JPH0715227B2 - Elastic-plastic damper - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an elasto-plastic damper that yields by an axial force to be plasticized and absorbs vibration energy input to a structure.

[0002]

2. Description of the Related Art A conventional elasto-plastic damper is a bending yielding method in which a bending moment is applied to a steel material by an external force so that the bending yields, and vibration energy is absorbed by hysteresis energy during the plastic deformation. Although the mold is generally used, the bending-yield elasto-plastic damper still has the following problems.

When a steel material is yielded by bending stress and a restoring force characteristic as a damper is modeled and analyzed into a bilinear type or a trilinear type, the restoring force characteristic on the analytical model and the restoring force characteristic of the full-scale damper are It is difficult to match them, and in order to match them, high precision is required for processing and manufacturing the damper.

Further, the scale of this bending yield type elasto-plastic damper cannot be said to be compact in comparison with its characteristic value, that is, the energy absorption capacity, so if the required energy absorption capacity is retained, In many cases, it becomes difficult to install the damper inside the frame of a building or a work structure due to the large scale.

Further, in order for the member for supporting or fixing the damper to resist the deformation due to the moment of the fixed end of the damper without causing deformation, it is necessary to make its size larger than that of other general members of the frame. As a result, even if the optimum damper characteristic value can be determined in response analysis, the support member cannot follow the scale of the damper at the actual design stage, making it impossible to apply. There is.

By the way, in order to yield and plasticize a steel material as an elasto-plastic damper, theoretically, in addition to the above bending stress method, there is a shear stress method, a torsion stress method, or an axial stress method. Conceivable.

Among these, in the method of yielding by shear stress or torsional stress, the steel material yields at a relatively low stress level, so if a large force is to be applied, the size of the damper becomes large, and Is difficult to install and is not suitable.

When yielding with bending stress, the yielding time can be delayed to a relatively high stress level,
Since the cross section does not always yield uniformly in the initial stage of yielding, the efficiency of energy absorption does not increase so much and a certain scale is required.

However, in the case of axial stress, it yields at a level higher than shear stress and torsional stress, and the stress tends to be uniform over the entire cross section. Can be small. in addition,
A higher equivalent spring value (rigidity) as a damper, which affects the yield stress, is preferable, but when yielding due to axial stress, the value can be increased by shortening the shaft length, and the member dimensions can be reduced. It is reasonable to do so.

As described above, the damper of the mechanism that yields and plasticizes by axial stress is advantageous in terms of member size, but stress-
There is a disadvantage in that the deformation characteristics are not the same for positive and negative applied forces, that is, the tensile axial force and the compression axial force, and the hysteresis characteristic is not stable. This is because an unstable phenomenon due to buckling is caused particularly in the region of compressive force, and the instability when the compressive force is applied is an obstacle to use as a damper.

The present invention has been made in view of the background of such an elasto-plastic damper, and theoretically has the highest efficiency of energy absorption, overcomes the above-mentioned problems of the type of yielding due to axial stress, and overcomes the conventional bending problem. We are going to propose a new elasto-plastic damper to replace the yield type.

[0012]

According to the present invention, a steel rod that receives an axial force is inserted into a cylindrical outer shell material, and the outer shell material that surrounds the steel rod extends in a direction perpendicular to the axis of the steel rod. By restraining the deformation to, the buckling in the range of compressive force is prevented and the hysteresis characteristics are stabilized, and a stable plastic deformation capacity is imparted to the steel bar under both positive and negative axial forces, The availability as a damper will be brought out, and the production of an elasto-plastic damper utilizing axial stress will be realized.

The steel rod is inserted into the outer shell material with a clearance, and the clearance causes the steel rod and the outer shell material to be structurally separated, and the axial force received by the steel rod is transmitted to the outer shell material. However, the outer shell material only serves to prevent deformation of the steel rod in the direction perpendicular to the axis.

In addition, the clearance between the steel rod and the outer shell material is filled with an insulating material that cuts the friction between them and enhances the insulating effect.

The steel rod is constrained by the outer shell material, particularly against deformation in the direction perpendicular to the axis when a compressive force is applied, so that the steel bar yields only by the axial force applied to its both ends and yields by bending stress. Similar to the type, the vibration energy input to the structure is absorbed by the elastic-plastic hysteresis energy.

[0016]

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

Elasto-plastic damper (hereinafter damper) A of the present invention
Is a steel rod 1 that bears an axial force as shown in FIGS.
And an outer shell material 2 that surrounds the steel rod 1 and restrains the steel rod 1 against deformation in a direction perpendicular to its axis. The steel rod 1 yields by repeated positive and negative axial stress, The vibration energy of the structure is absorbed by the hysteresis energy during plastic deformation.

As shown in FIG. 2, the outer shell member 2 has a cylindrical shape which is continuous in one direction and has an insertion hole 2a having the same sectional shape as that of the steel rod 1 and FIG. As shown in FIG. 4, the area of the insertion hole 2a is slightly larger than the sectional area of the steel rod 1, and the steel rod 1 is inserted into the insertion hole 2a with a clearance.
The steel rod 1 includes a reinforcing bar, and its sectional shape is not limited to a circular shape.

Only the steel rod 1 bears the axial force acting on the damper A when the steel rod 1 and the outer shell member 2 are separated from each other by this clearance, and the outer shell member 2 receives a compressive force on the steel rod 1. At this time, it restrains the deformation in the direction perpendicular to the axis and prevents the occurrence of buckling.

The outer shell material 2 is made of steel material such as steel pipe, casting, concrete, mortar, etc., and reinforced concrete such as reinforced concrete or fiber concrete, and has sufficient strength to prevent buckling of the steel rod 1. Produced.

The clearance is filled with an insulating material 3 if necessary in order to enhance the insulation state between the steel rod 1 and the outer shell material 2.

The insulating material 3 acts to cut the friction between the peripheral surface of the steel rod 1 and the inner peripheral surface of the insertion hole 2a of the outer shell member 2, and transmits the axial force as an external force only to the steel rod 1. It has the effect of causing the outer shell material 2 to perform only the function of preventing the deformation of the steel rod 1. A lubricant such as grease is used for the insulating material 3.

As shown in FIG. 5, the damper A is shown in FIGS.
Is installed across the structural members S, S or between the non-structural members that cause relative displacement mainly in the opposite direction, such as between the structures as shown in FIG. Axial force is applied during relative displacement between both members.

When the structural member S is a reinforced concrete structure, the damper A has, for example, anchors 4, 4 and the like connected to both ends of the steel rod 1, and the structural members such as slabs, beams or columns as shown in FIG. It is installed by being embedded and fixed in S, S, etc.

If the expected or predominant relative displacement between the structural members S, S, etc. on which the damper A is laid across is only one specific direction, the axis of the steel rod 1 is directed in that direction. As shown in FIG. 8, when the relative displacement occurs in only one direction, or in two horizontal directions, they are arranged in two directions as shown in FIG.

By the way, as shown in FIG.
When 4 is fixedly connected to the steel rods 1, 1, when a relative displacement between the structural members S, S, etc. other than the axial direction of the steel rod 1 occurs, a bending moment or The shearing force acts and the axial stress is not borne purely, and the combined stress of the two causes a hindrance to the characteristics of the steel rod 1 in the plastic region, but in order to avoid the action of these forces. The details of this are shown in FIG.

During the relative displacement between the structural members S, S, etc. in the axial direction of the steel rod 1 and the other directions, that is, in the case of horizontal and vertical three-dimensional relative displacement, the axial force is applied to the steel rod 1. The steel rod 1 and the anchor 4 may be connected by a universal joint in order to act only on them. Specifically, in the embodiment, FIGS.
As shown in Fig. 2, both ends 1a, 1a of the steel rod 1 are processed into spherical surfaces, and at the same time, the support member 5 on which the anchor 4 is projected is divided into two parts, and the end portion 1a of the steel rod 1 is fitted to the inner peripheral surface thereof. A spherical seat is formed, and the end portion 1a is sandwiched by the two support members 5 and 5, so that the steel rod 1 is rotatably supported in any direction with respect to the anchor 4.

The supporting members 5 and 5 sandwich the end portion 1a of the steel rod 1 in a pair, and bolts 6 are fastened at several points to integrally connect them to the steel rod 1. The anchor 4 is connected to each support member 5.

With this support structure, the steel rod 1 functions with respect to the absolute displacement between the both ends 1a, 1a at the time of arbitrary relative displacement in three dimensions.

In this manufacturing example, the damper A is installed by embedding the anchor 4 or the supporting member 5 in the structural member S made of reinforced concrete.

As described above, the damper A is installed by fixing the anchor 4 inside the structural member S when the structural member S is made of reinforced concrete, but when the structural member S is made of steel frame or steel frame reinforced concrete, the support members 5 and 5 are installed. It can also be installed by directly connecting to steel beams or columns with bolts or welding.

[0032]

The present invention is as described above, and an outer shell material is arranged around a steel rod that is easily destabilized when receiving a compressive force, and this outer shell material is used to move in a direction perpendicular to the axis of the steel rod. Since it constrains the deformation of the material, it overcomes the problem of buckling, which has been a hindrance to practical use in the past, and as a result, it is possible to increase the yield stress especially in the region of compressive force and restore force characteristics. Therefore, it is possible to realize an elasto-plastic damper that yields with axial stress and that has a theoretically high energy absorption efficiency.

[Brief description of drawings]

FIG. 1 is a perspective view showing a basic manufacturing example of the present invention.

2 is a cross-sectional view in the axial direction of FIG.

FIG. 3 is a perspective view showing another example of manufacturing an elasto-plastic damper.

4 is a sectional view in the axial direction of FIG.

FIG. 5 is a cross-sectional view showing an attached state of an elasto-plastic damper.

FIG. 6 is an elevational view showing an example of installation of an elasto-plastic damper on a structure.

FIG. 7 is an elevational view showing another installation example of the elasto-plastic damper.

FIG. 8 is a plan view showing an arrangement example of elasto-plastic dampers.

FIG. 9 is a plan view showing another arrangement example of the elastic-plastic damper.

FIG. 10 is a partially sectional elevational view showing a detailed production example of an elasto-plastic damper.

11 is a side view of FIG. 10.

FIG. 12 is a plan view of FIG.

[Explanation of symbols]

A ... Elasto-plastic damper, 1 ... Steel rod, 2 ... Outer shell material, 3 ...
... Insulating material, 4 ... Anchor, 5 ... Support member, 6 ... Bolt, S ... Structural member.

Claims (2)

[Claims] 1. A steel rod for bearing an axial force, and a cylindrical outer shell material that surrounds the outer circumference of the steel rod and restrains deformation in a direction perpendicular to the axis thereof. The steel rod is an outer shell. It is inserted with a clearance inside the material and structurally separated from the outer shell material, and the steel rod yields due to the axial force and elastically deforms to absorb energy. An elasto-plastic damper that does. 2. The elasto-plastic damper according to claim 1, wherein the clearance between the steel rod and the outer shell material is filled with an insulating material for separating the two.