A monitoring method for friction pendulum seismic isolation bearings

Abstract

This invention discloses a monitoring method for a friction pendulum seismic isolation bearing, comprising: an upper bearing plate; a lower bearing plate; a spherical cap slider disposed between the upper and lower bearing plates; PTFE friction plates disposed at the upper and lower ends of the spherical cap slider; and a sensing mechanism disposed between the lower bearing plate and the lower PTFE friction plate, or between the lower bearing plate and the lower PTFE friction plate and between the upper bearing plate and the upper PTFE friction plate. This invention has the following advantages and effects: by employing an external resistive sensing mechanism to form the sensing module of the entire friction pendulum seismic isolation bearing, it has comprehensive monitoring functions, can acquire data such as horizontal displacement and vertical pressure in real time, and can grasp the real-time displacement and compressive stress distribution of the spherical cap slider, thereby assessing the usage status of the friction pendulum seismic isolation bearing, providing dynamic monitoring support for structural safety, facilitating the determination of whether the spherical cap slider has slipped into a dangerous area, and thus achieving refined management of the structure.

Description

Technical Field

[0001] This invention relates to the field of seismic isolation technology in civil engineering, and in particular to a monitoring method for friction pendulum seismic isolation bearings. Background Technology

[0002] Friction pendulum seismic isolation bearings are devices used in the seismic design of building structures. Their main function is to convert the horizontal displacement caused by an earthquake into relative slippage within the device through the sliding friction behavior of the spherical cap slider, thereby reducing the seismic load on the superstructure and improving the safety and durability of the building. The design of this bearing is inspired by the principle of a pendulum, which uses oscillation to dissipate or transfer seismic energy, thus reducing the energy transmitted to the superstructure.

[0003] Friction pendulum seismic isolation bearings mainly consist of an upper bearing plate, a lower bearing plate, an intermediate sliding layer (usually made of polytetrafluoroethylene or other low-friction materials), and a lateral restraint device. When an earthquake occurs, the bearing allows the building to move to a limited extent in the horizontal direction. The friction of the sliding layer dissipates seismic energy, while the lateral restraint device limits the maximum displacement of the building, preventing excessive shaking and damage.

[0004] The long-term stability of friction pendulum seismic isolation bearings is crucial for the overall safety of buildings. However, performance monitoring of these bearings remains a challenge in the field of seismic isolation technology. Currently, stress monitoring of the bearings is limited by the fact that the building structure still bears enormous vertical loads during earthquakes, making it impossible to assess the local stress state of the spherical cap in real time.

[0005] Meanwhile, real-time displacement monitoring of bearings during earthquakes is also a challenge. Real-time monitoring of bearing displacement in two directions in the horizontal plane and avoiding errors caused by bearing torsion is costly and complex to install. Furthermore, it is impossible to determine whether the spherical crown has slipped into a dangerous area, and it is impossible to assess the actual usage status of the bearing in real time. As a result, it is impossible to achieve refined management of the structure, which needs to be improved. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the purpose of this invention is to provide a friction pendulum seismic isolation bearing that enables refined structural management.

[0007] The above-mentioned technical objective of the present invention is achieved through the following technical solution: a friction pendulum vibration isolation support, comprising: The upper seat plate is horizontally positioned, and its lower end face is curved. The lower seat plate is horizontally positioned, and its upper surface is curved. A spherical cap slider is disposed between the upper seat plate and the lower seat plate; PTFE friction plates are disposed at the upper and lower ends of the spherical cap slider; The sensing mechanism is disposed between the lower seat plate and the PTFE friction plate below the spherical cap slider, or between the lower seat plate and the PTFE friction plate below the spherical cap slider and between the upper seat plate and the PTFE friction plate above the spherical cap slider; The sensing mechanism includes a thin-film varistor, an inert protective layer, and a stainless steel plate. The thin-film varistor is horizontally arranged, the inert protective layer is disposed at the upper and lower ends of the thin-film varistor, and the stainless steel plate is disposed above the upper inert protective layer.

[0008] Another objective of this invention is to provide a monitoring method for friction pendulum seismic isolation bearings, which has the effect of enabling refined management of structures.

[0009] The above-mentioned technical objective of the present invention is achieved through the following technical solution: a monitoring method for a friction pendulum isolation bearing, wherein the contact surface between the spherical cap slider and the sensing mechanism is circular, the applied stress is continuous along the radial direction, that is, there is no concentrated shear stress on the contact surface, and the calculation process includes the following steps: S1, acquire measurement point data. The sensing mechanism uses a series of small measurement points to measure the normal stress. The measured values ​​of these measurement points are considered as the average stress of the area surrounding the measurement point. The position of each measurement point is ( ),in and These represent the polar coordinates of the measuring point on the entire contact surface. The stress value measured at the corresponding location; S2, Fitting the stress distribution function: Based on the data from each measuring point, a fitting calculation is performed to obtain the approximate stress distribution function of the contact surface. The fitted stress distribution function is as follows: ; in The stress distribution function is a three-dimensional fitted function used to represent the stress distribution in the entire contact area. The output three-dimensional stress distribution cloud map can be used for support condition monitoring. S3, function integral, based on the stress distribution function The total pressure can be calculated using the following integral formula: ; Where R is the radius of the contact circle, similarly, the integral of the combined two-dimensional stress distribution function of each column is the total pressure. The final value is obtained by averaging the total pressure mentioned above. S4, numerical integration, if the stress distribution function It is very complex and difficult to perform direct integration calculations. Therefore, a refined numerical method is used for integration, discretizing the contact circular surface into a fine grid, with each grid having an area of... If the distance between the center points of adjacent grids is at least one order of magnitude smaller than the distance between adjacent measuring points, then the approximate formula for calculating the total pressure is: ; Where N is the total number of discrete grid cells. These are the discrete intervals in the radial and angular directions, respectively. S5, Support stress calculation, the formula for calculating the vertical pressure on the support is: ; in, The angle of inclination of the support spherical crown; S6, Support displacement calculation. The measuring range of the positioning mechanism is the friction surface of the upper and lower supports, which is a circular surface. After the spherical cap slider is compressed, the circular surface that displays the stress distribution data in the entire measuring circular surface is the contact circular surface of the spherical cap slider. The display cloud map is fitted to form a circular function to represent the contact surface of the spherical cap slider, and the center point of the circular function is taken ( The displacement of the spherical cap slider relative to the upper and lower supports is: , ; If the sensing mechanism is only installed on the lower seat plate, the support displacement is calculated by the following formula: ; If sensing mechanisms are installed on both the upper and lower supports, the support displacement is calculated using the following formula: ; On the force cloud map of the sensing mechanism, the current displacement and historical displacement dynamic data of the spherical cap slider can be automatically displayed through program calculation, recorded and saved and uploaded to the cloud, which can realize real-time health monitoring of the friction pendulum seismic isolation bearing.

[0010] In a preferred embodiment, the present invention can be further configured as follows: In step S2, the function fitting calculation method is as follows: A1: By fitting and calculating the data of each row of measurement points at the same y-coordinate, a two-dimensional stress distribution function at the same y-coordinate is obtained. Assume the first... j The measurement point data of the row is ,in It is the first j The x-coordinate of the measurement point The corresponding stress data was obtained by fitting and calculating using linear interpolation, polynomial regression, and spline interpolation methods. ; A2: The fitting result for each row can be obtained in the following form: ; in, It is the first j The stress distribution function of each row is fitted, and the result is interpolated using bilinear interpolation and spline interpolation methods to obtain the stress distribution function of the entire contact surface. ; in, It reflects the change of stress in the x-direction with the y-coordinate.

[0011] In a preferred embodiment, the present invention can be further configured as follows: in the fitting calculation method A1 of step S2, the first contact circle surface obtained is... j Stress distribution function of the line Let be a two-dimensional curve function, and the evaluation criteria are the following three points: First, local stress extrema: the peak value of the curve function is the maximum value of the local stress, reflecting the maximum stress borne by a certain point on the spherical cap slider. The extreme point is found by calculating the derivative of the curve function, and the maximum value of the extreme point of each row of curve functions is selected as the stress peak value of the entire circular surface. The size of the peak value determines the stress concentration degree of the spherical cap slider material at a certain point, which is used to determine whether the local position is close to the yield or failure limit of the contact surface material. Secondly, stress eccentricity: defined by the x-coordinate of the peak point of the curve function. That is, the peak point is at the th j The eccentricity of the row is used to describe the first row. j The greater the eccentricity of the line, the larger the eccentricity, which indicates a larger eccentricity in the stress distribution, potentially leading to structural instability. Thirdly, the uniformity of distribution: Calculate the... j The coefficient of variation (CV) of the stress values ​​at each measuring point, which is the ratio of the standard deviation to the mean, measures the uniformity of the stress distribution on the spherical crown. The larger the CV value, the more uneven the stress distribution. When the CV value approaches 0, it indicates that the stress distribution on the surface of the spherical crown slider is basically uniform and there are no local stress protrusions on the material surface.

[0012] In summary, the present invention has the following beneficial effects: by using an external resistive sensing mechanism to form the sensing module of the entire friction pendulum seismic isolation bearing, it has a comprehensive monitoring function, can acquire data such as horizontal displacement and vertical pressure in real time, and can grasp the real-time displacement and compressive stress distribution of the spherical cap slider, thereby assessing the usage status of the friction pendulum seismic isolation bearing, providing dynamic monitoring support for structural safety, and facilitating the determination of whether the spherical cap slider has slipped into a dangerous area, thereby achieving refined management of the structure. Attached Figure Description

[0013] Figure 1 These are schematic diagrams of two layout configurations of the sensing mechanism in Embodiment 1; Figure 2 This is a schematic diagram of the sensing mechanism in Embodiment 1; Figure 3 This is a schematic diagram of the resultant force on the support in Example 2; Figure 4 This is a schematic diagram of the compressive stress distribution in Example 2; Figure 5 It is the first j A two-dimensional stress distribution function curve of the row.

[0014] Reference numerals: 1. Upper base plate; 2. Lower base plate; 3. Spherical cap slider; 4. PTFE friction plate; 5. Sensing mechanism; 51. Thin film varistor; 52. Inert protective layer; 53. Stainless steel plate. Detailed Implementation

[0015] The present invention will be further described in detail below with reference to the accompanying drawings.

[0016] Example 1: like Figure 1 As shown, a friction pendulum vibration isolation support includes an upper seat plate 1, a lower seat plate 2, a spherical cap slider 3, a PTFE friction plate 4, and a sensing mechanism 5.

[0017] like Figure 1 As shown, both the upper seat plate 1 and the lower seat plate 2 are horizontally arranged. The lower end surface of the upper seat plate 1 is arc-shaped, and the upper end surface of the lower seat plate 2 is arc-shaped. The arc-shaped surfaces of the upper seat plate 1 and the lower seat plate 2 are positioned opposite each other and are interlocked.

[0018] like Figure 1 As shown, the spherical cap slider 3 is disposed between the upper seat plate 1 and the lower seat plate 2, and the PTFE friction plates 4 are disposed at the upper and lower ends of the spherical cap slider 3. The sensing mechanism 5 is disposed between the lower seat plate 2 and the PTFE friction plates 4 below the spherical cap slider 3, or between the lower seat plate 2 and the PTFE friction plates 4 below the spherical cap slider 3 and between the upper seat plate 1 and the PTFE friction plates 4 above the spherical cap slider 3.

[0019] like Figure 2 As shown, the sensing mechanism 5 includes a thin-film varistor 51, an inert protective layer 52, and a stainless steel plate 53. The thin-film varistor 51 is horizontally arranged, and the inert protective layer 52 is disposed at both the upper and lower ends of the thin-film varistor 51. The inert protective layer 52 is a protective film material made of PC, PET, or similar materials. The stainless steel plate 53 is disposed above the upper inert protective layer 52.

[0020] When the sensing mechanism 5 is subjected to stress, the thin-film varistor 51 is compressed and its resistance value changes, which in turn causes the output voltage to transmit a change signal for acquisition and output. Furthermore, due to the inert protective layer 52, the corrosion resistance and water resistance of the sensing mechanism 5 will meet the requirements of the engineering application environment.

[0021] Therefore, by using an external resistive sensing mechanism 5 to form the sensing module of the entire friction pendulum isolation bearing, it has a comprehensive monitoring function, can acquire data such as horizontal displacement and vertical pressure in real time, and has an integrated stress-force-displacement monitoring function.

[0022] It can also monitor the real-time displacement and compressive stress distribution of the spherical cap slider 3, thereby assessing the usage status of the friction pendulum seismic isolation bearing, providing dynamic monitoring support for structural safety, and facilitating the determination of whether the spherical cap slider 3 has slipped into a dangerous area, thus achieving refined management of the structure.

[0023] Example 2: like Figure 3 , Figure 4 , Figure 5 As shown, a monitoring method for a friction pendulum isolation bearing is described. The contact surface between the spherical cap slider 3 and the sensing mechanism 5 is circular, and the applied stress is continuous along the radial direction, meaning there is no concentrated shear stress on the contact surface. The calculation process includes the following steps: S1, acquire measurement point data. Normal stress is measured at a series of small measurement points on the sensing mechanism 5. The measured values ​​of these points are considered as the average stress in the area surrounding the measurement point. The position of each measurement point is (…). ),in and These represent the polar coordinates of the measuring point on the entire contact surface. This represents the stress value measured at the corresponding location.

[0024] S2, Fitting the stress distribution function: Based on the data from each measuring point, a fitting calculation is performed to obtain the approximate stress distribution function of the contact surface. The fitted stress distribution function is as follows: ; in This is the stress distribution function after three-dimensional fitting, used to represent the stress distribution in the entire contact area. The output three-dimensional stress distribution cloud map can be used for support condition monitoring.

[0025] The function fitting calculation method is as follows: A1: By fitting and calculating the data of each row of measurement points at the same y-coordinate, a two-dimensional stress distribution function at the same y-coordinate is obtained. Assume the first... j The measurement point data of the row is ,in It is the first j The x-coordinate of the measurement point The corresponding stress data was obtained by fitting and calculating using linear interpolation, polynomial regression, and spline interpolation methods. ; A2: The fitting result for each row can be obtained in the following form: ; in, It is the first j The stress distribution function of each row is fitted, and the result is interpolated using bilinear interpolation and spline interpolation methods to obtain the stress distribution function of the entire contact surface. ; in, It reflects the change of stress in the x-direction with the y-coordinate.

[0026] In the fitting calculation method A1 of step S2, the first contact circle surface is obtained. j Stress distribution function of the line Let be a two-dimensional curve function, and the evaluation criteria are the following three points: First, local stress extrema: The peak value of the curve function is the maximum value of the local stress, which reflects the maximum stress borne by a certain point on the spherical cap slider 3. The extreme point is found by calculating the derivative of the curve function, and the maximum value of the extreme point of each row of curve functions is selected as the stress peak value of the entire circular surface. The size of the peak value determines the stress concentration degree of the material of the spherical cap slider 3 at a certain point, which is used to judge whether the local position is close to the yield or failure limit of the contact surface material. Secondly, stress eccentricity: defined by the x-coordinate of the peak point of the curve function. That is, the peak point is at the th j The eccentricity of the row is used to describe the first row. j The greater the eccentricity of the line, the larger the eccentricity, which indicates a larger eccentricity in the stress distribution, potentially leading to structural instability. Thirdly, the uniformity of distribution: Calculate the... j The coefficient of variation (CV) of the stress values ​​at each measuring point, which is the ratio of the standard deviation to the mean, measures the uniformity of the stress distribution on the spherical crown. The larger the CV value, the more uneven the stress distribution. When the CV approaches 0, it indicates that the stress distribution on the surface of the spherical crown slider 3 is basically uniform and there are no local stress protrusions on the material surface.

[0027] S3, function integral, based on the stress distribution function The total pressure can be calculated using the following integral formula: ; Where R is the radius of the contact circle, similarly, the integral of the combined two-dimensional stress distribution function of each column is the total pressure. The final value is obtained by averaging the total pressure mentioned above.

[0028] S4, numerical integration, if the stress distribution function It is very complex and difficult to perform direct integration calculations. Therefore, a refined numerical method is used for integration, discretizing the contact circular surface into a fine grid, with each grid having an area of... If the distance between the center points of adjacent grids is at least one order of magnitude smaller than the distance between adjacent measuring points, then the approximate formula for calculating the total pressure is: ; Where N is the total number of discrete grid cells. These are the discrete intervals in the radial and angular directions, respectively.

[0029] S5, Support stress calculation, the formula for calculating the vertical pressure on the support is: ; in, The angle of inclination of the support spherical crown.

[0030] S6, Support displacement calculation. The measuring range of the positioning mechanism is the friction surface of the upper and lower supports, which is a circular surface. After the spherical cap slider is compressed, the circular surface that displays the stress distribution data in the entire measuring circular surface is the contact circular surface of the spherical cap slider. The display cloud map is fitted to form a circular function to represent the contact surface of the spherical cap slider, and the center point of the circular function is taken ( The displacement of the spherical cap slider relative to the upper and lower supports is: , ; If the sensing mechanism is only installed on the lower seat plate, the support displacement is calculated by the following formula: ; If sensing mechanisms are installed on both the upper and lower supports, the support displacement is calculated using the following formula: ; On the force cloud map of the sensing mechanism 5, the current displacement and historical displacement dynamic data of the spherical cap slider can be automatically displayed through program calculation, recorded and saved and uploaded to the cloud, which can realize real-time health monitoring of the friction pendulum seismic isolation bearing.

[0031] The specific embodiments are merely illustrative of the present invention and are not intended to limit the invention. After reading this specification, those skilled in the art can make modifications to these embodiments without contributing any inventive step, but such modifications are protected by patent law as long as they are within the scope of the claims of the present invention.

Claims

1. A monitoring method for a friction pendulum isolation bearing, used for monitoring the friction pendulum isolation bearing, characterized in that: The friction pendulum seismic isolation bearing includes: The upper seat plate (1) is horizontally positioned, and its lower end face is curved. The lower seat plate (2) is horizontally set, and its upper end surface is set in an arc shape; A spherical cap slider (3) is disposed between the upper seat plate (1) and the lower seat plate (2); PTFE friction plates (4) are disposed at the upper and lower ends of the spherical cap slider (3); The sensing mechanism (5) is disposed between the lower seat plate (2) and the PTFE friction plate (4) below the spherical cap slider (3), or between the lower seat plate (2) and the PTFE friction plate (4) below the spherical cap slider (3) and between the upper seat plate (1) and the PTFE friction plate (4) above the spherical cap slider (3); The sensing mechanism (5) includes a thin-film varistor (51), an inert protective layer (52), and a stainless steel plate (53). The thin-film varistor (51) is horizontally arranged, the inert protective layer (52) is disposed at the upper and lower ends of the thin-film varistor (51), and the stainless steel plate (53) is disposed above the upper inert protective layer (52). The contact surface between the spherical cap slider (3) and the sensing mechanism (5) is circular, and the applied stress is continuous along the radial direction, that is, there is no concentrated shear stress on the contact surface. The calculation process includes the following steps: S1, acquire measurement point data. The normal stress is measured by a series of small measurement points on the sensing mechanism (5). The measured values ​​of these measurement points are regarded as the average stress of the area around the measurement point. The position of each measurement point is ( ),in and These represent the polar coordinates of the measuring point on the entire contact surface. The stress value measured at the corresponding location; S2, Fitting the stress distribution function: Based on the data from each measuring point, a fitting calculation is performed to obtain the approximate stress distribution function of the contact surface. The fitted stress distribution function is as follows: ； in The fitted three-dimensional stress distribution function is used to represent the stress distribution in the entire contact area, and the output three-dimensional stress distribution cloud map can be used for support condition monitoring. S3, function integral, based on the stress distribution function The total pressure can be calculated using the following integral formula: ； Where R is the radius of the contact circle, similarly, the integral of the combined two-dimensional stress distribution function of each column is the total pressure. The final value is obtained by averaging the total pressure mentioned above. S4, numerical integration, if the stress distribution function It is very complex and difficult to perform direct integration calculations. Therefore, a refined numerical method is used for integration, discretizing the contact circular surface into a fine grid, with each grid having an area of... If the distance between the center points of adjacent grids is at least one order of magnitude smaller than the distance between adjacent measuring points, then the approximate formula for calculating the total pressure is: ； Where N is the total number of discrete grid cells. These are the discrete intervals in the radial and angular directions, respectively. S5, Support stress calculation, the formula for calculating the vertical pressure on the support is: ； in, The angle of inclination of the support spherical crown; S6, Support displacement calculation, the measuring range of the measuring mechanism is the friction surface of the upper and lower supports, which is a circular surface. After the spherical cap slider (3) is compressed, the circular surface that displays the stress distribution data in the entire measuring circular surface is the contact circular surface of the spherical cap slider (3). The cloud map will be fitted to form a circular function to express the contact surface of the spherical cap slider (3), and the center point of the circular function will be taken ( The displacement of the spherical cap slider (3) relative to the upper and lower supports is: ， ； If the sensing mechanism (5) is only installed on the lower seat plate, the support displacement is calculated by the following formula: ； If sensing mechanisms (5) are installed on both the upper and lower supports, the support displacement is calculated by the following formula: ； On the force cloud map of the sensing mechanism (5), the current displacement and historical displacement dynamic data of the spherical cap slider (3) can be automatically displayed by the program calculation, recorded and saved and then uploaded to the cloud, so as to realize the real-time health monitoring of the friction pendulum seismic isolation support.

2. The monitoring method for a friction pendulum isolation bearing according to claim 1, characterized in that: In step S2: the function fitting calculation method is as follows: A1: By fitting and calculating the data of each row of measurement points at the same y-coordinate, a two-dimensional stress distribution function at the same y-coordinate is obtained. Assume the first... j The measurement point data of the row is ,in It is the first j The x-coordinate of the measurement point The corresponding stress data was obtained by fitting and calculating using linear interpolation, polynomial regression, and spline interpolation methods. ； A2: The fitting result for each row can be obtained in the following form: ； in, It is the first j The stress distribution function of each row is fitted, and the result is interpolated using bilinear interpolation and spline interpolation methods to obtain the stress distribution function of the entire contact surface. ； in, It reflects the change of stress in the x-direction with the y-coordinate.

3. The monitoring method for a friction pendulum isolation bearing according to claim 2, characterized in that: In the fitting calculation method A1 of step S2, the first contact circle surface is obtained. j Stress distribution function of the line Let be a two-dimensional curve function, and the evaluation criteria are the following three points: First, local stress extrema: the peak value of the curve function is the maximum value of the local stress, which reflects the maximum stress borne by a certain point on the spherical cap slider (3). The extreme point is found by calculating the derivative of the curve function, and the maximum value of the extreme point of each row of curve functions is selected as the stress peak value of the entire circular surface. The size of the peak value determines the stress concentration degree of the material of the spherical cap slider (3) at a certain point, which is used to determine whether the local position is close to the yield or failure limit of the contact surface material. Secondly, stress eccentricity: defined by the x-coordinate of the peak point of the curve function. That is, the peak point is at the th j The eccentricity of the row is used to describe the first row. j The greater the eccentricity of the line, the larger the eccentricity, which indicates that the stress distribution is more eccentric, which may lead to structural instability. Thirdly, the uniformity of distribution: Calculate the... j The coefficient of variation (CV) of the stress values ​​at each measuring point, i.e. the ratio of the standard deviation to the mean, measures the uniformity of the stress distribution on the spherical crown. The larger the CV value, the more uneven the stress distribution. When the CV approaches 0, it indicates that the stress distribution on the surface of the spherical crown slider (3) is basically uniform and there are no local stress protrusions on the material surface.

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