SMA-polyurethane self-adaptive self-resetting three-dimensional seismic isolation support and design method thereof

Abstract

The invention provides an SMA-polyurethane self-adaptive self-resetting three-dimensional seismic isolation support and a design method thereof. The support comprises a stainless steel mirror surface located at the bottom, a polyfluortetraethylene plate is arranged on the stainless steel mirror surface, and a slotted steel plate is arranged above the polyfluortetraethylene plate; four steel bars are arranged at four corners of the upper surface of the slotted steel plate; the steel bar, the slotted steel plate and the polyfluortetraethylene plate are fixed and then placed in the middle of the stainless steel mirror surface, and the four hinged supports are fixed to the four corners of the stainless steel mirror surface and used for fixing the SMA beams; a plurality of layers of polyurethane shock pads and a plurality of layers of steel plates are stacked on the slotted steel plate at intervals, and the polyurethane shock pads and the steel plates are bonded with each other; the steel sleeve is embedded in the middle of the four steel bars and then placed on the uppermost steel plate, the four rotatable pulleys are fixed to the four corners of the uppermost steel plate, and the four directional pulleys are fixed to the positions, close to the steel bars, of the uppermost steel plate and used for fixing the path of an SMA beam. According to the invention, the self-resetting performance in the horizontal direction is realized while the self-adaption of the vertical rigidity is met.

Description

Technical Field

[0001] The present invention relates to the technical field of vibration reduction and isolation, and in particular to an SMA-polyurethane adaptive self-resetting three-dimensional vibration isolation bearing and a design method thereof. The three-dimensional vibration isolation bearing can be used for vibration reduction of common buildings, transportation hub structures and equipment. Background Art

[0002] Earthquakes are a natural disaster that is difficult to predict and has great destructive power. They not only cause direct casualties, but also have an impact on buildings, bridges, roads, etc. my country is located between the Pacific Rim seismic belt and the Eurasian seismic belt. It is one of the countries with the most frequent seismic activities and the most serious earthquake disasters in the world. The traditional seismic design method is mainly to improve the overall stiffness of the structure to resist earthquakes. This not only costs a lot of manpower, material resources and financial resources, but also cannot play a good seismic effect. Therefore, the development of seismic isolation technology has received people's attention.

[0003] The traditional view is that compared with horizontal earthquake action, vertical earthquake action is smaller and the structure has a large vertical bearing redundancy, which generally does not cause serious impact on the structure. Therefore, most of the isolation bearings can achieve horizontal isolation but not vertical isolation. However, earthquake is a complex three-dimensional spatial movement, including horizontal and vertical movements. According to a large number of earthquake records and earthquake field survey results in recent years, the destructive effect of vertical earthquake on buildings cannot be ignored.

[0004] Traditional spring three-dimensional seismic isolation bearings do not have variable stiffness characteristics and may not be able to provide sufficient seismic resistance, especially in the face of extreme or unknown earthquake events. Rubber three-dimensional seismic isolation bearings may fatigue, age or degrade after long-term cyclic loading, which may affect the performance and life of the bearings. In addition, the mechanical properties of rubber are greatly affected by temperature. High temperature may cause the rubber to soften and reduce its bearing capacity; low temperature may harden the rubber and increase stiffness. Viscoelastic three-dimensional seismic isolation bearings may not provide sufficient stiffness and bearing capacity in vertical bearing, and may creep and relax under long-term loads. Traditional three-dimensional seismic isolation bearings often cannot achieve both vertical stiffness adaptation and horizontal self-reset performance. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of traditional three-dimensional seismic isolation bearings, such as the inability to achieve both vertical stiffness adaptation and horizontal self-resetting performance, the lack of durability due to easy aging of materials, and the lack of bearing capacity. An SMA-polyurethane adaptive self-resetting three-dimensional seismic isolation bearing and its design method are proposed, which can have good seismic reduction and isolation effects on horizontal and vertical earthquakes, and while meeting the vertical stiffness adaptation requirements, it also has self-resetting properties in the horizontal direction, thereby exerting a good seismic isolation effect.

[0006] The above purpose is achieved through the following technical solutions:

[0007] The present invention first provides an SMA-polyurethane adaptive self-resetting three-dimensional seismic isolation bearing, comprising a stainless steel mirror at the bottom, a polytetrafluoroethylene plate arranged on the stainless steel mirror, a slotted steel plate arranged above the polytetrafluoroethylene plate, a rectangular groove consistent with the size of the polytetrafluoroethylene plate on the lower surface of the slotted steel plate for embedding the polytetrafluoroethylene plate into the rectangular groove and bonding and fixing the polytetrafluoroethylene plate to the lower surface of the slotted steel plate; four threaded holes are arranged at the four corners of the upper surface of the slotted steel plate for installing four steel rods; after the steel rod, the slotted steel plate and the polytetrafluoroethylene plate are fixed, they are placed in the middle position of the stainless steel mirror, and four hinge supports are fixed at the four corners of the stainless steel mirror for fixing the SMA bundle; multiple layers of polyurethane shock-absorbing pads and multiple layers of steel plates are stacked on the slotted steel plate at intervals, and the polyurethane shock-absorbing pads and the steel plates are bonded to each other. The polyurethane shock-absorbing pad and the steel plate are provided with circular holes at the four corners that are the same size as the cross-sectional dimensions of the steel rod so that the steel rod can pass through them. The steel sleeve is embedded in the middle of the four steel rods and placed on the top steel plate. Four rotatable pulleys are fixed at the four corners of the top steel plate, and four directional pulleys are fixed on the top steel plate near the steel rods to fix the path of the SMA bundle.

[0008] Furthermore, a stopper is provided at the pulley edge of the rotating pulley and the directional pulley, and the pulley head of the rotating pulley can rotate 360 ​​degrees.

[0009] Furthermore, the directional pulley extends into the middle opening of the steel rod so that the section of the SMA bundle in the steel rod is vertically downward and the middle section connected to the vertical section is horizontal.

[0010] Furthermore, the steel rod is hollow and has a rectangular hole in the middle; the upper end of the inner side of the steel rod (4) is provided with a thread, and the lower end is provided with a bolt hole.

[0011] Furthermore, the four directional pulleys are fixed at a position of the topmost steel plate close to the steel rod, and the path for fixing the SMA bundle is specifically as follows: a thread is provided at the upper end of the steel rod for fixing a bolt, the size of the bolt is consistent with the thread size at the upper end of the steel rod, and there are connecting ports at the lower ends of the bolt and the fixing hook, one end of the SMA bundle is fixed on the bolt, and the other end is connected to the hinge support through the fixing hook.

[0012] The present invention also provides a design method for the above-mentioned SMA-polyurethane adaptive self-resetting three-dimensional seismic isolation bearing, and the parameters are designed according to the vertical stiffness K required by the design of the installation structure. The specific method is as follows:

[0013] The vertical stiffness K of the support consists of two parts:

[0014] K=k e +k SMA (1)

[0015] Where K is the vertical stiffness of the support, k e The vertical stiffness provided by the polyurethane elastomer, k SMA The vertical stiffness provided to the SMA bundle;

[0016]

[0017] Where F e is the vertical reaction force provided by the polyurethane elastomer, and Δz is the vertical compression of the support;

[0018] F e =σ e ·A e (3) where σ e is the vertical compressive stress of polyurethane elastomer, A e is the area of ​​the polyurethane elastomer;

[0019] σ e =E e γ e (4)

[0020] Where E e is the static compression modulus of the polyurethane elastomer in the support. It is necessary to introduce a correction factor to correct the vertical stiffness of the support. The correction factor includes a reduction factor λ and a constraint enhancement factor β:

[0021] E e =λ·β·E d (5)

[0022] Where E e is the static compression modulus of the polyurethane elastomer in the support, E d is the compression modulus of the polyurethane elastomer, which is determined by the material properties of the selected polyurethane elastomer;

[0023] γ e is the vertical compressive strain of the polyurethane elastomer:

[0024]

[0025] Where T e is the total thickness of the polyurethane elastomer:

[0026] T e =n·t e (7)

[0027] Where n is the number of layers of the polyurethane elastomer, t e is the thickness of a single layer of polyurethane elastomer;

[0028]

[0029] Where k SMA The vertical stiffness provided by the SMA bundle, F SMAz is the reaction force provided by an SMA bundle in the vertical direction;

[0030] By decomposing the force of an SMA beam into the vertical direction, we can get F SMAz ;

[0031]

[0032] Where F SMA is the force of an SMA bundle, L x1 , L z1 are the distances of the SMA bundle oblique line segment projected to the horizontal and vertical directions, respectively;

[0033] F SMA =A SMA ·σ SMA (10)

[0034] Where A SMA is the cross-sectional area of ​​the SMA bundle, σ SMA is the stress of the SMA bundle;

[0035] σ SMA =ε SMA ·E SMA (11)

[0036] Where ε SMA is the strain of the SMA bundle, E SMA is the elastic modulus of the SMA bundle;

[0037]

[0038] Where ΔL SMA is the elongation of the SMA bundle, L SMA is the length of the SMA bundle in the initial state;

[0039]

[0040]

[0041] Where L x2 is the length of the horizontal section of the SMA bundle, L z2 is the length of the vertical section of the SMA bundle;

[0042] The vertical stiffness K of the support is obtained by combining equations (1)-(14);

[0043]

[0044] The area A of the polyurethane elastomer is e, the total thickness of the polyurethane elastomer T e , the cross-sectional area of ​​the SMA bundle A SMA , the length of the horizontal section of the SMA bundle L x2 , the length of the vertical section of the SMA bundle L z2 , the distance L from the oblique line segment of the SMA beam to the horizontal direction x1 , the distance L from the projection of the oblique line segment of the SMA bundle to the vertical direction z1 Adjustments are made until the vertical stiffness K required by the design of the installation structure is met.

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] 1. The present invention can achieve both horizontal and vertical seismic isolation. The horizontal seismic isolation system can provide superior horizontal seismic isolation effect and ensure the safety and stability of the upper structure under a large earthquake. The vertical seismic isolation system can not only effectively isolate environmental vibration and vertical ground motion, but also reduce shock and energy consumption, consume earthquake energy, and better ensure the safety of buildings, bridges and other structures.

[0047] 2. The present invention has good adaptability. While satisfying the vertical stiffness adaptability, it also has the self-reset property in the horizontal direction. The greater the vertical load on the support, the greater the vertical stiffness provided by the support.

[0048] 3. The present invention uses an SMA bundle to be fixed on a bolt, and the bolt is screwed on the thread at the upper end of the steel rod. This not only fixes the SMA bundle, but also adjusts the tightness of the SMA bundle by screwing the bolt, which is easy to operate.

[0049] 4. The present invention adopts a new material polyurethane shock-absorbing pad, which is more wear-resistant, more durable, and more tear-resistant than traditional rubber pads, and has a higher bearing capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 It is a structural schematic diagram of the SMA-polyurethane adaptive self-resetting three-dimensional seismic isolation bearing of the present invention;

[0051] Figure 2 It is a schematic diagram of the planar structure of the SMA-polyurethane adaptive self-resetting three-dimensional seismic isolation bearing of the present invention;

[0052] Figure 3 This is a schematic diagram of the steel sleeve structure of the SMA-polyurethane adaptive self-resetting three-dimensional seismic isolation support of the present invention. Figure 3 In the figure, (a) is a front view of the steel sleeve, (b) is a top view of the steel sleeve, and (c) is a side view of the steel sleeve;

[0053] Figure 4This is a schematic diagram of the horizontal seismic isolation working principle of the SMA-polyurethane adaptive self-resetting three-dimensional seismic isolation support of the present invention. Figure 4 Among them, (a) is a schematic diagram of the support without horizontal displacement, (b) is a schematic diagram of the support with horizontal displacement to the left, and (c) is a schematic diagram of the support with horizontal displacement to the right;

[0054] Figure 5 This is a schematic diagram of the vertical seismic isolation working principle of the SMA-polyurethane adaptive self-resetting three-dimensional seismic isolation support of the present invention. Figure 5 In the figure, (a) is a schematic diagram of the support when it is not subjected to vertical compression, and (b) is a schematic diagram of the support deformation when it is subjected to vertical compression;

[0055] Figure 6 This is a schematic diagram of the rotatable pulley structure of the SMA-polyurethane adaptive self-resetting three-dimensional seismic isolation support of the present invention. Figure 6 In the figure, (a) is a three-dimensional schematic diagram of a rotating pulley, (b) is a front view of the rotating pulley, and (c) is a top view of the rotating pulley;

[0056] Figure 7 This is a schematic diagram of the SMA-polyurethane adaptive self-resetting three-dimensional seismic isolation support steel rod structure of the present invention. Figure 7 In the figure, (a) is a three-dimensional schematic diagram of the steel rod, (b) is a front view of the steel rod, (c) is a side view of the steel rod, and (d) is a schematic diagram of the internal structure of the steel rod;

[0057] Figure 8 This is a schematic diagram of the hinge support structure of the SMA-polyurethane adaptive self-resetting three-dimensional seismic isolation support of the present invention;

[0058] Fig. 9 This is a schematic diagram of the structure of the fixing hook of the SMA-polyurethane adaptive self-resetting three-dimensional seismic isolation support of the present invention;

[0059] Fig.10 This is a schematic diagram of the structure of the SMA-polyurethane adaptive self-resetting three-dimensional seismic isolation support bolt of the present invention;

[0060] Fig.11 This is a schematic diagram of the structure of the SMA-polyurethane adaptive self-resetting three-dimensional seismic isolation support directional pulley of the present invention. Fig.11 In the figure, (a) is a three-dimensional schematic diagram of a directional pulley, (b) is a front view of the directional pulley, and (c) is a side view of the directional pulley;

[0061] Fig.12 This is a deformation diagram of an SMA beam of the SMA-polyurethane adaptive self-resetting three-dimensional seismic isolation bearing of the present invention under vertical load;

[0062] Fig.13 This is a schematic diagram of the structure of the slotted steel plate of the SMA-polyurethane adaptive self-resetting three-dimensional seismic isolation support of the present invention. Fig.13In the figure, (a) is a front view of the slotted steel plate, (b) is a top view of the slotted steel plate, and (c) is a side view of the slotted steel plate;

[0063] Fig.14 This is a schematic diagram of the structure of the upper and lower connecting plates of the SMA-polyurethane adaptive self-resetting three-dimensional seismic isolation support of the present invention. Fig.14 In the figure, (a) is a front view of the upper and lower connecting plates, (b) is a top view of the upper and lower connecting plates, and (c) is a side view of the upper and lower connecting plates;

[0064] Fig.15 The vertical load and vertical stiffness relationship curve of the example taken for the SMA-polyurethane adaptive self-resetting three-dimensional seismic isolation bearing of the present invention;

[0065] Explanation of the reference numerals in the figure: 1-stainless steel mirror; 2-slotted steel plate; 3-polytetrafluoroethylene plate; 4-steel rod; 5-hinge support; 6-SMA (shape memory alloy) bundle; 7-polyurethane shock-absorbing pad; 8-steel plate; 9-steel sleeve; 10-rotating pulley; 11-directional pulley; 12-bolt; 13-fixing hook. DETAILED DESCRIPTION

[0066] like Figure 1 , Figure 2 As shown, the present invention provides an SMA-polyurethane adaptive self-resetting three-dimensional seismic isolation bearing device.

[0067] like Figure 1 As shown, the present invention is composed of a stainless steel mirror 1, a slotted steel plate 2, a polytetrafluoroethylene plate 3, a steel rod 4, a hinge support 5, an SMA (shape memory alloy) bundle 6, a polyurethane shock-absorbing pad 7, a steel plate 8, a steel sleeve 9, a rotating pulley 10, a directional pulley 11, a bolt 12, and a fixing hook 13.

[0068] The stainless steel mirror 1 is located at the bottom of the support. The lower surface of the slotted steel plate 2 has a rectangular groove that is consistent with the size of the polytetrafluoroethylene plate 3. The upper surface has four circular grooves that are consistent with the size of the steel rod 4 and a threaded hole is provided at the center of the circle. Fig.13As shown. The polytetrafluoroethylene plate 3 is embedded in the rectangular groove on the lower surface of the slotted steel plate 2 and is bonded and fixed to the lower surface of the slotted steel plate 2. The lower end of the steel rod 4 is embedded in the circular groove on the upper surface of the slotted steel plate 2 and is fixed to the slotted steel plate 2 by bolt connection. After the steel rod 4, the slotted steel plate 2 and the polytetrafluoroethylene plate 3 are fixed, they are placed in the middle of the stainless steel mirror 1. Four hinge supports 5 are fixed at the four corners of the stainless steel mirror 1 to fix the SMA bundle 6. The polyurethane shock-absorbing pad 7 and the steel plate 8 are both provided with circular holes of the same size as the cross-sectional size of the steel rod at the four corners. A polyurethane shock-absorbing pad 7 and a steel plate 8 are stacked in sequence along the steel rod 4 on the slotted steel plate 2, and the polyurethane shock-absorbing pad 7 and the steel plate 8 are bonded to each other. The steel sleeve 9 is embedded in the middle of the four steel rods 4 and is placed on the topmost steel plate 2. Four rotatable pulleys 10 are fixed at the four corners of the topmost steel plate, and four directional pulleys 11 are fixed at the position of the topmost steel plate close to the steel rod to fix the path of the SMA bundle 5. The rotating pulley 10 and the directional pulley 11 are both provided with a stopper at the edge of the pulley to prevent the SMA bundle 6 from escaping from the pulley. Figure 6 , Fig.11 The upper end of the steel rod 4 has threads for fixing the bolt 12, as shown in FIG. Figure 7 The fixing hook 13 and the lower end of the bolt 12 have SMA bundle connection ports, such as Fig. 9 , Fig.10 As shown. One end of the SMA bundle 6 is fixed on the bolt 12, and the other end is connected to the hinge support 4 through the fixing hook 13. The directional pulley 11 extends into the middle hole of the steel rod so that the section of the SMA bundle 6 in the steel rod is vertically downward and the middle section connected to the vertical section is horizontal, as shown in FIG. Figure 1 shown.

[0069] The structural diagram of the upper and lower connecting plates is shown in Fig.14 As shown, the upper connecting plate is welded on the steel sleeve, and the lower connecting plate is welded on the lower surface of the stainless steel mirror. The upper and lower connecting plates are connected to the upper structure and the lower structure respectively by bolts.

[0070] The working principle of the present invention is as follows:

[0071] The working principle of horizontal seismic isolation is as follows Figure 4 As shown, relative displacement is mainly generated between the polytetrafluoroethylene plate and the stainless steel mirror, and friction energy consumption occurs.

[0072] The working principle of vertical seismic isolation is as follows Figure 5 As shown in the figure, the polyurethane shock-absorbing pad bulges and deforms around under the action of vertical pressure, and the support deforms as shown in the figure. Figure 5 (b) as shown.

[0073] The self-resetting function of the present invention is achieved through the SMA bundle. Under the action of an earthquake, the SMA bundle on one side of the support is stretched, thereby generating a horizontal restoring force to achieve self-resetting.

[0074] Compared with the traditional three-dimensional seismic isolation bearing, the SMA-polyurethane adaptive self-resetting three-dimensional seismic isolation bearing proposed by the present invention not only meets the horizontal self-resetting but also has good vertical variable stiffness adaptability. As the vertical load increases, the vertical stiffness of the bearing also increases.

[0075] The present invention discloses a method for designing an SMA-polyurethane adaptive self-resetting three-dimensional seismic isolation bearing, wherein parameters are designed according to the designed vertical stiffness of the mounting structure, and the specific method is as follows:

[0076] The vertical stiffness of the support consists of two parts;

[0077] K=k e +k SMA (1)

[0078] Where K is the vertical stiffness of the support, k e The vertical stiffness provided by the polyurethane elastomer, k SMA The vertical stiffness provided to the SMA bundle;

[0079]

[0080] Where F e is the vertical reaction force provided by the polyurethane elastomer, and Δz is the vertical compression of the support;

[0081] F e =σ e ·A e (3)

[0082] Where σ e is the vertical compressive stress of polyurethane elastomer, A e is the area of ​​the polyurethane elastomer;

[0083] σ e =E e γ e (4)

[0084] Where E e is the static compression modulus of the polyurethane elastomer in the support, γ e is the vertical compressive strain of the polyurethane elastomer;

[0085] Introduce correction coefficient to correct the vertical stiffness of the support;

[0086] E e =λ·β·E d (5)

[0087] Where E e is the static compression modulus of the polyurethane elastomer in the support, E dis the compression modulus of the polyurethane elastomer. Under static load, the compression modulus needs to be multiplied by a reduction factor λ. In addition, in this design process, the contact surface between the steel plate and the polyurethane is a rough surface, and it is necessary to consider the certain constraint effect of the friction surface on the upper and lower polyurethanes. Therefore, the compression modulus needs to be multiplied by a constraint enhancement coefficient β;

[0088]

[0089] Where T e is the total thickness of the polyurethane elastomer;

[0090] T e =n·t e (7)

[0091] Where n is the number of layers of the polyurethane elastomer, t e is the thickness of a single layer of polyurethane elastomer;

[0092]

[0093] Where k SMA The vertical stiffness provided by the SMA bundle, F SMAz is the reaction force provided by an SMA bundle in the vertical direction;

[0094] Fig.12 This is a schematic diagram of the deformation of an SMA beam under vertical load. By decomposing the force of an SMA beam into the vertical direction, we can get F SMAz ;

[0095]

[0096] Where F SMA is the force of an SMA bundle, L x1 , L z1 They are the distances of the SMA beam oblique line segment projected to the horizontal and vertical directions respectively. Fig.12 ;

[0097] F SMA =A SMA ·σ SMA (10)

[0098] Where A SMA is the cross-sectional area of ​​the SMA bundle, σ SMA is the stress of the SMA bundle;

[0099] σ SMA =ε SMA ·E SMA (11)

[0100] Where ε SMA is the strain of the SMA bundle, E SMAis the elastic modulus of the SMA bundle;

[0101]

[0102] Where ΔL SMA is the elongation of the SMA bundle, L SMA is the length of the SMA bundle in the initial state;

[0103]

[0104]

[0105] Where L x2 is the length of the horizontal section of the SMA bundle, L z2 is the length of the vertical section of the SMA bundle. Fig.12 ;

[0106] The vertical stiffness K of the support can be obtained by combining the above equations;

[0107]

[0108] In this way, the area A of the polyurethane elastomer is e , the total thickness of the polyurethane elastomer T e , the cross-sectional area of ​​the SMA bundle A SMA , the length of the horizontal section of the SMA bundle L x2 , the length of the vertical section of the SMA bundle L z2 , the distance L from the oblique line segment of the SMA beam to the horizontal direction x1 , the distance L from the projection of the oblique line segment of the SMA bundle to the vertical direction z1 Adjustments are made until the vertical stiffness K required by the design of the installation structure is met.

[0109] Application examples:

[0110] Assuming that the SMA beam is elastic under the vertical load, the parameters in the design process are as follows:

[0111] Take the thickness t of a single layer of polyurethane elastomer e =0.08m, side length is L e =0.4m, the number of layers of polyurethane elastomer n=7, the compression modulus of polyurethane elastomer E d =12MPa, the reduction factor λ is 0.8, the constraint enhancement factor β is 1.4, L x1 =0.42m, L z1 =0.42m, L x2 =0.05m, L z2 = 0.05m, cross-sectional area of ​​SMA bundle A SMA =1cm 2 , the elastic modulus E of the SMA bundleSMA =60GPa.

[0112] Take the vertical compressive strain γ of the polyurethane elastomer e 2%, 4%, 6%, 8%, 10%, 12%, 14% and 16% (corresponding vertical vibration frequency is 5.3Hz-14.9Hz) to illustrate the relationship between the vertical load of the support and the vertical stiffness.

[0113] Substituting the above parameters into formula (1)-formula (15), we can obtain the corresponding vertical compressive strain γ e The reaction force F provided by the polyurethane elastomer e , the reaction force F provided by a single SMA bundle in the vertical direction SMAz And the vertical stiffness K of the support.

[0114] Draw the relationship curve between the vertical load and vertical stiffness of the support in this example as shown in Fig.15 It can be found that with the increase of vertical load, the vertical stiffness of the support also increases, showing good vertical stiffness adaptability.

[0115] The above description is only a description of the preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any ordinary technician familiar with the field may make some improvements and modifications without departing from the principle of the present invention, and these improvements and modifications are all within the scope of patent protection of the present invention.

Claims

1. A SMA-polyurethane adaptive self-resetting three-dimensional seismic isolation bearing, characterized in that: The invention comprises a stainless steel mirror surface (1) at the bottom, a polytetrafluoroethylene plate (3) is arranged on the stainless steel mirror surface (1), a slotted steel plate (2) is arranged above the polytetrafluoroethylene plate (3), a rectangular groove having the same size as the polytetrafluoroethylene plate (3) is arranged on the lower surface of the slotted steel plate (2) for embedding the polytetrafluoroethylene plate (3) into the rectangular groove and bonding and fixing it to the lower surface of the slotted steel plate (2); four threaded holes are arranged at the four corners of the upper surface of the slotted steel plate (2) for installing four steel rods (4); the steel rods (4), the slotted steel plate (2) and the polytetrafluoroethylene plate (3) are fixed and placed in the middle of the stainless steel mirror surface (1), and four hinge supports (5) are fixed at the four corners of the stainless steel mirror surface (1) for fixing SMA bundles (6); multiple layers of polyurethane shock-absorbing pads (7) and multiple layers of steel plates (8) are stacked on the slotted steel plate (2) at intervals, and the polyurethane shock-absorbing pads (7) and the steel plates (8) are bonded to each other. The polyurethane shock-absorbing pad (7) and the steel plate (8) are provided with circular holes at four corners with the same size as the cross-sectional dimensions of the steel rod (4) so ​​that the steel rod (4) can pass through them. The steel sleeve (9) is embedded in the middle of the four steel rods (4) and then placed on the topmost steel plate (2). Four rotatable pulleys (10) are fixed at the four corners of the topmost steel plate, and four directional pulleys (11) are fixed at the topmost steel plate near the steel rods to fix the path of the SMA bundle (5).

2. The SMA-polyurethane adaptive self-resetting three-dimensional seismic isolation bearing according to claim 1 is characterized in that: A stopper is provided at the pulley edge of the rotating pulley (10) and the directional pulley (11), and the pulley head of the rotating pulley (10) can rotate 360 ​​degrees.

3. The SMA-polyurethane adaptive self-resetting three-dimensional seismic isolation bearing according to claim 1 is characterized in that: The directional pulley (11) extends into the middle opening of the steel rod so that the section of the SMA (6) bundled in the steel rod is vertically downward and the middle section connected to the vertical section is horizontal.

4. The SMA-polyurethane adaptive self-resetting three-dimensional seismic isolation bearing according to claim 1 is characterized in that: The steel rod (4) is hollow and has a rectangular hole in the middle. The upper end of the inner side of the steel rod (4) is provided with a thread, and the lower end is provided with a bolt hole.

5. The SMA-polyurethane adaptive self-resetting three-dimensional seismic isolation bearing according to claim 1 is characterized in that: The four directional pulleys (11) are fixed at a position of the uppermost steel plate close to the steel rod. The path for fixing the SMA bundle (5) is specifically as follows: the upper end of the steel rod (4) is threaded for fixing the bolt (12), the size of the bolt (12) is consistent with the size of the thread at the upper end of the steel rod (4), and the lower ends of the bolt (12) and the fixing hook (13) are both provided with connection ports, one end of the SMA bundle (6) is fixed on the bolt (12), and the other end is connected to the hinge support (5) through the fixing hook (13).

6. A design method for a SMA-polyurethane adaptive self-resetting three-dimensional seismic isolation bearing as described in claims 1-5, characterized in that: The parameters are designed according to the vertical stiffness K required by the design of the installation structure. The specific method is as follows: The vertical stiffness K of the support consists of two parts: composition: K=k e +k SMA (1) Where K is the vertical stiffness of the support, k e The vertical stiffness provided by the polyurethane elastomer, k SMA The vertical stiffness provided to the SMA bundle; Where F e is the vertical reaction force provided by the polyurethane elastomer, and Δz is the vertical compression of the support; F e =s e ·A e (3) Where σ e is the vertical compressive stress of polyurethane elastomer, A e is the area of ​​the polyurethane elastomer; s e =E e ·c e (4) Where E e is the static compression modulus of the polyurethane elastomer in the support. It is necessary to introduce a correction factor to correct the vertical stiffness of the support. The correction factor includes a reduction factor λ and a constraint enhancement factor β: E e =λ·β·E d (5) Where E e is the static compression modulus of the polyurethane elastomer in the support, E d is the compression modulus of the polyurethane elastomer, which is determined by the material properties of the selected polyurethane elastomer; γ e is the vertical compressive strain of the polyurethane elastomer: Where T e is the total thickness of the polyurethane elastomer: T e =n·t e (7) Where n is the number of layers of the polyurethane elastomer, t e is the thickness of a single layer of polyurethane elastomer; Where k SMA The vertical stiffness provided by the SMA bundle, F SMAz is the reaction force provided by an SMA bundle in the vertical direction; By decomposing the force of an SMA beam into the vertical direction, we can get F SMAz ; Where F SMA is the force of an SMA bundle, L x1 , L z1 are the distances of the SMA bundle oblique line segment projected to the horizontal and vertical directions, respectively; F SMA =A SMA ·s SMA (10) Where A SMA is the cross-sectional area of ​​the SMA bundle, σ SMA is the stress of the SMA bundle; s SMA =e SMA ·E SMA (11) Where ε SMA is the strain of the SMA bundle, E SMA is the elastic modulus of the SMA bundle; Where ΔL SMA is the elongation of the SMA bundle, L SMA is the length of the SMA bundle in the initial state; Where L x2 is the length of the horizontal section of the SMA bundle, L z2 is the length of the vertical section of the SMA bundle; The vertical stiffness K of the support is obtained by combining equations (1)-(14); The area A of the polyurethane elastomer is e , the total thickness of the polyurethane elastomer T e , the cross-sectional area of ​​the SMA bundle A SMA , the length of the horizontal section of the SMA bundle L x2 , the length of the vertical section of the SMA bundle L z2 , the distance L from the oblique line segment of the SMA beam to the horizontal direction x1 , the distance L from the projection of the oblique line segment of the SMA bundle to the vertical direction z1 Adjustments are made until the vertical stiffness K required by the design of the installation structure is met.

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