JP2018040479A - Energy absorbing device and base isolation structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably absorb energy for an input load.SOLUTION: An energy absorbing device 10 absorbs energy by an input of a load in a horizontal direction while no vertical load is born. This energy absorbing device 10 comprises a cylindrical body 24 whose vertical direction is an axial direction, which is formed to have a symmetrically annular shape about a first horizontal direction H1 and a second horizontal direction H2 which are orthogonal to each other when viewed from a vertical direction, and in which a size in the first horizontal direction H1 is set to be larger than a size in the second horizontal direction H2. On one of a pair of opposed parts opposed to each other in the second horizontal direction H2 in the cylindrical body 24, a first connection part 32 to which a first member is connected, is provided. On the other of the pair of opposed parts opposed to each other in the second horizontal direction H2 in the cylindrical body 24, a second connection part 34 to which a second member is connected, is provided. Then the second connection part 34 is displaced in a horizontal direction relatively to the first connection part 32, so that plastic deformation is generated in the cylindrical body 24.SELECTED DRAWING: Figure 1A

Description

  The present invention relates to an energy absorbing device and a seismic isolation structure.

  In Patent Document 1 and Patent Document 2 below, a vibration damper that can absorb energy due to an earthquake or the like input to a building by plastic deformation of an annularly formed leaf spring or shock absorbing member. And the seismic isolation structure is disclosed.

JP 2004-183903 A JP 9-49346 A

By the way, in the damping damper which bent the leaf | plate spring described in the cited reference 1 circularly, the leaf | plate spring formed cyclically | annularly in the state which supported the load of the building, ie, the state into which the load to the up-down direction was input, It is deformed in the horizontal direction. Therefore, it is difficult to stabilize the load required for plastic deformation of the annularly formed leaf spring.
Moreover, in the seismic isolation structure described in the cited document 2, it arrange | positions in the state in which the axial direction of the impact-absorbing member formed circularly was orient | assigned to the horizontal direction of the building. Therefore, it is possible to effectively absorb the impact caused by the load acting in the vertical direction of the building. On the other hand, this shock absorbing member is difficult to deform in the axial direction. For this reason, the impact absorbing member has a problem in that the performance varies depending on the direction of absorption of the impact due to the load acting in the horizontal direction.

  In view of the above facts, an object of the present invention is to provide an energy absorbing device and a seismic isolation structure that can stably absorb energy with respect to an input load.

  The energy absorption device according to claim 1 is an energy absorption device that absorbs energy by being plastically deformed partly by a load in a horizontal direction without bearing a load in the vertical direction, the vertical direction being an axial direction The first direction and the second direction orthogonal to each other as viewed from above and below form a symmetrical ring, and the dimension in the first direction is set larger than the dimension in the second direction. A tubular body, a first connecting portion provided in one of a pair of opposed portions facing the second direction in the tubular body, to which a first member is connected, and in the second direction in the tubular body; A second connecting portion that is provided on the other of the pair of opposing portions, is connected to the second member, and causes plastic deformation of the cylindrical body due to relative displacement in the horizontal direction with respect to the first connecting portion. .

  According to the energy absorbing device of claim 1, when the load in the horizontal direction is input to at least one of the first connection portion and the second connection portion of the cylindrical body, the position of the second connection portion is the first. It changes relative to the connection. And energy is absorbed because plastic deformation arises in a cylindrical body.

  According to the first aspect of the present invention, the load in the horizontal direction is input without bearing the load in the vertical direction. As a result, plastic deformation occurs in the cylindrical body in a state where no vertical shearing or twisting occurs. As a result, the load required for plastic deformation of the cylindrical body can be stabilized. In addition, since the dimension in the first direction of the cylindrical body is set to be longer than the dimension in the second direction, the load required for plastic deformation of the cylindrical body is prevented from varying depending on the load input direction. be able to. Thereby, energy can be stably absorbed with respect to the load input to the energy absorbing device.

  The energy absorption device according to claim 2, wherein a horizontal load input to the second connection portion is P, and a displacement amount of the second connection portion in the horizontal direction with respect to the first connection portion is δ, The ratio of the increment of the load P to the increment of the displacement amount δ is a rigidity K, and at least the second connection portion is in the second direction with respect to the first connection portion and away from the first connection portion. In the process in which the displacement amount δ when relatively displaced increases to a displacement amount that is ½ of the dimension in the second direction of the cylindrical body before being deformed, the value of the rigidity K The shape and size of the cylindrical body before being deformed so as not to increase are set.

  According to the energy absorbing device of claim 2, at least the displacement amount δ of the second connecting portion in the direction with respect to the first connecting portion is 1 / of the dimension in the second direction of the cylindrical body before being deformed. In the process of increasing the displacement amount to 2, the rigidity K does not turn up. As a result, in the region where the amount of displacement δ in the horizontal direction of the second connection portion relative to the first connection portion is ½ or less of the dimension in the second direction of the cylindrical body before being deformed, the second connection It can suppress that the load P to the horizontal direction input into a part rises rapidly. As a result, energy can be stably absorbed with respect to the load input to the energy absorbing device.

  The energy absorbing device according to claim 3 is the energy absorbing device according to claim 1 or 2, wherein a horizontal load input to the second connecting portion is P, and the first absorbing portion is the first connecting portion. The displacement amount in the horizontal direction of the two connecting portions is δ, the ratio of the increment of the load P to the increment of the displacement amount δ is the rigidity K, and the dimension of the outer method of the cylindrical body in the second direction is DS And the thickness dimension of the cylindrical body is t, and in the process of increasing the displacement amount δ, the displacement amount δ when the value of the stiffness K starts to increase is assumed to be δf, and δf / (DS−t) The shape and dimensions of the cylindrical body before being deformed so that the value is 0.28 or more are set.

  According to the energy absorbing device of the third aspect, the shape and dimensions of the cylindrical body are set so that the value of δf / (DS−t) is 0.28 or more. As a result, when the cylindrical body is deformed by being displaced in the second direction with respect to the first connecting section in the direction away from the first connecting section, the circumference of the cylindrical body is reduced. It can suppress that the tension | tensile_strength which acts in an in-plane direction along the said cylindrical body arises. As a result, it is possible to suppress a sudden increase in the load (load required for plastic deformation of the cylindrical body) accompanying the progress of deformation of the cylindrical body, and to stabilize the energy against the load input to the energy absorbing device. Can be absorbed.

  The energy absorption device according to claim 4, wherein the second connection portion is in the second direction with respect to the first connection portion, and the energy absorption device according to any one of claims 1 to 3. The load input to the second connection portion when the cylindrical body yields by being relatively displaced in a direction approaching the first connection portion is defined as a yield load Pc, and the second connection portion is The load input to the second connection portion when the cylindrical body yields by being displaced relative to the first connection portion in the first direction is defined as a yield load Ps, and Pc / Ps The shape and size of the cylindrical body before being deformed are set so that the value of is in the range of 0.66 or more and 1.18 or less.

  According to the energy absorbing device of claim 4, the shape and dimensions of the cylindrical body before being deformed are set so that the value of Pc / Ps is in the range of 0.66 or more and 1.18 or less. Therefore, it is possible to suppress variation in the load required for plastic deformation of the cylindrical body depending on the load input direction. Thereby, energy can be stably absorbed with respect to the load input to the energy absorbing device.

The energy absorbing device according to claim 5 is the energy absorbing device according to claim 4, wherein an outer dimension of the cylindrical body in the first direction is DL, and the cylindrical body is in the second direction. The dimension of the outer method is DS, the thickness dimension of the cylindrical body is t, the vertical dimension of the cylindrical body is B, the yield strength of the material forming the cylindrical body is σy, The yield load Pc and the yield load Ps satisfy the following expressions (1) and (2).
Pc = (2 × t ² × B × σy) / (DL−t) Formula (1)
Ps = (t ² × B × σy) / (DS−t) Formula (2)

  According to the energy absorbing device of claim 5, the ratio of the yield load Pc and the yield load Ps is set by setting the thickness dimension t, the width dimension B, the yield strength σy, and the external dimensions DL and DS of the cylindrical body. It is possible to easily adjust Pc / Ps and prevent the load required for plastic deformation of the cylindrical body from varying depending on the load input direction.

  The energy absorption device according to claim 6 is the energy absorption device according to any one of claims 1 to 4, wherein DL is an external dimension of the cylindrical body in the first direction, and The outer dimension of the tubular body in the second direction is DS, the thickness of the tubular body is t, and the flatness Fm of the tubular body is (DS−t) / (DL−t). The dimension of the cylindrical body before being deformed is set so that the value of the flatness Fm is in a range of 0.33 or more and 0.59 or less.

  According to the energy absorbing device of claim 6, by setting the dimensions of the cylindrical body before being deformed so that the flatness Fm is in the range of 0.33 or more and 0.59 or less. The load required for plastic deformation of the cylindrical body can be suppressed from varying depending on the load input direction. Thereby, energy can be stably absorbed with respect to the load input to the energy absorbing device.

  The energy absorbing device according to claim 7 is the energy absorbing device according to any one of claims 1 to 6, wherein the cylindrical body includes the first connection portion and the cylindrical body. A deformation restricting member is provided that restricts deformation of the portion adjacent to the first connection portion and the second connection portion and the portion adjacent to the second connection portion.

  According to the energy absorption device of claim 7, the deformation of the cylindrical body adjacent to the first connection portion and the first connection portion and the portion adjacent to the second connection portion and the second connection portion. A deformation restricting member for restricting is provided inside the cylindrical body. Thereby, damage due to ductile fracture, brittle fracture, fatigue fracture, etc. of the first connection part in the cylindrical body and its peripheral part and second connection part and its peripheral part due to local strain or increase in stress Can be suppressed.

  The seismic isolation structure according to claim 8 is provided between the upper structure and the lower structure of a building, and supports the upper structure so as to be movable in a horizontal direction with respect to the lower structure; The energy absorbing device according to any one of claims 1 to 7, wherein the cylindrical body is plastically deformed by moving the upper structure in a horizontal direction with respect to the lower structure. I have.

  According to the seismic isolation structure of the eighth aspect, the upper structure is supported by the support portion so as to be movable in the horizontal direction with respect to the lower structure. When a load due to an earthquake or the like acts on the building having the upper structure and the lower structure, and the upper structure is moved in the horizontal direction with respect to the lower structure, the cylindrical body of the energy absorbing device is plastically deformed. Is done. Thereby, energy, such as an earthquake applied to a building, can be absorbed stably.

  The energy absorbing device and the seismic isolation structure according to the present invention have an excellent effect that energy can be stably absorbed with respect to an input load.

It is the top view which looked at the energy absorption device concerning a 1st embodiment from the up-and-down direction. It is a sectional side view which shows the cross section which cut | disconnected the energy absorption device which concerns on 1st Embodiment along the line corresponding to the 1B-1B line shown by FIG. It is a side view which shows the example in which the seismic isolation structure of this embodiment was applied between the upper structure of a building, and the lower structure. It is a top view corresponding to Drawing 1A showing an energy absorption device concerning a 2nd embodiment. It is a top view corresponding to Drawing 1A showing an energy absorption device concerning a 3rd embodiment. It is a top view corresponding to Drawing 1A showing the energy absorption device concerning a 4th embodiment. It is a top view corresponding to Drawing 1A showing the energy absorption device concerning a 5th embodiment. It is a perspective view which shows the analysis model of the energy absorption device which concerns on 1st Embodiment. It is a top view for demonstrating the direction of the load input into the analysis model of the energy absorption device shown by FIG. 5A. It is a table | surface which shows the dimension etc. of each part of the energy absorption device which analyzed. It is a graph for demonstrating the definition of rigidity, proof stress, and displacement in the relationship between the load and displacement of a cylindrical body. It is a graph which shows the relationship between the load input into the cylindrical body of the energy absorption device which concerns on case number 2 shown by FIG. 6, and a displacement. It is a graph which shows the relationship between the load input into the cylindrical body of the energy absorption device which concerns on case number 6 shown by FIG. 6, and a displacement. It is a figure which shows the stress and deformation | transformation which arise in the said cylindrical body, when the load to 0 degree direction is input into the cylindrical body of the energy absorption device which concerns on case number 2 shown by FIG. It is a figure which shows the stress and deformation | transformation which arise in the said cylindrical body, when the load to a 0 degree direction is input into the cylindrical body of the energy absorption device which concerns on case number 6 shown by FIG. It is a graph which shows the relationship between the load input into the cylindrical body of the energy absorption device which concerns on case number 9 shown by FIG. 6, and a displacement. In the energy absorbing device according to case numbers 1 to 10 shown in FIG. 6, the first direction (the minor axis orthogonal direction) with respect to the proof stress Pc when compressive deformation is applied in the second direction (minor axis direction) of the cylindrical body. 6 is a graph for explaining the influence of the ratio Pc / Ps of the yield strength Ps when shear deformation is applied to the yield strength (yield strength Py). In the energy absorbing device according to case numbers 1 to 10 shown in FIG. 6, the first direction (the minor axis orthogonal direction) with respect to the proof stress Pc when compressive deformation is applied in the second direction (minor axis direction) of the cylindrical body. 5 is a graph for explaining the influence of the ratio Pc / Ps of the proof stress Ps when shear deformation is applied to the proof stress ((DS-t) × 1/2 deformation proof strength Pe when ½ displacement occurs). In the energy absorbing device according to case numbers 11 to 19 shown in FIG. 6, the first direction (short axis orthogonal direction) to the proof stress Pc when compressive deformation is applied in the second direction (short diameter direction) of the cylindrical body. 6 is a graph for explaining the influence of the ratio Pc / Ps of the yield strength Ps when shear deformation is applied to the yield strength (yield strength Py). In the energy absorbing device according to case numbers 11 to 19 shown in FIG. 6, the first direction (short axis orthogonal direction) to the proof stress Pc when compressive deformation is applied in the second direction (short diameter direction) of the cylindrical body. 5 is a graph for explaining the influence of the ratio Pc / Ps of the proof stress Ps when shear deformation is applied to the proof stress ((DS-t) × 1/2 deformation proof strength Pe when ½ displacement occurs). 7 is a graph for explaining the influence of the flatness Fm of the cylindrical body on the proof stress Py in the energy absorbing devices according to case numbers 1 to 10 shown in FIG. 6. 7 is a graph for explaining the influence of the flatness Fm of the cylindrical body on the proof stress Pe in the energy absorbing devices according to case numbers 1 to 10 shown in FIG. 6. FIG. 19 is a graph for explaining the influence of the flatness Fm of the cylindrical body on the proof stress Py in the energy absorbing devices according to case numbers 11 to 19 shown in FIG. 6. FIG. 19 is a graph for explaining the influence of the flatness Fm of the cylindrical body on the proof stress Pe in the energy absorbing devices according to case numbers 11 to 19 shown in FIG. 6. The ratio of the displacement δf at which the inflection point of the rigidity appears with respect to the dimension (DS-t) in the second direction of the cylindrical body and 0 ° with respect to the proof strength Pe (Pe (180 °)) in the 180 ° direction of the cylindrical body. It is a graph which shows the relationship with the ratio of the yield strength Pe (Pe (0 degree)) in a direction. It is a figure which shows the stress and deformation | transformation which arise in the said cylindrical body, when the load to a 180 degree direction is input into the cylindrical body of the energy absorption device which concerns on case number 6 shown by FIG. It is a figure which shows the stress and deformation | transformation which arise in the said cylindrical body, when the load to a 90 degree direction is input into the cylindrical body of the energy absorption device which concerns on case number 6 shown by FIG. It is a figure which shows the model for evaluating the yield strength with respect to a deformation | transformation to the 180 degree direction of a cylindrical body. It is a figure which shows the model for evaluating the yield strength with respect to a 90 degree direction deformation | transformation of a cylindrical body.

  The energy absorbing device and the seismic isolation structure according to the first embodiment of the present invention will be described with reference to FIGS. 1A, 1B, and 2. FIG. In addition, the up-down direction of the building provided with the energy absorption device of this embodiment is indicated by an arrow V, and the horizontal direction of the building is indicated by an arrow H.

  As shown in FIG. 2, the energy absorbing device 10 of the present embodiment is applied to a base-isolated structure of a building 12, and the energy absorbing device 10 absorbs energy against an external force such as an earthquake that acts on the building 12. To do. The building 12 includes a lower structure 14 constituting a foundation thereof, an upper structure 18 supported by the lower structure 14 via an isolator 16 as a support portion (in FIG. 2, a first floor floor beam is illustrated), The energy absorbing device 10 is provided between the lower structure 14 and the upper structure 18.

  The isolator 16 of this embodiment is a rolling bearing in which bearing steel or the like is formed in a spherical shape, and a plurality of isolators 16 are arranged between the upper structure 18 and the lower structure 14 with a space in the horizontal direction H. ing. The upper structure 18 can move in the horizontal direction H with respect to the lower structure 14 by rolling a plurality of rolling obstacles (isolators 16). The isolator 16 may be an isolator having another configuration such as a sliding bearing or a laminated rubber.

  As shown in FIG. 1B, a lower connecting member 20 and an upper connecting member 22 to which the energy absorbing device 10 is attached are fixed to the upper structure 18 and the lower structure 14. The lower connecting member 20 and the upper connecting member 22 are connected in the horizontal direction H via the energy absorbing device 10.

  Here, as shown in FIG. 2, in the present embodiment, the load acting on the lower side from the upper structure 18 (the weight of the building or the load due to the load) is handled by the isolator 16. As a result, the load on the lower side is not input from the upper structure 18 to the energy absorbing device 10, and the load on the upper side is not input from the lower structure 14 to the energy absorbing device 10. It is like that.

  When an external force due to an earthquake or the like acts on the building 12, the upper structure 18 is moved in the horizontal direction H with respect to the lower structure 14, so that the horizontal direction between the lower connection member 20 and the upper connection member 22 is increased. The interval to H changes. Thereby, energy such as an earthquake input to the building 12 can be absorbed by the energy absorbing device 10 being deformed.

  Next, a detailed configuration of the energy absorbing device 10 will be described.

  As shown in FIG. 1A, the energy absorbing device 10 includes a cylindrical body 24 formed in an annular shape when viewed from the upper direction (or the lower direction), and the lower connecting member 20 and the upper connecting member 22 in the cylindrical body 24. And two deformation restricting members 26 provided along a portion to which are connected.

  The tubular body 24 is formed by cutting a steel pipe material having a thickness t into a predetermined width B (dimension in the vertical direction) and deforming (processing) it into a predetermined shape. The cylindrical body 24 is formed in a substantially elliptical shape when viewed from the upper direction (or the lower direction), and is used in a state where its axial direction is directed in the vertical direction. In addition, the dimension (diameter) of the outer method to the major axis direction of the cylindrical body 24 is set to DL, and the dimension (diameter) of the outer method to the minor axis direction of the cylindrical body 24 is set to DS. The major axis direction of the cylindrical body 24 is a first horizontal direction H1 as a first direction, the second axis is a direction perpendicular to the first horizontal direction H1 and the minor axis direction of the cylindrical body 24 is a second direction. The horizontal direction is H2. Moreover, the cylindrical part 24 of this embodiment has comprised the cyclic | annular form symmetrical in each of the 1st horizontal direction H1 and the 2nd horizontal direction H2 seeing from upper direction (or lower direction).

  One portion of the cylindrical body 24 in the second horizontal direction H <b> 2 is a first connection portion 32 to which the lower connecting member 20 is connected via a bolt 28 and a nut 30. In addition, the other side portion of the cylindrical body 24 in the second horizontal direction H2 is connected to the upper connecting member 22 via a bolt 28 and a nut 30 and is opposed to the first connecting portion 32 and the second horizontal direction H2. It is set as the 2nd connection part 34 arrange | positioned. And when external force acts on the building 12 (refer FIG. 2), the space | interval to the horizontal direction H of the lower side connection member 20 and the upper side connection member 22 will change. That is, the relative position of the first connection part 32 and the second connection part 34 in the cylindrical body 24 changes. Thereby, a load in the horizontal direction is input to the cylindrical body 24, and the cylindrical body 24 is plastically deformed, so that energy is absorbed against a force such as an earthquake acting on the building 12.

  Further, inside the tubular body 24, the deformation of the first connection portion 32 and the second connection portion 34 of the tubular body 24 is restricted, and the deformation of both side portions of the first connection portion 32 and the second connection portion 34 is restricted. Two deformation restricting members 26 for limiting the amount are provided. One deformation restricting member 26 is fixed to the first connecting portion 32 via a bolt 28 and a nut 30 for connecting the lower connecting member 20 to the first connecting portion 32 of the cylindrical body 24. The other deformation restricting member 26 is fixed to the second connecting portion 34 via a bolt 28 and a nut 30 for connecting the upper connecting member 22 to the second connecting portion 34 of the cylindrical body 24. And the 1st connection part 32 and the 2nd connection part 34 are pinched | interposed between the deformation | transformation control member 26 and the lower side connection member 20 or the upper side connection member 22, and the 1st connection part 32 and the 2nd connection part 34 are inserted. Bending deformation is regulated. Further, both side portions 26 </ b> A of the portion where the bolts 28 are inserted in the deformation regulating member 26 are gently curved in a direction away from the tubular body 24 and separated from the tubular body 24.

  Here, the load in the horizontal direction input to the second connecting portion 34 of the cylindrical body 24 due to the load caused by an earthquake or the like acting on the building 12 (see FIG. 2) is defined as P, and the first of the cylindrical body 24. A displacement amount in the horizontal direction of the second connection portion 34 with respect to the connection portion 32 is represented by δ, and a ratio of an increment of the load P to an increment of the displacement amount δ is represented by a rigidity K. In the present embodiment, the shape and dimensions of the tubular body 24 before being deformed are set so that the value of the rigidity K does not increase in the process of plastically deforming the tubular body 24. Specifically, in the present embodiment, the amount of displacement δ in the horizontal direction of the second connection portion 34 with respect to the first connection portion 32 of the cylindrical body 24 increases to the amount of displacement of the cylindrical body 24 assumed in design. In the process, the shape and dimensions of the cylindrical body 24 before being deformed are set so that the value of the rigidity K does not increase. Note that the amount of displacement of the cylindrical body 24 assumed in design is a displacement amount (0 which is ½ of the dimension in the second horizontal direction H2 of the cylindrical body 24 before being deformed, as will be described later. The amount of displacement of the cylindrical body 24 assumed in the design is appropriately determined by taking into account the load, acceleration, etc. caused by the earthquake or the like acting on the building 12. That's fine. Further, the shape and dimensions of the cylindrical body 24 may be determined by performing a single test of the energy absorbing device 10 or an analysis described later.

(Operation and effect of this embodiment)
Next, the operation and effect of this embodiment will be described.

  As shown in FIGS. 1A to 2, according to the energy absorbing device 10 described above, a load in the horizontal direction H is input without bearing a load in the vertical direction V of the building 12. Thereby, the cylindrical body 24 is plastically deformed in a state where no vertical shearing or twisting occurs. As a result, the load (energy absorption load) required for plastic deformation of the cylindrical body 24 can be stabilized.

  Moreover, in this embodiment, the dimension DL to the 1st horizontal direction H1 of the cylindrical body 24 is set longer than the dimension DS to the 2nd horizontal direction H2, Therefore The cylindrical body 24 is set according to the load input direction. It is possible to prevent the load required for plastic deformation of the material from varying. Thereby, energy can be stably absorbed with respect to the load input to the energy absorbing device 10.

  Further, in the present embodiment, the rigidity K increases in the process in which the amount of displacement δ in the horizontal direction of the second connection portion 34 with respect to the first connection portion 32 of the cylindrical body 24 increases to the amount of displacement assumed in design. Don't turn into Thereby, in the process in which the amount of displacement δ increases to the amount of displacement assumed in design, it is possible to suppress a sudden increase in the horizontal load P input to the second connecting portion 34. As a result, energy can be absorbed more stably with respect to the load input to the energy absorbing device 10.

  In the present embodiment, two deformation restricting members 26 are provided along the first connecting portion 32 and the second connecting portion 34 of the cylindrical body 24. Thereby, when the cylindrical body 24 is deformed, the deformation of the first connection portion 32 and the second connection portion 34 which are the load input portion and the load receiving portion in the cylindrical body 24 is restricted and the first connection is made. The amount of deformation of both side portions of the portion 32 and the second connection portion 34 is limited. As a result, due to ductile fracture, brittle fracture, fatigue fracture, etc. of the annular portion 24 due to local strain and stress increase in the first connection portion 32 and its both side portions and the second connection portion 34 and its both side portions. The occurrence of damage can be suppressed.

  In the present embodiment, the example in which the cylindrical body 24 is formed in a substantially elliptical shape has been described, but the present invention is not limited to this. For example, like the energy absorbing device 36 according to the second embodiment shown in FIG. 3A, the first and second portions of the cylindrical body 24 in the second horizontal direction H2 extend in parallel with each other, and A portion on one side and the other side of one horizontal direction H1 may be curved with a predetermined radius of curvature to form a ring-like shape like a land track when viewed from above and below. Further, like the energy absorbing device 40 according to the third embodiment and the energy absorbing device 42 according to the fourth embodiment shown in FIGS. 3B and 3C, the cylindrical body 24 includes a plurality of curved plate members 44 (upward direction). A plate material curved in a U shape as viewed from (or downward) may be combined to form an annular shape. As an example, the cylindrical body 24 can be configured by overlapping and joining the end portions of the two curved plate members 44 in the first connection portion 32 and the second connection portion 34. When the dimension DS is different between the one curved plate member 44 and the other curved plate member 44, the flatness Fe or the like described later may be calculated with the larger value. Furthermore, like the energy absorbing device 38 according to the fifth embodiment shown in FIG. 4, the one side and the other side of the first horizontal direction H1 and the one side of the second horizontal direction H2 in the cylindrical body 24 and By extending the other side portions in parallel to each other, they may be formed in a rectangular ring shape having four corners as viewed from above and below.

(Explanation of CAE analysis of effect by parameter)
Next, the evaluation result by CAE analysis of the effect by the parameter of the energy absorption load of the energy absorption device 10 of this embodiment is demonstrated using FIG. 5A-FIG. 22B.

(Definition of analysis conditions and parameters)
First, analysis conditions and definitions of parameters will be described.
FIG. 5A shows an analysis model in which the cylindrical body 24 is modeled by a thick shell element with reference to the plate thickness center (thickness center) of the cylindrical body 24 of the energy absorbing device 10. In addition, in the analysis model of the said cylindrical body 24, the deformation | transformation control member 26 (refer FIG. 1) is abbreviate | omitted.

  As shown in FIG. 5B, a load in the horizontal direction was applied using the first connection portion 32 in the analysis model of the cylindrical body 24 as a fixed point and the second connection portion 34 as a loading point. Note that the first connecting portion 32, which is a fixed point, and the second connecting portion 34, which is a loading point, rotate around the first horizontal direction H1, rotate around the second horizontal direction H2, and the vertical direction V (perpendicular to the page). The rotation around is restricted. Further, in this analysis, the first connection part 32 and the second connection part 34 by the lower connection member 20 and the upper connection member 22 (see FIG. 1) are integrally formed over the width B (the dimension in the vertical direction), respectively. Deformation is constrained to be fixed and deformed. Furthermore, the direction in which the second connecting portion 34 is displaced to the other side of the second horizontal direction H2 is defined as a 0 ° direction, and the direction in which the second connecting portion 34 is displaced to one side of the second horizontal direction H2 is defined as a 180 ° direction. The direction in which the second connecting portion 34 is displaced to one side of the first horizontal direction H1 is a 90 ° direction, and the direction in which the second connecting portion 34 is displaced to the other side of the first horizontal direction H1 is a 270 ° direction. And in this analysis, the 2nd connection part 34 of the cylindrical body 24 set to the dimension of case number 1-case number 19 shown by FIG. 6 is 0 degree direction, 45 degree direction, 90 degree direction, 180 degree | times. The characteristics of the energy absorption load when displaced in the ° direction and the 225 ° direction were evaluated. The analysis model of the cylindrical body 24 under the conditions of case number 1 and case number 11 is an analysis model according to a comparative example of the present invention. In case numbers 2 to 10, the same plate thickness t (= 12 mm) and width B (= 150 mm) as in case number 1 are used, and the dimension DL in the first direction and the second direction of the cylindrical body 24 are the same, under the condition that the circumference is constant. The dimension DS is changed. In case numbers 12 to 19, the same plate thickness t (= 22 mm) and width B (= 150 mm) as in case number 11 are used, and the dimension DL and The dimension DS in two directions is changed.

  Here, as shown in FIGS. 5A and 6, the radius of the cylindrical body 24 in the first horizontal direction H1 is RL, and the radius of the cylindrical body 24 in the second horizontal direction H2 is RS. And the flatness of the cylindrical body 24 calculated from the dimension of the outer method of the cylindrical body 24 is calculated by DS / DL, and this flatness is expressed by Fe.

Further, the dimension (diameter) in the major axis direction of the plate thickness center of the cylindrical body 24 is DL-t, and the dimension (diameter) in the minor axis direction of the thickness center of the cylindrical body 24 is DS-t. Further, the radius in the major axis direction of the plate thickness center of the cylindrical body 24 is RL-t / 2, and the radius in the minor axis direction of the plate thickness center of the cylindrical body 24 is RS-t / 2. And the flatness of the cylindrical body 24 calculated from the dimension of the center of the plate thickness of the cylindrical body 24 is calculated by (DS−t) / (DL−t), and this flatness is expressed by Fm. To do.
Further, when the second connecting portion 34 of the cylindrical body 24 is displaced in the 180 ° direction, the load input to the second connecting portion 34 when the cylindrical body 24 yields is defined as the yield load Pc, and the cylindrical shape A load input to the second connection portion 34 when the cylindrical body 24 yields by the displacement of the second connection portion 34 of the body 24 in the 90 ° direction is defined as a yield load Ps. The ratio of the yield load Pc to the yield load Ps is defined as the yield strength ratio Pc / Ps.

The yield strength of the material forming the cylindrical body 24 was σ _y , and the yield strength σ _y was 400 MPa. The Young's modulus of the material forming the cylindrical body 24 was 205 GPa, the Poisson's ratio was 0.3, and the stress-strain characteristics after yielding were approximated by multi-linearity.

In FIG. 7, the load P (proof strength) input to the second connection portion 34 of the cylindrical body 24 is taken on the vertical axis, and the displacement amount δ of the second connection portion 34 of the cylindrical body 24 is taken on the horizontal axis. The resulting load-displacement diagram is illustrated. As shown in the load-displacement diagram, the ratio of the increment of the load P to the increment of the displacement amount δ of the second connection portion 34 of the cylindrical body 24 is represented by rigidity K.
Further, the yield of the stiffness K of the proportional limit the relationship between the load P displacement amount δ is proportional relationship to the initial stiffness K _0, the load P when the stiffness K becomes 1/3 of initial stiffness K ₀ The proof stress P _y (the white triangle mark in the figure) is used.
Further, the displacement amount when the reduced rigidity K starts to increase again as the displacement amount δ increases (as the deformation of the cylindrical body 24 progresses) is denoted by δf (black circle in the figure). In the following description, the point that becomes the displacement amount δf may be referred to as an “inflection point”.

As shown in FIGS. 5A and 5B, the displacement δ until the second connecting portion 34 of the cylindrical body 24 abuts on the first connecting portion 32 by being displaced in the 180 ° direction is set to the maximum amount of the cylindrical body 24. The displacement amount is δmax. Here, for deformations in directions other than the 180 ° direction (0 ° direction, 45 ° direction, 90 ° direction, 225 ° direction), data up to δ = 300 mm is shown, but in these directions, δ = 300 mm. In the deformation region up to, the contact of the first connection portion 32 and the second connection portion 34 described above does not occur.
As shown in FIG. 7, the load P when the second connecting portion 34 of the cylindrical body 24 is displaced (DS−t) × 1/2 (RS−t / 2 displaced) in the 180 ° direction is 1 / 2 Deformation yield strength Pe (open circle in the figure).

(Analysis result)
In FIG. 8, the second connection portion 34 of the cylindrical body 24 under the condition of case number 2 shown in FIG. 6 (bearing ratio Pc / Ps = 1.59, flatness Fm = 0.80) is in the horizontal direction. A load-displacement diagram when displaced in each direction (0 ° direction, 45 ° direction, 90 ° direction, 180 ° direction, 225 ° direction) is shown. In FIG. 9, the second connection portion 34 of the cylindrical body 24 under the condition of the case number 6 shown in FIG. 6 (proof strength ratio Pc / Ps = 0.88, flatness Fm = 0.44) is horizontal. A load-displacement diagram when displaced in each direction (0 ° direction, 45 ° direction, 90 ° direction, 180 ° direction, 225 ° direction) is shown. As shown in these figures, in any case, the load-displacement diagram when the second connecting portion 34 is displaced in the 180 ° direction reaches the yield strength P _y (see FIG. 7). It can be seen that the proof stress variation accompanying the progress of deformation is small and stable energy absorption performance is exhibited.

  As shown in FIG. 8, in the cylindrical body 24 under the condition of case number 2 (bearing ratio Pc / Ps = 1.59, flatness Fm = 0.80), the second connecting portion 34 is in the 0 ° direction. When the displacement is caused, the rigidity K starts to increase again in a region where the displacement amount δ of the second connecting portion 34 is equal to or less than RS−t / 2 (the displacement amount δf when the rigidity K starts increasing again). Recognize. More specifically, in the cylindrical body 24 under the condition of case number 2, as shown in FIG. 10A, the process in which the displacement amount δ of the second connecting portion 34 increases in the 0 ° direction in the region of RS−t / 2 or less. , Tension T (force generated in the in-plane direction along the circumference of the cylindrical body 24) acts on one side and the other side of the cylindrical body 24 in the first horizontal direction H1. To do. Thereby, the deformation resistance of the cylindrical body 24 increases (the rigidity K starts to increase again), and the load P (energy absorption load) for displacing the second connecting portion 34 in the 0 ° direction increases rapidly. Further, as shown in FIG. 8, in the cylindrical body 24 under the condition of case number 2, a load P (energy absorption load) for displacing the second connection portion 34 in the 90 ° direction is the second connection portion 34. Is lower than the load P for displacing in the 0 ° direction, 45 ° direction, 180 ° direction and 225 ° direction. Note that two ellipses drawn by solid lines in FIG. 10A and FIGS. 10B, 21A, and 21B described later are the upper edge and the lower edge of the cylindrical body 24 before being deformed.

  On the other hand, as shown in FIG. 9, in the cylindrical body 24 under the condition of the case number 6 (bearing ratio Pc / Ps = 0.88, flatness Fm = 0.44), the second connecting portion 34 In the region where the displacement amount δ is equal to or less than RS−t / 2, the variation of the load P (energy absorption load) for displacing the second connecting portion 34 in each direction is the cylindrical body 24 under the condition of case number 2. It can be seen that it is smaller than More specifically, in the cylindrical body 24 under the condition of case number 6, as shown in FIG. 10B, tension in the second horizontal direction H2 does not act on one side and the other side in the first horizontal direction H1 ( Or very small). Thereby, in the cylindrical body 24 under the condition of case number 6, in the region where the displacement amount δ of the second connecting portion 34 is RS−t / 2 or less, the 0 ° direction, the 45 ° direction, the 90 ° direction, and the 180 ° direction. In any of the directions of 225 ° and 225 °, the rigidity K does not increase again (the displacement amount δf when the rigidity K starts increasing again is not reached). As a result, a stable energy absorption load can be obtained even when the second connecting portion 34 is displaced in any direction.

  On the other hand, as shown in FIG. 11, in the cylindrical body 24 having the condition of case number 9 (proof strength ratio Pc / Ps = 0.58, flatness Fm = 0.29), the second connecting portion 34 is oriented in the 90 ° direction. The load P (energy absorption load) for displacing in the 225 ° direction is higher than the load P for displacing the second connecting portion 34 in the 0 °, 45 °, and 180 ° directions.

(Effect of yield strength ratio Pc / Ps on energy absorption load)
Analysis similar to case numbers 2, 6, and 9 described above was performed for case numbers 1, 3 to 5, 7, 8, and 10. When focusing on the proof stress ratio Pc / Ps in these analysis results, when the proof stress ratio Pc / Ps is higher or lower than a predetermined value, the load P () for displacing the second connecting portion 34 in each direction. It was found that the variation in the energy absorption load) increased.

In FIG. 12, for the case number 1 to case number 10, the yield strength Pc / Ps based on the calculated values of the yield load Pc and the yield load Ps to be described later is taken on the horizontal axis, and the second connection portion 34 of the cylindrical body 24 _Is the ratio of the yield strength P _y when displaced in other directions (0 ° direction, 45 ° direction, 90 ° direction, 225 ° direction) with respect to the yield strength P _y when displaced in the 180 ° direction. Is a graph showing the degree of increase in the yield strength Py with respect to the strength ratio Pc / Ps. FIG. 13 also shows the case number 1 to case number 10 when the proof stress ratio Pc / Ps is taken on the horizontal axis and the second connecting portion 34 of the cylindrical body 24 is displaced in the 180 ° direction. other directions for the two deformation proof stress _{P e} by plotting (0 ° direction, 45 ° direction, 90 ° direction, 225 ° direction) ratio of 1/2 deformation proof stress _{P e} when is displaced to the longitudinal axis, graph showing the degree of increase of 1/2 deformation strength _{P e} for strength ratio Pc / Ps is shown. As shown in these figures, by setting the value of the proof stress ratio Pc / Ps within the range of 0.66 or more and 1.18 or less, the second connection portion 34 is displaced in each direction. It was found that the variation in the load P (energy absorption load) can be reduced. That is, by setting the value of Pc / Ps within the range of 0.66 or more and 1.18 or less, the yield strength P when the second connection portion 34 of the cylindrical body 24 is displaced in the 180 ° direction. other directions with respect to _y and 1/2 variations strength _{P e} (0 ° direction, 45 ° direction, 90 ° direction, 225 ° direction) yield strength when is displaced to _{P y} and 1/2 variation of deformation proof stress _{P e} Was found to be suppressed to about 50%. Thus, yield strength P _y and by suppressing variation of 1/2 deformation proof stress P _e, together with the stabilizing energy absorption performance of the energy absorbing device, component (connecting portion of the energy absorbing device, the connecting member, a bolt Etc.) and the burden on the surrounding structure (lower structure, upper structure) can be reduced.

  14 and 15 respectively correspond to FIGS. 12 and 13 related to case numbers 11 to 19 in which the plate thickness t of the cylindrical body 24 is changed with respect to case numbers 1 to 10. A graph is shown. As shown in these drawings, regardless of the plate thickness t, the value of the proof stress ratio Pc / Ps is set within the range of 0.66 or more and 1.18 or less, so that the second connecting portions 34 are respectively set. It was found that the variation in the load P (energy absorption load) for displacing in the direction can be reduced.

(Effect of flatness Fm on energy absorption load)
Further, when attention is paid to the flattening rate Fm in the analysis results of case numbers 1 to 10, the load for displacing the second connecting portion 34 in each direction when the flattening rate Fm is higher or lower than a predetermined value. It was found that the variation in P (energy absorption load) becomes large.

Figure 16 is intended for case number 1 case number 10, the horizontal axis of the flat rate Fm, the other for the yield strength P _y at the time of displacing the second connecting portion 34 of the tubular body 24 to the 180 ° direction direction (0 ° direction, 45 ° direction, 90 ° direction, 225 ° direction) by plotting the ratio of the yield strength P _y when is displaced to the longitudinal axis, the increase in yield strength Py for flattening Fm A graph showing the degree is shown. Further, FIG. 17 shows a case where the flattening rate Fm is taken on the horizontal axis and the second connecting portion 34 of the cylindrical body 24 is displaced in the 180 ° direction by a half deformation for case numbers 1 to 10. other directions for strength P _e by plotting (0 ° direction, 45 ° direction, 90 ° direction, 225 ° direction) ratio of 1/2 deformation proof stress P _e when is displaced to the longitudinal axis, an aspect ratio graph showing the degree of increase of the yield strength 1/2 deformation strength P _e for Fm is illustrated. As shown in these figures, the load P for displacing the second connecting portion 34 in each direction is set by setting the value of the flatness Fm within a range of 0.33 or more and 0.59 or less. other directions variation can be reduced (the second connecting portion 34 of the cylindrical body 24 with respect to the yield strength P _y and 1/2 variations strength P _e when is displaced to 180 ° direction (the energy absorbing load) (0 ° direction, 45 ° direction, 90 ° direction, 225 ° direction) variation of the yield strength _{P y} and 1/2 variations strength _{P e} when is displaced to have been found suppressed is) that approximately 50%.

  18 and 19 respectively correspond to FIGS. 16 and 17 relating to case numbers 11 to 19 in which the plate thickness t of the cylindrical body 24 is changed with respect to case numbers 1 to 10. A graph is shown. As shown in these drawings, regardless of the plate thickness t, the flatness Fm is set within the range of 0.33 or more and 0.59 or less, so that the second connecting portion 34 can be moved in each direction. It has been found that the variation in the load P (energy absorption load) for displacing in the direction can be reduced.

(Displacement where inflection point appears for short diameter of cylindrical body)
Further, in the analysis results of case number 1 to case number 19, the ratio of the displacement (δf) at which the inflection point appears to the dimension (short diameter) (DS-t) in the minor axis direction of the center of the thickness of the cylindrical body 24 When the ratio is higher than a predetermined value, it has been found that the variation in the load P (energy absorption load) for displacing the second connecting portion 34 in each direction becomes small.

FIG. 20 shows the ratio δf / (Ds−t) of the displacement (δf) at which the inflection point appears with respect to the short diameter (DS−t) of the cylindrical body 24 for the case numbers 1 to 19. Ratio Pe (0 °) of the 1/2 deformation resistance Pe when the cylindrical body 24 is displaced in the 0 ° direction with respect to the 1/2 deformation strength Pe when the cylindrical body 24 is displaced in the 180 ° direction on the shaft ) / Pe (180 °) is plotted on the vertical axis, showing the relationship between the displacement at which the inflection point appears and the increase in yield strength. As shown in this drawing, regardless of the relationship between the dimension of the cylindrical body 24 and the plate thickness, in the region where δf / (Ds−t) is smaller than 0.28, Pe (0 °) with respect to Pe (180 °). °) has risen significantly. On the other hand, in the region where δf / (Ds−t) is 0.28 or more, an increase in Pe (0 °) with respect to Pe (180 °) is suppressed, and the second connecting portion 34 is displaced in each direction. other directions for the 1/2 deformation strength P _e when variation can be reduced (the second connecting portion 34 of the cylindrical body 24 is displaced to the 180 ° direction of the load P (energy absorbing load) for ( 0 ° direction) 1/2 variations in the deformation proof stress P _e when is displaced to have found that the suppressed is) to about 50%.

(Calculation of yield load Pc and yield load Ps)
Next, calculation formulas for the yield load Pc and the yield load Ps that determine the above-mentioned yield strength ratio Pc / Ps will be described.

FIG. 21A shows the stress generated in each part of the cylindrical body 24 when the second connecting portion 34 of the cylindrical body 24 is displaced in the 180 ° direction. Here, based on the stress distribution of the cylindrical body 24 shown in FIG. 21A, assuming the yield strength evaluation model shown in FIG. 22A, the external work and internal work on the cylindrical body 24 are expressed by the following equation (3 ) And formula (4).
External work = Pc × Δ Equation (3)
Internal work = 8 × Mp × θ × B Formula (4)

Here, Mp is a plastic moment per unit width formed by the plastic hinge, and is given by Mp = t ² × σy / 4. Θ is the rotation angle of the plastic hinge, and is given by θ = Δ / (DL−t). And the following formula | equation (5) which gives the yield load Pc is calculated | required from the balance of external work and internal work.
Pc = 2 × t ² × B × σy / (DL−t) Formula (5)

FIG. 21B shows the stress generated in each part of the cylindrical body 24 when the second connecting portion 34 of the cylindrical body 24 is displaced in the 90 ° direction. Here, as in the case of obtaining Equation (5) giving the yield load Pc described above, the yield strength evaluation model shown in FIG. 22B is assumed based on the stress distribution of the cylindrical body 24 shown in FIG. 21B. Then, the external work and internal work to the cylindrical body 24 are represented by the following formulas (6) and (7).
External work = Ps × Δ Equation (6)
Internal work = 4 x Mp x θ x B (7)

Here, θ is the rotation angle of the plastic hinge and is given by θ = Δ / (DS−t). And the following formula | equation (8) which gives the yield load Ps is calculated | required from the balance of external work and internal work.
Ps = t ² × B × σy / (DS−t) Formula (8)

By setting the dimensions of the cylindrical body 24 using the following formula (9) derived from the formulas (5) and (8) described above, an energy absorption device having a desired yield ratio Pc / Ps is obtained. 10 can be obtained.
Pc / Ps = 2 (DS-t) / (DL-t) Formula (9)

  Although one embodiment of the present invention has been described above, the present invention is not limited to the above, and various modifications other than the above can be implemented without departing from the spirit of the present invention. Of course.

10 Energy absorbing device 16 Isolator (supporting part)
24 cylindrical body 32 1st connection part 34 2nd connection part 36 energy absorption device 38 energy absorption device H1 1st horizontal direction (1st direction)
H2 Second horizontal direction (second direction)

Claims (8)

An energy absorbing device that absorbs energy by being plastically deformed partially by a load in the horizontal direction without bearing a load in the vertical direction,
The vertical direction is the axial direction, and when viewed from the vertical direction, the first direction and the second direction perpendicular to each other form a symmetrical ring, and the dimension in the first direction is greater than the dimension in the second direction. A cylindrical body which is set to be large,
A first connecting portion provided on one of a pair of facing portions facing the second direction in the cylindrical body, to which a first member is connected;
Provided on the other of the pair of opposed portions facing the second direction in the cylindrical body, the second member is connected, and plastic deformation is generated in the cylindrical body by horizontal relative displacement with respect to the first connecting portion. A second connection part;
An energy absorbing device comprising: The horizontal load input to the second connection portion is P,
The amount of displacement in the horizontal direction of the second connection portion relative to the first connection portion is δ,
The ratio of the increment of the load P to the increment of the displacement amount δ is the rigidity K,
At least the displacement amount δ when the second connection portion is displaced relative to the first connection portion in the second direction and in a direction away from the first connection portion is not changed. The shape of the cylindrical body before being deformed so that the value of the rigidity K does not start to increase in the process of increasing the displacement amount to ½ of the dimension in the second direction of the cylindrical body, and The energy absorbing device according to claim 1, wherein the dimension is set. The horizontal load input to the second connection portion is P,
The amount of displacement in the horizontal direction of the second connection portion relative to the first connection portion is δ,
The ratio of the increment of the load P to the increment of the displacement amount δ is the rigidity K,
The outer dimension of the cylindrical body in the second direction is DS,
The thickness dimension of the cylindrical body is t,
In the process of increasing the displacement amount δ, the displacement amount δ when the value of the rigidity K starts to increase is assumed to be δf,
The energy absorption device according to claim 1 or 2, wherein a shape and a dimension of the cylindrical body before being deformed so that a value of δf / (DS-t) is 0.28 or more are set. The second connecting portion is displaced relative to the first connecting portion in the second direction and in a direction close to the first connecting portion, so that the second body is yielded when the cylindrical body yields. The load input to the connection is the yield load Pc,
The load input to the second connecting portion when the cylindrical body yields by the second connecting portion being displaced relative to the first connecting portion in the first direction. Ps,
The shape and dimension of the said cylindrical body before deform | transforming so that the value of Pc / Ps may be in the range of 0.66 or more and 1.18 or less, Any one of Claims 1-3 2. The energy absorbing device according to item 1. DL is an outer dimension of the cylindrical body in the first direction,
The outer dimension of the cylindrical body in the second direction is DS,
The thickness dimension of the cylindrical body is t,
The width dimension in the vertical direction of the cylindrical body is B,
The yield strength of the material forming the cylindrical body is σy,
The energy absorption device according to claim 4, wherein the yield load Pc and the yield load Ps satisfy the following expressions (1) and (2).
Pc = (2 × t ² × B × σy) / (DL−t) Formula (1)
Ps = (t ² × B × σy) / (DS−t) Formula (2) DL is an outer dimension of the cylindrical body in the first direction,
The outer dimension of the cylindrical body in the second direction is DS,
The thickness dimension of the cylindrical body is t,
The flatness Fm of the cylindrical body is (DS−t) / (DL−t),
The dimension of the said cylindrical body before deform | transforming so that the value of the said flatness Fm may be in the range of 0.33 or more and 0.59 or less, The any one of Claims 1-4 The energy absorbing device according to item.   In the cylindrical body, the first connecting portion and the portion adjacent to the first connecting portion, the second connecting portion and the portion adjacent to the second connecting portion of the cylindrical body are provided. The energy absorption device according to any one of claims 1 to 6, wherein a deformation regulating member that regulates the deformation is provided. A support portion provided between an upper structure and a lower structure of a building, and supporting the upper structure so as to be movable in a horizontal direction with respect to the lower structure;
The energy absorption device according to any one of claims 1 to 7, wherein the cylindrical body is plastically deformed by moving the upper structure in a horizontal direction with respect to the lower structure.
Seismic isolation structure with