JPH10253004A - Aseismatic unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To relax impact force by shaping an elastoplastic bumper having one end being inserted between structural members rolling through earthquake and the other end secured to a fixed supporting member such that the deformation strain caused by a horizontal force from the structural member will be substantially uniform over the longitudinal direction. SOLUTION: An aseismatic unit 10 being fixed to a boiler has one end being inserted between structural members 12 rolling through earthquake and the other end provided with an elastoplastic bumper 16 secured to a fixed supporting member 14. The structural member 12 is a pair of load receiving arms secured to the back stay 8 of boiler and the fixed supporting member 14 is the bumper pole of the boiler. The elastoplastic bumper 16 comprises a plurality of arcuate flat plates having width being set such that the strain distribution is substantially uniform in the longitudinal direction at the time of deformation. Since the elastoplastic bumper 16 can be shaped such that the strain distribution due to a horizontal force from the structural member will be substantially uniform in the longitudinal direction, allowable strain can be increased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an earthquake-resistant device against an earthquake, and more particularly to an elasto-plastic bumper that absorbs seismic energy by elasto-plastic deformation.

[0002]

2. Description of the Related Art As a measure to reduce damage to structures due to an earthquake,
The addition of a damping device is effective. Various types of such damping devices have been put to practical use or proposed, such as a type provided at the lower end of a spherical tank, a type inserted into a brace portion of a steel structure, and a type provided between a boiler and a support structure. As a method of generating a damping force, viscosity of a fluid, hysteresis of a ductile material, friction, and the like are used.

For example, a suspended boiler largely rolls or vibrates due to a horizontal force during an earthquake, and its seismic devices are Japanese Utility Model Publication No. 57-132903 and Japanese Patent Publication No. 58-362.
No. 45 and Japanese Patent Publication No. Sho 62-33481 have already been proposed.

As shown in FIG. 7, a "sway-preventing device" disclosed in Japanese Utility Model Laid-Open No. 57-132903 has a main body 1 and a supporting steel frame 2 as shown in FIG.
The impact force generated on the steady rest 3 by the relative vibration of the above is transmitted by the frictional force generated on the surface between the backing plate 4 and the connecting portion 5 by tightening the bolts to reduce the impact force. As shown in FIG. 8, a "reinforcement device for a suspended boiler" disclosed in Japanese Patent Publication No. 58-36245 has a male stopper 6 as shown in FIG.
Alternatively, at least one of the female stoppers 7 is provided with a portion having a cross section smaller than that of the general portion, so that a plastic strain history is intentionally generated in a part of the stopper member of the boiler at the time of a large earthquake to enhance the damping effect.

Further, in Japanese Patent Publication No. Sho 62-33481, the "seismic structure of a suspended boiler" has a pair of male stoppers in which a stopper 3 is attached to a boiler frame 2 and a boiler body 1, respectively, as exemplified in FIG. 6 and a female stopper 7, the rigidity of at least one of the two stoppers is configured to be weaker so as to be plastically deformed faster than the strength member by receiving the seismic force. When a large external force is applied, the reaction force from the boiler frame 2 is reduced. At least one of the male stopper 6 and the female stopper 7 is plastically deformed earlier than both the strength members so as not to be transmitted to the main body 1, thereby preventing the boiler main body from being seriously damaged.

[0006]

Problems to be Solved by the Invention
In the anti-seismic device of No. 132903 (FIG. 7), the shock force is reduced by the frictional force of bolt tightening, so that it is difficult to accurately set a buffering force. Nevertheless, there is a problem that the stroke at the time of shock absorption is small.

Further, Japanese Patent Publication No. 58-36245 (FIG. 8)
And Japanese Patent Publication No. 62-33481 (Fig. 9),
If the rigidity of the plastic deformation portion (male stopper 6 or female stopper 7) is too small, plastic deformation occurs even with a small seismic force, and the allowable load is insufficient for a large seismic force.
If the stiffness is too large, there is a problem that the transmission force up to plastic deformation becomes excessive and the structure is damaged.

Further, in such a conventional seismic device, only a part of the device (a part of the male stopper 6 or the female stopper 7) is used for plastic deformation. In addition, since the plastically deformed portion has a welded structure, the fatigue strength due to welding is reduced, and therefore, the allowable strain must be reduced, and as a result, there has been a problem that the device is enlarged.

The present invention has been made to solve the above problems. That is, the object of the present invention is:
To provide an earthquake-resistant device capable of relaxing an impact force without yielding at a low load, having a sufficiently high allowable load against a large seismic force, and further suppressing a transmission force to a structure to an allowable load or less. It is in. Further, another object of the present invention is to provide a substantially uniform distortion of the entire deformable member, whereby a large load can be received by a small and lightweight member with little waste, and a sufficient stroke can be obtained at a large load. An object of the present invention is to provide a seismic device capable of setting a high allowable strain with a small decrease in fatigue strength.

[0010]

According to the present invention, there is provided an elasto-plastic bumper having one end inserted between structural members that roll laterally due to an earthquake and the other end fixed to a fixed support member. Has a shape set so that the deformation strain due to the horizontal force from the structural member is substantially uniform in the length direction.

According to the structure of the present invention, the strain distribution in the length direction of the elasto-plastic bumper is made uniform so that the entire deformable member can be effectively used, and the same device dimensions and the same allowable deformation can be obtained. The maximum plastic strain generated in the device can be reduced. In other words, by making the deformation strain almost uniform in the length direction, the deformation energy at the time of deformation can be received by the entire deformation member, and at low load, the impact force is reduced by the entire elastic deformation without yielding at each part at low load For large seismic force, the whole can be elastically and plastically deformed almost uniformly and receive a large load.Moreover, since the whole is deformed almost uniformly, a large stroke can be obtained. The transmission force to the structure can be suppressed to the allowable load or less. Further, since the entire deformable member deforms substantially uniformly, a large load can be received by a small and lightweight member with little waste.

According to a preferred embodiment of the present invention, the elasto-plastic bumper is composed of a plurality of arc-shaped flat plates forming an approximately 1/4 circle, and the width of the arc-shaped flat plate has a long strain distribution when deformed. It is set so as to be substantially uniform over the width direction.
With this configuration, the welded joint can be eliminated, the fatigue strength characteristics of the device can be improved, and the allowable strain can be increased.

The elasto-plastic bumper is composed of straight portions at both ends whose center lines are substantially orthogonal to each other and an arc of about 90 ° connecting the straight portions. The width of one end is narrow, the width of the other end is wide, and the space between them is smooth. Connected by simple curves. With this configuration, the horizontal force acting on one end can be smoothly transmitted as the vertical force acting on the other end, and the stress concentration portion on the member surface can be eliminated, and the fatigue strength characteristics can be improved.

The structural member is a pair of load receiving arms fixed to a back stay of the boiler, the fixed support member is a bumper column of the boiler, and the upper end of the elasto-plastic bumper has a space between the load receiving arms. And the lower end is preferably fixed to the bumper column. With this configuration, the seismic device of the boiler can be reduced in size and weight, and restrictions on the arrangement of the boiler can be reduced.

[0015]

Preferred embodiments of the present invention will be described below with reference to the drawings. In each of the drawings, common portions are denoted by the same reference numerals, and redundant description will be omitted. FIG. 1 is a perspective view of a boiler provided with the seismic device of the present invention, and FIG. 2 is a partially enlarged view of FIG. As shown in FIG. 1 and FIG. 2, an earthquake-resistant device 10 of the present invention includes an elastic-plastic bumper 16 having one end inserted between structural members 12 that roll laterally due to an earthquake and the other end fixed to a fixed support member 14. Have. In this embodiment, the structural member 12 is a pair of load receiving arms fixed to the back stay 8 of the boiler, and the fixed support member 14 is a bumper column of the boiler. That is, in this embodiment, the elastic-plastic bumper 16 has an upper end inserted with a gap between the pair of load receiving arms 12 and a lower end fixed to the bumper column 14.
With this configuration, the earthquake-resistant device can be reduced in size and weight, and restrictions on the arrangement of the boiler can be reduced.

The present invention is not limited to seismic devices for boilers, but can be applied to many other structures (for example, spherical tanks). Hereinafter, the case of a boiler earthquake-resistant device will be described for explanation.

FIG. 3 is a perspective view of an elastic-plastic bumper according to the present invention. As shown in this figure, the elastic-plastic bumper 16
It is composed of a plurality of arc-shaped flat plates 16a forming a substantially 1/4 circle. The width B of the arc-shaped flat plate 16a is set such that the strain distribution during deformation is substantially uniform in the length direction. With this configuration, the elastic-plastic bumper 16 can
The shape can be set so that the deformation strain due to the horizontal force from 2 (load receiving arm) is almost uniform in the length direction,
In addition, the fatigue strength characteristics of the device can be improved by eliminating the welded joint, and the allowable strain can be increased.

FIG. 4 is a model diagram of an elasto-plastic bumper.
In this figure, (A) shows the upper end of the arc-shaped flat plate 16a as y.
= 0, and shows a curved beam on the xy coordinate where the lower end is x = 0. (B) shows a stress distribution in the width direction of the bent beam, and (C) similarly shows a strain distribution. Hereinafter, a method of determining the shape of the arc-shaped flat plate 16a using this model will be described.

As shown in FIG. 4A, the elasto-plastic bumper 16 (that is, the arc-shaped flat plate 16a) of the present invention has linear portions ab at both ends whose center lines (in this case, neutral axes) are substantially orthogonal to each other. An arc b of approximately 90 ° connecting cd and the space between cd
c (the radius is R). With this configuration, the horizontal force acting on one end a can be smoothly transmitted as the vertical force acting on the other end d.

Assuming that the bumper member is a perfect elastic-plastic body,
In the state where plastic deformation occurs, one end in the width direction (ξ =
0) to the other end (と す る = B) is as shown in FIG. 4 (B). The bending moment M0 and the axial force F0 generated by this stress distribution are expressed by (Equation 1). Can be represented.

[0021]

(Equation 1)

FIG. 4C shows a strain distribution from one end (assuming ξ = 0) to the other end (assume ξ = B) in the width direction. Is εp, the relationship of (Equation 2) holds.

[0023]

(Equation 2)

From equations (1) and (2) of (Equation 1) and (3) of (Equation 2), b1 and b2 are eliminated and B is solved.
(Equation 3) is obtained.

[0025]

(Equation 3)

On the other hand, the axial load and bending moment due to external force can be expressed by (Equation 4). Here, tx is the x component of the tangent vector of the section center line.

[0027]

(Equation 4)

Therefore, assuming that the plastic strain ε is constant, the bumper width B can be determined from (4) in (Equation 3) using the bending moment M0 and the axial force F0.

As shown in FIGS. 3 and 4A, the arc-shaped flat plate 16a thus obtained has a narrow width B at one end (upper end in this figure) and a lower end (lower end in this figure). The part B has a wide width B and is connected by a smooth curve therebetween. With this configuration, the stress concentration portion on the member surface can be eliminated, and the fatigue strength characteristics can be improved. It should be noted that the present invention is not limited to each of the above mathematical expressions, but can be changed freely.

[0030]

EXAMPLE The elasto-plastic bumper 16 described above was compared with a conventional bumper (yield load: 30 tons, allowable displacement: 205 mm), and elasto-plastic analysis was performed by the finite element method. As the analysis conditions, the coordinates of a and b are (500, 0), (0,-).
500), and the radius R of the bc arc was 350 mm. The results will be described below.

FIG. 5 is a comparison diagram of the stress distribution of the elasto-plastic bumper, and FIG. 6 is a comparison diagram of the strain distribution of the elasto-plastic bumper. 5 and 6, (A) shows the present invention (new bumper),
(B) shows a conventional elasto-plastic bumper (current bumper). Although the shading in the figure indicates the magnitude of stress and strain, the description is omitted here. Table 1 summarizes the results of FIGS. 5 and 6.

[0032]

[Table 1]

From FIGS. 5 and 6 and Table 1, in the elasto-plastic bumper of the present invention, both the stress at yield and the strain at maximum deformation are uniformly distributed over the entire bumper.
It can be seen that it is concentrated only on the parallel part. In addition, the plastic strain at the time of the maximum deformation is concentrated near the intersection of the parallel part and the vertical part. As a result, the elasto-plastic bumper of the present invention has a yield load and a plastic strain at the time of maximum deformation which are equal to those of the conventional bumper, although the size can be reduced to about 1/2 of the conventional one.

According to the configuration of the present invention described above, by making the strain distribution in the length direction of the elasto-plastic bumper 16 uniform,
Enables effective use of the entire deformed member, equivalent device dimensions,
It is possible to reduce the plastic strain generated in the device at the same allowable deformation amount. In other words, by making the deformation strain almost uniform in the length direction, the deformation energy at the time of deformation can be received by the entire deformation member, and at low load, the impact force is reduced by the entire elastic deformation without yielding at each part at low load For large seismic force, the whole can be elastically and plastically deformed almost uniformly and receive a large load.Moreover, since the whole is deformed almost uniformly, a large stroke can be obtained. The transmission force to the structure can be suppressed to the allowable load or less. Further, since the entire deformable member deforms substantially uniformly, a large load can be received by a small and lightweight member with little waste.

It should be noted that the present invention is not limited to the above-described embodiment, but can be variously modified without departing from the gist of the present invention.

[0036]

As described above, the earthquake-resistant device of the present invention
It can reduce impact force without yielding at low load, has a sufficiently high allowable load against large seismic force,
The transmission force to the structure can be suppressed to the allowable load or less, and the entire deformed member becomes almost uniformly deformed, so that a small and lightweight member with little waste can receive a large load, and sufficient load can be applied at a large load. The stroke can be taken, and the allowable strain can be set higher with less decrease in fatigue strength.
And so on.

[Brief description of the drawings]

FIG. 1 is a perspective view of a boiler provided with the earthquake-resistant device of the present invention.

FIG. 2 is a partially enlarged view of FIG.

FIG. 3 is a perspective view of an elastic-plastic bumper according to the present invention.

FIG. 4 is a model diagram of an elastic-plastic bumper.

FIG. 5 is a comparison diagram of a stress distribution of an elastic-plastic bumper.

FIG. 6 is a comparison diagram of strain distribution of an elasto-plastic bumper.

FIG. 7 is a configuration diagram of a conventional earthquake-resistant device.

FIG. 8 is a configuration diagram of another conventional seismic device.

FIG. 9 is a configuration diagram of still another conventional earthquake-resistant device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main body (boiler main body) 2 Supporting steel frame (boiler frame) 3 Anti-sway (stopper) 4 Backing plate 5 Connecting part 6 Male stopper 7 Female stopper 8 Backstay 10 Seismic device 12 Structural member (load receiving arm) 14 Fixed support member ( Bumper column) 16 Elastic-plastic bumper 16a Arc-shaped flat plate

Continued on the front page (72) Inventor Keiji Irizawa 3-2-1-16 Toyosu, Koto-ku, Tokyo Ishikawajima Harima Heavy Industries, Ltd. Toyosu General Office

Claims (4)

[Claims] 1. An elasto-plastic bumper, one end of which is inserted between structural members rolled by an earthquake and the other end of which is fixed to a fixed support member, wherein the elasto-plastic bumper is deformed by a horizontal force from the structural member. A seismic device characterized in that the shape is set so that the strain is substantially uniform over the length direction. 2. The elasto-plastic bumper is composed of a plurality of arc-shaped flat plates forming a substantially 1/4 circle, and the width of the arc-shaped flat plate is such that the strain distribution when deformed becomes substantially uniform in the length direction. The anti-seismic device according to claim 1, wherein the seismic resistance is set as follows. 3. The elasto-plastic bumper has a straight line at both ends whose center lines are substantially perpendicular to each other, and an arc of approximately 90 ° connecting the straight lines. One end has a narrow width and the other end has a wide width. The earthquake-resistant device according to claim 2, wherein are connected by a smooth curve. 4. The structural member is a pair of load receiving arms fixed to a backstay of the boiler, the fixed support member is a bumper column of the boiler, and the upper end of the elasto-plastic bumper is between the load receiving arms. The seismic device according to any one of claims 1 to 2, wherein the lower end is fixed to the bumper column and inserted at an interval.