JPH01247666A - Damper - Google Patents

Abstract

PURPOSE:To make a damping function demonstrable all the time by installing a viscous damper, having a damping capacity against a large amplitude vibration in attaching one end to the upper part and the other end to the substructure respectively, and also an elastic damper with the damping capacity for plastic deformation against a small amplitude vibration with an elastic plastic material. CONSTITUTION:An orifice 5 is installed in a cylinder 2 filled up with a viscous fluid 14 in a viscous damper 1, and damping force is given to a horizontal vibration of a superstructure U to a substructure D by dint of viscous resistance made by movements of a piston 3 fitted free of sliding motion. In addition, the upper end of an elastic plastic damper 21 is fixed to the superstructure U, and the upper end of a lead cylindrical bar body 22 with a clearance on the upper part is fixed to the superstructure D, inserting it into a holding cylinder 23. At a small earthquake, periodic damping for the superstructure U is carried out quickly by plastic deformation in the bar body 22, and at the time of large amplitude, viscous resistance in the viscous damper 1 is made larger and thereby the periodic damping for the superstructure U is carried out. With this constitution, the superstructure can be make into a standstill.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention provides an insulation material that is interposed between a superstructure and a substructure, such as a building and its foundation, to reduce seismic energy transmitted from the substructure to the superstructure. This invention relates to a damping device used in seismic devices, etc.

<Conventional technology> As shown in Figure 3, one of the earthquake-resistant structures for buildings is
A plurality of isolators 51, 51, which are seismic isolation devices, are sandwiched between the upper structure 52 and the lower structure 53, and the upper structure 5
There is a story that supports 2. This isolator 51 has a large vertical loading capacity of rubber and a small horizontal spring stiffness due to shear deformation of the rubber. Therefore, the heavy upper structure is supported with good stability, and horizontal movement is restricted by weak springs. Supporting in this way increases the horizontal vibration period of the entire system of structures,
Make it larger than the period of the maximum energy component of the earthquake. Therefore, it is possible to reduce the response acceleration of the building to human force from the earthquake when an earthquake occurs.

However, if the upper structure 52 is supported only by the isolator 51, the following problem occurs because the horizontal spring force of the isolator 51 is small.

The first problem is that once the upper structure 52
When the vibration begins to vibrate, the amplitude of the vibration becomes larger than when the upper structure 52 is directly supported by the lower structure 53 without using the isolator 5I, and it takes time for the vibration to subside. In other words, even if physical safety is guaranteed, residents will remain in a psychologically unstable state for a long time, making it inappropriate as a seismic isolation structure for buildings.

The second problem is that when a lateral load such as a typhoon Q wind load is applied to the building, the superstructure 52 may shift in that direction, and the stability of the superstructure 52 is not guaranteed. .

In order to solve these problems, recently a damping device consisting of a viscous damper that utilizes the viscous resistance of fluid has been interposed between the upper and lower structures of buildings, and the viscous resistance absorbs vibration energy. It has been proposed to do so (for example, Utility Model Publication No. 59-41218).
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<Problems to be Solved by the Invention> By the way, in the design of the above-mentioned conventional viscous damper, the maximum possible displacement is greater than or equal to the amplitude of the largest earthquake (250 mm in terms of displacement) among the earthquakes acting on the building. design.

On the other hand, the viscous shear force F is F-η-・S F-viscous shear force S-resistance plate shear area V - relative velocity d=distance between two surfaces η = viscosity coefficient (see Figure 2), and is proportional to the relative velocity V.

However, when a building shakes due to an earthquake, the natural frequency is constant depending on the building, so the vibration velocity of a large-amplitude earthquake is greater than that of a small-amplitude earthquake. Therefore, when designing a viscous damper in response to large earthquakes, a viscous fluid with a small viscosity coefficient is used, but when such a viscous damper experiences a small-amplitude earthquake, which occurs most often, the relative velocity increases. Because it is small, a large viscous shear force cannot be obtained, i.e.
Unable to absorb the vibration energy, the building will sway for a long time. Psychologically disturbing for residents.

Therefore, the purpose of this invention is to
It is an object of the present invention to provide a damping device that can effectively absorb vibration energy and exhibit a damping function even when vibrations have a large amplitude.

<Means for Solving the Problems> In order to achieve the above object, the damping device of the present invention has one end attached to the upper structure and the other end attached to the lower structure, and a viscous damper that increases damping ability during large amplitude vibrations. and an elasto-plastic damper having one end attached to the upper structure and the other end attached to the lower structure, made of an elasto-plastic material, and having a damping ability by plastic deformation during small amplitude rocking.

<Effect> When the superstructure vibrates slightly due to a small earthquake, a viscous damper has a small relative velocity and a small viscous shear force, so it cannot absorb much energy, but an elasto-plastic damper deforms in its plastic region, so Small vibration energies are absorbed by the hysteresis effect of this elastoplastic damper. Therefore, even if a small-amplitude earthquake occurs, the vibrations of the superstructure will attenuate in an extremely short time, and the time it takes for residents to no longer feel the vibrations after an earthquake occurs is extremely shortened.

On the other hand, when the superstructure vibrates significantly due to a large earthquake, the relative velocity of the viscous damper increases and the viscous resistance increases. Vibrational energy is absorbed by this viscous resistance, and the vibration of the superstructure is quickly damped.

Note that at this time, the elastoplastic damper undergoes plastic destruction, but this poses no practical problem since earthquakes that cause such large vibrations are extremely rare.

<Example> Hereinafter, the present invention will be explained in detail with reference to illustrated embodiments.

In FIG. 1, l is a viscous damper interposed approximately horizontally between the upper structure U and the lower structure aD, and 21 is an elastoplastic damper interposed between the upper structure U and the lower structure. .

The viscous damper 1 has a piston 3 slidably fitted into the cylinder 2, and the piston 3 is provided with an orifice 5. One end of the piston rod 6 protruding left and right from the piston 3 is connected to a bracket 7 by two pins perpendicular to each other.

This bracket 7 is embedded in the upper structure U and is fixed to an anchor bolt 9 passing through a plate 8 with a nut 10. On the other hand, a clevis II fixed to the left end of the cylinder 2 is connected to the bracket 12 with a pin. This bracket 12 is fixed to an anchor bolt 14 embedded in the lower structure and passed through a plate I3 by a nut I5. Inside the cylinder 2 is a viscous fluid 14.
is filled with. Therefore, the movement of the piston 3 within the cylinder 2 causes the viscous fluid to flow through the orifice 5 from the chamber on one side of the piston 3 to the chamber on the other side, and the viscous resistance causes the horizontalization of the upper structure U relative to the lower structure. It is designed to provide braking force against vibrations. Since the magnitude of this viscous resistance is determined by the magnitude of the relative speed of the piston 3 with respect to the cylinder 2, this braking force will provide a moderately large braking force against an earthquake with a large amplitude.

On the other hand, the elastic-plastic damper 21 has a cylindrical rod body 22 made of lead.
Equipped with. The upper end of this rod 22 is inserted into a holding cylinder 23 fixed to the upper structure U with a gap left in the upper part. The holding cylinder 23 has a cylindrical portion 23a and a flange portion 23.
This flange portion 23b is attached by a nut 26 to an anchor bolt 25 that is embedded in the upper structure U and passes through a plate 24. The tip of the cylindrical portion 23a widens toward the end, making it easier to insert the rod 22. The lower part of the rod 22 is inserted into a holding cylinder 27. This holding cylinder 27 has exactly the same structure as the above-mentioned holding cylinder 23, is embedded in the lower structure, and is fixed to an anchor bolt 30 passing through a plate 29 with a nut 26. The lead rod 22 has a large plastic region and a thick diameter, so that it can withstand large external forces.

Although not shown, an isolator made by vertically stacking tonal plates such as steel plates and thin elastic plates such as natural rubber or neoprene rubber is interposed between the lower structure and the upper structure U. There is.

According to the damping device configured as described above, when an earthquake with a small amplitude occurs, almost no viscous resistance occurs because the relative speed of the piston 3 of the viscous damper l to the cylinder 2 is small, but the lead rod of the elastic-plastic damper 2 The body 22 is plastically deformed,
Vibration energy is absorbed by the hysteresis effect caused by the plastic deformation. Therefore, when a small-amplitude earthquake occurs, the hysteresis effect caused by the plastic deformation of the rod 22 of the elastic-plastic damper 21 quickly damps the vibrations of the upper structure U, and the shaking of the upper structure quickly stops. Therefore, the residents will not feel psychologically uneasy. Further, since the lead rod 22 has a large cross-sectional area and a short length, it provides a large braking force against small vibrations.

On the other hand, for earthquakes with large amplitudes, the moving speed of the piston 3 of the viscous damper 1 increases, so the viscous damper! The viscous resistance of
The vibrations are damped, and the superstructure U immediately stops. Note that in the case of this large amplitude vibration, the lead rod 22 of the elastoplastic damper 21 is destroyed because its deformability is small.

However, since such large-amplitude earthquakes occur very infrequently, there is no practical problem in making the elastic-plastic damper 21 break only when a large earthquake occurs.

In the above embodiment, vibration energy is absorbed by plastic deformation of a cylindrical lead rod as an elasto-plastic damper. However, in the elasto-plastic damper, steel is formed into a ring shape, and this ring is shaped like the edge of a propeller. In other words, the ring-shaped steel rod may be arranged in a petal-like manner so that the braking force is applied equally in all directions by plastic deformation of the ring-shaped steel rod.

<Effects of the Invention> As is clear from the above, the damping device of the present invention is made of a viscous damper that has a damping ability during large amplitude vibrations and an elastoplastic material, and has a damping ability due to plastic deformation during small amplitude vibrations. Equipped with an elastoplastic damper,
It can effectively absorb vibration energy and exhibit a damping function both in the case of small amplitude vibrations and large amplitude vibrations, and therefore, the -L section structure can be quickly brought to a standstill in both large and small earthquakes. You can do it.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a damping device according to an embodiment of the present invention, and FIG.
The figure is a diagram explaining viscous resistance, and FIG. 3 is a sectional view of a conventional seismic isolation device. 1. Viscous damper, 2. Rinder, 3.
Piston, 5... Orifice, 21... Elastoplastic damper, U... Upper structure, D... Lower structure.

Claims (1)

[Claims] (1) A viscous damper, which is attached at one end to the upper structure and the other end to the lower structure, and has a damping capacity during large amplitude vibrations; and an elasto-plastic damper that has a damping ability through plastic deformation during small amplitude swings.