JPH0762353B2 - Vibration control device - 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 for reducing the vibration of a foundation of a seismic resistant experimental apparatus in which a large vibration table is installed via a dynamic damper and a foundation in which a vibration source including other equipment is installed.

[0002]

2. Description of the Related Art FIG. 5 is a diagram for explaining the outline of a conventional seismic resistance test apparatus.

In chemical plants, nuclear power plants, etc., it is required to design a seismic structure that can withstand a large earthquake and is sufficiently reliable. Especially in an earthquake-prone country such as Japan, it is necessary and indispensable to verify the quality of seismic design when constructing and installing these.

Conventionally, for example, as shown in FIG. 5, for example, as shown in FIG. 5, a vibrating table 41 having a size of 15 m × 15 m has been used to elucidate the destruction mechanism of a large structure due to vibration and to confirm the response property of a structure having a longer period. A large-scale seismic test device with is used. In such a large-sized device, the dynamic damper 42 is provided between the base 43 and the base 43, but since the vibration is still transmitted to the 1 km square,
Causes environmental problems around.

Therefore, in order to solve the above-mentioned problems, conventionally, a dynamic damper is constructed by placing a soft spring such as a vibration-isolating rubber between the double foundations, and the surroundings sway even if the inner foundation sways. The structure that does not exist is adopted.

[0006]

However, since the characteristics of the conventional dynamic damper are fixed by the spring and the viscous damper, when the vibration frequency changes, for example, in the range of 1 Hz to 50 Hz, the vibration is reduced. There is a problem that the vibration suppressing effect cannot be sufficiently exerted depending on the frequency.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a vibration damping device which can more effectively use a dynamic damper in the vibration frequency range of a large vibration table. It is a thing.

[0008]

To this end, the present invention provides a control for reducing the vibration of a foundation of a seismic resistant experimental apparatus having a large vibration table installed via a dynamic damper and a foundation having a vibration source composed of other equipment. As a vibration damper, a continuously variable dynamic damper consisting of a constant constant variable spring part, a mass part, and a mass support part was attached to the foundation as a vibration suppressor, and the spring constant was adjusted according to the vibration frequency of the vibration source. ,
It is characterized in that it is configured so as to suppress free vibration of the mass portion after the vibration source is stopped, and the spring portion is a hydraulic cylinder.

[0009]

In the vibration damping device of the present invention, since the characteristic continuously variable dynamic damper consisting of the constant constant variable spring portion, the mass portion, and the mass support portion is attached to the foundation as a vibration damper, the constant of the spring portion is applied to the vibration source. The vibration suppression effect can be enhanced by adjusting according to the vibration frequency, and free vibration of the mass part is suppressed after the vibration source is stopped, so it is possible to reliably suppress vibration after the vibration source is stopped. it can. Further, by using the hydraulic cylinder as the spring portion, a great effect can be obtained with a simple configuration.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing one embodiment of a vibration damping device of the present invention, and FIG. 2 is a diagram for explaining a spring portion as a model. In the figure,
Reference numerals 1 and 1'denominate a spring portion, 2 a mass portion, 3 a mass support portion, 4 a device mounting base portion, 5 a vibrating table, 6 a dynamic damper, 7 a housing, and 8 a foundation.

In FIG. 1 (a), the spring portion 1 uses a hydraulic cylinder, and is attached between the device attachment base portion 4 and the mass portion 2 by a case and a piston rod. The mass part (mass) 2 is made of concrete or an iron ingot, and the mass support part 3 supports the mass part 2 on the device mounting base part 4, and is a rail system, a tire system, a roller system, a roller. A bearing system, a static pressure bearing system, an air spring system, a link support system, or the like, which has a degree of freedom of movement by being supported by a link, static pressure, or air, is adopted. It goes without saying that the device mounting base 4 is integrated with the base 8, and the device mounting base 4 may be omitted and the spring portion 1 may be directly mounted on the base 8. The foundation 8 is to install the large vibration table 5 via the dynamic damper 6. FIG. 2B shows an example in which the spring portion 1 as described above is constituted by an air spring instead of the hydraulic cylinder.

A model of a spring portion using a hydraulic cylinder is shown in FIG. 2 (a). C ₁ and C ₂ are hydraulic cylinder chambers, V ₁₀ is an oil reservoir volume on the C ₁ side, and V ₂₀ is C ₂ Where A is the cross-sectional area of the piston, P ₁ is the pressure of C ₁ , P ₂ is the pressure of C ₂ and β is the bulk modulus of the oil, the spring coefficient k is k = βA ² [ (1 / (x ₁ A + V ₁₀ )) + (1 / (x ₂ A + V ₂₀ ))] Therefore, the spring coefficient k is βA ² [(1 / V ₁₀ ) + by moving the piston position in the hydraulic cylinder. (1 / ((x ₁ + x ₂ ) A + V ₂₀ )] to βA ² [(1 / a) + (1 / b)] where a = (x ₁ + x ₂ ) (A / 2) + V ₁₀ b = ( _{x 1 + x 2) (a} / 2) to + V ₂₀ can be changed continuously. the present invention, control dynamic damper Wotsu using this property Is shall.

In this case, if the mass of the mass part is m _d ,
Natural frequency ω ₀ of the damping machine becomes ω ₀ = k / m _d. When the transition to x _d, the _{m d x d / A = P} 1 -P 2. The pressure given by this formula is applied to the hydraulic cylinder by the movement of the vibration damper.

A model of a spring portion using an air spring is shown in FIG.
(B) is an example of an n-stage bellows type. x is the displacement from the standard height, P ₀ is the absolute internal pressure at the standard height,
D ₀ is the effective diameter at the standard height, A ₀ is the effective pressure receiving area at the standard height, V _SO is the internal volume of the bellows at the standard height, V _t is the internal volume of the auxiliary tank, P _a is the atmospheric pressure, P
Is the load, and V ₀ = V _SO + V _t , the load P when x is bent is P = A ₀ [(P ₀ / Ha ^r ) −P _a ] [1+ (π / n) (1 / ni ) (x / D ₀ )] However, Ha = 1− (A ₀ / V ₀ ) x, d = 1 + (π / 2) φ ₀ Differentiating the above equation with respect to x gives the spring constant k of the air spring. .

K = r (A ₀ ² / V ₀ ) (P ₀ / ha ^{r + 1} ) × [1+ (π / n) (1 / d) (x / D ₀ )] + A ₀ [(P ₀ / C ^r ) −P _a ] × (π / n) (1 / d) (1 / D ₀ ) x → 0, k = r (A ₀ ² / V ₀ ) P ₀ + (P ₀ −P _a ) (A ₀ / D ₀ ) (π / n) (1 / d). In this way, the air spring can continuously change the spring constant by increasing or decreasing the absolute internal pressure.

The present invention uses the continuously variable dynamic damper having the constant constant variable spring portion, the mass portion, and the mass support portion as the vibration damper, and the hydraulic cylinder or the air spring as the spring portion. Is.

FIG. 3 is an overall configuration diagram of a large-scale seismic resistance test apparatus equipped with the vibration damping device of the present invention, and FIG. 4 is a diagram for explaining an operation procedure and its effect.

In FIG. 3, the constant continuously variable spring 15 is
As described above, the hydraulic cylinders and the air springs are adopted, which have the smallest damping in order to increase the vibration absorbing ability of the vibration damping device, and the number of units is increased or decreased as necessary. The spring constant control mechanism 13 includes a servo valve, a piston displacement meter, a servo amplifier, and a feedback amplifier in the hydraulic cylinder, and a pressure regulating valve and a servo control system in the air spring. The spring constant adjusting mechanism power source 12 is
It consists of a hydraulic source (hydraulic pump) or an air source (compressor). For the mass support portion 14 of the vibration damper, as described above, a rail system, a tire system, a roller system, a roller bearing system, a static pressure bearing system, an air spring system, a link support system, or the like is adopted. The brake 16 has a mass section 25.
Is used to forcibly stop the vibration of the spring-mass system of the vibration damper after the large vibration table 19 has stopped. The brake operating mechanism 17 is composed of an orifice control valve or a brake operating actuator, and these control units. Control device 11 including a control computer
Is a vibrating table excitation signal of the vibrating table control unit 18, a vibrating table response signal of the vibrating sensor 21 attached to the vibrating table 19, a basic response signal of the vibrating sensor 22 attached to the vibrating table foundation 24, and a mass section 25. The vibration sensor vibration signal from the vibration sensor 23 is input, a spring constant control command and a brake control command are generated, and the spring constant control mechanism 13 and the brake actuation mechanism 17 are controlled.

As described above, the vibration damping device of the present invention is such that the constant constant variable spring is used and the characteristic of the dynamic damper is changed by remote control. The control unit 11 including a computer or the like adjusts the dynamic damper so that the dynamic damper is most effective in accordance with the vibration frequency of the large vibration table 19. If free vibration of the dynamic damper continues after the vibration of the large vibration table 19 is stopped, the dynamic damper will shake the vibration table foundation 24. Therefore, the large vibration table 24 for suppressing this free vibration is generated.
The brake or damper of the dynamic damper is activated by the vibration stop command signal (vibration table vibration signal) of.

In the vibration damping device of the present invention, the control device adjusts the characteristics of the vibration damping device in accordance with the operation of the vibrating table which is the vibration source, so that the vibration damping device can maximize its performance. This point is different from the existing dynamic damper. The effect of the vibration damping device of the present invention is improved as the damping of the vibration damping device is made smaller by the spring (hydraulic pressure or air spring) and the mass support portion with small damping.

The operation procedure of the vibration damping device of the present invention is shown in FIG.
First, when the input signal of the vibration table is set as shown in (a), the vibration damper spring constant is calculated and the vibration damper spring is set. Then, the vibration of the vibrating table is started. When the vibration of the vibration table is stopped, the brake of the vibration damper is activated and the vibration damper is stopped.

When tuning is performed, FIG.
The dotted route of is added. That is, the effect of the vibration damper is determined, and the setting of the vibration table input signal, the setting of the vibration damper spring, and the start of vibration of the vibration table are repeatedly performed until the result becomes OK.

If the brakes do not work, FIG.
As shown in (b), the dynamic damper remains in operation () even when the vibrating table stops operating, so the vibration of the foundation increases after the vibrating table stops operating, but if the brake functions, it will vibrate. The vibration of the dynamic damper is rapidly attenuated at the same time when the operation of the platform is stopped, and the vibration control state of the foundation is maintained.

The present invention is not limited to the above embodiment, but various modifications can be made. For example, for the spring portion, an air spring and a hydraulic cylinder may be combined. Air springs are effective at relatively low frequencies,
The hydraulic cylinder is effective for obtaining the resonance characteristic of high frequency, and it is necessary to lengthen the stroke to obtain the characteristic of low frequency. In addition, for a random wave input, a plurality of vibration dampers having different characteristics may be installed and the continuously variable spring constant of each vibration damper may be set so as to absorb the predominant vibration. Furthermore, although it was explained as a vibration control device that reduces the vibration of the foundation of the seismic resistance test equipment with a large vibration table installed, it becomes a vibration source mounted on vehicles, ships, and aircraft, such as the mounting frame and base of the engine etc. It is needless to say that the same can be applied to the (foundation), the foundation of the factory in which the device such as the machine / processing machine is installed, and other similar foundations as a vibration damping device for reducing the vibration. Nor.

[0025]

As described above, according to the present invention,
As a vibration damper, a characteristic continuously variable dynamic damper consisting of a constant constant variable spring part, a mass part, and a mass support part is attached to the foundation, so the constant of the spring part can be adjusted according to the vibration frequency, and large vibration It is possible to reduce the vibration of the foundation on which the table is installed and also reduce the pollution vibration generated in the peripheral foundation. Moreover, since the vibration damper of the present invention may be attached to the foundation, it can be easily applied to existing seismic resistance test equipment, and can be realized by a hydraulic cylinder or the like, so that it can be realized with a simple configuration and low cost. In particular, a sufficient effect can be expected in the frequency band of 3 Hz or more, which is frequently used in shaking table experiments, and increases as the mass of the vibration damper increases and the damping decreases. For example, if = 0.01 (1% attenuation) is obtained, 600 ton on both sides
The basic vibration can be reduced to 1/4 or less with the mass of the vibration suppressor.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of a vibration damping device of the present invention.

FIG. 2 is a diagram for explaining a spring part as a model.

FIG. 3 is an overall configuration diagram of a large-scale seismic resistance test apparatus including the vibration damping device of the present invention.

FIG. 4 is a diagram for explaining an operation procedure and its effect.

FIG. 5 is a diagram for explaining the outline of a conventional seismic resistance test apparatus.

[Explanation of symbols]

1 and 1 '... Spring part, 2 ... Mass part, 3 ... Mass support part, 4 ...
Device mounting base, 5 ... Shaking table, 6 ... Dynamic damper, 7 ... Housing, 8 ... Foundation

Claims (3)

[Claims] 1. A vibration damping device for reducing the vibration of a foundation in which a vibration source is installed via a dynamic damper, wherein the vibration damping device is a continuously variable characteristic consisting of a constant constant variable spring part, a mass part, and a mass support part. A vibration damping device characterized in that a dynamic damper is attached to the foundation, the spring constant is adjusted according to the vibration frequency of the vibration source, and free vibration of the mass part is suppressed after vibration of the vibration source is stopped. . 2. The vibration damping device according to claim 1, wherein the vibration of the foundation of the seismic resistant experimental apparatus equipped with a large vibration table as a vibration source is reduced. 3. The vibration damping device according to claim 1, wherein the spring portion is a hydraulic cylinder.