Pier bottom shock insulation control method for T-shaped rigid frame bridge based on hydraulic drive

Abstract

The invention relates to the field of bridge seismic resistance, and particularly discloses a T-shaped rigid frame bridge pier bottom seismic isolation control method based on hydraulic drive, which comprises the following steps: installing a hydraulic energy recovery system at the bottom of a pier, converting micro-vibration energy into electric energy and realizing self power supply; the sensor network is driven by the recycled electric energy, and the critical seismic oscillation state is recognized in real time; the working mode of the hydraulic actuator is dynamically adjusted according to the seismic characteristics, and multi-dimensional self-adaptive seismic isolation control is achieved; and optimizing control parameters based on real-time damage identification and completing post-earthquake rapid evaluation. Hydraulic drive control, energy recovery, state perception, self-adaptive control and damage identification are integrated, a complete intelligent control closed loop is formed, the technical problems that a traditional shock insulation system is large in energy consumption and poor in adaptability are effectively solved, and the shock resistance safety and the full-life economical efficiency of the T-shaped rigid frame bridge are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of bridge seismic resistance technology, and in particular to a seismic isolation control method for the bottom of a T-shaped rigid frame bridge pier based on hydraulic drive. Background Technology

[0002] As an important type of bridge in modern transportation infrastructure, the seismic safety of T-shaped rigid frame bridges has always been a major concern. Traditional bridge seismic isolation mainly uses passive isolation devices, such as lead-core rubber bearings and friction pendulum bearings, to reduce seismic energy transmission by extending the structural period and increasing damping. However, these passive isolation systems have significant limitations: First, their mechanical parameters are fixed after installation and cannot be adjusted in real time according to actual seismic motion characteristics and structural response; second, traditional devices do not adequately consider the coupling effect under multidimensional seismic action, often making it difficult to effectively control torsional vibration of the structure; third, existing seismic isolation technologies generally lack the ability to sense structural damage states, and when an earthquake causes stiffness degradation in the structure, the original control parameters may no longer be applicable, or even exacerbate the structural response.

[0003] In recent years, hydraulic drive technology has shown advantages in structural vibration control, such as fast response and large output. However, existing hydraulic seismic isolation systems still face several key technical challenges: on the one hand, the system continuously consumes external power during earthquake intervals, which is not economical and poses a risk of power outage; on the other hand, the coupling between the control strategy and the real-time state of the structure is insufficient, failing to fully utilize the structure's own dynamic characteristics; in addition, existing technologies lack the ability to identify and respond to the accumulation of structural damage during earthquakes and cannot adaptively adjust control parameters according to the damage state.

[0004] It is particularly noteworthy that traditional seismic isolation systems cannot provide a rapid assessment of the structural safety status after an earthquake, requiring on-site inspection by professionals, which significantly prolongs emergency response time. Therefore, constructing an intelligent seismic isolation system that integrates energy self-sufficiency, state perception, adaptive control, and damage identification has become a key technological bottleneck in improving the seismic performance of T-shaped rigid frame bridges.

[0005] Therefore, there is an urgent need for a hydraulically driven seismic isolation control method for the bottom of T-shaped rigid frame bridge piers to solve the above problems. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the existing technology and propose a hydraulically driven seismic isolation control method for the bottom of T-shaped rigid frame bridge piers.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A seismic isolation control method for the bottom of a T-shaped rigid frame bridge pier based on hydraulic drive, comprising: A hydraulic actuator system with energy recovery function is installed at the bottom of the bridge pier to convert the structural micro-vibration energy into electrical energy for storage, and at the same time control the micro-vibration. The aforementioned electrically driven sensor network is used to monitor structural response data in real time and identify critical ground motion states. Under critical ground motion conditions, the hydraulic actuator working mode is dynamically adjusted according to the identified critical ground motion conditions to achieve multi-dimensional adaptive vibration isolation control. Based on the structural response data, the structural damage status is identified in real time. The control parameters of the multidimensional adaptive seismic isolation control are dynamically adjusted according to the damage identification results, and a structural safety status report is generated after the earthquake.

[0008] As a further technical solution of the present invention, the hydraulic actuator system with energy recovery function installed at the bottom of the bridge pier converts the structural micro-vibration energy into electrical energy for storage, and simultaneously controls the micro-vibration, specifically including: Multiple hydraulic actuator units are symmetrically arranged between the bottom of the pier and the foundation. Each hydraulic actuator unit includes a main hydraulic cylinder, an accumulator and a hydraulic generator. The two ends of the main hydraulic cylinder are connected to the bottom of the pier and the foundation respectively through multi-directional ball joints. When the T-shaped rigid frame bridge experiences slight vibrations under normal load, the main hydraulic cylinder converts the relative motion mechanical energy between the pier and the foundation into hydraulic energy. The converted hydraulic energy is divided into two paths: one path drives the hydraulic generator to generate electricity and stores the electrical energy in the battery; the other path is sent to the accumulator for temporary storage. Meanwhile, by monitoring the frequency and amplitude characteristics of structural micro-vibrations, the opening of the electro-hydraulic proportional valve in the hydraulic circuit is adjusted in real time to change the resistance of the hydraulic circuit, thereby achieving semi-active control of structural micro-vibrations.

[0009] As a further technical solution of the present invention, the method of monitoring the frequency and amplitude characteristics of structural micro-vibrations and adjusting the opening of the electro-hydraulic proportional valve in the hydraulic circuit in real time to change the resistance of the hydraulic circuit, thereby achieving semi-active control of structural micro-vibrations, specifically includes: Real-time monitoring of structural micro-vibration frequency and amplitude ; Flow rate and opening of electro-hydraulic proportional valve and pressure difference The relationship is: ,in: This represents the rate of change of volume within the hydraulic cylinder. This represents the flow coefficient of the electro-hydraulic proportional valve. This refers to the opening degree of the electro-hydraulic proportional valve. The pressure difference in the hydraulic circuit. The density of the hydraulic oil; To better suppress vibration, the resistance of the hydraulic circuit is increased when the vibration frequency or amplitude is high. The control function is as follows: ,in: This is the initial opening degree of the electro-hydraulic proportional valve. It is an adjustment coefficient used to control the magnitude of changes in opening degree; This is a reference amplitude, used to normalize the actual amplitude. ; It is a reference frequency used to normalize the actual frequency. ; and It is an exponential coefficient used to adjust the degree of influence of amplitude and frequency on opening degree; According to the control function, the opening degree of the electro-hydraulic proportional valve It will be based on the frequency of the structural micro-vibrations and amplitude Dynamic adjustment, therefore the pressure difference in the hydraulic circuit This will also change accordingly, enabling precise control of the hydraulic circuit resistance, thereby effectively suppressing the micro-vibrations of the structure.

[0010] As a further technical solution of the present invention, the method of using an electrically driven sensor network to monitor structural response and identify critical seismic states in real time specifically includes: The stored electrical energy in the battery is used to power a sensor network consisting of acceleration sensors, displacement sensors, and strain sensors arranged at the top and bottom of the piers and in the middle of the main beam, so as to collect structural dynamic response data in real time. The collected acceleration signals are subjected to short-time Fourier transform to extract the time-frequency features of the signals, and machine learning algorithms are used to distinguish between normal loads and seismic inputs. When ground motion characteristics are detected and the peak acceleration exceeds the preset threshold, the structure is determined to have entered a critical ground motion state. The full-power seismic isolation control mode is immediately activated, and the hydraulic actuator is switched from micro-vibration control state to strong earthquake control state.

[0011] As a further technical solution of the present invention, the step of performing a short-time Fourier transform on the acquired acceleration signal, extracting the time-frequency features of the signal, and combining it with a machine learning algorithm to distinguish between normal loads and seismic motion inputs specifically includes: The collected acceleration signal Perform a short-time Fourier transform to extract the time-frequency features of the signal. The calculation formula is as follows: ,in: For Hanning window, ; For frequency variables, For time variables, For integration variables, The imaginary unit satisfies The result is a two-dimensional matrix representing the amplitude distribution of the acceleration signal at different times and frequencies. The machine learning algorithm is used to classify the time-frequency features extracted by the short-time Fourier transform. The machine learning model is as follows: Its input is the result of the short-time Fourier transform, and its output is the load type: ,in: Load types include normal loads and ground motion.

[0012] As a further technical solution of the present invention, the step of dynamically adjusting the working mode of the hydraulic actuator according to the identified critical ground motion state under critical ground motion conditions to achieve multi-dimensional adaptive vibration isolation control specifically includes: Under critical ground motion conditions, the hydraulic actuator automatically selects its operating mode based on the ratio of the identified dominant ground motion frequency to the fundamental frequency of the structure: when the ratio is less than 0.8, a high-damping mode is used to control the displacement response; when the ratio is in the range of 0.8-1.2, a variable stiffness and variable damping mode is used to break the resonance effect; and when the ratio is greater than 1.2, a hybrid mode is used. The output force and phase of the hydraulic actuators in the longitudinal and transverse directions are independently adjusted by the hydraulic servo system. Based on the real-time monitoring of displacement and acceleration response, the optimal control force of each actuator is calculated by the feedback control algorithm. Based on the torsional vibration response of the bridge piers, the output phase of adjacent hydraulic actuators is adjusted differentially to suppress the coupled vibration in the longitudinal and transverse directions of the bridge, especially to control the torsional vibration component of the structure.

[0013] As a further technical solution of the present invention, the method of independently adjusting the output magnitude and phase of the longitudinal and transverse hydraulic actuators through a hydraulic servo system, and calculating the optimal control force of each actuator based on real-time monitored displacement and acceleration response using a feedback control algorithm, specifically includes: Establish a state-space model and select state vectors. ,in: The structural displacement vector. , This represents the longitudinal displacement of the bridge. This represents the lateral displacement of the bridge. The angle of twist about the vertical axis; The structure velocity vector; System Dynamics ,in: For the system matrix; For the input matrix, Number of actuators; This is the control force vector; For the seismic motion input matrix; Input for seismic acceleration; Let the control objective function of the control force be... ,in: As a cost of state deviation, To control energy costs, The state weight matrix is... This is the control force weight matrix; Optimal Feedback Gain ,in: For the algebraic Riccati equation The solution; The optimal real-time control force for each actuator is then: .

[0014] As a further technical solution of the present invention, the step of differentially adjusting the output phase of adjacent hydraulic actuators based on the torsional vibration response of the bridge pier to suppress coupled vibrations in the longitudinal and transverse directions, particularly controlling the torsional vibration component of the structure, specifically includes: Decompose the total control force into ,in: For translation components, , and These are the translation components in the x and y directions, respectively; For the torsional component, derived from the torsion angle Calculate the required torque ,in For torsional stiffness coefficient, The torsional damping coefficient is... ; Distributing torque to adjacent actuators generates differentiated phase forces. ,in: For the first The distance from the actuator to the center of torsion The initial phase angle of the actuator. This is the phase offset that is adjusted in real time according to the direction of torsion; No. Instantaneous control force output by a hydraulic actuator ,in: For the first The piston area of ​​the actuator For actuator cavity pressure; No. The volumetric flow rate of a hydraulic cylinder in an actuator, i.e., the rate at which oil enters and exits the cylinder. ,in: For valve flow coefficient, For servo valve opening, For the system oil supply pressure, This refers to the density of the hydraulic oil.

[0015] As a further technical solution of the present invention, the real-time identification of structural damage status based on structural response data, the dynamic adjustment of the control parameters of the seismic isolation control according to the damage identification results, and the generation of a structural safety status report after the earthquake specifically include: Based on the extended Kalman filter algorithm, the acceleration, displacement and strain response data collected by multiple sensors are fused in real time. By comparing the difference between the predicted response and the measured response of the non-destructive finite element model, the degree of structural stiffness degradation and the distribution of damage locations are identified. Based on the identified degree of stiffness degradation, the target control force and maximum permissible displacement of the hydraulic actuator are adjusted proportionally. For every 10% increase in stiffness degradation rate, the target control force is reduced by 15%, and the maximum permissible displacement limit is tightened by 20%. After the earthquake, the cumulative energy consumption is calculated based on the force-displacement hysteresis curve of the hydraulic actuator. The degree of structural damage is assessed by combining the material fatigue characteristics. A structural safety status report is automatically generated, which includes the overall structural damage index, the damage level of key parts, and the remaining load-bearing capacity. The report is then sent to the bridge maintenance unit via a wireless transmission module.

[0016] As a further technical solution of the present invention, the method of using the extended Kalman filter algorithm to fuse acceleration, displacement, and strain response data collected by multiple sensors in real time, and identifying the degree of structural stiffness degradation and damage location distribution by comparing the difference between the predicted response of the non-destructive finite element model and the measured response, specifically includes: EKF residual vector The amplitude and spatial distribution directly reflect the location of stiffness degradation. ,in: This represents the measured vectors of acceleration / displacement / strain. The observation equations for the non-destructive finite element model; Element-level stiffness degradation rate ,in: The stiffness is real-time, estimated by EKF in real time; For the first Initial undamaged stiffness of the element; Global average stiffness degradation rate ,in: This represents the total number of elements in the finite element model involved in stiffness identification; like Then the unit enters the suspected damage set. For the center coordinates of the suspicious unit Perform kernel density estimation: ,in: h is the kernel bandwidth, taken as 0.3-0.5 times the sensor spacing; of The quantile contour lines indicate the location of the damage.

[0017] The beneficial effects of this invention are as follows: 1. Achieved an organic combination of energy self-supply and micro-vibration control: Through hydraulic energy recovery technology, the micro-amplitude vibration energy of the structure is converted into electrical energy, which not only solves the problem of system self-power supply, but also achieves effective control of structural micro-vibration, forming a dual benefit of energy recovery and vibration suppression.

[0018] 2. A damage adaptive control mechanism was established: Through real-time damage identification technology, the structural stiffness degradation state is dynamically perceived, and the control parameters are adaptively adjusted accordingly, ensuring the matching between the control strategy and the actual state of the structure, and overcoming the control failure problem of traditional methods under damaged conditions.

[0019] 3. A multi-dimensional adaptive coordinated control strategy was developed: Based on the seismic frequency characteristics, the control mode was intelligently switched, and the output parameters of each hydraulic actuator were independently adjusted to effectively suppress longitudinal and transverse coupled vibrations and torsional vibrations, thus achieving optimal seismic isolation control across the entire frequency range. Attached Figure Description

[0020] Figure 1 This is a flowchart summarizing the seismic isolation control method for the bottom of a T-shaped rigid frame bridge pier based on hydraulic drive proposed in this invention. Figure 2 This is a detailed flowchart of a hydraulically driven seismic isolation control method for the bottom of a T-shaped rigid frame bridge pier proposed in this invention. Figure 3 This is a schematic diagram of the design of a seismic isolation system for a T-shaped rigid frame bridge. Figure 4 This is a comparison diagram of the effects of the method of the present invention and the prior art method in Example 1; Figure 5 This is a diagram showing the damage identification accuracy of the method of the present invention in Example 1.

[0021] Figure 6 Enlarged view of part A of the hydraulic actuator system installed at the bottom of the bridge pier; Figure 7 A partial enlarged view of section B for the seismic isolation design at the end of a T-shaped rigid frame bridge; Among them, 11. Upper ball joint; 12. Lower ball joint; 13. Center positioning pin; 14. Upper bearing platform; 15. Lower bearing platform; 16. Sacrificial post-sealing concrete zone; 17. Connecting reinforcement; 18. Hydraulic support foot; 21. Variable curvature curved beam end structure; 22. Stainless steel sliding plate; 23. Low friction sliding plate; 24. Comb-shaped expansion joint; 25. Bridge pier; 26. Main beam; 27. Seismic isolation bearing. Detailed Implementation

[0022] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0023] Example 1 Please see the appendix Figures 1-3 A seismic isolation control method for the bottom of a T-shaped rigid frame bridge pier based on hydraulic drive, comprising: S1. Install a hydraulic actuator system with energy recovery function at the bottom of the T-shaped rigid frame pier to convert the structural micro-vibration energy into electrical energy for storage, and at the same time control the micro-vibration; Specifically, ,in: It's the quality of the bridge piers. It is the acceleration of the bridge pier. It is the equivalent damping between the bridge pier and the foundation. It is the relative velocity between the bridge pier and the foundation. It is the equivalent stiffness between the bridge pier and the foundation. It is the relative displacement between the bridge pier and the foundation. It is the output force of the main hydraulic cylinder and the pressure inside the hydraulic cylinder. and piston area related: ; The main hydraulic cylinder converts mechanical vibration energy into hydraulic energy. The calculation formula is: ; Hydraulic energy is divided into two paths: one part drives a hydraulic generator to generate electricity, which is then stored in a battery. ,in: The electrical energy output by the hydraulic generator. It refers to the efficiency of converting hydraulic energy into electrical energy; Another portion of the hydraulic energy is temporarily stored in the accumulator: ,in: Hydraulic energy temporarily stored in the accumulator; Simultaneously, by monitoring the frequency of structural micro-vibrations and amplitude Real-time adjustment of the opening degree of the electro-hydraulic proportional valve in the hydraulic circuit By changing the resistance of the hydraulic circuit, semi-active control of structural micro-vibrations can be achieved: Flow rate and opening of electro-hydraulic proportional valve and pressure difference The relationship is: ,in: This represents the rate of change of volume within the hydraulic cylinder. This represents the flow coefficient of the electro-hydraulic proportional valve. This refers to the opening degree of the electro-hydraulic proportional valve. The pressure difference in the hydraulic circuit. The density of the hydraulic oil; To better suppress vibration, the resistance of the hydraulic circuit is increased when the vibration frequency or amplitude is high. The control function is as follows: ,in: It is the initial opening degree of the electro-hydraulic proportional valve; It is an adjustment coefficient used to control the magnitude of changes in opening degree; This is a reference amplitude, used to normalize the actual amplitude. ; It is a reference frequency used to normalize the actual frequency. ; and It is an exponential coefficient used to adjust the degree of influence of amplitude and frequency on opening degree; According to the control function, the opening degree of the electro-hydraulic proportional valve It will be based on the frequency of the structural micro-vibrations and amplitude Dynamic adjustment, therefore the pressure difference in the hydraulic circuit This will also change accordingly, enabling precise control of the hydraulic circuit resistance, thereby effectively suppressing the micro-vibrations of the structure.

[0024] S2. Utilizing the aforementioned electrically driven sensor network to monitor structural response data in real time and identify critical ground motion states; specifically including: S21. Utilizing electrical energy stored in an energy storage device Power is supplied to the sensor network consisting of accelerometers, displacement sensors, and strain sensors deployed at the top and bottom of the piers and in the main girder span to ensure the continuous operation of the sensor network; the total power consumption of the sensor network... The output power needs to be less than or equal to that of the battery to ensure stable system operation. ,in: It is the system's runtime.

[0025] S22. The sensor network acquires dynamic response data of the structure in real time, including: acceleration signals. Displacement signal and strain signal sampling frequency Data collection was performed at intervals of 1000 to 1000. The number of sampling points is ,in: This is the length of the sliding window.

[0026] S23. The acquired acceleration signal Short-Time Fourier Transform (STFT) is performed to extract the time-frequency features of the signal. The formula for calculating STFT is: ,in: For Hanning window, ; For frequency variables, For time variables, For integration variables, The imaginary unit satisfies The result of STFT is a two-dimensional matrix representing the amplitude distribution of the acceleration signal at different times and frequencies.

[0027] S24. Classify the time-frequency features extracted by STFT using a machine learning algorithm. The machine learning model is as follows: Its input is the result of STFT, and its output is the load type: ,in: The load type includes normal loads or ground motion.

[0028] S25. When the machine learning model identifies seismic motion characteristics, further examine the peak acceleration within the sliding window. Does it exceed the preset threshold? , , ,in: This is a dimensionless coefficient, typically ranging from 0.05 to 0.10. ;if If so, the structure is determined to have entered a critical ground motion state.

[0029] S26. Once the structure is determined to have entered a critical ground motion state, immediately activate the full-power seismic isolation control mode and switch the hydraulic actuators from the micro-vibration control state. Transition to strong earthquake control state During routine micro-vibration control, the opening of the electro-hydraulic proportional valve is continuously adjusted between 0 and 1. After triggering the strong vibration mode, the opening of the high-speed servo valve... Instantly set to 1 to ensure maximum damping / stiffness of the hydraulic actuator output; battery bus output voltage Switching from a first voltage level suitable for micro-vibration monitoring to a second voltage level that is higher than the first voltage level and suitable for strong vibration driving, in order to meet the energy consumption and output requirements under different working conditions. For example, the first voltage level can be a low voltage in the range of 12V to 24V for sensor power supply and micro-vibration control; the second voltage level can be a higher voltage in the range of 36V to 72V for driving the hydraulic servo system to cope with strong vibration.

[0030] S3. Under critical ground motion conditions, the hydraulic actuator's operating mode is dynamically adjusted based on the identified critical ground motion conditions to achieve multi-dimensional adaptive seismic isolation control; specifically including: S31. Under critical ground motion conditions, firstly utilize the identified dominant ground motion frequency. With the fundamental frequency of the structure ratio Automatically selects the operating mode of the hydraulic actuator, i.e. High-damping mode is used at this time. The variable stiffness-variable damping mode is used. When using a hybrid mode, where: In the STFT results, the dominant frequency of the seismic input is... The frequency component defined as having the highest energy spectral density: ; ,in: The equivalent lateral stiffness of the pier-foundation system. To achieve equivalent participation in quality.

[0031] S32. The output force and phase of the hydraulic actuators in the longitudinal (x-direction) and transverse (y-direction) directions are independently adjusted via a hydraulic servo system; the optimal control force is calculated using an LQR feedback control algorithm based on real-time displacement and acceleration feedback; specifically including: Establish a state-space model (for LQR) and select state vectors. ,in: The structural displacement vector. , This represents the longitudinal (x-direction) displacement of the bridge. This represents the transverse (y-direction) displacement of the bridge. The angle of twist about the vertical axis; The structure velocity vector; System Dynamics ,in: For the system matrix; For the input matrix, Number of actuators; This is the control force vector; For the seismic motion input matrix; Input for seismic acceleration ( Towards); Let the control objective function of the control force be... ,in: This is the cost of state deviation (such as penalties for displacement or velocity deviating from zero). To control energy consumption (to avoid excessive actuator output). It is a state weight matrix (diagonal matrix, weights for displacement, velocity, and torsion angle). The control force weight matrix (diagonal matrix, to avoid actuator saturation); Optimal Feedback Gain ,in: For the algebraic Riccati equation The solution; The optimal real-time control force for each actuator is: .

[0032] S33. Based on the pier torsional angle response Differential phase adjustment is applied to adjacent actuators to suppress longitudinal-lateral coupled vibrations, especially the torsional component; specifically including: Decompose the total control force into ,in: For translation components, , and These are the translation components in the x and y directions, respectively; For the torsional component, derived from the torsion angle Calculate the required torque ,in For torsional stiffness coefficient, The torsional damping coefficient is... ; Distributing torque to adjacent actuators generates differentiated phase forces. ,in: For the first The distance from the actuator to the center of torsion The initial phase angle of the actuator. This is the phase offset that is adjusted in real time according to the direction of torsion; No. Instantaneous control force output by a hydraulic actuator ,in: For the first The piston area of ​​the actuator For actuator cavity pressure; No. The volumetric flow rate of a hydraulic cylinder in an actuator, i.e., the rate at which oil enters and exits the cylinder. ,in: For valve flow coefficient, For servo valve opening, For the system oil supply pressure, This refers to the density of the hydraulic oil.

[0033] S4. Based on the structural response data, identify the structural damage state in real time, dynamically adjust the control parameters of the multi-dimensional adaptive seismic isolation control according to the damage identification results, and generate a structural safety status report after the earthquake; specifically including: S41. Throughout the earthquake process, using the Extended Kalman Filter (EKF) as the core, data from three types of sensors—acceleration, displacement, and strain—are fused in real time. By comparing the predicted response with the measured response from the non-destructive finite element model, the structural stiffness degradation rate and spatial distribution of damage are identified online; specifically including: EKF residual vector The amplitude and spatial distribution directly reflect the location of stiffness degradation. ,in: This represents the measured vectors of acceleration / displacement / strain. The observation equations for the non-destructive finite element model; Element-level stiffness degradation rate ,in: The stiffness is real-time, estimated by EKF in real time; For the first Initial undamaged stiffness of the element; Global average stiffness degradation rate ,in: This represents the total number of elements in the finite element model involved in stiffness identification; like Then the unit enters the suspected damage set. For the center coordinates of the suspicious unit Perform kernel density estimation: ,in: h is the kernel bandwidth, taken as 0.3-0.5 times the sensor spacing; of The quantile contour lines indicate the location of the damage.

[0034] S42. According to Dynamically adjust the target control force of the hydraulic actuator With the maximum allowable displacement limit Stiffness degradation rate For every 10% increase, the target control force Reduce by 15%, displacement limit Tighten by 20%; Target control correction ,in: For the first The initial target control force of the actuator is set at a lower limit of 0.3 to prevent excessive conservatism. Maximum permissible displacement limit correction ,in: The initial allowable displacement is set at a lower limit of 0.4 to prevent overly conservative approaches.

[0035] S43. After the earthquake, the cumulative energy dissipation is obtained based on the actuator force-displacement hysteresis loop integral: (The...) Energy consumption of actuator force-displacement hysteresis loop ,in: This is the moment when the earthquake began. The moment when the earthquake ends. For the first Instantaneous speed of the actuator piston; total energy consumption ,in: This represents the total number of hydraulic actuators arranged in the system. Damage parameters are calculated based on material fatigue curves: ,in: For the first Damage index of the unit, For the first Unit 1 Level strain amplitude, For the corresponding number of loops, The fatigue curve of the material. These are material constants; Automatically generate an overall damage index Damage level and remaining load-bearing capacity of key components Structural safety status report, and through The wireless module was pushed to the bridge maintenance unit.

[0036] Example 2 In this embodiment, a hydraulic actuator system with energy recovery function is installed at the bottom of the T-shaped rigid frame bridge pier to convert the structural micro-vibration energy into electrical energy for storage, while simultaneously controlling the micro-vibration. Specifically, the T-shaped rigid frame bridge includes a pier, an upper abutment, a lower abutment, and a main beam. A complete pier bottom seismic isolation and controllable damage system is set between the bottom of the pier and the foundation.

[0037] Please refer to Figure 3 Overall layout elevation and Figure 6 Detailed structural diagram of the pier base. This system specifically includes the following components and their positional relationships: pier base seismic isolation system A and beam end seismic isolation design B. The pier base seismic isolation system includes the following structure: (1) Rotating ball joint mechanism: This mechanism includes an upper ball joint 11, a lower ball joint 12, and a central positioning pin 13; the upper ball joint is fixedly connected to the center of the bottom surface of the upper bearing platform 14 by pre-embedded steel plates and bolts. The lower ball joint is welded to the center of the top surface of the lower bearing platform 15 and matches the spherical surface of the upper ball joint. The central positioning pin 13 passes through the central hole of the upper and lower ball joints, and its function is to limit the horizontal relative displacement between the upper and lower ball joints, but allow them to rotate relative to each other around the pin.

[0038] (2) Sacrificial Post-Sealing Concrete Zone 16: Includes post-cast micro-expansion concrete and a small number of connecting steel bars 17. Between the upper and lower abutments, a ring of post-sealing concrete is poured around the rotating ball joint mechanism. This zone bears shear and compression loads during the normal service phase of the bridge, ensuring the overall stiffness of the structure. The key is that only a small number of weakened connecting steel bars are arranged in this zone (for example, a small number of ordinary steel bars are arranged, which need to be calculated to ensure that the structure will not fail under normal service conditions, but will yield first under strong earthquakes). Its strength is actively designed to be much lower than that of the piers and abutments under earthquakes, thus becoming a "fuse" in the entire system.

[0039] (3) Hydraulic support leg 18: includes several hydraulically controllable damping support legs, i.e., hydraulic actuator units. The support legs are evenly arranged around the rotating ball joint mechanism and located within the post-sealed concrete area. The upper end of each support leg is connected to the upper bearing platform 14 via the upper ball joint 11, and the lower end is connected to the lower bearing platform 15 via the lower ball joint 12, forming a connection that can transmit tensile and compressive loads and allow a certain degree of rotation. Each support leg has a built-in hydraulic servo system, which can adjust its damping characteristics and output force in real time according to the instructions of the control system, thereby achieving: During normal use, it provides appropriate stiffness and damping to control the micro-vibration of the structure under vehicle and wind loads; Under seismic action, based on the real-time identified ground motion status and structural response, the output magnitude, phase and direction of each support are actively adjusted to achieve coordinated control of longitudinal, transverse and torsional vibrations. After an earthquake, the upper limit of output force and the travel limit are adaptively adjusted based on the damage identification results to protect the damaged structure from excessive secondary effects.

[0040] The hydraulic support leg and hydraulic actuator system are functionally identical and serve as the actuator for achieving adaptive seismic isolation control at the pier base.

[0041] (4) Sensor network: The electrical energy stored in the energy storage device is used to power the sensor network to ensure the continuous operation of the sensor network. The sensor network includes acceleration sensors arranged on the top and bottom of the pier, strain sensors on the main beam span, and angular velocity sensors and displacement sensors evenly arranged around the ball joint.

[0042] like Figure 7 As shown, beam end seismic isolation design B includes variable curvature curved beam end structure 21, stainless steel sliding plate 22, low friction sliding plate 23, and comb-shaped expansion joint 24.

[0043] The variable curvature curved beam end structure 21 includes: a prefabricated built-in steel end box on the bottom surface of the cantilever end of the main beam, the bottom surface of which is a variable curvature geometric surface. The radius of curvature of the surface is designed to increase from the beam end towards the mid-span. A low-friction sliding plate 23 (such as an ultra-high molecular weight polyethylene UHMW-PE plate) is fixedly installed on the variable curvature surface of the steel end box. At the corresponding position on the top of the abutment or transition pier, a high-strength stainless steel plate 22 is pre-embedded, which pairs with the low-friction sliding plate at the beam end to form a sliding friction pair.

[0044] The beam ends are supported on the bridge piers / caps 25 via this "low-friction sliding plate / stainless steel plate" interface, forming a sliding support relationship. At the same time, the load of the main beam 26 is transferred to the substructure through the seismic isolation bearings 27, allowing the beam ends to slide and rotate freely during earthquakes.

[0045] Sealing and bridge deck continuity: Sufficient design displacement clearance is reserved between the end of the main beam and the abutment, and a comb-shaped expansion joint 24 is installed on the bridge deck above this clearance. The structure of this expansion joint can adapt to large multi-directional displacement during earthquakes and effectively achieve bridge deck sealing, waterproofing and dustproofing, but its substructure is not rigidly connected to the main beam and does not restrain the horizontal sliding of the beam end.

[0046] Experimental verification Three representative seismic waves were selected for time history analysis: EL Centro wave (1940, NS component), Kobe wave (1995, NS component), and artificial wave (consistent with site characteristics).

[0047] The method of this invention is implemented step by step: a hydraulic energy recovery system is installed, and the micro-vibration control effect is tested under vehicle load; the sensor network is calibrated to verify the accuracy of ground motion identification; The switching effects of various control modes were tested under different levels of seismic loading; structural damage was simulated to verify the damage adaptive control function.

[0048] Comparative Analysis of Effects 1. Finite element simulation test setup To verify the effectiveness of the method of the present invention, a finite element simulation test was used to analyze a T-shaped rigid frame bridge of a highway. The bridge has a span arrangement of 60m+100m+60m, a pier height of 35m, is located in an area with a seismic intensity of 8 degrees, and has a design basic seismic acceleration value of 0.20g.

[0049] Finite Element Model Construction: A three-dimensional model of the entire bridge was built in finite element software. Piers and main girders were simulated using beam elements, and foundations were simulated using spring elements. Four sets of hydraulic actuator elements were simulated between the bottom of the piers and the foundations. Each set of elements achieved its mechanical behavior through nonlinear connection elements, with parameters set as follows: maximum output 2000kN, stroke ±150mm. The hydraulic energy recovery system was implemented through a custom user subroutine, simulating the coupling behavior between the accumulator (capacity 50L, working pressure 21MPa) and the hydraulic generator (rated power 5kW). The sensor network was implemented through measuring points in the model, simulating the placement of accelerometers (range ±2g), displacement sensors (range ±200mm), and strain sensors (range ±2000με) at the top and bottom of the piers and the mid-span of the main girder. The control algorithm was embedded in the finite element solver and implemented through an external control module, with a control cycle set to 10ms. Control parameter settings: seismic motion identification threshold is 0.05g, stiffness degradation identification cycle is 1s, control mode switching threshold is λ=0.8 (low frequency) and λ=1.2 (high frequency), and maximum allowable displacement is 120mm.

[0050] 2. Finite element simulation test process Three representative seismic waves were selected as inputs: the EL Centro wave (1940, NS component), the Kobe wave (1995, NS component), and an artificial wave consistent with the site characteristics. The simulation experiment was conducted according to the following steps: (1) Micro-vibration control and energy recovery simulation: Apply vehicle load and wind load to the model to simulate normal micro-vibration. Run the hydraulic energy recovery and control module to record the power generation, battery status and structural vibration response.

[0051] (2) Validation of seismic motion identification algorithm: Input seismic waves of different intensities, test the data acquisition and processing module of the sensor network model, and verify the accuracy of short-time Fourier transform and machine learning algorithm in identifying seismic events.

[0052] (3) Control mode switching and multi-dimensional seismic isolation simulation: Input seismic waves with low frequency, resonance frequency and high frequency characteristics respectively, observe whether the control module automatically switches to high damping, variable stiffness-variable damping and hybrid modes according to the λ value, and record the structural displacement, acceleration, torsional angle and other responses.

[0053] (4) Damage identification and adaptive control verification: In the finite element model, local stiffness reduction (simulated damage) is preset, and the extended Kalman filter algorithm module is run to verify its ability to identify the degree and location of stiffness degradation, and observe whether the control parameters are adaptively adjusted according to the identification results.

[0054] 3. Analysis of Finite Element Simulation Test Results The effects of the method of the present invention and the prior art methods are compared as shown in Table 1 below and Figures 4-5 as follows: Table 1: Effect comparison table Specific effect analysis Seismic response control effect: Under the action of EL Centro wave (PGA = 0.4g), when only seismic isolation bearings are set at the beam ends, the peak value of the pier bottom moment is reduced by 22%, and the displacement of the seismic isolation layer reaches 95 mm; the peak value of the pier bottom moment is reduced by 28%, and the displacement of the seismic isolation layer is 78 mm; the peak value of the pier bottom moment of the method of the present invention is reduced by 52%, and the displacement of the seismic isolation layer is controlled at 58 mm, and the self-resetting effect is obvious.

[0055] Energy recovery effect: Under normal use conditions (vehicle load, wind load), the daily average power generation is 18 - 25 kWh, the self-power consumption of the system is 12 - 15 kWh, and the net power generation is 6 - 10 kWh (which can be supplied for the use of the bridge monitoring system).

[0056] Damage identification accuracy: As Figure 5 shown, through simulating different damage conditions for verification, the identification accuracy rate for minor damage (stiffness degradation of 10%) is 92%, for moderate damage (stiffness degradation of 30%) is 96%, and for severe damage (stiffness degradation of 50%) is 98%.

[0057] Control mode switching effect: Under the action of seismic waves with different frequency characteristics, when the low-frequency seismic wave (f < 0.8f0), it automatically switches to the high-damping mode, and the displacement control effect is improved by 35%; in the resonance situation (0.8f0 < f < 1.2f0), it automatically switches to the variable stiffness and variable damping mode, and the acceleration response is reduced by 45%; when the high-frequency seismic wave (f > 1.2f0), it automatically switches to the hybrid mode, and the comprehensive shock absorption effect reaches 50%.

[0058] 4. Conclusion The finite element simulation test of this embodiment shows that: the method of the present invention has a significant improvement in the shock absorption effect compared with the traditional method; the hydraulic energy recovery module can achieve self-power supply of the system; the damage identification and parameter adaptive adjustment mechanism can effectively ensure the optimality of the whole control process; the multi-dimensional coordinated control algorithm can significantly suppress the coupled vibration under complex seismic actions. This method provides an effective numerical simulation tool and theoretical support for the seismic design and safety assessment of T-shaped rigid frame bridges.

[0059] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects: This invention achieves a groundbreaking integration of energy self-sufficiency and intelligent sensing, solving the technical challenge of high energy consumption in traditional hydraulic systems. Traditional hydraulic control systems require continuous external power, resulting in high energy consumption and the risk of power outages. This invention innovatively converts the micro-vibration energy of a structure under normal loads into electrical energy through hydraulic energy recovery technology, achieving complete self-sufficiency. Specifically, under normal operating conditions, the system generates an average of 18-25 kWh per day, leaving a net surplus of 6-10 kWh after meeting self-consumption requirements. Simultaneously, by adjusting the hydraulic circuit resistance based on micro-vibration response characteristics, the vibration acceleration of the structure under vehicle loads is reduced by 30%-40%. This innovation not only completely solves the energy consumption problem of hydraulic systems but also achieves effective control of structural micro-vibrations, extending the structural lifespan and creating a virtuous cycle of "vibration-based vibration control."

[0060] A damage adaptive control mechanism was established, achieving a technological leap from "damage-free assumption control" to "real-time damage adaptive control." Traditional seismic isolation control methods are based on the ideal assumption that the structure remains elastic, neglecting the cumulative damage effects that may occur during actual earthquakes. This invention, through a real-time damage identification algorithm based on extended Kalman filtering, can accurately capture the structural stiffness degradation process (with an identification accuracy of 92%-98%) and dynamically adjust control parameters accordingly. Specific innovative effects are reflected in: adjusting the target control force of the hydraulic actuator proportionally (the target control force decreases by 15% for every 10% increase in stiffness degradation rate) and displacement limit value based on the identified stiffness degradation rate; automatically generating a structural safety status report based on the cumulative damage assessment results after the earthquake. This mechanism ensures that the control strategy always matches the actual structural state, avoiding a decline in control effectiveness or even negative effects caused by mismatched control parameters.

[0061] A multi-dimensional adaptive coordinated control strategy was developed, overcoming the technical bottleneck of coupled vibration control under complex seismic loading. Addressing the complex response characteristics of T-shaped rigid frame bridges under seismic loading, this invention proposes a multi-mode control strategy and a multi-dimensional coordinated control algorithm based on frequency identification. An adaptive switching mechanism for three control modes was designed: a hybrid mode is adopted for high-frequency ground motions (frequency ratio > 1.2), solving the problem of poor control performance in the high-frequency range by coordinating high-frequency filtering and active damping distribution. Practical application shows that this strategy reduces the peak bending moment at the pier base by 45%-55%, while strictly controlling the displacement of the seismic isolation layer within the allowable range. By independently controlling the output magnitude and phase of each hydraulic actuator, coupled vibrations in the longitudinal and transverse directions are effectively suppressed, especially reducing the difficult-to-control torsional vibration by more than 40%. This innovation achieves truly intelligent seismic isolation control, providing comprehensive seismic protection for T-shaped rigid frame bridges.

[0062] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention is limited to these examples; within the framework of the invention, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity.

[0063] This invention is intended to cover all such substitutions, modifications, and variations that fall within the broad scope of this specification. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A method for seismic isolation control of the bottom of a T-shaped rigid frame bridge pier based on hydraulic drive, characterized in that, include: A hydraulic actuator system with energy recovery function is installed at the bottom of the bridge pier to convert the structural micro-vibration energy into electrical energy for storage, and at the same time control the micro-vibration. The aforementioned electrically driven sensor network is used to monitor structural response data in real time and identify critical ground motion states. Under critical ground motion conditions, the hydraulic actuator working mode is dynamically adjusted according to the identified critical ground motion conditions to achieve multi-dimensional adaptive vibration isolation control. Based on the structural response data, the structural damage status is identified in real time. The control parameters of the multidimensional adaptive seismic isolation control are dynamically adjusted according to the damage identification results, and a structural safety status report is generated after the earthquake.

2. The method for seismic isolation control of T-shaped rigid frame bridge piers based on hydraulic drive according to claim 1, characterized in that, The hydraulic actuator system with energy recovery function installed at the bottom of the bridge pier converts the structural micro-vibration energy into electrical energy for storage and simultaneously controls the micro-vibration. Specifically, it includes: Multiple hydraulic actuator units are symmetrically arranged between the bottom of the pier and the foundation. Each hydraulic actuator unit includes a main hydraulic cylinder, an accumulator and a hydraulic generator. The two ends of the main hydraulic cylinder are connected to the bottom of the pier and the foundation respectively through multi-directional ball joints. When the T-shaped rigid frame bridge experiences slight vibrations under normal load, the main hydraulic cylinder converts the relative motion mechanical energy between the pier and the foundation into hydraulic energy. The converted hydraulic energy is divided into two paths: one path drives the hydraulic generator to generate electricity and stores the electrical energy in the battery; the other path is sent to the accumulator for temporary storage. Meanwhile, by monitoring the frequency and amplitude characteristics of structural micro-vibrations, the opening of the electro-hydraulic proportional valve in the hydraulic circuit is adjusted in real time to change the resistance of the hydraulic circuit, thereby achieving semi-active control of structural micro-vibrations.

3. The method for seismic isolation control of T-shaped rigid frame bridge piers based on hydraulic drive according to claim 2, characterized in that, The method involves monitoring the frequency and amplitude characteristics of structural micro-vibrations and adjusting the opening of the electro-hydraulic proportional valve in the hydraulic circuit in real time to change the resistance of the hydraulic circuit, thereby achieving semi-active control of structural micro-vibrations. Specifically, this includes: Real-time monitoring of structural micro-vibration frequency and amplitude ; Flow rate and opening of electro-hydraulic proportional valve and pressure difference The relationship is: ,in: This represents the rate of change of volume within the hydraulic cylinder. This represents the flow coefficient of the electro-hydraulic proportional valve. This refers to the opening degree of the electro-hydraulic proportional valve. The pressure difference in the hydraulic circuit. The density of the hydraulic oil; When the vibration frequency is high or the amplitude is large, the resistance of the hydraulic circuit is increased, and the control function is: ,in: This is the initial opening degree of the electro-hydraulic proportional valve. It is the adjustment coefficient. This is a reference amplitude. It is a reference frequency. and It is the exponential coefficient; According to the control function, the opening degree of the electro-hydraulic proportional valve It will be based on the frequency of the structural micro-vibrations and amplitude Dynamic adjustment, therefore the pressure difference in the hydraulic circuit This will also change accordingly, enabling precise control of the hydraulic circuit resistance, thereby effectively suppressing the micro-vibrations of the structure.

4. The method for seismic isolation control of the bottom of a T-shaped rigid frame bridge pier based on hydraulic drive according to claim 2, characterized in that, The method of using an electrically driven sensor network to monitor structural response and identify critical seismic states in real time specifically includes: The stored electrical energy in the battery is used to power a sensor network consisting of acceleration sensors, displacement sensors, and strain sensors arranged at the top and bottom of the piers and in the middle of the main beam, so as to collect structural dynamic response data in real time. The collected acceleration signals are subjected to short-time Fourier transform to extract the time-frequency features of the signals, and machine learning algorithms are used to distinguish between normal loads and seismic inputs. When ground motion characteristics are detected and the peak acceleration exceeds the preset threshold, the structure is determined to have entered a critical ground motion state. The full-power seismic isolation control mode is immediately activated, and the hydraulic actuator is switched from micro-vibration control state to strong earthquake control state.

5. The method for seismic isolation control of the bottom of a T-shaped rigid frame bridge pier based on hydraulic drive according to claim 4, characterized in that, The process of performing a short-time Fourier transform on the acquired acceleration signal to extract its time-frequency features, and then combining this with machine learning algorithms to distinguish between normal loads and seismic motion inputs, specifically includes: The collected acceleration signal Perform a short-time Fourier transform to extract the time-frequency features of the signal. The calculation formula is as follows: ,in: For Hanning window, ; For frequency variables, For time variables, For integration variables, The imaginary unit satisfies The result is a two-dimensional matrix representing the amplitude distribution of the acceleration signal at different times and frequencies. The machine learning algorithm is used to classify the time-frequency features extracted by the short-time Fourier transform. The machine learning model is as follows: Its input is the result of the short-time Fourier transform, and its output is the load type: ,in: Load types include normal loads and ground motion.

6. The method for seismic isolation control of the bottom of a T-shaped rigid frame bridge pier based on hydraulic drive according to claim 1, characterized in that, Under critical ground motion conditions, the hydraulic actuator's operating mode is dynamically adjusted based on the identified critical ground motion conditions to achieve multi-dimensional adaptive vibration isolation control, specifically including: Under critical ground motion conditions, the hydraulic actuator's operating mode is automatically selected based on the ratio of the identified dominant ground motion frequency to the fundamental frequency of the structure. The output force and phase of the hydraulic actuators in the longitudinal and transverse directions are independently adjusted by the hydraulic servo system. Based on the real-time monitoring of displacement and acceleration response, the optimal control force of each actuator is calculated by the feedback control algorithm. Based on the torsional vibration response of the bridge piers, the output phase of adjacent hydraulic actuators is adjusted differentially to suppress the coupled vibration in the longitudinal and transverse directions of the bridge, especially to control the torsional vibration component of the structure.

7. The method for seismic isolation control of the bottom of a T-shaped rigid frame bridge pier based on hydraulic drive according to claim 6, characterized in that, The hydraulic servo system independently adjusts the output magnitude and phase of the longitudinal and transverse hydraulic actuators. Based on real-time monitoring of displacement and acceleration response, a feedback control algorithm is used to calculate the optimal control force for each actuator, specifically including: Establish a state-space model and select state vectors. ,in: The structural displacement vector. , This represents the longitudinal displacement of the bridge. This represents the lateral displacement of the bridge. The angle of twist about the vertical axis; The structure velocity vector; System Dynamics ,in: For the system matrix; For the input matrix, Number of actuators; This is the control force vector; For the seismic motion input matrix; Input for seismic acceleration; Let the control objective function of the control force be... ,in: As a cost of state deviation, To control energy costs, The state weight matrix is... This is the control force weight matrix; Optimal Feedback Gain ,in: For the algebraic Riccati equation The solution; The optimal real-time control force for each actuator is then: .

8. The method for seismic isolation control of the bottom of a T-shaped rigid frame bridge pier based on hydraulic drive according to claim 7, characterized in that, The method of differentially adjusting the output phase of adjacent hydraulic actuators based on the torsional vibration response of the bridge piers to suppress coupled vibrations in the longitudinal and transverse directions, particularly controlling the torsional vibration component of the structure, specifically includes: Decompose the total control force into ,in: For translation components, , and These are the translation components in the x and y directions, respectively; For the torsional component, derived from the torsion angle Calculate the required torque ,in For torsional stiffness coefficient, The torsional damping coefficient is... ; Distributing torque to adjacent actuators generates differentiated phase forces. ,in: For the first The distance from the actuator to the center of torsion The initial phase angle of the actuator. This is the phase offset that is adjusted in real time according to the direction of torsion; No. Instantaneous control force output by a hydraulic actuator ,in: For the first The piston area of ​​the actuator For actuator cavity pressure; No. The volumetric flow rate of a hydraulic cylinder in an actuator, i.e., the rate at which oil enters and exits the cylinder. ,in: For valve flow coefficient, For servo valve opening, For the system oil supply pressure, This refers to the density of the hydraulic oil.

9. The method for seismic isolation control of the bottom of a T-shaped rigid frame bridge pier based on hydraulic drive according to claim 1, characterized in that, The process of real-time identification of structural damage status based on structural response data, dynamic adjustment of control parameters for seismic isolation control based on damage identification results, and generation of a structural safety status report after an earthquake specifically includes: Based on the extended Kalman filter algorithm, the acceleration, displacement and strain response data collected by multiple sensors are fused in real time. By comparing the difference between the predicted response and the measured response of the non-destructive finite element model, the degree of structural stiffness degradation and the distribution of damage locations are identified. Based on the identified degree of stiffness degradation, the target control force and maximum allowable displacement of the hydraulic actuator are adjusted proportionally. After the earthquake, the cumulative energy consumption is calculated based on the force-displacement hysteresis curve of the hydraulic actuator. The degree of structural damage is assessed by combining the material fatigue characteristics. A structural safety status report is automatically generated, which includes the overall structural damage index, the damage level of key parts, and the remaining load-bearing capacity. The report is then sent to the bridge maintenance unit via a wireless transmission module.

10. A method for seismic isolation control of the bottom of a T-shaped rigid frame bridge pier based on hydraulic drive, as described in claim 9, is characterized in that... The method, based on the extended Kalman filter algorithm, fuses acceleration, displacement, and strain response data collected from multiple sensors in real time. By comparing the difference between the predicted response from the non-destructive finite element model and the measured response, it identifies the degree of structural stiffness degradation and the distribution of damage locations. Specifically, this includes: EKF residual vector The amplitude and spatial distribution directly reflect the location of stiffness degradation. ,in: This represents the measured vectors of acceleration / displacement / strain. The observation equations for the non-destructive finite element model; Element-level stiffness degradation rate ,in: The stiffness is real-time, estimated by EKF in real time; For the first Initial undamaged stiffness of the element; Global average stiffness degradation rate ,in: This represents the total number of elements in the finite element model involved in stiffness identification; like Then the unit enters the suspected damage set. For the center coordinates of the suspicious unit Perform kernel density estimation: in: h is the kernel bandwidth, taken as 0.3-0.5 times the sensor spacing; of The quantile contour lines indicate the location of the damage.

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