A self-resetting negative stiffness isolation bearing

Abstract

The present invention discloses a self-resetting negative stiffness seismic isolation bearing, comprising: a self-resetting element and a top plate, an upper cambered body, a rocking body, a lower cambered body, and a bottom plate arranged coaxially; the upper cambered body is installed at the bottom of the top plate, the lower cambered body is installed at the top of the bottom plate, and the rocking body is located in the middle of the upper and lower cambered bodies; the middle part of the bottom of the upper cambered body is a horizontal plane, and the rest of the bottom is a spherical cambered surface, with a first slot provided in the middle of the horizontal plane; the structure of the lower cambered body is the same as that of the upper cambered body; the upper and lower end faces of the rocking body are respectively provided with an upper shear block and a lower shear block, and the upper and lower shear blocks are located in the slots on the upper and lower cambered bodies; the self-resetting elements are symmetrically arranged on both sides of the bearing to achieve self-resetting of the bearing under strong earthquakes. When the earthquake force of the bearing of the present invention is relatively small, the rocking body does not rock and deform to resist the effects of small earthquakes or wind loads. When the earthquake force increases, the rocking body begins to rock and deform, and the bearing produces negative stiffness behavior.

Description

Technical Field

[0001] The present invention relates to the technical field of engineering seismic isolation, and in particular to a self-resetting negative stiffness seismic isolation bearing. Background Art

[0002] Seismic isolation technology is considered one of the most effective ways to mitigate earthquake damage. Its principle is to extend the structural period and increase damping by placing isolation layers at the foundation or between floors, thereby reducing the transmission of seismic energy to the upper structure and protecting the main structure. Currently, the most widely used seismic isolation bearing in practical engineering projects in my country is the lead-rubber isolation bearing. In lead-rubber isolation bearings, the laminated rubber layer primarily bears the vertical load above the bearing. During horizontal deformation, the lead core provides the primary damping and energy dissipation. Lead-rubber isolation bearings feature a clear shock absorption mechanism, high horizontal deformation capacity, and easy construction and installation. Previous research on isolation bearings has primarily focused on their horizontal deformation characteristics, vertical bearing capacity, and damping properties, but has paid less attention to their ability to reset after deformation. While isolation devices can effectively withstand large deformations under strong earthquakes or strong winds, after deformation, due to the contribution of energy dissipation damping in the bearing, they may have difficulty automatically returning to their initial state under certain earthquake conditions. If an isolation structure produces significant residual deformation in the isolation layer, it may adversely affect equipment and pipelines passing through the isolation layer, thereby limiting the normal use of the main structure. If the isolation structure produces large residual deformation, it is very difficult to return the isolation layer to its original position after the deformation stabilizes. Significant residual deformation also makes it difficult for the isolation device to continue to function effectively during multiple aftershocks or future earthquakes. At the same time, under certain strong earthquakes, the deformation of the isolation bearing may exceed the expected design displacement, resulting in shear failure of the isolation bearing itself. Although existing isolation design standards have provisions for the post-deformation restoring force of the isolation bearing, most of them are essentially based on increasing the post-yield stiffness of the bearing to increase the restoring force. If the post-yield stiffness of the isolation bearing is large, the isolation effect on the superstructure will be weakened. In addition, based on the current isolation design method, the effect is more obvious under large earthquakes, but the isolation effect is relatively weak under moderate earthquakes, and there is a problem that the isolation effect is difficult to achieve under earthquake inputs of different intensities. Summary of the Invention

[0003] The present invention provides a self-resetting negative stiffness seismic isolation bearing to solve the above technical problems in the prior art.

[0004] The technical solution adopted by the present invention is to provide a self-resetting negative stiffness isolation bearing, comprising:

[0005] A self-resetting element and a top plate, an upper arc-shaped body, a rocking body, a lower arc-shaped body, and a bottom plate arranged coaxially;

[0006] The upper cambered body is fixedly mounted or integrally formed on the bottom of the top plate, the lower cambered body is fixedly mounted or integrally formed on the top of the bottom plate, and the rocking body is located between the upper cambered body and the lower cambered body;

[0007] The middle part of the bottom of the upper cambered body is a horizontal surface, and a first slot is provided in the middle of the horizontal surface, and the rest of the bottom of the upper cambered body is a spherical cambered surface; the middle part of the top of the lower cambered body is a horizontal surface, and a second slot is provided in the middle of the horizontal surface, and the rest of the top of the lower cambered body is a spherical cambered surface; the upper end surface and the lower end surface of the rocking body are respectively provided with an upper shear block and a lower shear block, the upper shear block is located in the first slot, and the lower shear block is located in the second slot;

[0008] The self-resetting elements are symmetrically arranged on both sides of the upper arc-shaped body, the rocking body and the lower arc-shaped body, and the two ends of the self-resetting elements are respectively connected to the top plate and the bottom plate to achieve self-resetting of the support under strong earthquakes.

[0009] Furthermore, a first sunken groove is provided in the middle of the upper end surface of the top plate, and the top plate and the upper arc surface body are fixedly connected by a plurality of first bolts; a second sunken groove is provided in the middle of the lower end surface of the bottom plate, and the bottom plate and the lower arc surface body are fixedly connected by a plurality of second bolts.

[0010] Furthermore, the first clamping slot and the second clamping slot are truncated cone-shaped, and the upper anti-shear clamping block and the lower anti-shear clamping block are cylindrical or hemispherical.

[0011] Furthermore, the self-resetting element includes a rod body, a buckling restraint sleeve and a blocking nut. The rod body includes a threaded section, a sliding section, a threaded section, a deformation section, a threaded section, an installation and fixing section, and a threaded section from one end to the other end; a blocking nut is installed on each threaded section, and the buckling restraint sleeve is sleeved on the deformation section.

[0012] Furthermore, the diameter d of the thread segment t >1.3×diameter d of deformation section SMA The diameters of the sliding section, the installation and fixing section and the deformation section are the same, all d SMA .

[0013] Furthermore, the inner diameter d of the buckling restraining sleeve is tube =d SMA +(l2-l4)ν / l2, ν is the Poisson's ratio of the material, l2 is the length of the deformation section, and l4 is the length of the buckling restraint sleeve.

[0014] Furthermore, the sliding section and the installation and fixing section are respectively fixed between the top plate and the bottom plate through the upper connecting plate and the lower connecting plate; the upper connecting plate is fixed to the lower end surface of the top plate, and a first U-shaped long hole is provided on the upper connecting plate; the lower connecting plate is fixed to the upper end surface of the bottom plate, and a second U-shaped long hole is provided on the lower connecting plate; the first U-shaped long hole is located in the middle of the sliding section, and the second U-shaped long hole is located in the installation and fixing section.

[0015] Furthermore, the length of the sliding segment l1 = 2×0.6d total +b4,d total is the maximum displacement of the support deformation design, b4 is the thickness of the upper connecting plate and the lower connecting plate; and l3=b4, l3 is the length of the installation and fixing section.

[0016] Furthermore, the rod body is made of superelastic shape memory alloy.

[0017] The beneficial effects of the present invention are as follows: the support of the present invention includes an upper cambered body, a lower cambered body and a rocking body. When the seismic force is relatively small, the rocking body does not undergo rocking deformation to resist the effects of small earthquakes or wind loads. When the seismic force increases, the rocking body begins to rock and deform. When the rocking deformation gradually increases, the support produces negative stiffness behavior due to the mutual contact between the spherical arc surfaces of the upper cambered body, the lower cambered body and the rocking body. Therefore, under the action of an earthquake, the support can not only provide vertical bearing capacity, but also reduce the stiffness of the entire isolation layer due to the negative stiffness provided by the support, thereby effectively playing the role of seismic isolation. Secondly, a reset element is provided in the support of the present invention, which can not only limit the excessive deformation of the support under strong earthquakes, but also, due to its self-reset characteristics, can effectively reduce the influence of the residual deformation of the isolation layer after the earthquake, thereby ensuring the advantage of rapid recovery of the isolation structure's use function after the earthquake. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a front view of the self-resetting negative stiffness isolation bearing disclosed in the present invention;

[0019] Figure 2 It is a right side view of the self-resetting negative stiffness seismic isolation bearing disclosed in the present invention;

[0020] Figure 3 This is an axonometric drawing of the self-resetting negative stiffness seismic isolation bearing disclosed in the present invention;

[0021] Figure 4 A top view of the self-resetting negative stiffness seismic isolation bearing disclosed in the present invention;

[0022] Figure 5 for Figure 4 AA section view;

[0023] Figure 6A top view of the upper curved surface disclosed in the present invention;

[0024] Figure 7 It is a front view of the upper arc-shaped body disclosed in the present invention;

[0025] Figure 8 for Figure 6 BB cross-sectional view;

[0026] Figure 9 It is a bottom view of the upper arc-shaped body disclosed in the present invention;

[0027] Figure 10 It is an axonometric drawing of the upper cambered body disclosed in the present invention;

[0028] Figure 11 It is a front view of the rocking body disclosed in the present invention;

[0029] Figure 12 It is an axonometric view of the swing body disclosed in the present invention;

[0030] Figure 13 It is a cross-sectional view of the lower curved body disclosed in the present invention;

[0031] Figure 14 A bottom view of the base plate disclosed in the present invention;

[0032] Figure 15 It is an axonometric view of the reset element disclosed in the present invention;

[0033] Figure 16 It is a front view of the rod body disclosed in the present invention;

[0034] Figure 17 is an axonometric view of the buckling restraint sleeve disclosed in the present invention;

[0035] Figure 18 It is an axonometric view of the blocking nut disclosed in the present invention;

[0036] Figure 19 This is an axonometric view of the upper connecting plate disclosed in the present invention;

[0037] Figure 20 This is an axonometric view of the lower connecting plate disclosed in the present invention.

[0038] Figure markings: 1-top plate, 11-upper end surface of the top plate, 12-first sunken groove, 13-first bolt, 14-first bolt hole, 2-upper arc surface, 21-first slot, 22-second bolt hole, 3-swinging body, 31-upper shear block, 32-lower shear block, 4-lower arc surface, 41-second slot, 42-third bolt hole, 5-bottom plate, 51-lower end surface of the bottom plate, 52-second sunken groove, 53-second bolt, 54-fourth bolt hole, 6-resetting element, 61-sliding section, 62-deformation section, 63-installation and fixing section, 64-threaded section, 65-buckling restraint sleeve, 66-blocking nut, 7-upper connecting plate, 71-first U-shaped long hole, 8-lower connecting plate, 81-second U-shaped long hole. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings, but the embodiments of the present invention are not limited thereto. It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected" to another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0040] In the present invention, terms such as "upper," "lower," "left," "right," "front," "back," "top," "bottom," "inner," "outer," "center," "vertical," "horizontal," "transverse," and "longitudinal" indicate positions or locations based on the positions or locations shown in the accompanying drawings. These terms are primarily intended to better describe the present invention and its embodiments and are not intended to limit the devices, elements, or components indicated to having a specific orientation, or to being constructed or operated in a specific orientation.

[0041] Furthermore, some of the above terms may be used to express other meanings besides indicating a position or location. For example, the term "on" may also be used to indicate a dependency or connection in certain circumstances. Those skilled in the art will understand the specific meanings of these terms in the present invention based on the specific circumstances.

[0042] Furthermore, the terms "installed," "disposed," "provided with," "connected," and "connected" should be interpreted broadly. For example, they can refer to fixed connections, removable connections, or integral structures; mechanical connections; direct connections, indirect connections through an intermediary, or internal communication between two devices, elements, or components. Those skilled in the art will understand the specific meanings of these terms in the present invention based on specific circumstances.

[0043] Example 1:

[0044] See also Figure 1-Figure 5 , this embodiment discloses a self-resetting negative stiffness seismic isolation bearing, comprising: a self-resetting element 6 and a top plate 1, an upper arc surface body 2, a rocking body 3, a lower arc surface body 4, and a bottom plate 5 arranged coaxially; the upper arc surface body 2 is fixedly installed or integrally formed at the bottom of the top plate 1, the lower arc surface body 4 is fixedly installed or integrally formed at the top of the bottom plate 5, and the rocking body 3 is located between the upper arc surface body 2 and the lower arc surface body 4; the middle part of the bottom of the upper arc surface body 2 is a horizontal plane, and a first slot 21 is provided in the middle of the horizontal plane, and the rest of the bottom of the upper arc surface body 2 is a spherical arc surface; the lower arc surface body 4 The middle part of the top is a horizontal surface, and a second slot 41 is provided in the middle of the horizontal surface. The rest of the top of the lower arc-shaped body 4 is a spherical arc surface. The upper end surface and the lower end surface of the rocking body 3 are respectively provided with an upper shear block 31 and a lower shear block 32. The upper shear block 31 is located in the first slot 21, and the lower shear block 32 is located in the second slot 41. The self-resetting element 6 is symmetrically provided on both sides of the upper arc-shaped body 2, the rocking body 3 and the lower arc-shaped body 4, and the two ends of the self-resetting element 6 are respectively connected to the top plate 1 and the bottom plate 5 to achieve self-resetting of the support under strong earthquakes.

[0045] For details, see Figure 4 The top plate 1 is provided with a first sinking groove 12 in the middle of the upper end surface 11, and the top plate 1 is fixedly connected to the upper arc surface body 2 by a plurality of first bolts 13. The top plate 1 is also provided with first bolt holes 14 around it for connecting with the upper main structure. Figure 14 A second sinking groove 52 is provided in the middle of the lower end surface 51 of the bottom plate, and the bottom plate 5 is fixedly connected to the lower arc-shaped body 4 by a plurality of second bolts 53. The bottom plate 5 is also provided with fourth bolt holes 54 around it for connecting with the lower main structure.

[0046] For details, see Figures 6-10, the top end face of the upper arc body 2 is a horizontal plane with a diameter of B1, and a plurality of second bolt holes 22 are provided around its edge for connection with the first bolt 13. The middle part of the bottom of the upper arc body 2 is a horizontal plane with a diameter of b1, and a first slot 21 is provided in the middle of the horizontal plane, and the rest of the bottom of the upper arc body 2 is a spherical arc surface. The seismic isolation bearing is designed not to undergo swing deformation under the action of small earthquakes or wind loads, so the horizontal plane diameter b1 of the middle part of the bottom is determined according to when the bearing undergoes swing deformation. When the swing deformation gradually increases, due to the mutual contact between the spherical arc surfaces of the upper arc body 2 and the lower arc body 4 and the rocking body, the bearing produces negative stiffness behavior. In order to coordinate the realization of the negative stiffness mechanism of the bearing so that the rocking body can swing freely, the first slot 21 is designed to be truncated cone-shaped (that is, the diameter from the opening to the bottom of the slot gradually increases), the opening diameter is b2, and the depth is h1. For the structure of the lower arc body 4, see Figure 13 The bottom of the lower arc-shaped body 4 is horizontal, and a plurality of third bolt holes 42 are provided around its edge for connection with the second bolts 53. The structure of the lower arc-shaped body 4 is the same as that of the upper arc-shaped body 2, and the upper arc-shaped body 2 and the lower arc-shaped body 4 are mirror-imaged at the top and bottom of the rocking body 3.

[0047] See also Figure 11 and Figure 12 The rocking body 3 is cylindrical, and its upper and lower end surfaces are respectively provided with an upper shear block 31 and a lower shear block 32, each with a diameter of b3. The upper and lower shear blocks 31 and 32 are cylindrical. In order to facilitate the installation of the rocking body and allow it to swing and deform freely, the diameter of the groove in the arcuate body is preferably b2 = 1.05b3; in order to allow the upper and lower shear blocks 31 and 32 to be inserted into the first and second slots 21 and 41 and also meet the requirements of their swing deformation, h2 must be met.

[0048] See also Figures 15-18 The self-resetting element 6 includes a rod body, a buckling restraining sleeve 65 and a blocking nut 66. The rod body includes a threaded section 64, a sliding section 61, a threaded section 64, a deformation section 62, a threaded section 64, a mounting and fixing section 63, and a threaded section 64 from one end to the other; a blocking nut 66 is installed on each threaded section 64, and the buckling restraining sleeve 65 is sleeved on the deformation section 62.

[0049] Specifically, the reset elements 6 are symmetrically arranged on both sides of the support, and can be arranged in one pair or multiple pairs according to the actual bearing capacity requirements of the support.​

[0050] In order to concentrate the deformation of the reset element 6 on the deformation section and ensure that the threaded section 64 remains elastic during the entire deformation process, it is preferred that the diameter d of the threaded section 64 t > 1.3 × the diameter d of the deformation section 62 SMA . For the convenience of design, the diameters of the sliding section 61, the installation and fixing section 63 and the deformation section 62 are the same, all being d SMA . In order to prevent the deformation section 62 from buckling when being compressed and deformed, a buckling restraint sleeve 65 is designed on the deformation section 62. The inner diameter of the buckling restraint sleeve 65 is preferably d tube = d SMA +(l2 - l4)ν / l2, where ν is the Poisson's ratio of the material, l2 is the length of the deformation section 62, and l4 is the length of the buckling restraint sleeve 65. The superelastic shape memory alloy rod of the rod body of the reset element 6 is preferably processed from superelastic shape memory alloy materials such as nickel-titanium-based and copper-based, or can also be made of other materials with deformation and reset characteristics. The shape memory alloy screw can provide a large deformation limit and a post-earthquake reset mechanism through the mutual relationship between the U-shaped long holes of the upper and lower connecting plates and the limit nuts at the threaded section of itself

[0051] Specifically, the sliding section 61 and the installation and fixing section 63 are respectively fixed between the top plate 1 and the bottom plate 5 through the upper connecting plate 7 and the lower connecting plate 8. As Figure 19-20 shown, the upper connecting plate 7 is welded and fixed to the lower end surface of the top plate 1, and a first U-shaped long hole 71 is opened on the upper connecting plate 7; the lower connecting plate 8 is welded and fixed to the upper end surface of the bottom plate 5, and a second U-shaped long hole 81 is opened on the lower connecting plate 8; the first U-shaped long hole 71 is located at the middle position of the sliding section 61, and the second U-shaped long hole 81 is located at the installation and fixing section 63, and b4 is the thickness of the upper connecting plate 7 and the lower connecting plate 8

[0052] For the convenience of installation, it is necessary to satisfy d SMA < d1. In order to enable the reset element to neither affect the normal deformation of the bearing under medium earthquake action and at the same time play the role of limiting and resetting under large earthquakes, the length of the sliding section 61 in the reset element 6 is preferably l1 = 2×0.6d total + b4, d total is the maximum displacement designed for the deformation of the bearing. The design parameters of the lower connecting plate 8 and the upper connecting plate 7 are the same. In order to completely fix the lower connecting plate 8 and the reset element 6, it is preferred that l3 = b4

[0053] The advantage of the present invention is that the support includes an upper cambered body 2, a lower cambered body 4 and a rocking body 3. When the seismic force is relatively small, the rocking body 3 does not undergo rocking deformation. When the seismic force increases, the rocking body 3 begins to rock and deform and provides negative stiffness for the support. Due to the mutual contact between the upper cambered body 2, the lower cambered body 4 and the rocking body 3, the support can not only provide vertical bearing capacity, but also reduce the stiffness of the entire isolation layer due to the negative stiffness provided by the support, which can effectively play the role of seismic isolation. Secondly, a reset element 6 is provided in the support of the present invention, which not only limits the excessive deformation of the support under strong earthquakes, but also, due to its self-reset characteristics, can effectively reduce the influence of the residual deformation of the isolation layer after the earthquake, thereby ensuring the advantage of rapid recovery of the isolation structure's use function after the earthquake. When the bearing provides negative stiffness, it can effectively solve the problem that traditional seismic isolation bearings are difficult to exert their isolation effect under earthquake inputs of different intensities; the shape memory alloy screw can slide freely when the bearing deformation is small, and when the bearing deformation is large, the shape memory alloy screw plays a horizontal limit and provides reset ability, which can effectively solve the problem of large deformation damage of the seismic isolation bearing and difficulty in reset after the earthquake.

[0054] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A self-resetting negative stiffness isolation bearing, characterized in that: include: A self-resetting element and a top plate, an upper arc-shaped body, a rocking body, a lower arc-shaped body, and a bottom plate arranged coaxially; The upper cambered body is fixedly mounted or integrally formed on the bottom of the top plate, the lower cambered body is fixedly mounted or integrally formed on the top of the bottom plate, and the rocking body is located between the upper cambered body and the lower cambered body; The middle part of the bottom of the upper cambered body is a horizontal surface, and a first slot is provided in the middle of the horizontal surface, and the rest of the bottom of the upper cambered body is a spherical cambered surface; the middle part of the top of the lower cambered body is a horizontal surface, and a second slot is provided in the middle of the horizontal surface, and the rest of the top of the lower cambered body is a spherical cambered surface; the upper end surface and the lower end surface of the rocking body are respectively provided with an upper shear block and a lower shear block, the upper shear block is located in the first slot, and the lower shear block is located in the second slot; The self-resetting elements are symmetrically arranged on both sides of the upper arc-shaped body, the rocking body and the lower arc-shaped body, and the two ends of the self-resetting elements are respectively connected to the top plate and the bottom plate to achieve self-resetting of the support under strong earthquakes.

2. The self-resetting negative stiffness isolation bearing according to claim 1, characterized in that: A first sinking groove is provided in the middle of the upper end surface of the top plate, and the top plate is fixedly connected to the upper cambered body by a plurality of first bolts; a second sinking groove is provided in the middle of the lower end surface of the bottom plate, and the bottom plate is fixedly connected to the lower cambered body by a plurality of second bolts.

3. The self-resetting negative stiffness isolation bearing according to claim 1, characterized in that: The first clamping slot and the second clamping slot are truncated cone-shaped, and the upper anti-shear clamping block and the lower anti-shear clamping block are cylindrical or hemispherical.

4. The self-resetting negative stiffness isolation bearing according to claim 1, characterized in that: The self-resetting element includes a rod body, a buckling restraint sleeve and a blocking nut. The rod body includes a threaded section, a sliding section, a threaded section, a deformation section, a threaded section, an installation and fixing section, and a threaded section from one end to the other; a blocking nut is installed on each threaded section, and the buckling restraint sleeve is sleeved on the deformation section.

5. The self-resetting negative stiffness isolation bearing according to claim 4 is characterized in that: The diameter of the thread segment d t >1.3×diameter of deformation section d SMA The diameters of the sliding section, the installation and fixing section and the deformation section are the same, all of which are d SMA .

6. The self-resetting negative stiffness isolation bearing according to claim 5, characterized in that: The inner diameter of the buckling restraining sleeve d tube = d SMA +( l 2 - l 4) ν / l 2, ν is the Poisson's ratio of the material, l 2 is the length of the deformation segment, l 4 is the length of the buckling restraint sleeve.

7. The self-resetting negative stiffness isolation bearing according to claim 4, characterized in that: The sliding section and the installation and fixing section are respectively fixed between the top plate and the bottom plate through the upper connecting plate and the lower connecting plate; the upper connecting plate is fixed to the lower end surface of the top plate, and a first U-shaped long hole is provided on the upper connecting plate; the lower connecting plate is fixed to the upper end surface of the bottom plate, and a second U-shaped long hole is provided on the lower connecting plate; the first U-shaped long hole is located in the middle of the sliding section, and the second U-shaped long hole is located in the installation and fixing section.

8. The self-resetting negative stiffness isolation bearing according to claim 7, characterized in that: The length of the sliding section l 1 = 2 × 0.6 d total + b 4. d total is the maximum displacement designed for support deformation, b 4 is the thickness of the upper connecting plate or the lower connecting plate; and l 3= b 4. l 3 is the length of the installation fixed section.

9. The self-resetting negative stiffness isolation bearing according to claim 4, characterized in that: The rod body is made of superelastic shape memory alloy.

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