Fatigue test equipment and method for overhead rigid suspension expansion joint
By linking the fiber optic strain sensor array and the control system module, the phase and displacement of horizontal and vertical vibrations are dynamically adjusted, which solves the shortcomings of existing test equipment in simulating multi-directional composite fatigue loads, realizes more accurate fatigue testing of expansion joints, and improves the authenticity and accuracy of the test.
Patent Information
- Application Number
- CN202512005085.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-29
- Publication Date
- 2026-03-17
AI Technical Summary
Existing fatigue testing equipment for expansion joints cannot effectively simulate the multi-directional composite fatigue loads faced under real working conditions, and lacks a synchronous coupling loading mechanism for multi-directional dynamic response, resulting in load spectrum distortion and making it difficult for test data to reflect the dynamic response characteristics under complex stress states.
By employing a fiber optic strain sensor array combined with a control system module, a three-dimensional strain field model is constructed using finite element inversion algorithms and material constitutive equations. This dynamically generates the hysteresis compensation time for horizontal vibration, enabling the coordinated control of vertical and horizontal vibration dynamics and ensuring that the horizontal vibration reaches its maximum displacement at the peak of the vertical vibration.
This improves the authenticity and accuracy of fatigue testing of expansion joints, avoids load spectrum distortion, ensures that test data fully reflects the dynamic response characteristics under complex stress conditions, simplifies the operation process and improves testing efficiency, and provides an accurate basis for life prediction.
Smart Images
Figure CN121678167A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of structural testing technology, and in particular to a fatigue testing device and method for an overhead rigid suspension expansion joint. Background Technology
[0002] As a key infrastructure for low-clearance tunnels of electrified railways and urban rail transit, the overhead rigid suspension system uses expansion joints to absorb the linear deformation of the busbars caused by ambient temperature fluctuations, thereby maintaining the geometric stability of the contact wire structure.
[0003] Current fatigue testing methods for expansion joints in the industry have significant limitations: First, conventional testing schemes generally focus on simulating periodic expansion or vibration in a single direction, making it difficult to effectively reproduce the multi-directional composite fatigue loads faced by the equipment under real working conditions. Second, existing testing devices generally suffer from discrete functional modules; even when multi-directional testing is possible, the lack of a coordinated control mechanism between the dynamic forces in each direction prevents the synchronous coupling loading of multi-directional dynamic responses. This simplification of testing conditions leads to load spectrum distortion, making it difficult for test data to fully reflect the dynamic response characteristics of expansion joints under complex stress states. Summary of the Invention
[0004] This invention provides a fatigue testing device and method for an overhead rigid suspension expansion joint, which addresses the problems mentioned in the background art.
[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A fatigue testing device for an overhead rigid suspension expansion joint, wherein an array of fiber optic strain sensors is distributed on the surface of the expansion joint; The device includes: The fatigue host module, connected to the expansion joint at a predetermined position, provides reciprocating vertical vibration power to the expansion joint; the integrated platform module, fixedly connected to the fatigue host module, provides reciprocating horizontal vibration power to the fatigue host module; and the control system module performs linkage control of the vertical and horizontal vibration power. The control system module includes: A strain data processing unit is connected to the fiber optic strain sensor array to acquire strain data in real time and construct a three-dimensional strain field model and calculate stress distribution based on the strain data. A phase compensation generation unit, connected to the strain data processing unit, is used to dynamically generate the hysteresis compensation time of the horizontal vibration force relative to the vertical vibration force based on the peak time of the vertical strain and the stress distribution. The drive control unit is connected to the phase compensation generation unit and adjusts the phase of the horizontal vibration in real time based on the hysteresis compensation time, so that the horizontal vibration reaches the maximum displacement value at the peak of the vertical vibration.
[0006] Furthermore, the strain data processing unit includes: The finite element inversion algorithm maps the discrete strain data into a three-dimensional strain field model of the expansion joint surface; The conversion unit, based on the material constitutive equation, converts the three-dimensional strain field model into a three-dimensional stress tensor.
[0007] Furthermore, the phase compensation generation unit includes: The time offset extraction subunit extracts the time offset of the maximum stress point based on the peak strain time in the vertical direction and the three-dimensional stress tensor. The compensation calculation subunit calculates the lag compensation time based on the time offset.
[0008] Furthermore, the compensation calculation subunit includes: The historical delay acquisition module acquires the historical response delay parameters of the horizontal vibration dynamics; The dynamic compensation calculation module adds the time offset to the weighted value of the historical response delay parameter to obtain the dynamic compensation amount; The filtering output module performs a moving average filtering process on the dynamic compensation amount and outputs the lag compensation time.
[0009] Furthermore, the fatigue host module includes two motion mechanisms and a clamping device; The motion mechanism includes a linear motor, a telescopic rod, and a force sensor. The power output end of the linear motor is fixedly connected to one end of the telescopic rod, and the power output direction is in the same direction as the extension and retraction direction of the telescopic rod. The other end of the telescopic rod is connected to the clamping device through the force sensor. The clamping device is fixed at the set position of the expansion joint, and the two motion mechanisms are symmetrically arranged on both sides of the vertical direction of the clamping device; The linear motor is connected to the control system module.
[0010] Furthermore, the integrated platform module includes a basic support frame, a slide rail device, and a motor assembly; Both linear motors of the aforementioned motion mechanism are fixed to the slide rail device, and the motor assembly drives the slide rail device to slide along the basic support frame; The motor assembly is connected to the control system module.
[0011] A fatigue test method for an overhead rigid suspension expansion joint, wherein an array of fiber optic strain sensors is distributed on the surface of the expansion joint; The method includes: Apply reciprocating vertical vibration power directly to the expansion joint at the designated location; By applying vertical vibration force to the structure, reciprocating horizontal vibration force is indirectly applied to the expansion joint; Real-time acquisition of strain data from the fiber optic strain sensor array on the surface of the expansion joint; A three-dimensional strain field model is constructed based on the strain data, and the stress distribution is calculated. Based on the peak time of vertical strain and the stress distribution, the hysteresis compensation time of horizontal vibration dynamics relative to vertical vibration dynamics is dynamically generated. The phase of the horizontal vibration is adjusted in real time based on the hysteresis compensation time, so that the horizontal vibration reaches the maximum displacement value at the peak of the vertical vibration.
[0012] Furthermore, based on the strain data, a three-dimensional strain field model is constructed and the stress distribution is calculated, including: The discrete strain data is mapped to a three-dimensional strain field model of the expansion joint surface using the finite element inversion algorithm. Based on the material constitutive equation, the three-dimensional strain field model is converted into a three-dimensional stress tensor.
[0013] Furthermore, the hysteresis compensation time of the horizontal vibration force relative to the vertical vibration force is dynamically generated, including: Based on the peak time of strain in the vertical direction and the three-dimensional stress tensor, the time offset of the maximum stress point is extracted. The lag compensation time is calculated based on the time offset.
[0014] Further, calculating the lag compensation time based on the time offset includes: Obtain the historical response delay parameters of the horizontal vibration dynamics; The dynamic compensation amount is obtained by adding the time offset to the weighted value of the historical response delay parameter. The dynamic compensation amount is subjected to moving average filtering to output the lag compensation time.
[0015] The technical solution of this invention can achieve the following technical effects: This invention effectively improves the authenticity, accuracy, and reliability of fatigue testing for expansion joints. During implementation, a linkage control mechanism within the control system module, combined with real-time strain data acquisition from a fiber optic strain sensor array, dynamically adjusts the phase and displacement synchronization of horizontal and vertical vibrations, effectively reproducing the multi-directional composite fatigue loads encountered in actual operation. This invention overcomes the limitations of traditional tests, which are confined to a single direction, avoids load spectrum distortion, and ensures that the test data comprehensively reflects the dynamic response characteristics of the expansion joint under complex stress states. Simultaneously, the modular design enables coordinated loading in the vertical and horizontal directions, simplifying the operation process, improving testing efficiency, and providing a more accurate basis for predicting the lifespan of expansion joints. Attached Figure Description
[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0017] Figure 1 A frame diagram of a fatigue testing device for an overhead rigid suspension expansion joint; Figure 2 This is a schematic diagram of the operation of the strain data processing unit and the phase compensation generation unit. Figure 3 A flowchart of the fatigue test method for expansion joints in overhead rigid suspension; Figure 4 This is a flowchart for calculating the lag compensation time based on the time offset. Detailed Implementation
[0018] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.
[0019] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly attached to the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.
[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items. Example 1
[0021] like Figure 1 As shown, a fatigue testing device for an overhead rigid suspension expansion joint is provided, wherein an array of fiber optic strain sensors is distributed on the surface of the expansion joint. The equipment includes: The fatigue host module, connected to the expansion joint at a set position, provides reciprocating vertical vibration power to the expansion joint; the integrated platform module, fixedly connected to the fatigue host module, provides reciprocating horizontal vibration power to the fatigue host module; and the control system module performs linkage control of the vertical and horizontal vibration power. The control system module includes: The strain data processing unit is connected to the fiber optic strain sensor array to acquire strain data in real time and construct a three-dimensional strain field model and calculate stress distribution based on the strain data. The phase compensation generation unit is connected to the strain data processing unit and is used to dynamically generate the hysteresis compensation time of the horizontal vibration dynamic relative to the vertical vibration dynamic based on the peak time of the vertical strain and the stress distribution. The drive control unit is connected to the phase compensation generation unit, which adjusts the phase of the horizontal vibration in real time based on the hysteresis compensation time, so that the horizontal vibration reaches the maximum displacement value at the peak of the vertical vibration.
[0022] This invention can effectively improve the authenticity, accuracy, and reliability of fatigue testing of expansion joints. During implementation, through the linkage control mechanism of the control system module, combined with the real-time acquisition of strain data by the fiber optic strain sensor array, the phase and displacement synchronization of horizontal and vertical vibrations are dynamically adjusted, effectively reproducing the spatial multi-directional composite fatigue load in actual operation.
[0023] The above technical solutions overcome the limitations of traditional testing, which is confined to a single direction, and avoid load spectrum distortion, ensuring that test data comprehensively reflects the dynamic response characteristics of the expansion joint under complex stress conditions. Simultaneously, the modular design enables coordinated loading in both vertical and horizontal directions, simplifying the operation process, improving testing efficiency, and providing a more accurate basis for predicting the lifespan of the expansion joint.
[0024] During implementation, by precisely synchronizing the horizontal vibration with the peak vertical vibration to achieve the maximum displacement, the most severe combined stress state experienced by the expansion joint can be simulated. The synchronization mechanism creates a maximum stress superposition effect within the material, reproducing the peak value of spatially coupled loads under real working conditions, thereby enabling the identification of potential fatigue weak points. Compared to traditional asynchronous loading methods, this design can capture the material response characteristics when both vertical and horizontal bidirectional loads reach their limits simultaneously, significantly improving the detection accuracy of crack initiation and propagation behavior.
[0025] As a preferred embodiment of the above, the strain data processing unit includes: The finite element inversion algorithm maps discrete strain data into a three-dimensional strain field model of the expansion joint surface; The conversion unit, based on the material constitutive equation, converts the three-dimensional strain field model into a three-dimensional stress tensor.
[0026] In this preferred scheme, the accuracy and efficiency of stress field reconstruction are improved through the synergistic effect of the finite element inversion algorithm and the material constitutive equation. In specific implementation, the discrete fiber optic sensor data is first converted into a continuous full-field strain distribution of the expansion joint, which can overcome the limitation of traditional point measurement in capturing complex deformations; then, based on the stress tensor transformation of the material constitutive equation, the true stress state under multi-directional load superposition can be restored, providing a key data foundation for subsequent phase compensation.
[0027] In some embodiments of this application, a three-dimensional strain field model of the expansion joint surface is established using a finite element inversion algorithm. Based on the discrete placement of the fiber optic strain sensor array, shape function interpolation can be used to extend the local strain data into a continuous spatial distribution field. As a further optimization method, measured strain constraints are applied to the model boundaries, and the reconstruction error is minimized through iterative solving, ultimately outputting a three-dimensional strain field model covering the entire surface of the expansion joint.
[0028] During implementation, material constitutive relation loading is required. Specifically, the strain-stress conversion relationship is established by calling the pre-stored expansion joint material property database. This process is based on the physical kernel of the generalized Hooke's law. The conversion relationship in the above embodiment follows the linear response law of the material in the elastic deformation stage, mapping the strain tensor component of each spatial point to the corresponding normal stress and shear stress components.
[0029] In some embodiments of this application, the synthesis of the three-dimensional stress tensor includes principal stress analysis and stress state reconstruction. In the principal stress analysis, the strain state of each calculation point is decomposed into eigenvalues, and the principal strain values in three mutually perpendicular directions are extracted. The first, second, and third principal stresses are directly calculated through constitutive relations. In the stress state reconstruction, the principal stresses are synthesized according to the spatial coordinate system direction to generate a complete three-dimensional stress tensor containing six independent components, specifically three normal stress components and three shear stress components, which accurately characterize the multiaxial stress coupling state of any point inside the expansion joint.
[0030] In the above preferred scheme, the discrete strain data is reconstructed into a three-dimensional strain field model through the finite element inversion algorithm. Combined with the three-dimensional stress tensor transformation driven by the material constitutive equation, the limitations of traditional point measurement are broken through, and the real stress state under multi-directional load superposition is restored.
[0031] As a preferred embodiment of the above, such as Figure 2 As shown, the phase compensation generation unit includes: The time offset extraction sub-unit extracts the time offset of the maximum stress point based on the peak strain time in the vertical direction and the three-dimensional stress tensor. The compensation calculation subunit calculates the lag compensation time based on the time offset.
[0032] In the specific implementation process, the time offset extraction sub-unit monitors the vertical strain component of each point on the surface of the expansion joint in real time based on the three-dimensional strain field model. By dynamically tracking the temporal change of the strain component in this direction, the time point when it reaches its maximum value is identified and recorded, which is the peak time of the vertical strain.
[0033] In this preferred embodiment, the peak value of vertical strain is the reference time point when the structural deformation reaches its maximum; while the time offset of the maximum stress point characterizes the lag time of the stress response at that point relative to the reference time point. Together, they reveal the phase difference characteristics of the material's dynamic response under vibration load, providing a time difference basis for lag compensation of horizontal vibration. By dynamically extracting the time offset of the maximum stress point and calculating the lag compensation time, precise synchronization of the peak values of horizontal and vertical vibrations is achieved, improving the accuracy of multi-directional dynamic response simulation in fatigue tests.
[0034] Under the experimental conditions, the horizontal vibration frequency and the vertical vibration frequency were set to be the same.
[0035] As a preferred embodiment of the above, the compensation calculation subunit includes: The historical delay acquisition module acquires historical response delay parameters of horizontal vibration dynamics. The dynamic compensation calculation module adds the time offset to the weighted value of the historical response delay parameter to obtain the dynamic compensation amount; The filter output module performs moving average filtering on the dynamic compensation amount and outputs the lag compensation time.
[0036] In this preferred scheme, the historical response delay parameter refers to the inherent control error of the horizontal vibration dynamic system, and the time offset reflects the lag of the material dynamic response. By assigning weights to the historical delay parameter and superimposing the real-time time offset, the coupling effect between material lag and equipment control error can be resolved, and a comprehensive compensation quantity can be generated. The dynamic compensation quantity is processed by moving average filtering to suppress the jump in compensation quantity caused by sensor noise or instantaneous interference, and output a stable lag compensation time to ensure that the control command for the peak value of horizontal vibration displacement is smooth and reliable.
[0037] In some embodiments of this application, the operation of the dynamic compensation calculation module includes: The system acquires real-time operating status parameters of the integrated platform module, including equipment temperature, current load, and vibration frequency. It then determines the weighting coefficients corresponding to the real-time operating status parameters based on a preset weight mapping table. Finally, it multiplies the weighting coefficients by the historical response delay parameters to generate a weighted value.
[0038] Furthermore, the weight mapping table can be dynamically updated in the following ways: record the error between the actual response delay and the predicted delay of the horizontal vibration dynamics; when the error of N consecutive tests exceeds the threshold, N is greater than or equal to 3, and the coefficients in the weight mapping table are corrected based on the error gradient descent algorithm.
[0039] As a preferred embodiment of the above, the fatigue host module includes two motion mechanisms and a clamping device; The motion mechanism includes a linear motor, a telescopic rod, and a force sensor. The power output end of the linear motor is fixedly connected to one end of the telescopic rod, and the power output direction is in the same direction as the extension and retraction direction of the telescopic rod. The other end of the telescopic rod is connected to the clamping device through the force sensor. The clamping device is fixed at the set position of the expansion joint, and two motion mechanisms are symmetrically arranged on both sides of the vertical direction of the clamping device; the linear motor is connected to the control system module.
[0040] The output shaft of the linear motor is rigidly coaxially connected with the piston rod of the telescopic rod, eliminating the lateral force component of the traditional hinge mechanism. The vibration energy is transmitted to the expansion joint along a single axis, avoiding energy attenuation caused by multi-stage transmission. During the extension and retraction process, the telescopic rod outputs vibration power to the expansion joint, which can provide a certain degree of protection for the force sensor and the fiber optic strain sensor array on the surface of the expansion joint through its own buffering effect.
[0041] As a preferred embodiment of the above, the integrated platform module includes a basic support frame, a slide rail device, and a motor assembly; the linear motors of both motion mechanisms are fixed on the slide rail device, and the motor assembly drives the slide rail device to slide along the basic support frame; the motor assembly is connected to the control system module. In this preferred embodiment, the slide rail device supports the two motion mechanisms as a whole, allowing the vertical excitation unit to slide freely in the horizontal direction, thereby achieving the set test effect. Example 2
[0042] like Figure 3 As shown, a fatigue test method for an overhead rigid suspension expansion joint is provided, wherein an array of fiber optic strain sensors is distributed on the surface of the expansion joint. The methods include: A1: Apply reciprocating vertical vibration power directly to the expansion joint at the set position; A2: By applying vertical vibration force to the structure, reciprocating horizontal vibration force is indirectly applied to the expansion joint; A3: Real-time acquisition of strain data from the fiber optic strain sensor array on the surface of the expansion joint; A4: Construct a three-dimensional strain field model based on strain data and calculate stress distribution; A5: Based on the peak strain time and stress distribution in the vertical direction, dynamically generate the hysteresis compensation time of the horizontal vibration dynamic relative to the vertical vibration dynamic. A6: The phase of the horizontal vibration is adjusted in real time based on the hysteresis compensation time, so that the horizontal vibration reaches the maximum displacement value at the peak of the vertical vibration.
[0043] As a preferred embodiment of the above, constructing a three-dimensional strain field model based on strain data and calculating the stress distribution includes: The discrete strain data is mapped to a three-dimensional strain field model of the expansion joint surface using the finite element inversion algorithm; based on the material constitutive equation, the three-dimensional strain field model is converted into a three-dimensional stress tensor.
[0044] As a preferred embodiment of the above, dynamically generating the hysteresis compensation time of the horizontal vibration force relative to the vertical vibration force includes: Based on the peak strain time in the vertical direction and the three-dimensional stress tensor, the time offset of the maximum stress point is extracted; the hysteresis compensation time is calculated based on the time offset.
[0045] As a preferred embodiment of the above, such as Figure 4 As shown, the lag compensation time is calculated based on the time offset, including: B1: Obtain the historical response delay parameters of horizontal vibration dynamics; B2: Add the time offset to the weighted value of the historical response delay parameter to obtain the dynamic compensation amount; B3: Performs moving average filtering on the dynamic compensation amount and outputs the lag compensation time.
[0046] The technical effects achieved in this embodiment are the same as those in Embodiment 1 above, and will not be repeated here.
[0047] Those skilled in the art should understand that this invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to this invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.
Claims
1. An overhead rigid hanger expansion joint fatigue test apparatus, characterized by, An array of fiber optic strain sensors is distributed on the surface of the expansion joint; The device comprises: a fatigue host module, which provides reciprocating vertical vibration power for the expansion joint by connecting with a set position of the expansion joint; a comprehensive platform module, which is fixedly connected with the fatigue host module and provides reciprocating horizontal vibration power for the fatigue host module; and a control system module, which controls the vertical vibration power and the horizontal vibration power in linkage. The control system module comprises: a strain data processing unit, which is connected to the array of fiber optic strain sensors, is used to acquire strain data in real time, and constructs a three-dimensional strain field model and calculates stress distribution based on the strain data; a phase compensation generation unit, which is connected to the strain data processing unit, is used to dynamically generate a lag compensation time of the horizontal vibration power relative to the vertical vibration power according to a vertical direction strain peak time and the stress distribution; a driving control unit, which is connected to the phase compensation generation unit, adjusts the phase of the horizontal vibration in real time based on the lag compensation time, so that the horizontal vibration reaches a maximum displacement value at the vertical vibration peak time.
2. The overhead rigid suspension expansion joint fatigue test apparatus of claim 1, wherein, The strain data processing unit comprises: a finite element inversion algorithm, which maps discrete strain data into a three-dimensional strain field model of the surface of the expansion joint; a conversion unit, which converts the three-dimensional strain field model into a three-dimensional stress tensor based on a material constitutive equation.
3. The overhead rigid suspension expansion joint fatigue test apparatus of claim 2, wherein, The phase compensation generation unit comprises: a time offset extraction subunit, which extracts a time offset amount of a maximum stress point based on the vertical direction strain peak time and the three-dimensional stress tensor; a compensation calculation subunit, which calculates the lag compensation time according to the time offset amount.
4. The overhead rigid suspension expansion joint fatigue test apparatus of claim 3, wherein, The compensation calculation subunit comprises: a historical delay acquisition module, which acquires a historical response delay parameter of the horizontal vibration power; a dynamic compensation calculation module, which adds a weighted value of the time offset amount and the historical response delay parameter to obtain a dynamic compensation amount; a filter output module, which performs sliding average filtering processing on the dynamic compensation amount and outputs the lag compensation time.
5. The overhead rigid suspension expansion joint fatigue test apparatus of claim 1, wherein, The fatigue host module comprises two motion mechanisms and a clamping device. The motion mechanism comprises a linear motor, a telescopic rod and a force value sensor, a power output end of the linear motor is fixedly connected with one end of the telescopic rod, a power output direction is the same as an extension direction of the telescopic rod, and the other end of the telescopic rod is connected with the clamping device through the force value sensor. The clamping device is clamped and fixed at a set position of the expansion joint, and the two motion mechanisms are symmetrically arranged on two vertical sides of the clamping device. The linear motor is connected with the control system module.
6. The overhead rigid suspension expansion joint fatigue test apparatus of claim 5, wherein, The comprehensive platform module comprises a base support frame, a slide rail device and a motor assembly. The linear motors of the two motion mechanisms are fixed on the slide rail device, and the motor assembly drives the slide rail device to slide along the base support frame. The motor assembly is connected with the control system module.
7. A method of fatigue testing an overhead rigid suspension expansion joint, characterized by, An array of fiber optic strain sensors is distributed on the surface of the expansion joint; The method comprises: directly applying reciprocating vertical vibration power to the expansion joint at a set position; The structure is applied with vertical vibration power, indirectly to the expansion joint to apply reciprocating horizontal vibration power; Real-time acquisition of strain data of the expansion joint surface optical fiber strain sensor array; Based on the strain data, a three-dimensional strain field model is constructed and stress distribution is calculated; According to the vertical direction strain peak time and the stress distribution, the lag compensation time of the horizontal vibration power relative to the vertical vibration power is dynamically generated; Based on the lag compensation time, the phase of the horizontal vibration is adjusted in real time, so that the horizontal vibration reaches the maximum displacement value at the vertical vibration peak time.
8. The method of fatigue testing overhead rigid suspension expansion joints according to claim 7, wherein, Based on the strain data, a three-dimensional strain field model is constructed and stress distribution is calculated, including: Through the finite element inversion algorithm, the discrete strain data is mapped to the three-dimensional strain field model of the expansion joint surface; Based on the material constitutive equation, the three-dimensional strain field model is converted into a three-dimensional stress tensor.
9. The method of fatigue testing overhead rigid suspension expansion joints of claim 8, wherein, Dynamically generating the lag compensation time of the horizontal vibration power relative to the vertical vibration power includes: Based on the vertical direction strain peak time and the three-dimensional stress tensor, the time offset of the maximum stress point is extracted; According to the time offset, the lag compensation time is calculated.
10. The method of fatigue testing overhead rigid suspension expansion joints of claim 9, wherein, According to the time offset, the lag compensation time is calculated, including: Obtain the historical response delay parameter of the horizontal vibration power; Add the time offset and the weighted value of the historical response delay parameter to obtain the dynamic compensation amount; The dynamic compensation amount is subjected to a sliding average filtering process, and the lag compensation time is output.