damper

Abstract

To provide a damper with superior fatigue performance compared to arc-shaped dampers. [Solution] The damper has a straight section and arm sections, which are provided at both ends of the straight section and are attached to structural members that undergo relative displacement. The line connecting these attachment sections is parallel to the axis of the straight section, and the arm section maintains an elastic state when the straight section bends and yields due to the relative displacement occurring at the attachment sections.

Description

Technical Field

[0008] , , , , ,

[0004] ,

[0006] , , ,

[0005] , , , , ,

[0007] , ,

[0001] The present disclosure relates to a damper.

Background Art

[0002] Patent Document 1 discloses a seismic isolation device including an elastoplastic bumper made of an arc-shaped flat plate, with one end inserted between structural members that sway horizontally due to an earthquake and the other end fixed to a fixed support member.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] [[]]In an arc-shaped damper such as that of Patent Document 1, since the maximum strain occurs at substantially the same location during compression and tension, there is room for improvement in fatigue performance.

[0005] The present disclosure provides a damper having better fatigue performance than an arc-shaped damper.

Means for Solving the Problems

[0006] The damper according to the first aspect has a linear straight portion, and arms provided at both ends of the straight portion, respectively, such that a line connecting the respective attachment portions attached to the relatively displaceable structural members is parallel to the axis of the straight portion, and the straight portion maintains an elastic state when bending and yielding due to the relative displacement occurring in the attachment portions.

[0007] When the attachment portion (fulcrum) of the arm portion attached to the structural member is separated or approached due to an earthquake, a bending moment is generated at both ends of the straight portion through the arm portion.

[0008] ​Here, the line connecting the mounting points of the arm section and the material axis of the straight section are parallel. When the mounting points are displaced in the direction of approaching each other, i.e., during compression, the straight section curves outward, and the maximum strain occurs at the center of the straight section furthest from the line connecting the mounting points.

[0009] On the other hand, when the mounting portion is displaced in a direction that separates it, i.e., under tension, the straight portion curves inward, and the maximum strain occurs at the end of the straight portion furthest from the line connecting the mounting portions.

[0010] In this embodiment, since the location of the maximum strain in the damper differs between compression and tension, it exhibits superior fatigue performance compared to an arc-shaped damper where the maximum strain occurs at almost the same location during compression and tension.

[0011] Furthermore, the yield bending moment of the arm portion is greater than the yield bending moment of the straight portion, and the arm portion deforms within the elastic range, so it can maintain its function as a damper until the straight portion has absorbed sufficient energy.

[0012] The damper of the second embodiment is the damper of the first embodiment, wherein the straight portion is a first metal plate, the arm portion is a second metal plate extending parallel to the end of the first metal plate in directions perpendicular to each other, and the mounting portion is a round hole formed at the end of the second metal plate and pin-jointed to the structural member.

[0013] In this embodiment, the design of the damper becomes easier.

[0014] The damper of the third embodiment is the damper of the second embodiment, wherein the corners of the first metal plate and the second metal plate are rounded.

[0015] In this embodiment, the manufacturing of the damper becomes easier.

[0016] The damper of the fourth embodiment is the damper of the third embodiment, wherein the corner portion is the inner corner portion of the first metal plate and the second metal plate.

[0017] In this embodiment, excessive stress concentration in the inner corner can be alleviated. [Effects of the Invention]

[0018] According to this disclosure, it is possible to provide a damper with superior fatigue performance compared to an arc-shaped damper. [Brief explanation of the drawing]

[0019] [Figure 1] This is a front view showing the damper of this embodiment installed at the intersection of a column and a beam. [Figure 2] (A) is a front view of the damper in this embodiment, and (B) is a side view. [Figure 3] (A) is a conceptual diagram showing a state in which a compressive force acting on the mounting portion of the arm member in this embodiment deforms the center of the yield portion in a direction that separates it from the mounting portion, and (B) is a conceptual diagram showing the bending moment of the yield portion corresponding to the state in (A). [Figure 4] (A) is a conceptual diagram showing a state in which a tensile force acting on the mounting portion of the arm member in this embodiment deforms the center of the yield portion in a direction approaching the mounting portion, and (B) is a conceptual diagram showing the bending moment of the yield portion corresponding to the state in (A). [Figure 5] Regarding the results of the analysis of the damper in this embodiment, (A) is a diagram of the original shape showing the damper divided into multiple parts by the finite element method, and (B) is a load-displacement curve comparing compression and tension. Furthermore, regarding the results, (C) is a contour plot showing the part where the plastic strain is maximum during compression, and (D) is a contour plot showing the part where the plastic strain is maximum during tension. [Figure 6] Regarding the analysis results of the comparative example arc-shaped damper, (A) is a diagram of the original shape showing the damper divided into multiple parts by the finite element method, and (B) is a load-displacement curve comparing compression and tension. Furthermore, regarding these results, (C) is a contour plot showing the area where the plastic strain is maximum during compression, and (D) is a contour plot showing the area where the plastic strain is maximum during tension. [Figure 7]It is a front view of the first modification of the present embodiment. [Figure 8] (A) is a front view of the second modification of the present embodiment, and (B) is a front view of the third modification of the present embodiment.

Modes for Carrying Out the Invention

[0020] Hereinafter, an example of an embodiment (this embodiment) of the technology of the present disclosure will be described with reference to the drawings. The same reference numerals are given to the same components and parts in each drawing. Also, the dimensional ratios in the drawings are exaggerated for the convenience of explanation and may be different from the actual ratios.

[0021] The arrow W shown in the figure indicates the width direction of the damper, the arrow H indicates the vertical direction of the damper, and the arrow D indicates the thickness direction of the damper, respectively. The width direction, the vertical direction, and the thickness direction are orthogonal to each other. In this embodiment, the above directions are used for explanation, but the posture of the damper is not limited to these directions. Also, in FIG. 1, the vertical direction in the figure is the vertical direction, and the left-right direction in the figure is the width direction.

[0022] <Overall Configuration> As shown in FIG. 1, the building 10 of this embodiment is a structure in which a beam B extending in the horizontal direction is spanned over columns P extending in the vertical direction. The columns P and the beam B are an example of structural members. In the building 10, when an external force such as an earthquake is applied, the beam B is displaced relative to the column P with respect to the joint C between the column P and the beam B as a reference. The building 10 has dampers 20 respectively attached to the columns P and the beam B and disposed vertically below the floor S. Note that the floor S may be a slab. The damper 20 is disposed only on one side surface of the column P or the beam B.

[0023] As shown in Figure 2, the damper 20 is a U-shaped plate material having a predetermined thickness and having a plurality of mounting portions 42 formed thereon. The damper 20 is, for example, made from cut material. The damper 20 limits the amount of displacement between the column P and beam B that are displacing relative to each other. The damper 20 is an axial damper that absorbs energy from axial displacement at both ends by bending deformation of the member. The damper 20 has a yield portion 30, an arm portion 40, and a corner portion 50.

[0024] The yield portion 30 is a metal plate (first metal plate) formed in a straight line along an axis L1 extending in the width direction. The yield portion 30 is an example of a straight section. As shown in Figure 1, the yield portion 30 is positioned in the building 10 at an angle to the beam B and column P.

[0025] As shown in Figure 2(A), the arm portions 40 are provided at both ends of the yield portion 30 and have a rectangular shape in plan view. The arm portions 40 are made up of a pair of parallel metal plates (second metal plates) that extend vertically from the ends of the metal plates constituting the yield portion 30. In other words, the arm portions 40 are made up of a pair of column-side portions 40P and beam-side portions 40B.

[0026] The length of the arm portion 40 in the vertical direction, which is the longitudinal direction, is set to be approximately the same as, or shorter than, the length of the yield portion 30 in the width direction, which is the longitudinal direction. In this embodiment, the length of the second metal plate in the longitudinal direction is set to be approximately the same as, or shorter than, the length of the first metal plate in the longitudinal direction.

[0027] The arm portion 40 has a plurality of mounting portions 42. The mounting portions 42 are round holes formed at the ends of the column side portion 40P and beam side portion 40B, which are metal plates, particularly at the ends furthest from the yield portion 30, and are pin-connected to the column P and beam B. The mounting portions 42 penetrate the arm portion 40 in the thickness direction, as shown in Figure 2(B). The mounting portion 42P is located in the center in the width direction of the column side portion 40P. The mounting portion 42B is located in the center in the width direction of the beam side portion 40B. The imaginary line L2 connecting the mounting portion 42P and the mounting portion 42B is parallel to the axis L1 of the yield portion 30 at a distance d (see Figure 3). The imaginary line L2 is an example of a line.

[0028] In the arm section 40, the mounting section 42P of the column side section 40P can be connected to the column P via a pin (not shown). Also, the mounting section 42B of the beam side section 40B can be connected to the beam B via a pin (not shown).

[0029] Furthermore, the arm portion 40 maintains its elastic state when the yield portion 30 bends and yields due to a displacement in which one of the mounting portions 42 approaches or moves away from the other, that is, a relative displacement occurring between the mounting portion 42P and the mounting portion 42B. In other words, the arm portion 40 does not yield and maintains its elasticity even when a relative displacement occurs that would cause the yield portion 30 to yield.

[0030] The corner portion 50 is formed at the connection point between the yield portion 30 and the arm portion 40. In this embodiment, the corner portion 50 is formed at the connection point between the first metal plate, which is the yield portion 30, and the second metal plate, which is the arm portion 40. The corner portion 50 has an inner corner portion 52 and an outer corner portion 54.

[0031] The damper 20, as described above, is attached to the column P via the rib RP of the mounting plate TP, which is fixed to the column P by a plurality of fastening parts FP that penetrate the column P in the width direction, as shown in Figure 1. The damper 20 is also attached to the beam B via the rib RB of the mounting plate TB, which is fixed to the beam B by fastening parts FB that penetrate the beam B in the vertical direction.

[0032] <External forces acting on the damper> Next, we will explain the effect of external forces applied to the damper 20.

[0033] (In the case of compression) First, let's explain the case where the external force applied to the damper 20 is a compressive force. As shown in Figure 3(A), when an external force that brings the mounting portion 42P and the mounting portion 42B closer together in the width direction, i.e., a compressive force (two white arrows in the width direction in the figure), acts on the damper 20, the central portion of the yield portion 30 deforms in a direction that moves away from the imaginary line L2 along the vertical direction (direction of the upward-pointing white arrow in the vertical direction). In other words, the central portion deforms to be greater than the distance d compared to the case where no external force is applied. As a result, as shown in Figure 3(B), the bending moment BM acting on the yield portion 30 has a distribution that is slightly larger in the central portion compared to a uniform distribution.

[0034] (In the case of tension) Next, we will explain the case where the external force applied to the damper 20 is a tensile force. As shown in Figure 4(A), when an external force that separates the mounting portion 42P and the mounting portion 42B in the width direction, i.e., a tensile force (two white arrows in the width direction in the figure), acts on the damper 20, the central portion of the yield portion 30 deforms in a direction that approaches the imaginary line L2 along the vertical direction (direction of the white arrow pointing downward in the vertical direction). In other words, the central portion deforms so that the distance d is smaller than that when no external force is applied. As a result, as shown in Figure 4(B), the bending moment BM acting on the yield portion 30 has a distribution in which the central portion is slightly smaller than the uniform distribution.

[0035] <Effects and Effects> Next, the effects of the damper 20 of this embodiment (see Figure 5) will be explained in comparison with a comparative example, an arc-shaped damper (see Figure 6). The comparison between the two was performed by applying the same external force to the same location (the position corresponding to the mounting part) on the finite element method analysis model shown in Figures 5(A) and 6(A). The external force was applied to the positions shown in Figures 3(A) and (B) and Figures 4(A) and (B).

[0036] (Load displacement characteristics) The load displacement characteristics will now be explained. As shown in Figures 5(B) and 6(B), the load displacement characteristics differ between the compression and tension states of the damper. Specifically, the difference in load relative to displacement between compression and tension states in the damper 20 of this embodiment shown in Figure 5(B) is smaller than the difference in load relative to displacement between compression and tension states in the comparative example arc-type damper shown in Figure 6(B). In other words, the damper 20 of this embodiment exhibits almost the same behavior in compression and tension states as the comparative example arc-type damper, and can demonstrate unbiased energy absorption capacity even in asymmetrical configurations such as one-sided placement.

[0037] (Comparison of the maximum value of plastic strain and the location where it occurs) Next, we will compare the maximum value of plastic strain and the position where it occurs for the damper 20 of this embodiment and the arc-shaped damper of the comparative example.

[0038] As shown in Figure 5(C), when the damper 20 of this embodiment is compressed, the plastic strain is maximum at the circled portion in the figure (the central portion of the yield portion 30). Also, as shown in Figure 5(D), when the damper 20 of this embodiment is stretched, the plastic strain is maximum at the circled portion in the figure (the inside corner 52 of the yield portion 30 and the arm portion 40). Furthermore, the generated plastic strain is distributed almost uniformly throughout the entire yield portion 30. In other words, in the damper 20 of this embodiment, the location where the plastic strain is maximum differs between compression and stretching, and localized concentration is avoided.

[0039] On the other hand, as shown in Figure 6(C), when the comparative example's arc-shaped damper is compressed, the plastic strain is maximum at the circled area in the figure (the central part of the area corresponding to the yield point). Also, as shown in Figure 6(D), when the comparative example's arc-shaped damper is stretched, the plastic strain is maximum at the circled area in the figure (the central part of the area corresponding to the yield point). Furthermore, the plastic strain that occurs is concentrated in the center of the area corresponding to the yield point. In other words, in the comparative example's damper, the position where the plastic strain is maximum is the same whether it is compressed or stretched, and a large strain concentration occurs at that location.

[0040] Based on the above, the following configuration and effects can be obtained.

[0041] The damper 20 of this embodiment includes a linear yield portion 30 and arm portions 40 provided at both ends of the yield portion 30, respectively, and an imaginary line L2 connecting the respective mounting portions 42P and mounting portion 42B attached to the column P and beam B which are displaced relative to each other, is parallel to the axis L1 of the yield portion 30, and maintains an elastic state when the yield portion 30 bends and yields due to the relative displacement that occurs between the mounting portions 42P and 42B.

[0042] The attachment points 42P and 42B of the support arm portion 40, which are attached to the column P and beam B, separate or move closer together due to an earthquake, causing a bending moment BM to be generated at both ends of the yield portion 30 via the arm portion 40.

[0043] Here, the imaginary line L2 connecting the mounting portion 42P and the mounting portion 42B of the arm portion 40 is parallel to the axis L1, which is the material axis of the yield portion 30. In this state, when the mounting portion 42P and the mounting portion 42B are displaced in the direction of approaching each other, that is, during compression, the yield portion 30 curves outward (towards the side where the axis L1 moves away from the imaginary line L2), and the maximum strain occurs at the center of the yield portion 30 that is furthest from the imaginary line L2.

[0044] On the other hand, when the mounting portion 42P and the mounting portion 42B are displaced in a direction that separates them, that is, during tension, the yield portion 30 curves inward (towards the side where the axis L1 approaches the imaginary line L2), and the maximum strain occurs at the inner corner 52 of the yield portion 30 that is furthest from the imaginary line L2.

[0045] In this embodiment, since the location where the maximum plastic strain occurs in the damper 20 differs between compression and tension, the fatigue performance when subjected to repeated compression and tension loads is superior compared to an arc-shaped damper where the maximum plastic strain occurs at almost the same location during compression and tension.

[0046] Furthermore, the yield bending moment of the arm portion 40 is greater than the yield bending moment of the yield portion 30, and the arm portion 40 deforms within the elastic range, so it can maintain its function as a damper 20 until the yield portion 30 has absorbed sufficient energy.

[0047] Furthermore, in this embodiment, since the difference in load-displacement relationship between compression and tension is smaller compared to the arc-shaped damper in the comparative example, a one-sided arrangement can be adopted in which the damper 20 is placed on only one side of the column P or beam B.

[0048] Furthermore, in the damper 20 of this embodiment, the yield portion 30 is a first metal plate, the arm portion 40 is a second metal plate extending parallel to the end of the first metal plate in directions perpendicular to each other, and the mounting portion 42B and mounting portion 42P are round holes formed at the end of the second metal plate and pin-connected to the column P and beam B. This configuration simplifies the design of the damper 20.

[0049] <Variation> Furthermore, the present disclosure can also be constructed by partially combining the configurations illustrated in the attached drawings. As described above, this disclosure includes various embodiments not described above, and the technical scope of this disclosure is determined solely by the inventive features of the claims that are reasonable from the above description.

[0050] (First variation) As shown in Figure 7, the damper 120 according to the first modified example differs from the damper 20 of the above embodiment in the shape of the arm portion 140, the mounting portion 142, and part of the corner portion 150. However, the basic configuration (yield portion 30, axis line L1, imaginary line L2) is the same, and the explanation of the points that do not differ is omitted.

[0051] ((Arm section))

[0052] First, the shape of the arm portion 140 will be described. The arm portion 140 is provided at both ends of the yield portion 30 and has a shape that includes a straight portion and a circular portion in plan view. The length w1 in the width direction of the straight portion is, for example, 12 mm.

[0053] The circular portion is formed at the end away from the yield portion 30. The outer diameter 01 of the circular portion is, for example, φ20 mm.

[0054] A mounting portion 142, which is a round hole, is formed inside the circular part. The inner diameter i1 of the mounting portion 142 is set to φ10 mm.

[0055] In other words, in the damper 120, the circular portion protrudes more in the first direction than the straight portion. With this configuration, the arm portion 140 can be made more compact while ensuring the thickness of the outer portion of the mounting portion 142 (the difference between о1 and i1).

[0056] ((Corner section)) Next, the shape of the corner portion 150 will be described. In the first modified example, the corner portion 150 of the damper 120 has rounded edges (R) at both the inner corner portion 152 and the outer corner portion 154. For example, the inner corner portion 152 and the outer corner portion 154 are rounded to R3. This configuration makes it easier to manufacture the damper 120.

[0057] In the above modified example, the inner corner 152 and outer corner 154 are given a rounded edge (R-shape), but this is not the only option. For example, it is preferable that at least the inner corner 152 is given a rounded edge (R-shape). In this case, excessive stress concentration in the inner corner 152 can be alleviated.

[0058] (Second variation) Next, a second modified example, which is different from the first modified example, will be described. As shown in Figure 8(A), in the damper 220 according to the second modified example, the angle θ between the yield portion 230 and the arm portion 240 is greater than 90° and is set to an obtuse angle. In other words, in a plan view, the damper 220 is formed in a trapezoidal shape in which the arm portion 240 extends outward in the width direction beyond the end of the yield portion 230. As long as the imaginary line L2 and the axis line L1 are parallel to each other, it has the same function as the damper 20 of the above embodiment. With this configuration, the straight portion of the yield portion 230 can be shortened compared to the configuration in which the angle θ between the yield portion 230 and the arm portion 240 is 90°.

[0059] (Third variation) Next, a third modification, which is a different modification from the second modification, will be described. As shown in Figure 8(B), in the damper 320 according to the third modification, the angle θ between the yield portion 330 and the arm portion 340 is set to be less than 90°, and is an acute angle. In other words, in a plan view, the damper 320 is formed in a trapezoidal shape in which the arm portion 340 extends inward in the width direction from the end of the yield portion 330. In the third modification, the angle θ is set to 45°. As long as the imaginary line L2 and the axis line L1 are parallel to each other, it has the same function as the damper 20 of the above embodiment. With this configuration, compared to the configuration in which the angle θ is 90°, the column side portion 340P of the arm portion 340 follows the column P, and the beam side portion 340B of the arm portion 340 follows the beam B, so a damper 320 with less protrusion from the column P and beam B can be provided.

[0060] (Other variations, etc.) In the above embodiment, as shown in Figure 1, the damper 20 is positioned above the beam B and below the floor S, but it is not limited to this. For example, the damper 20 may be positioned below the beam B and above the floor S.

[0061] Furthermore, while the damper 20 is designed to be positioned on only one side of the column P or beam B, it is not limited to this configuration. For example, the damper 20 may be positioned on both sides of the column P or beam B.

[0062] In the damper 20 of the above embodiment, the mounting portion 42B and mounting portion 42P are round holes formed at the end of the second metal plate and pin-connected to the column P and beam B, but the damper is not limited to this. The mounting portion 42 of the damper 20 may be connected to the column P and beam B by a method other than pin connection. Furthermore, the mounting portion 42 may be a hole of a shape other than a round hole. [Explanation of Symbols]

[0063] 10 Buildings 20 dampers 30. Yielding section (an example of a straight section) 40 Arm section 42 Mounting part 50 Corner 52 Inside corner 54 Corner section 120 damper 140 Arm section 142 Mounting part 150 Corner 152 Corner section 154 Corner section 220 damper 230 Yielding section (an example of a straight section) 240 Arm section 320 damper 330 Yielding section (an example of a straight section) 340 Arm section B beam L1 axis L2 virtual line (an example of a line) P pillar S floor BM bending moment

Claims

1. A straight, linear section, An arm portion is provided at both ends of the straight portion, and the line connecting the respective mounting portions, which are attached to a structural member that undergoes relative displacement, is parallel to the axis of the straight portion, and the arm portion maintains an elastic state when the straight portion bends and yields due to the relative displacement occurring at the mounting portions, A damper having a damper.

2. The straight portion is a first metal plate, The arm portion is a second metal plate that extends parallel to the end of the first metal plate in directions perpendicular to each other. The damper according to claim 1, wherein the mounting portion is a round hole formed at the end of the second metal plate and pin-connected to the structural member.

3. The damper according to claim 2, wherein the corners of the first metal plate and the second metal plate are rounded.

4. The damper according to claim 3, wherein the corner portion is the inner corner portion of the first metal plate and the second metal plate.

Images