invention, the additional mass body 17 is arranged on the ground 11 as described above. Specifically, the mass of the additional mass body 17 is supported on the ground 11 via the roller 18,
In addition, the ground motion at the time of the earthquake is insulated by the support of the runnable rollers 18 so that no inertial force is generated in the additional mass body 17. And in this invention comprised in this way, the additional mass body 17 is not
Since it is installed on the ground 11, there is no need to mount an additional mass body that becomes a dead load as a structure as in the TMD method, so that the additional mass body 17 increases the burden on the structure 12. No structure 12
The vibration damping device can be installed with good equipment efficiency without impairing its own functionality.

Further, in the present invention, since the additional mass body 17 is installed on the ground 11 and the mass thereof is supported by the ground 11, specifically, the additional mass body 17 is attached to the ground 11.
Since the upper running surface 11a is supported by the roller 18 via the roller 18, the mass of the additional mass body 17 does not act as the initial tension on the tension members 14a and 14b of the vibration system 16, so that the damper 13 and the tension member The design and setting of 14a and 14b can be easily performed with a high degree of freedom.

Further, in the TMD method, the vibration of the structure 2 is attenuated by the damping force of the damper 19, but a large reaction force is required to secure this damping force. For this reason, the additional mass body 2 that obtains the reaction force of the damping force of the damper 19
1 is required to generate a large inertial force, and therefore requires a large mass, for example, about 10% of the mass of the structure 2. On the other hand, in the present invention,
Since the ground 11 bears the reaction force of the damper 13, the mass of the additional mass body 17 may be set to a mass necessary for adjusting the natural vibration frequency of the vibration system 16. Can also be facilitated.

A further preferred embodiment of the installation of the additional mass body 17 will be described with reference to FIG.
The purpose of using the additional mass body 17 in the present invention is as follows.
In order to eliminate the influence of the phase delay caused by the elasticity of the a and b, the vibration system 16 composed of the damper 13 and the tensile members 14a and 14b is formed by the additional mass body 17.
The purpose of the present invention is to adjust the natural vibration frequency of the vibration system 16 so as to resonate at the natural vibration frequency and exhibit an effective vibration damping ability. Therefore, as long as the effect can be obtained, the mass of the additional mass body 17 actually used may be small, and the smaller mass is preferable in terms of equipment. In the following embodiments, a configuration is shown in which the same effect as when an apparently large mass is used can be ensured while having a small mass.

As shown in FIG. 3, in this embodiment, amplifying means for amplifying and transmitting the behavior of the tensile members 14a, 14b is provided between the tensile members 14a, 14b and the additional mass body 17, specifically, Is provided with a lever 23 for increasing the moving speed of the tension members 14a and 14b for transmission. As shown in the drawing, a lever 23 has a support shaft 24 serving as a fulcrum thereof fixed to the ground 11, the other end of a pair of tension members 14a, 14b connected to the end of a short portion 23a, and the long portion 2
An additional mass body 17 is provided at an end of 3b. Then, the piston rod 1 of the damper 13 is
3b are connected. Therefore, even in this embodiment, the mass of the additional mass body 17 is supported by the ground 11 via the support shaft 24 of the lever 23, and the inertial force of the additional mass body 17 generated in the ground motion direction during an earthquake is also reduced by this support shaft. 24, the structure 12 is configured such that its inertial force is not transmitted to the structure 12, and only the damping force of the damper 13 can be transmitted to the structure 12.

In the configuration shown in FIG. 1, the additional mass body 17 is directly connected to the tension members 14a and 14b.
It is necessary to set 7 to a considerably large mass. On the other hand, as shown in FIG. 3, if the lever 23 is provided between the tension members 14a and 14b and the additional mass body 17, the tension members 14a and 14b
The movement of 14 b can be doubled and transmitted to the additional mass body 17. Considering the kinetic energy, the mass and the speed of the motion have a squared motion speed. From this, by increasing the movement speed of the additional mass body 17 with respect to the movement speed of the tension members 14a and 14b by the lever ratio of the lever 23, as a mechanical effect, the direct tension member 14
The weight of the additional mass body 17 can be reduced in comparison with the use of the mass obtained by multiplying the square of the leverage by comparison with the additional mass body 17 connected to a and 14b. In other words, similar effects can be obtained by using the additional mass body 17 having a mass ratio of one-square of the leverage ratio as compared to the additional mass body 17 directly connected to the tensile members 14a and 14b. A large natural vibration frequency adjusting ability can be obtained with the additional mass body 17 having a small mass.

Further, since the damper 13 is connected to the additional mass body 17 connected to the lever 23, the movement of the tension members 14a and 14b is amplified and transmitted to the damper. Can be amplified, and a large vibration damping effect can be obtained by using the damper 13 having a small capacity.

In the configuration shown in FIG. 3, one elongated portion 23b is formed on one side from the support shaft 24, and one additional mass body 17 is provided at the end thereof. Another long portion may be formed on the opposite side of the long portion 23b, and another additional mass body may be additionally provided at the end. With such a configuration, a lighter one can be used as each additional mass body 17.

FIG. 4 shows an apparatus configuration constructed by further pushing this concept. As shown, in this embodiment, a support shaft 24 of the lever 23 is rotatably supported on the ground 11 and has a rotation shaft 25 having a considerable outer diameter.
A plurality of arms 26 are provided on the rotating shaft 25 so as to extend radially outward in a point-symmetrical manner with respect to the rotating shaft 25, and additional mass bodies 17 are provided at the respective ends of the arms 26. I have. The piston rods 13b of the plurality of dampers 13 fixed to the ground 11 are connected to any of the additional mass bodies 17, respectively. Further, tension members 14a and 14b are wound around the rotating shaft 25. When the tension members 14a and 14b are pulled in the left-right direction, the rotation shaft 25 is rotated at a considerable swing rotation angle,
Thus, the additional mass body 17 is swung through the arm 26. Also in the present embodiment, the ratio between the rotation radius of the rotation shaft 25 around which the tension members 14a and 14b are wound and the rotation radius of the arm 26 corresponds to the leverage ratio described above. Tensile members 14a, 14b
The effect of using the mass obtained by multiplying the square of the radius of gyration by amplifying the motion of the additional mass body 17 with respect to the movement of the motor can be obtained, and a large natural vibration frequency adjusting ability can be obtained with the small additional mass body 17. Can be. Further, if configured as shown in the drawing, the plurality of additional mass bodies 17 can be arranged collectively around the rotation shaft 25, and each of the additional mass bodies 17 can be further reduced in weight. In addition, facility work can be facilitated. Also in this embodiment, the damper 1 is attached to the additional mass 17 connected to the arm 26.
3, the large vibration damping effect can be obtained by using the damper 13 having a small capacity.

In the following, the vibration equation and its optimum value in the case of FIG. 4 will be described. Tensile members 14a, 14
The radius of the rotation shaft 25 around which b is wound is r ₀ , and the radius of rotation of the additional mass body 17 swung about this is r
_m, the radius of rotation of the mounting position of the damper 13 and r _d. If the mass of the structure is m, the elastic modulus in the horizontal direction is k, and the elastic modulus of the tensile member is k ₀ , the kinetic energy T, potential energy V, and damping energy R of this system
Is represented by the following equation.

[0041]

(Equation 1) Here, m ₀ is the mass of the additional mass body 17 and c ₀ is the damper 1
3, .theta. Is the rotation angle of the rotating shaft 25, .PHI.
4a and 14b are inclination angles with respect to a horizontal plane. X is the horizontal vibration displacement of the structure 12, and y is the ground motion displacement at the time of the earthquake.

Here, Lagrange (Lag
When the equation of (range) is established, the vibration equation of this system is expressed as follows.

[0043]

(Equation 2) Where M ₀ = m ₀ α _m2 , C ₀ = c ₀ α _d2 , z = r
_{0 θ, g = cosΦ, α} m = r m / r 0, α d = r d /
r ₀ .

As can be seen from M ₀ and C ₀ , the rotation axis 25
The radius r _m of the mounting position of the additional mass body 17 and the damper 13 to the radius r _0, by setting larger the ratio of r _d, apparent mass and damping coefficient, radius ratio alpha _m,
It can be seen that there is an amplification effect proportional to the square of α _d .

Here, the mass m _{0 of the} additional mass body 17 used.
It is considered that the optimum value of the damping coefficient c ₀ of the damper 13 can be derived by a method similar to Hartog's general TMD method.
If the vibration transfer function (x / y) for the ground motion of the structure obtained from the above vibration equation is F (ω), this vibration transfer function F (ω) is the transfer function F when the damper is infinite.
(Ω) C0 = ∞ and transfer function F without damper
The fixed point theorem that two intersections where (ω) C0 = 0 intersects regardless of the size of the damper is established. The mass ratio μ (M ₀₎ that equalizes the height of the transmissivity at the two intersections
/ M) is the optimum mass ratio, and when solved under this condition, this mass ratio μ is expressed by the following equation.

[0046]

(Equation 3) Here, μ = M ₀ / m and β = k ₀ / k.

Next, regarding the optimum damper, the frequency ωp at the intersection shown below is obtained from the condition that the vibration transfer function F (ω) takes an extreme value of the amplitude at each of the two intersections.
, Ωq

(Equation 4) Thus, the optimum attenuation coefficient C ₀ is determined so that
The ωp and ωq are obtained by the following equations.

[0048]

(Equation 5) However, unlike the case of the Hartog-type TMD method, C ₀ obtained from Expression (2) cannot be simply represented in the form of a function. Here, the solution of equation (2), using the optimal value derived so far as numbers were the formula (1) as determined by solving the simplified equation for an unknown only C _0. The resulting optimal damping coefficient C ₀ is
Equation for the damping constant h ₀ used in the general TMD method of

(Equation 6) Using,

(Equation 7) Was sought. Therefore, by using the additional mass body 17 and the damper 13 that satisfy the equations (1) and (3), the phase of the damping force transmitted by the tensile members 14a and 14b can be corrected, and the structure can be optimally damped. 12 can be acted upon.

In the conventional vibration damping device, no additional mass body for adjusting the natural vibration frequency is used, so that only the damper is examined. In this case, as described with reference to FIG. Single intersection point V where the transfer function f2 in the case and the transfer function f1 without the damper intersect
Is optimal, and the damping coefficient C _{0 of the} damper is

(Equation 8) Given by At this time, the damping constant h as a structural system
Is

(Equation 9) Becomes

In both the conventional apparatus and the apparatus of the present invention, as the ratio β of the elastic modulus k ₀ of the tensile member to the elastic coefficient k of the structure increases, and as the inclination angle Φ of the tensile member decreases, It is possible to obtain a large damping constant,
Here, when the inclination angle of the tensile member is set to 60 °, the damping constant of the apparatus of the present invention is about 10% (the maximum vibration transfer function is 5%).
When the elastic modulus ratio β is obtained, β = 0.33.
When this elastic modulus ratio β is applied to a conventional device, its damping constant is as very small as 2%.

On the other hand, a trial calculation of an actual case will be made below the vibration equation and the optimum value. In the conventional apparatus, the vibration transmissibility (x / y) at the one intersection is obtained by 1 / (2h) = ω1 / (ω2−ω1). Here, ω1 is the natural vibration frequency of the structure 2 itself, which is (k / m) ^1/2 . Ω2 is the natural vibration frequency when the damper 3 is infinite,
{(K + k ₀ · cos ² θ) / m} ^1/2 .

Here, in the conventional apparatus shown in FIG. 6, a wire having a diameter of 10 cm is used as a tensile material for a structure having a square projection of 50 m on a side, a height of 127 m, an effective weight of 42,000 tons, and a period of 3 seconds. The damping constant h obtained when the optimal damper is used is 1 / (2h) = 50 and h = 1%, as is clear from the graph of FIG.
The degree and effect were small.

On the other hand, in the case of FIG.
The damping constant h obtained when 9% and α _m = 4 are used and the optimal damper is used is 1 / (2h) = 7, as is clear from the graph of FIG. A large vibration damping effect of about h = 7% was obtained.

The device of the present invention described above may be individually installed in accordance with each vibration mode, such as for the primary mode or the secondary mode of vibration.

[0055]

As described above, according to the vibration damping device and the vibration damping method according to the present invention, the damping force from the damper is actually applied to the structure due to the considerable elastic action of the tensile member. Phase delays that occur during transmission can be corrected with this additional mass. By providing the additional mass body to the vibration system including the damper and the tension member, the natural vibration frequency can be made to match the natural vibration frequency of the structure itself, and the vibration of the structure is most remarkable. At the peak of the vibration transfer function, the damping force of the damper can be transmitted to the structure without phase delay, and an excellent vibration damping effect can be obtained.

Further, since the additional mass body is installed not on the structure but on the ground, it is necessary to obtain a good vibration damping effect, but the structure has a dead load. Such an additional mass does not increase the load on the structure at all, and therefore, the vibration damping device can be installed with good equipment efficiency without impairing the functionality of the structure itself.

Further, since the additional mass body is installed on the ground and the mass is supported on the ground, the mass of the additional mass body does not act as the initial tension on the tension member of the vibration system. Can be easily designed and set with a high degree of freedom.

Further, since the ground responds to the reaction force of the damper, the mass of the additional mass body may be set to a mass necessary for adjusting the natural vibration frequency of the vibration system. The facility work can also be facilitated.

Further, since the additional mass body is connected to the tensile member via the amplifying means for amplifying and transmitting the behavior of the additional mass body, the mechanical effect of the additional mass body can be amplified.
A large natural vibration frequency adjusting ability can be obtained with an additional mass having a small mass.

Since the damper is connected to the tensile member via the amplifying means for amplifying and transmitting the behavior of the damper, the damping function of the damper can be amplified. A large vibration damping effect can be obtained.

[Brief description of the drawings]

FIG. 1 is a side view showing a schematic configuration of a vibration damping device according to a preferred embodiment of the present invention.

FIG. 2 is a schematic diagram showing a model for comparing configurations of a vibration damping device according to the present invention, a conventional vibration damping device, and a vibration damping device according to a TMD method.

FIG. 3 is an enlarged side view of a main part showing a modification of the attachment structure of the additional mass body in the embodiment of FIG. 1;

FIG. 4 is a side view showing a schematic configuration of another embodiment of the present invention.

FIG. 5 is a graph comparing the performance of the vibration damping device according to the present invention with that of a conventional vibration damping device.

FIG. 6 is a schematic side view showing a conventional vibration damping device.

FIG. 7 is a graph for explaining a limit of energy absorption efficiency of a damper.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 11 Ground 12 Structure 13 Damper 14a, 14b Tensile material 16 Vibration system 17 Additional mass body 23 Lever 25 Rotation axis 26 Arm

Claims (6)

(57) [Claims] A tension member such as a cable is stretched between a structure and a damper fixed to the ground, and the damping force of the damper is transmitted to the structure via the tension member to reduce the vibration. In the vibration damping device configured to attenuate, in order to correct a phase delay of the damping force transmission caused by the elasticity of the tensile member, the vibration system including the tensile member and the damper is installed on the ground. A vibration damping device comprising an additional mass body for adjusting the natural vibration frequency of the vibration damper. 2. The vibration damping device according to claim 1, wherein the additional mass body is connected to the tension member via amplifying means for amplifying and transmitting the behavior of the additional mass member. 3. The vibration damping device according to claim 1, wherein the damper is connected to the tension member via amplifying means for amplifying and transmitting the behavior of the damper. 4. A tension member such as a cable is stretched between a structure and a damper fixed to the ground, and the damping force of the damper is transmitted to the structure via the tension member to reduce the vibration. In the vibration damping method configured to attenuate, in a vibration system configured by the tension member and the damper, an additional mass body that is installed on the ground and adjusts its natural vibration frequency is provided. A vibration damping method, wherein a phase delay of damping force transmission caused by the elasticity of the tensile member is corrected. 5. The control system according to claim 4, wherein said additional mass body is connected to said tension member via an amplification means so as to amplify and transmit the behavior of said tension member. Shaking method. 6. The control according to claim 4, wherein the damper is connected to the tension member via an amplification means so as to amplify and transmit the behavior of the tension member. Shaking method.