Anti-overturning variable-rigidity slope friction isolation bearing and design method thereof

Abstract

The invention discloses an anti-overturning variable-rigidity inclined plane friction shock insulation support and a design method of the anti-overturning variable-rigidity inclined plane friction shock insulation support. The support comprises two base assemblies which provide a bidirectional self-resetting function and are orthogonally arranged, a sliding connection assembly is arranged between the two base assemblies and can slide between the base assemblies, and each base assembly comprises a base limiting device and a base provided with sliding rails with different inclination angles. The base of the sliding rails with the different inclination angles comprises outer side sliding rails and an inner side sliding rail, the inner side sliding rail is arranged between the two outer side sliding rails, the outer side sliding rails and the inner side sliding rail are both V-shaped inclined faces, and the inclination angle of the V-shaped inclined faces of the outer side sliding rails is larger than that of the V-shaped inclined faces of the inner side sliding rail. By designing different inclination angles and friction coefficients of the inner and outer sliding rails, the contradiction between the shock insulation rate and the shock insulation layer displacement can be balanced; and meanwhile, when the support is locally pulled or the support tends to be pulled away due to inertia of an upper structure, the support is prevented from being pulled away, and the anti-overturning effect is achieved.

Description

Technical Field

[0001] The invention relates to an anti-overturning variable-rigidity inclined friction isolation support and a design method thereof, which are used in the technical field of isolation control of electrical equipment that is sensitive to vibration and prone to overturning. Background Art

[0002] The earliest friction-sliding isolation system consisted of a friction-sliding mechanism for isolating earthquake action and a damping centripetal mechanism for limited reset, mostly plane-sliding isolation systems. However, this system cannot reset itself, and an additional reset device is required to improve the self-reset performance. In the 1880s, the University of California, Berkeley, developed a friction pendulum isolation device, called the Friction Pendulum System / Bearing (FPS / FPB). This device has the low sensitivity and high stability of the plane-sliding isolation device to the earthquake excitation frequency range, and its unique arc sliding makes it self-reset. When working, it can do pendulum-like motion, extend the self-vibration period of the isolation structure, avoid the outstanding period of the earthquake, and convert kinetic energy into heat energy through the bearing friction pair, reducing the impact of the earthquake on the structure. However, there is still the problem that the residual displacement of the bearing is difficult to eliminate. With the development of isolation technology, inclined friction bearings have become more and more research hotspots due to their stable restoring force and the ability to completely eliminate residual displacement.

[0003] However, the sliding surface of the traditional inclined isolation bearing has a single inclination angle, which makes it difficult to balance the isolation effect and the control of the displacement of the isolation layer. When the inclination angle of the sliding surface is reduced, the bearing can achieve a smaller starting acceleration to ensure the isolation effect of the bearing under small earthquakes. However, a large displacement of the isolation layer is prone to occur in large earthquakes or long-period earthquakes, posing a threat to the safety of the isolation layer. In order to prevent the slider from deviating from the track, the slide rail needs to be extended, but the volume and cost of the isolation bearing will be increased. When the inclination angle of the sliding surface is increased, the displacement of the isolation layer can be effectively controlled, but the starting acceleration will increase, reducing the isolation effect under small earthquakes. The impact effect when the slider passes through the inclined surface transition will also be amplified, reducing the isolation effect. Based on the above, a variable stiffness inclined friction isolation bearing has been developed, which can make up for the shortcomings of the traditional inclined friction isolation bearing and achieve a balance between the isolation effect and the displacement of the isolation layer.

[0004] In addition, by reasonably designing the smaller inclination angle and friction coefficient of the inner slide rail, the seismic isolation effect of the bearing under small earthquakes can be guaranteed; by increasing the inclination angle and friction coefficient of the outer slide rail, the displacement of the seismic isolation layer can be effectively controlled. At the same time, the inner inclination angle also plays a transitional role. The multi-inclination inclined surface setting reduces the instantaneous impact of the sliding connection assembly when passing through the discontinuous inclined surface, thereby improving the stability and applicability of the bearing.

[0005] For some electrical equipment, such as converter valves with a bottom support structure, their high center of gravity makes them very sensitive to vibration. Horizontal vibration can easily lead to the failure of the support structure, vertical vibration is likely to cause damage to the upper power module, and the coupling effect of horizontal and vertical vibrations is prone to local tension in the isolation layer and the phenomenon of the isolation bearing being lifted off. The existing inclined-plane friction isolation bearings are difficult to meet the requirements of electrical equipment for anti-pulling and anti-overturning performance due to their low anti-pulling performance, which is likely to cause damage to electrical equipment under strong earthquakes and seriously affect the popularization and application of isolation technology in the field of electrical isolation. Summary of the Invention

[0006] In view of the above problems, the present invention proposes an anti-overturning variable-stiffness inclined-plane friction isolation bearing and its design method, which takes into account the advantages of traditional inclined-plane friction isolation bearings and makes up for their deficiencies, achieving the balance between the isolation effect and the displacement of the isolation layer. The upper and lower base assemblies arranged orthogonally are connected to the upper equipment and the lower structure. A sliding connection assembly is provided between the upper and lower bases to reduce the transmission of seismic energy to the upper structure and ensure the normal operation of the isolated structure under seismic action. When the isolation bearing is locally tensioned or there is a tendency for the bearing to be lifted off due to the inertia of the upper structure, it can prevent the bearing from being lifted off, and has a wider applicability and stronger reliability compared with traditional inclined-plane friction bearings.

[0007] The above object is achieved by the following technical solutions:

[0008] The present invention first provides an anti-overturning variable-stiffness inclined-plane friction isolation bearing, which includes two base assemblies arranged orthogonally to provide bidirectional self-resetting functions. A sliding connection assembly is provided between the two base assemblies and can slide between the base assemblies. Each base assembly includes a base limiting device and a base with different-inclination slide rails. The base with different-inclination slide rails includes an outer slide rail and an inner slide rail. The inner slide rail is arranged between two outer slide rails. Both the outer slide rail and the inner slide rail are V-shaped inclined planes, and the inclination angle of the V-shaped inclined plane of the outer slide rail is greater than that of the V-shaped inclined plane of the inner slide rail.

[0009] The upper half and the lower half of the sliding connection assembly have the same structure but a phase difference of 90°. The upper half and the lower half of the sliding connection assembly both have the following structure: groove-shaped assembly limiting devices are provided on both sides to cooperate with the base limiting devices of the base assemblies to prevent the bearing from being lifted off, and sliding connection assembly outer friction pairs are provided on both sides to slide on the base limiting devices of the base assemblies; inner slide rail friction pairs and outer slide rail friction pairs are arranged on both the upper and lower sides of the middle sliding connection assembly to slide on the inner slide rails and outer slide rails of the upper and lower two base assemblies respectively.

[0010] Further, the sliding friction coefficient between the outer slide rail friction pair and the outer slide rail is μout The sliding friction coefficient between the inner slide rail friction pair and the inner slide rail is μ in , μ out > μ in .

[0011] Furthermore, angle steel for fixing the base is arranged on the outer side of the base assembly, and bolt holes are arranged on the base assembly and the angle steel for fixing the base so that the base assembly can be bolted to the structure.

[0012] Furthermore, lateral limiting devices are arranged at both ends of each base assembly, and lateral limiting rubber gaskets are arranged on the inner sides of the lateral limiting devices.

[0013] The present invention also provides a design method for the above anti-overturning variable-stiffness inclined-plane friction isolation bearing, and the method comprises the following steps:

[0014] S1. First, according to the isolation requirements of the isolated structure, determine the designed displacement D c-in of the inner slide rail of the isolation bearing and the maximum designed displacement D max ;

[0015] S2. Initially determine the friction coefficients μ in , μ out of the inner slide rail and the outer slide rail, and then design the inclination angles θ in , θ out of the inner slide rail and the outer slide rail, and it is necessary to ensure that μ in < tanθ in , μ out < tanθ out to ensure the self-resetting performance of the bearing after an earthquake;

[0016] S3. Establish a mechanical model of the bearing and analyze the force conditions of the inner slide rail and the outer slide rail at different displacement stages as follows:

[0017] The starting force F start for sliding between the base assembly and the sliding connection assembly is as shown in formula (1):

[0018] F start = W(sinθ in + μ in cosθ in ) (13)

[0019] The initial stiffness K in is as shown in formula (2):

[0020]

[0021] In the formula, W is the vertical load; h inis the vertical distance from the centroid of the sliding connection component to the sliding surface of the inner slide rail;

[0022] Restoring force F reset As shown in Equation (3):

[0023] F reset = W(sinθ in - μ in cosθ in ) (15)

[0024] It can be known from Equation (1) that by reducing θ in and μ in , F start can be reduced, enabling the structure to start sliding under minor earthquakes and avoiding brittle response;

[0025] It can be known from Equation (2) that the low inclination angle θ in and the low friction coefficient μ in design result in the initial stiffness K in being at a relatively low level, meeting the flexible seismic isolation requirements under frequent earthquakes;

[0026] It can be known from Equation (3) that when the inner slide rail is unloaded, the component of gravity along the inclined plane (Wsinθ in ) drives the slider to return to its position. At the same time, the low friction coefficient (μ in <tanθ in ) ensures that the restoring force is always greater than zero;

[0027] When the displacement value exceeds the critical value D c-in , the outer slide rail intervenes, and its equivalent stiffness K out is approximately:

[0028]

[0029] It can be known from Equation (4) that by increasing the inclination angle and friction coefficient of the outer slide rail, a larger restoring force and secondary yield stiffness can be achieved, and the displacement of the seismic isolation layer can be effectively controlled; the higher θ out and μ out result in K out being at a relatively high level, forming a significant secondary stiffness platform to suppress the displacement growth under major earthquakes; at the same time, the increase in the inclination angle θ out of the outer slide rail leads to an increase in the component of gravity;

[0030] S4. Calculate the required inclined plane length of each slide rail to ensure that derailment or stress overrun does not occur under the designed displacement. The calculation formula for the inclined plane length is shown in Equations (5) and (6);

[0031]

[0032] In the formula, L inis the required inclined plane length for the inner slide rail, L out is the required inclined plane length for the outer slide rail, D c-in is the designed displacement of the inner side; D max is the maximum designed displacement, and the maximum displacement requirement under rare earthquakes is determined according to the code or time history analysis of the structure; △L safe is the safety capacity to prevent derailment;

[0033] S5. Use the genetic algorithm, combine the maximum energy dissipation objective function and constraint conditions for parametric analysis and numerical simulation verification to achieve the determination and optimization of the inclined plane length; specifically, the maximum energy dissipation objective function is constructed as follows:

[0034] The energy dissipation capacity is measured by the area enclosed by the hysteresis curve, and the total energy dissipation E total is expressed as Equations (7) - (9):

[0035] E total = E in + E out (19)

[0036] E in = 4μ in WD c-in (20)

[0037] E out = 4μ out W(D max - D c-in ) (21)

[0038] In the formula, the coefficient 4 represents the energy dissipation of a complete hysteresis cycle, E in represents the frictional energy dissipation of the inner slide rail, E out represents the frictional energy dissipation of the outer slide rail;

[0039] The constraint conditions include the following:

[0040] Self-resetting condition of the slide rail:

[0041] μ in < tanθ in ; μ out < tanθ out (22)

[0042] Safety limit of contact stress:

[0043]

[0044] In the formula, A 滑块 is the contact area between the sliding connection component and the slide rail; f allow is the allowable stress of the material;

[0045] Feasibility of the slide rail length:

[0046] L in cosθ in +L out cosθ out ≥D max +△L safe (24)

[0047] The beneficial effects of the present invention compared with the prior art are as follows:

[0048] 1. The entire bearing of the present invention adopts an assembled structure. The base is an integral body, and different inclination angles of the inner and outer slide rails are realized through the processing technology. After placing the sliding connection component into the base, the base limiting device and the base fixing angle steel are sequentially bolted to the base. Similarly, the lateral limiting rubber gasket, the lateral limiting device and the base are bolted. When the present invention is in use, the seismic isolation structure is bolted to the upper base, the lower base is bolted to the ground or other equipment, and a sliding connection component is arranged between the upper and lower bases. During an earthquake, the seismic energy is reduced from being transmitted to the upper structure through the sliding friction of the bearing, playing a role in horizontal seismic isolation. By designing different inclination angles and friction coefficients of the inner and outer slide rails, the contradiction between the seismic isolation rate and the displacement of the seismic isolation layer can be balanced. At the same time, when the bearing is locally tensioned or there is a tendency for the bearing to be pulled off due to the inertia of the upper structure, the base limiting device and the sliding connection component limiting device cooperate with each other to prevent the bearing from being pulled off and play an anti-overturning role. The present invention can achieve a smaller starting force and a lower initial stiffness by designing the inclination angle and friction coefficient of the inner slide rail, and can achieve complete self-reset after an earthquake; by increasing the inclination angle and friction coefficient of the outer slide rail, a larger restoring force and a secondary yield stiffness can be achieved, and the displacement of the seismic isolation layer can be effectively controlled, reducing the impact on the upper structure.

[0049] 2. The inclined sliding surface structure of the bearing slide rail helps to reduce the base shear force of the structure during the operation of the bearing and significantly reduces the inter-story drift angle of the structure at the epicenter. By designing different inclination angles and friction coefficients of the inner and outer groups of slide rails, the contradiction between the seismic isolation rate and the displacement of the seismic isolation layer can be effectively balanced.

[0050] 3. The optimal solution of the inclined plane lengths of the inner and outer slide rails can be obtained through simulation and optimization of the seismic isolation structure type. After determining the design parameters of the seismic isolation structure according to the required specifications, a mechanical model of the bearing is established, and the force conditions of the inner and outer slide rails at different displacement stages are analyzed. The inclined plane lengths of the slide rails are initially calculated, and then an optimization algorithm (such as the genetic algorithm) is used to perform parametric analysis and numerical simulation verification in combination with the objective function (such as maximum energy dissipation) and the constraint conditions (such as the design displacement not exceeding the inclined plane length, stress overrun, etc.), so as to scientifically determine and optimize the inclined plane length, taking into account both the seismic isolation performance and the engineering economy.

[0051] 4. Through the setting of multi-inclination slopes, the smooth conversion between slopes is achieved, reducing the instantaneous impact that occurs when the sliding connection component passes through discontinuous slopes. At the same time, the characteristic of variable stiffness of the bearing can effectively prevent the occurrence of resonance phenomena, improving the stability and applicability of the inclined plane friction isolation bearing.

[0052] 5. The limiting device of the sliding connection component and the limiting device of the base cooperate with each other to prevent the bearing from being pulled out when the isolation bearing is locally tensioned or the bearing has a tendency to be pulled out due to the inertia of the upper structure.

[0053] 6. The friction pair is made of polytetrafluoroethylene friction material, which can dissipate seismic energy during the sliding friction process.

[0054] 7. The entire bearing adopts an assembled structure, which is convenient for the replacement of damaged parts after an earthquake and the restoration of the bearing function, reducing the maintenance cost of the bearing after an earthquake.

[0055] 8. The bearing can also achieve a two-way vibration reduction independent design, and can achieve a two-way isolation independent design for structures with large differences in two-way mechanical characteristics, improving the isolation effect of the bearing. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 is the schematic diagram of the overall structure of the present invention;

[0057] Figure 2 is the schematic diagram of the structure of the sliding connection component of the present invention;

[0058] Figure 3 is the schematic diagram of the base assembly of the present invention;

[0059] Figure 4 is the sectional view of the bearing and the sliding connection component of the present invention;

[0060] Figure 5 is the sectional view of the cooperation between the base device and the limiting device of the sliding connection component of the present invention;

[0061] Figure 6 is the schematic diagram of the relevant parameters of the inclined plane of the bearing of the present invention.

[0062] Explanation of the reference numerals in the drawings: 1. Base assembly; 1.1. Base limiting device; 1.2. Inner slide rail; 1.3. Outer slide rail; 2. Base fixing angle steel; 3. Lateral limiting rubber gasket; 4. Lateral limiting device; 5. Sliding connection component; 5.1. Inner slide rail friction pair; 5.2. Outer slide rail friction pair; 5.3. Outer friction pair of the sliding connection component; 5.4. Limiting device of the sliding connection component; 6. Bolt hole; 7. Bolt. DETAILED DESCRIPTION OF THE INVENTION

[0063] The principles and features of the present invention will be described below in conjunction with the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0064] As Figures 1 to 5 shown, an anti-overturning variable-stiffness inclined-plane friction isolation bearing according to this embodiment includes two base assemblies 1 arranged orthogonally to provide a two-way self-resetting function. A sliding connection assembly 5 is arranged between the two base assemblies 1 and can slide between the base assemblies 1. Each base assembly 1 includes a base limiting device 1.1 and a base provided with slide rails at different inclinations. The base with slide rails at different inclinations includes an outer slide rail 1.3 and an inner slide rail 1.2. The inner slide rail 1.2 is arranged between two outer slide rails 1.3. Both the outer slide rail 1.3 and the inner slide rail 1.2 are V-shaped inclined planes, and the inclination angle of the V-shaped inclined plane of the outer slide rail 1.3 is greater than the inclination angle of the V-shaped inclined plane of the inner slide rail 1.2.

[0065] The upper half and the lower half of the sliding connection assembly 5 have the same structure but a phase difference of 90°. The upper half and the lower half of the sliding connection assembly 5 both have the following structure: on both sides, there are groove-shaped assembly limiting devices 5.4 for cooperating with the base limiting devices 1.1 of the base assemblies 1 to prevent the bearing from being pulled out, and on both sides, there are outer friction pairs 5.3 of the sliding connection assembly for sliding on the base limiting devices 1.1 of the base assemblies 1; on the upper and lower sides of the middle sliding connection assembly 5, inner slide rail friction pairs 5.1 and outer slide rail friction pairs 5.2 are arranged respectively for sliding on the inner slide rail 1.2 and the outer slide rail 1.3 of the upper and lower two base assemblies 1.

[0066] In this embodiment, the sliding friction coefficient between the outer slide rail friction pair 5.2 and the outer slide rail 1.3 is μ out , and the sliding friction coefficient between the inner slide rail friction pair 5.1 and the inner slide rail 1.2 is μ in , μ out > μ in .

[0067] In this embodiment, a base fixing angle steel 2 is arranged outside the base assembly 1, and bolt holes 6 are arranged on the base assembly 1 and the base fixing angle steel 2 to connect the base assembly 1 and the structure with bolts 7.

[0068] In this embodiment, lateral limiting devices 4 are arranged at both ends of each base assembly 1, and lateral limiting rubber gaskets 3 are arranged inside the lateral limiting devices 4.

[0069] As Figure 6 shown, a design method for the anti-overturning variable-stiffness inclined-plane friction isolation bearing according to this embodiment includes the following steps:

[0070] S1. First, according to the seismic isolation requirements of the seismic isolation structure, determine the design displacement D of the inner slide rail (1.2) of the seismic isolation bearing c-in and the maximum design displacement D max ;

[0071] S2. Initially, determine the friction coefficients μ in 、μ out of the inner slide rail 1.2 and the outer slide rail 1.3, and then design the inclination angles θ in 、θ out of the inner slide rail 1.2 and the outer slide rail 1.3, ensuring that μ in < tanθ in 、μ out < tanθ out to ensure the self - reset performance of the bearing after an earthquake;

[0072] S3. Establish the mechanical model of the bearing and analyze the force conditions of the inner and outer slide rails at different displacement stages as follows:

[0073] The starting force F for sliding between the base assembly 1 and the sliding connection assembly 5 start is shown in Equation (1):

[0074] F starr =W(Sinθ in +μ in cosθ in ) (25)

[0075] The initial stiffness K in is shown in Equation (2):

[0076]

[0077] In the formula, W is the vertical load; h in is the vertical distance from the centroid of the sliding connection assembly 5 to the sliding surface of the inner slide rail 1.2;

[0078] The restoring force f reset is shown in Equation (3):

[0079] f reset =W(sinθ in -μ in cosθ in ) (27)

[0080] It can be seen from Equation (1) that by reducing θ in and μ in , F start can be reduced, enabling the structure to start sliding under minor earthquakes and avoiding brittle responses;

[0081] It can be seen from Equation (2) that a low inclination angle θ inand a low coefficient of friction μ in is designed such that the initial stiffness K in is at a low level to meet the flexible seismic isolation requirements under frequent earthquakes;

[0082] As can be seen from Equation (3), when the inner slide rail is unloaded, the component of gravity along the inclined plane (Wsinθ in ) drives the slider to return to its position. At the same time, the low coefficient of friction (μ in <tanθ in ) ensures that the restoring force is always greater than zero;

[0083] When the displacement value exceeds the critical value D c-in , the outer slide rail intervenes, and its equivalent stiffness K out is approximately:

[0084]

[0085] As can be seen from Equation (4), by increasing the inclination angle and coefficient of friction of the outer slide rail by 1.3, a larger restoring force and secondary yield stiffness can be achieved, and the displacement of the seismic isolation layer can be effectively controlled; a higher θ out and μ out make K out be at a high level, forming a significant secondary stiffness platform to inhibit the displacement growth under major earthquakes; at the same time, the increase in the inclination angle θ out of the outer slide rail leads to an increase in the component of gravity;

[0086] S4. Calculate the required inclined plane lengths of each slide rail to ensure that derailment or stress overrun does not occur under the design displacement. The calculation formulas for the inclined plane lengths are shown in Equations (5) and (6);

[0087]

[0088] In the formula, L in is the required inclined plane length of the inner slide rail, L out is the required inclined plane length of the outer slide rail, D c-in is the inner design displacement; D max is the maximum design displacement, and the maximum displacement requirement under rare earthquakes is determined according to the code or time history analysis of the structure; △L safe is the safety capacity to prevent derailment;

[0089] S5. Use the genetic algorithm to perform parametric analysis and numerical simulation verification in combination with the maximum energy dissipation objective function and constraint conditions to achieve the determination and optimization of the inclined plane length; specifically, the maximum energy dissipation objective function is constructed as follows:

[0090] The energy dissipation capacity is measured by the area enclosed by the hysteresis curve, and the total energy dissipation E total is expressed as Equations (7)-(9):

[0091] E total = E in + E out (31)

[0092] E in = 4μ in WD c-in (32)

[0093] E out = 4μ out W(D max - D c-in ) (33)

[0094] In the formula, the coefficient 4 represents the energy dissipation of a complete hysteretic cycle, E in represents the frictional energy dissipation of the inner slide rail, and E out represents the frictional energy dissipation of the outer slide rail;

[0095] The constraint conditions include the following:

[0096] Self-resetting condition of the slide rail:

[0097] μ in < tanθ in ; μ out < tanθ out (34)

[0098] Safety limit of contact stress:

[0099]

[0100] In the formula, A 滑块 is the contact area between the sliding connection component and the slide rail; f allow is the allowable stress of the material;

[0101] Feasibility of the slide rail length:

[0102] L in cosθ in + L out cosθ out ≥ D max + △L safe (36)

[0103] With the above structure, the working principle of the variable-stiffness inclined-plane friction isolation bearing with anti-overturning function of the present invention is as follows: In the initial state, the inner slide-rail friction pair 5.1 is in direct contact with the inner slide rail 1.2, and the outer slide-rail friction pair 5.2 is not in contact with the outer slide rail 1.3. When an earthquake occurs, the inner slide-rail friction pair and the inner slide rail dissipate energy through friction. When the sliding connection assembly 5 moves to a certain displacement, the outer slide-rail friction pair comes into contact with the inner slide rail and dissipates energy through friction, effectively controlling the displacement of the isolation layer. When the isolation bearing is locally tensioned or has a tendency to be pulled out due to the inertia of the upper structure, the sliding connection assembly limiting device 5.4 and the base vertical limiting device 1.1 cooperate with each other to prevent the bearing from being pulled out.

[0104] The base slide rails are two groups of V-shaped inclined planes with different angles on the inside and outside, and a smaller starting force F can be achieved by designing the inclination angle and friction coefficient of the inner slide rail 1.2 start and a lower initial stiffness K in , and complete self-resetting after an earthquake can be achieved.

[0105] The inclined sliding surface structure of the slide rails helps to reduce the base shear force of the structure during the operation of the bearing, and significantly reduces the inter-story displacement angle of the structure at the epicenter. By designing different inclination angles and friction coefficients of the two groups of inner and outer slide rails 1.2 and 1.3, the contradiction between the isolation rate and the displacement of the isolation layer can be effectively balanced. In the small earthquake stage, the inner slide rail dominates. The low inclination angle reduces the gravity component, and the low friction coefficient reduces the hysteretic energy dissipation, achieving a high isolation rate. In the large earthquake stage, the outer slide rail intervenes. The high inclination angle increases the geometric stiffness, and the high friction coefficient enhances the friction energy dissipation, forming a stiffness jump and actively suppressing the growth of the isolation layer displacement.

[0106] This bearing can provide a high bearing capacity during normal use. At the same time, the low-inclination inner inclined plane also plays a transitional role. Through the setting of multi-inclination inclined planes, the smooth conversion between the inclined planes is realized, the instantaneous impact occurring when the slider passes through the discontinuous inclined plane is reduced, and it is ensured that the bearing will not produce excessive deformation or even damage.

[0107] The lengths of the inclined planes of the inner and outer slide rails can be optimized to obtain the optimal solution through the simulation of the isolation structure type. After determining the design parameters of the isolation structure according to the required requirements, a mechanical model of the bearing is established, the stress conditions of the inner and outer slide rails at different displacement stages are analyzed, the length of the inclined plane of the slide rail is initially calculated, and then an optimization algorithm (such as genetic algorithm) is used, combined with the objective function (maximum energy dissipation, etc.) and constraint conditions (design displacement not exceeding the inclined plane length, stress overrun, etc.) to perform parametric analysis on it and conduct numerical simulation verification, realizing the scientific determination and optimization of the inclined plane length, and taking into account the isolation performance and engineering economy.

[0108] The described base limiting device 1.1 is fixed to the base through bolt holes 6 and bolts 7, ensuring that when the sliding connection assembly 5 slides on the base sliding rails 1.2 and 1.3, the sliding connection assembly slides along a predetermined track. When the isolation bearing is locally tensioned or there is a tendency for the bearing to be pulled off due to the inertia of the superstructure, the sliding connection assembly limiting device 5.4 and the base limiting device 1.1 cooperate with each other to prevent the bearing from being pulled off.

[0109] The friction pair is made of polytetrafluoroethylene friction material and can dissipate seismic energy during the sliding friction process.

[0110] The entire bearing adopts an assembled structure, which is convenient for replacing damaged parts after an earthquake and restoring the function of the bearing, reducing the maintenance cost of the bearing after an earthquake.

[0111] To limit the present invention, any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An anti-overturning variable-rigidity inclined friction isolation bearing, characterized in that: The invention comprises two orthogonally arranged base assemblies (1) providing a bidirectional self-resetting function, a sliding connection assembly (5) being arranged between the two base assemblies (1) and being capable of sliding between the base assemblies (1), each of the base assemblies (1) comprising a base limiting device (1.1) and a base provided with slide rails of different inclination angles, the base with the slide rails of different inclination angles comprising an outer slide rail (1.3) and an inner slide rail (1.2), the inner slide rail (1.2) being arranged between the two outer slide rails (1.3), the outer slide rail (1.3) and the inner slide rail (1.2) both being V-shaped inclined surfaces, and the inclination angle of the V-shaped inclined surface of the outer slide rail (1.3) being greater than the inclination angle of the V-shaped inclined surface of the inner slide rail (1.2). The upper and lower parts of the sliding connection component (5) have the same structure but a phase difference of 90°. Both the upper and lower parts of the sliding connection component (5) have the following structure: groove-shaped component limit devices (5.4) are arranged on both sides for cooperating with the base limit device (1.1) of the base component (1) to prevent the support from being pulled out, and sliding connection component outer friction pairs (5.3) are arranged on both sides for sliding on the base limit device (1.1) of the base component (1); inner slide rail friction pairs (5.1) and outer slide rail friction pairs (5.2) are arranged on the upper and lower sides of the middle sliding connection component (5) for sliding on the inner slide rail (1.2) and the outer slide rail (1.3) on the upper and lower base components (1), respectively.

2. The anti-overturning variable stiffness inclined friction isolation bearing according to claim 1 is characterized in that: The sliding friction coefficient between the outer slide rail friction pair (5.2) and the outer slide rail (1.3) is μ out The sliding friction coefficient between the inner slide rail friction pair (5.1) and the inner slide rail (1.2) is μ in , μ out >μ in .

3. The anti-overturning variable-rigidity inclined friction isolation bearing according to claim 1 is characterized in that: A base fixing angle steel (2) is arranged on the outside of the base assembly (1), and bolt holes (6) are arranged on the base assembly (1) and the base fixing angle steel (2) so that the base assembly (1) can be connected to the structure by bolts (7).

4. The anti-overturning variable-rigidity inclined friction isolation bearing according to claim 1 is characterized in that: Both ends of each base assembly (1) are provided with lateral limiting devices (4), and the inner side of each lateral limiting device (4) is provided with a lateral limiting rubber gasket (3).

5. A design method for the anti-overturning variable-rigidity inclined friction isolation bearing according to any one of claims 1 to 4, characterized in that The method comprises the following steps: S1. First, according to the seismic isolation requirements of the seismic isolation structure, the design displacement D of the inner slide rail (1.2) of the seismic isolation support is determined. c-in And the maximum design displacement D max ; S2. Preliminary calculation of the friction coefficient μ between the inner rail (1.2) and the outer rail (1.3) in , μ out , then design the inclination angle θ of the inner slide rail (1.2) and the outer slide rail (1.3) in ,θ out , it is necessary to ensure μ in <tanθ in , μ out <tanθ out To ensure the self-reset performance of the bearing after the earthquake; S3. Establish a mechanical model of the support and analyze the stress conditions of the inner and outer slide rails at different displacement stages as follows: The starting force F for sliding between the base assembly (1) and the sliding connection assembly (5) start As shown in formula (1): F start =W(sinθ in +m in cosθ in ) (1) Initial stiffness K in As shown in formula (2): Where W is the vertical load; h in is the vertical distance from the center of mass of the sliding connection assembly (5) to the sliding surface of the inner slide rail (1.2); Resilience F reset As shown in formula (3): F reset =W(sinθ in -m in cosθ in ) (3) From formula (1), we know that by reducing θ in and μ in , which can reduce F start , so that the structure can start sliding under a small earthquake and avoid brittle response; From formula (2), we know that the low inclination angle θ in and low friction coefficient μ in Design so that the initial stiffness K in It is at a relatively low level, matching the flexible seismic isolation requirements under frequent earthquakes; From formula (3), we know that when the inner slide rail is unloaded, the gravity component along the inclined surface (Wsinθ in ) drives the slider back to its original position, and the low friction coefficient (μ in <tanθ in ) ensure that the restoring force is always greater than zero; When the displacement value exceeds the critical value D c-in When the outer slide rail intervenes, its equivalent stiffness K out Approximately: From formula (4), we know that by increasing the inclination angle and friction coefficient of the outer slide rail (1.3), a larger restoring force and secondary yield stiffness can be achieved and the displacement of the seismic isolation layer can be effectively controlled; a higher θ out and μ out Make K out At a relatively high level, a significant secondary stiffness platform is formed to suppress the displacement growth under a large earthquake; at the same time, the inclination angle θ of the outer slide rail out The increase leads to an increase in the gravity component; S4. Calculate the required inclined plane length of each rail to ensure that derailment or stress exceeding the limit does not occur under the designed displacement. The inclined plane length calculation formula is shown in formula (5) and formula (6); Where, L in L is the required inclined length of the inner rail. out D is the required slope length of the outer rail. c-in is the inner design displacement; D max is the maximum design displacement, which is determined according to the code or time-history analysis structure under rare earthquakes; △L safe To ensure safe capacity and prevent derailment; S5. Using genetic algorithm, combined with the maximum energy consumption objective function and constraint conditions, parametric analysis and numerical simulation verification are performed to determine and optimize the inclined plane length; specifically, the maximum energy consumption objective function is constructed as follows: The energy dissipation capacity is measured by the area enclosed by the hysteresis curve. The total energy dissipation E total It can be expressed as formula (7)-formula (9): AND total =And in +E out (7) E in =4μ in WD c-in (8) E out =4μ out W(D max -D c-in ) (9) Where the coefficient 4 represents the energy consumption of a complete hysteresis cycle, E in Indicates the friction energy consumption of the inner rail, E out Indicates the friction energy consumption of the outer slide rail; Constraints include the following: Slide rail self-reset conditions: m in <tanθ in ;m out <tanθ out (10) Contact stress safety limit: In the formula, A 滑块 is the contact area between the sliding connection assembly and the slide rail; f allow is the allowable stress of the material; Rail length feasibility: L in cosθ in +L out cosθ out ≥D max +△L safe (12)

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