Device and method for simulating sudden fracture of inclined cables based on electromagnetic principle

Abstract

The present invention relates to the field of cable detection, and specifically to a cable sudden fracture simulation device and method based on electromagnetic principle; including a main beam, a main tower, a cable, a connection structure and a monitoring device; the connection structure includes a cable connector, a tension meter, an electromagnet and an anchor plate; the anchor plate is fixedly installed on the first section of the cable and connected to the electromagnet; the monitoring device includes a dynamic strain gauge, a dynamic displacement meter and an information processor, wherein the information processor includes a signal acquisition module, a signal noise removal module, a signal processing module and an execution module; the signal processing module is used to perform algorithmic processing on the data, identify the peak and trough data and the corresponding time, and select the maximum value for recording, and then divide these maximum values ​​by the static response, and finally calculate the dynamic amplification coefficient of the structure. The present invention fully understands the influence of cable breakage on the dynamic behavior of the structure, and is conducive to accurately understanding the dynamic amplification effect, and taking corresponding design measures to ensure the safety and reliability of the bridge.

Description

Technical Field

[0001] The invention relates to the technical field of cable-stayed cable stress detection, and in particular to a cable-stayed cable sudden fracture simulation device and a method thereof based on electromagnetic principles. Background Art

[0002] The cable is one of the main load-bearing components of a cable-stayed bridge and bears the main task of transferring the bridge load. The breakage of the cable will directly affect the internal force distribution and stability of the bridge, and may lead to a dangerous state of the overall structure. In addition, the broken cable will also cause an impact effect, that is, the dynamic load generated when the broken cable suddenly fails, which will cause severe vibration and impact to the bridge structure. This impact effect may aggravate the fatigue failure of other components, trigger a chain reaction, and ultimately lead to a serious accident. In terms of dynamics, the damage of the broken cable will also affect the dynamic response and characteristics of the cable-stayed bridge. The vibration frequency and stiffness changes of the broken cable will change the dynamic characteristics of the entire bridge, which may lead to resonance and unstable operation. Therefore, when considering the design and maintenance of a cable-stayed bridge, it is necessary to fully understand the impact of the broken cable on the dynamic behavior of the structure and take corresponding measures to ensure the safety and reliability of the bridge.

[0003] Dynamic effects of cable breakage: Under dynamic loads, structures may produce responses much greater than those under static loads. When the action is applied slowly to the structure, the response of the structure is almost the same as its static response. However, if the action is applied suddenly, the structure will show a significant dynamic response. In actual engineering, the instantaneous breakage of the cable is the most unfavorable situation for the structure. Sudden cable breakage can cause unexpected violent oscillations, resulting in dynamic amplification effects that are difficult to predict in existing specifications. Therefore, considering the dynamic amplification effect in structural design is crucial to ensure the safety of the structure.

[0004] The dynamic amplification factor (DAF) is the ratio of the dynamic response to the static response. It reflects the amplification degree of the response of the structure under dynamic loads and is an important indicator for measuring the dynamic performance of the structure. The dynamic amplification factor is usually used in earthquake engineering, wind engineering and structural dynamics analysis to evaluate the response of the structure under earthquake, wind or other dynamic excitations. The dynamic amplification factor can be obtained by calculating the ratio of the response of the structure under dynamic loads (such as displacement, force, velocity, etc.) to the corresponding response under static loads. The dynamic amplification factor is affected by many factors, including the dynamic characteristics of the structure itself (such as natural frequency, damping ratio), the characteristics of the dynamic load (such as frequency, amplitude), and the interaction between the structure and the load. Summary of the invention

[0005] In order to solve the above-mentioned shortcomings and deficiencies in the prior art of stress detection of cable-stayed cables before and after cable breakage, and the influence of cable breakage on the dynamic behavior of cable-stayed bridge structures, the present invention provides a cable-stayed cable sudden fracture simulation device based on electromagnetic principles and a method thereof, which has a reasonable structural design, fully understands the influence of cable breakage on the dynamic behavior of the structure and accurately understands the dynamic amplification effect, and takes corresponding design measures to ensure the safety and reliability of the bridge.

[0006] In order to achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a device for simulating sudden fracture of a cable-stayed cable based on electromagnetic principle, the simulation device comprising a main beam, a main tower, a cable, a connecting structure and a monitoring device; the main beam is horizontally distributed, the main tower is vertically distributed, and is vertically arranged at the center of the main beam; the cable is evenly distributed in a plurality and obliquely distributed between the main tower and the main beam, and the cable is divided into a first section of the cable connected to the main tower and a second section of the cable connected to the main beam, and the connecting structure is arranged between the first section of the cable and the second section of the cable; the connecting structure includes The invention comprises a cable connector, a tension meter, an electromagnet and an anchor plate; one end of the cable connector is connected to the second section of the cable, and the other end is connected to the tension meter; the other end of the tension meter is connected to the electromagnet, and the anchor plate is fixedly installed on the first section of the cable and connected to the electromagnet, so that the electromagnet is powered on and the first section of the cable is fixedly connected to the second section of the cable; the electromagnet is powered off and the first section of the cable is disconnected from the second section of the cable; the monitoring device comprises a dynamic displacement meter, a dynamic strain meter and an information processor; the dynamic strain meter and the dynamic displacement meter are both arranged at any preset detection point on the main beam and the main tower;

[0007] The information processor includes a signal acquisition module, a signal denoising module, a signal processing module and an execution module; the signal acquisition module maintains signal connection with the dynamic displacement meter, the dynamic strain meter and the dynamometer respectively, and is used to collect corresponding signal parameters; the signal denoising module is used to perform denoising preprocessing on the signal data collected by the signal acquisition module; the signal processing module is used to perform algorithm processing on the data preprocessed by the signal denoising module, identify the peak and trough data and the time corresponding to the corresponding position points, and screen out the maximum values ​​therein for recording, and then divide these maximum values ​​by the static response, and finally calculate the dynamic amplification factor of the structure; the execution module is used to complete the corresponding processing of the on and off of the electromagnet, and adjust the magnetic attraction of the electromagnet according to the size of the cable force, while ensuring that the electromagnet is demagnetized 0.005s-0.02s after the power is turned off;

[0008] The algorithm formula includes:

[0009] {x}_{smoothed}[i]=\frac {1} {N}\sum ^{k}_{j=-k} {x[i+j]} ;

[0010] Use moving average, low-pass filter, and convolution methods to smooth the data; where x is the original data; is the smoothed data; N is the size of the smoothing window, usually an odd number, such as 3, 5, 7, and so on; ; i and j represent the serial numbers of the collected sample data;

[0011] Then calculate the first-order derivative of the smoothed data to find possible extreme points:

[0012] {x}^{,}[i]={x}_{smoothed}[i+1]-{x}_{smoothed}[i] ;

[0013] Identify the peak: Traverse the derivative data and find the points where the derivative changes from positive to negative. These points correspond to local maxima. If {x}^{,}[i] >0 and {x}^{,}[i+1] <0, then i is the index of a local maximum;

[0014] Calculate the dynamic amplification factor: Divide the found peak maximum dynamic response value by the corresponding static response value:

[0015]

[0016] Where DAF is the dynamic amplification factor for dynamic response in structural dynamics; is the maximum dynamic response parameter obtained under dynamic load; is the static response parameter under static load.

[0017] As a preferred technical solution: the cable connector, the dynamometer and the electromagnet are all connected via screws.

[0018] A further preferred technical solution: the cable connector includes a sleeve, a conical fastening block, a center adjustment block and a connecting screw; the sleeve is a through structure, and the conical fastening block is adapted to be installed inside; the cross-section of the center adjustment block is a cross-shaped structure, and the two ends are threaded structures, which are respectively threadedly connected to the sleeve and the connecting screw; the second section of the cable passes through the sleeve and the conical fastening block to form a fastened connection between the three; the connecting screw is provided with a thread inside to match the screw.

[0019] A further preferred technical solution is that the dynamometer is a digital external push-pull dynamometer, and fixed auxiliary plates are provided at both ends, and the screw rod is connected to the auxiliary plate by threads.

[0020] A further preferred technical solution: the anchor plate is connected and fixed to the first section of the cable through the sleeve, the conical fastening block and the center adjustment block; wherein the first section of the cable passes through the sleeve and the conical fastening block connected by the anchor plate to form a connection, and the fastening and installation operation is completed under the rotation of the center adjustment block; and one end of the center adjustment block at the anchor plate can rotate relative to the anchor plate but cannot move relative to it.

[0021] A further preferred technical solution: the carrier of the information processor is a computer terminal, and provides a 12-24V DC power supply for the on and off of the electromagnet.

[0022] A further preferred technical solution: the information processor also includes a data storage module, which is used to record real-time sample data of signal acquisition and peak data of algorithm processing, and store them in the form of an Excel spreadsheet, while also completing color marking processing of the peak data.

[0023] A simulation method of a stay cable sudden fracture simulation device based on electromagnetic principle comprises the following steps:

[0024] Step 1: Install the main beam, main tower, first section of cable, second section of cable and connecting structure components to form a stable main structure, turn on the electromagnet and complete the maximum magnetic attraction force of not less than 2 times the design cable force to simulate the initial state of the inclined cable;

[0025] Step 2: Adjust the tension of the set cable and adjust it to the designed cable tension through the monitoring parameter value of the tension meter to complete the designed bridge state of the simulated inclined cable;

[0026] Step 3: When the electromagnetic attraction of the electromagnet is disconnected, the first and second cable sections are quickly disconnected to simulate cable breakage. The dynamic signal parameters of the dynamometer, dynamic displacement meter, and dynamic strain gauge are collected in real time through the monitoring device, and the signal data collected by the signal acquisition module are first pre-processed for noise removal.

[0027] Step 4: Smoothing and calculating derivatives: The signal processing module uses the moving average, low-pass filter, and convolution methods to smooth the data through the optimization algorithm formula, and calculates the first-order derivative of the smoothed data to find possible extreme points;

[0028] Step 5: Identify the peak: Traverse the derivative data and find the points where the derivative changes from positive to negative. These points correspond to local maxima (peaks); if and ,but is the index of a local maximum; determine the peak position and value: once the peak position is found, the corresponding peak can be extracted from the original data;

[0029] Step 6: Calculate the dynamic amplification factor DAF: Divide the peak maximum dynamic response value found by the corresponding static response value to obtain the final structural dynamic amplification factor.

[0030] Compared with the prior art, the beneficial effects of the present invention are as follows: the simulation device has a reasonable structural design, and a stable supporting frame structure is formed by arranging the main beam, the main tower and the cable, and with the assistance of the dynamic strain gauge, the dynamic displacement gauge, the cable connector, the tension gauge, the electromagnet and the anchor plate, the reading accuracy is high, the signal acquisition is fast, the installation and disassembly are convenient, the cost performance is high, and the use effect is good; and through the monitoring device for a series of structural dynamic response data, it fluctuates around a certain value over time, and has peaks and troughs; at the same time, the internal algorithm can effectively process noise, and identify the peak and trough data and their corresponding times, and give the maximum value therein, and then divide these maximum values ​​by the static response to finally calculate the dynamic amplification coefficient of the structure; the simulation device realizes that when designing and maintaining the cable-stayed bridge, the influence of broken cables on the dynamic behavior of the structure is fully understood, and the role of dynamic amplification is accurately understood, which is conducive to taking corresponding design measures in the early design stage to ensure the safety and reliability of the bridge, and is more practical. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0032] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0033] Figure 2 for Figure 1 A magnified view of the structure of part A;

[0034] Figure 3 It is a structural schematic diagram of the cable connector of the present invention;

[0035] Figure 4 It is a block diagram of the connection principle of the monitoring device of the present invention;

[0036] Figure 5 It is a dynamic displacement diagram of the simulation device of the present invention after testing the broken cable;

[0037] Figure 6 This is a strain curve diagram of the simulation device of the present invention after testing the broken cable;

[0038] Figure 7 A schematic diagram of a state in which the electromagnet of the simulation device of the present invention is powered off;

[0039] Figure 8 It is a schematic diagram of the connection structure of the anchor plate of the present invention.

[0040] In the figure: 1. main beam; 2. main tower; 3. cable; 4. connecting structure; 5. first section of cable; 6. second section of cable; 7. cable connector; 8. dynamometer; 9. electromagnet; 10. anchor plate; 11. monitoring device; 12. signal acquisition module; 13. signal noise reduction module; 14. signal processing module; 15. execution module; 16. screw; 17. sleeve; 18. conical fastening block; 19. center adjustment block; 20. connecting screw; 21. auxiliary board; 22. data storage module; 23. dynamic displacement meter; 24. dynamic strain gauge; 25. information processor. DETAILED DESCRIPTION

[0041] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] It should be noted that, in the specific implementation of the present invention, the terms such as "first" and "second" and other relational terms that may appear are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms such as "include", "comprise" or any other variants thereof that may appear are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements includes not only those elements, but also other elements that are not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the possible appearance of the sentence "including a ..." and other defined elements does not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0043] In the description of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "provided with" that may appear should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be internal communication between two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0044] Example: Figures 1 to 8 As shown: A simulation device for sudden fracture of a cable based on electromagnetic principle, the simulation device comprises a main beam 1, a main tower 2, a cable 3 and a connecting structure 4. The main beam 1 is horizontally distributed, and the main tower 2 is vertically distributed and vertically arranged at the center of the main beam 1. Figure 1 As shown, a cross-shaped support frame structure is formed between the main beam and the main tower, and is fixedly installed on the external table surface to ensure sufficient stability. The cables 3 are evenly distributed in multiple numbers and are obliquely distributed between the main tower 2 and the main beam 1, and the cables 3 are divided into a first section of cables 5 connected to the main tower and a second section of cables 6 connected to the main beam, and the connecting structure 4 is arranged between the first section of cables 5 and the second section of cables 6; in this way, the split structure is easy to connect and install, providing a strong foundation for subsequent cable breaking.

[0045] like Figure 2 As shown in the figure: In this embodiment, the connection structure 4 includes a cable connector 7, a tension gauge 8, an electromagnet 9 and an anchor plate 10. One end of the cable connector 7 is connected to the second cable 6, and the other end is connected to the tension gauge 8. The cable connector 7, the tension gauge 8 and the electromagnet 9 are all connected by a screw 16. Figure 3 As shown: the cable connector 7 includes a sleeve 17, a conical fastening block 18, a central adjustment block 19 and a connecting solenoid 20; the sleeve 17 is a through structure, and the conical fastening block 18 is adapted to be installed inside; the center of the conical fastening block 18 is also a through structure. The cross section of the central adjustment block 19 is a cross-shaped structure, and the two ends are threaded structures, which are respectively threadedly connected to the sleeve 17 and the connecting solenoid 20; the second section of the cable 6 passes through the corresponding sleeve and conical fastening block here to form a three-way fastening connection; the connecting solenoid 20 is provided with a thread inside to match the screw 16. The traditional cable connector structure is a two-way double-pass structure. In order to connect and install, this embodiment adopts a single-side cable connection structure (that is, a combination structure of a sleeve, a conical fastening block and a central adjustment block). The other end of the central adjustment block 19 is connected to the connecting solenoid 20, forming a "cable connector" specially upgraded and modified by the simulation device of this embodiment, which is mainly used for conveniently connecting and installing the screw 16, with a reasonable structural design and strong practicality.

[0046] like Figure 2As shown: the other end of the dynamometer 8 is connected to the electromagnet 9, and the anchor plate 10 is fixedly installed on the first section of the cable 5 and connected to the electromagnet 9, so that when the electromagnet is powered on, the first section of the cable is tightly connected to the second section of the cable; when the electromagnet is powered off, the first section of the cable is disconnected from the second section of the cable. The dynamometer 8 adopts a digital external push-pull dynamometer, and a fixed auxiliary plate 21 is provided at both ends, and the screw 16 is connected to the auxiliary plate 21 by threads. The anchor plate 10 is connected and fixed to the first section of the cable 5 through the sleeve 17, the conical fastening block 18, and the center adjustment block 19; refer to Figure 8 The structure shown. The first section of the cable 5 passes through the sleeve 17 and the conical fastening block 18 connected by the anchor plate 10 to form a connection, and the fastening and installation operation is completed under the rotation of the central adjustment block 19; and one end of the central adjustment block 19 at the anchor plate 10 can be relatively rotated and cannot be relatively moved with the anchor plate 10 (specifically, it can be achieved through the keyway, which will not be repeated here), which is convenient for completing the fastening and installation of the cable through the rotation of the central adjustment block. That is, here, the anchor plate, the central adjustment block, the sleeve and the conical fastening block are also modified special connection structures.

[0047] like Figure 1 As shown: Specifically, the second section of the cable is connected to the corresponding sleeve of the cable connector, and the connecting solenoid is connected to a screw (the lower screw). Then the screw is connected to the auxiliary plate on one side of the dynamometer, and the auxiliary plate on the other side of the dynamometer is connected through another screw. Finally, one end of the electromagnet is connected and installed with the upper screw to form an integrated connection structure. At the same time, the first section of the cable is connected and fixed through the sleeve and the central adjustment block connected to the anchor plate, and the anchor plate is specially connected to the central adjustment block here; at this time, a fixed connection is also formed between the anchor plate and the first section of the cable. The electromagnet is energized to generate a strong magnet to complete the adsorption and fastening to the anchor plate. The steel cable (cable) is tensioned at the end of the beam, and the tension is measured by the dynamometer. The acquisition frequency of the dynamometer can be as high as 1000Hz, and the dynamic changes of the force of the adjacent cable can be obtained. The demagnetization response time of the electromagnet is 100 milliseconds, about 0.01 seconds; it can more accurately simulate sudden cable breakage. The shorter the cable breakage time, the more obvious the power amplification effect. The electromagnet has strong electromagnetic attraction and good reliability. The magnetic attraction of the electromagnet can be adjusted according to the size of the cable force, and the maximum magnetic attraction is not less than 2 times the designed cable force. A connection structure corresponding to multiple cables can be set, which can flexibly simulate cable breakage at any position, as well as simultaneous or continuous breakage of multiple cables. According to test needs, cable-breaking devices and monitoring devices can be arranged on different cables to test the power amplification effect of different components and positions. In order to better demonstrate the simulation state before and after power failure, this embodiment takes the connection structure of the first and second sections of the cables on the left as an example for analysis. Refer to Figure 7 As shown, Figure 75 is a schematic diagram of the state of the electromagnet of the simulation device of the present invention being powered off. The dynamic displacement diagram of the simulation device of the present invention after the cable is broken is shown in FIG5 . The strain curve diagram of the simulation device of the present invention after the cable is broken is shown in FIG6 .

[0048] In this embodiment, the monitoring device 11 includes a dynamic displacement meter 23, a dynamic strain meter 24 and an information processor 25; the dynamic strain meter and the dynamic displacement meter are both arranged at any preset detection point on the main beam or the main tower. That is, the dynamic displacement meter and the dynamic strain meter are used in combination, and are fixedly installed at any position to be measured on the main beam or any position to be measured on the main tower by bolts. At the same time, for a series of structural dynamic response data, it fluctuates around a certain value over time, with peaks and troughs. The algorithm can also remove noise, identify the peak and trough data and their corresponding times, and give the maximum values ​​therein, and then divide these maximum values ​​by the static response to calculate the dynamic amplification factor of the structure. Refer to Figure 4 As shown: the information processor 25 includes a signal acquisition module 12, a signal denoising module 13, a signal processing module 14 and an execution module 15; the signal acquisition module 12 maintains signal connection with the dynamic displacement meter 23, the dynamic strain gauge 24 and the tension meter 8 respectively, and is used to collect corresponding signal parameters. The signal denoising module 13 is used to perform denoising preprocessing on the signal data collected by the signal acquisition module; the signal processing module 14 is used to perform algorithm processing on the data preprocessed by the signal denoising module, identify the peak and trough data and the time corresponding to the corresponding position point, and filter out the maximum value therein for recording, and then divide these maximum values ​​by the static response, and finally calculate the dynamic amplification coefficient of the structure. The execution module 15 is used to complete the corresponding processing of the on and off of the electromagnet, and adjust the magnetic attraction of the electromagnet according to the size of the cable force, while ensuring that the electromagnet is demagnetized 0.005s-0.02s after the power is turned off. Preferably, the carrier of the information processor 25 is a computer terminal, and a 12-24V DC power supply is provided for the on and off of the electromagnet. The information processor 25 also includes a data storage module 22, which is used to record real-time sample data of signal acquisition and algorithm processing peak data, and store them in the form of an Excel table, and also complete color marking processing of the peak data.

[0049] The algorithm formula includes:

[0050] {x}_{smoothed}[i]=\frac {1} {N}\sum ^{k}_{j=-k} {x[i+j]} ;

[0051] In order to identify peaks and remove noise, it is usually necessary to smooth the data; the smoothing process uses methods such as moving average, low-pass filter, convolution, etc. (existing technology, so it is not repeated here) to smooth the data; where x is the original data; is the smoothed data; N is the size of the smoothing window, usually an odd number, such as 3, 5, 7, and so on; ; i and j represent the serial numbers of the collected sample data;

[0052] Then calculate the first-order derivative of the smoothed data to find possible extreme points:

[0053] {x}^{,}[i]={x}_{smoothed}[i+1]-{x}_{smoothed}[i] ;

[0054] Identify the peak: Traverse the derivative data and find the points where the derivative changes from positive to negative. These points correspond to local maxima. If {x}^{,}[i] >0 and {x}^{,}[i+1] <0, then i is the index of a local maximum value; after identifying the peak, a threshold can be set to retain only the peaks greater than the threshold, thereby removing the false peaks caused by small noise;

[0055] Determine peak position and value: Once the peak position is found, the corresponding peak can be extracted from the raw data;

[0056] Calculate the dynamic amplification factor: Divide the found peak maximum dynamic response value by the corresponding static response value:

[0057]

[0058] Where DAF is the dynamic amplification factor for dynamic response in structural dynamics; is the maximum dynamic response parameter obtained under dynamic load; is the static response parameter under static load.

[0059] A simulation method of a stay cable sudden fracture simulation device based on electromagnetic principle comprises the following steps:

[0060] Step 1: Install the main beam, main tower, first section of cable, second section of cable and connecting structure components to form a stable main structure, turn on the electromagnet and complete the maximum magnetic attraction force of not less than 2 times the design cable force to simulate the initial state of the inclined cable;

[0061] Step 2: Adjust the tension of the set cable and adjust it to the designed cable tension through the monitoring parameter value of the tension meter to complete the designed bridge state of the simulated inclined cable;

[0062] Step 3: When the electromagnetic attraction of the electromagnet is disconnected, the first and second cable sections are quickly disconnected to simulate cable breakage. The dynamic signal parameters of the dynamometer, dynamic displacement meter, and dynamic strain gauge are collected in real time through the monitoring device, and the signal data collected by the signal acquisition module are first pre-processed for noise removal.

[0063] Step 4: Smoothing and calculating derivatives: The signal processing module uses the moving average, low-pass filter, and convolution methods to smooth the data through the optimization algorithm formula, and calculates the first-order derivative of the smoothed data to find possible extreme points;

[0064] Step 5: Identify the peak: Traverse the derivative data and find the points where the derivative changes from positive to negative. These points correspond to local maxima (peaks); if {x}^{,}[i] >0 and {x}^{,}[i+1] <0, then i is the index of a local maximum; Determine the peak position and value: Once the peak position is found, the corresponding peak can be extracted from the original data;

[0065] Step 6: Calculate the dynamic amplification factor DAF: Divide the peak maximum dynamic response value found by the corresponding static response value to obtain the final structural dynamic amplification factor.

[0066] This simulation device enables a full understanding of the impact of cable breakage on the dynamic behavior of the structure and an accurate understanding of the role of dynamic amplification during the design and maintenance of cable-stayed bridges. It is conducive to taking corresponding design measures in the early stages of design to ensure the safety and reliability of the bridge, and is more practical.

[0067] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A device for simulating sudden fracture of a stay cable based on electromagnetic principle, characterized in that: The simulation device includes a main beam, a main tower, a cable, a connection structure and a monitoring device; the main beam is horizontally distributed, the main tower is vertically distributed and vertically arranged at the center of the main beam; the cables are evenly distributed in multiple numbers and obliquely distributed between the main tower and the main beam, and the cables are divided into a first section of cables connected to the main tower and a second section of cables connected to the main beam, and the connection structure is arranged between the first section of cables and the second section of cables; the connection structure includes a cable connector, a dynamometer, an electromagnet and an anchor plate; One end of the cable connector is connected to the second section of the cable, and the other end is connected to the tension meter; the other end of the tension meter is connected to the electromagnet, and the anchor plate is fixedly installed on the first section of the cable and connected to the electromagnet, so that when the electromagnet is powered on, the first section of the cable is tightly connected to the second section of the cable; when the electromagnet is powered off, the first section of the cable is disconnected from the second section of the cable; the monitoring device includes a dynamic displacement meter, a dynamic strain meter and an information processor; the dynamic strain meter and the dynamic displacement meter are both arranged at any preset detection point on the main beam and the main tower; The information processor includes a signal acquisition module, a signal denoising module, a signal processing module and an execution module; the signal acquisition module maintains signal connection with the dynamic displacement meter, the dynamic strain meter and the dynamometer respectively, and is used to collect corresponding signal parameters; the signal denoising module is used to perform denoising preprocessing on the signal data collected by the signal acquisition module; the signal processing module is used to perform algorithm processing on the data preprocessed by the signal denoising module, identify the peak and trough data and the time corresponding to the corresponding position points, and screen out the maximum values ​​therein for recording, and then divide these maximum values ​​by the static response, and finally calculate the dynamic amplification factor of the structure; the execution module is used to complete the corresponding processing of the on and off of the electromagnet, and adjust the magnetic attraction of the electromagnet according to the size of the cable force, while ensuring that the electromagnet is demagnetized 0.005s-0.02s after the power is turned off; The algorithm formula includes: ; Use moving average, low-pass filter, and convolution methods to smooth the data; where x is the original data; is the smoothed data; N is the size of the smoothing window, usually an odd number; ; i and J represent the serial numbers of the collected sample data; Then calculate the first-order derivative of the smoothed data to find possible extreme points: ； Identify the peak: Traverse the derivative data and find the points where the derivative changes from positive to negative. These points correspond to local maxima, that is, peaks. ， [i]>0 and x ， [i+1]<0, then i is the index of a local maximum; Calculate the dynamic amplification factor: divide the peak maximum dynamic response value found by the corresponding static response value; ； Where DAF is the dynamic amplification factor of dynamic response in structural dynamics; x d is the maximum dynamic response parameter obtained under dynamic load; x st is the static response parameter under static load.

2. The electromagnetic principle-based stay cable sudden fracture simulation device according to claim 1, characterized in that: The cable connector, the tension meter and the electromagnet are all connected via screws.

3. The electromagnetic principle-based stay cable sudden fracture simulation device according to claim 2, characterized in that: The cable connector includes a sleeve, a conical fixing block, a center adjustment block and a connecting screw; the sleeve is a through structure, and the conical fixing block is adapted to be installed inside; the cross-section of the center adjustment block is a cross-shaped structure, and the two ends are threaded structures, which are respectively threadedly connected to the sleeve and the connecting screw; the second section of the cable passes through the sleeve and the conical fixing block to form a fixed connection between the three; the connecting screw is provided with a thread inside to match the screw rod.

4. The electromagnetic principle-based stay cable sudden fracture simulation device according to claim 3, characterized in that: The dynamometer is a digital external push-pull dynamometer, and fixed auxiliary plates are provided at both ends, and the screw rod is connected to the auxiliary plate through threads.

5. The electromagnetic principle-based stay cable sudden fracture simulation device as claimed in claim 4, characterized in that: The anchor plate is connected and fixed with the first section of the cable through the sleeve, the conical fastening block and the center adjustment block; wherein the first section of the cable passes through the sleeve and the conical fastening block connected by the anchor plate to form a connection, and the fastening and installation operation is completed under the rotation of the center adjustment block; and one end of the center adjustment block at the anchor plate can rotate relative to the anchor plate but cannot move relative to it.

6. The electromagnetic principle-based stay cable sudden fracture simulation device according to claim 5, characterized in that: The carrier of the information processor adopts a computer terminal and provides a 12-24V DC power supply for the on and off of the electromagnet.

7. The electromagnetic principle-based stay cable sudden fracture simulation device according to claim 6, characterized in that: The information processor also includes a data storage module, which is used to record real-time sample data of signal acquisition and peak data of algorithm processing, and store them in the form of an Excel table, and also complete color marking processing of the peak data.

8. A simulation method for a stay cable sudden fracture simulation device based on electromagnetic principle as claimed in any one of claims 1 to 7, characterized in that: The steps include: Step 1: Install the main beam, main tower, first section of cable, second section of cable and connecting structure components to form a stable main structure, turn on the electromagnet and complete the maximum magnetic attraction force of not less than 2 times the design cable force to simulate the initial state of the inclined cable; Step 2: Adjust the tension of the set cable and adjust it to the designed cable tension through the monitoring parameter value of the tension meter to complete the designed bridge state of the simulated inclined cable; Step 3: When the electromagnetic attraction of the electromagnet is disconnected, the first and second cable sections are quickly disconnected to simulate cable breakage. The dynamic signal parameters of the dynamometer, dynamic displacement meter, and dynamic strain gauge are collected in real time through the monitoring device, and the signal data collected by the signal acquisition module are first pre-processed for noise removal. Step 4: Smoothing and calculating derivatives: The signal processing module uses the moving average, low-pass filter, and convolution methods to smooth the data through the optimization algorithm formula, and calculates the first-order derivative of the smoothed data to find possible extreme points; Step 5: Identify the peak: Traverse the derivative data and find the points where the derivative changes from positive to negative. These points correspond to local maxima, that is, peaks. ， [i]>0 and x ， [i+1]<0, then i is the index of a local maximum; Determine the peak position and value: Once the peak position is found, the corresponding peak can be extracted from the original data; Step 6: Calculate the dynamic amplification factor DAF: Divide the peak maximum dynamic response value found by the corresponding static response value to obtain the final structural dynamic amplification factor.

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