Method and system for calculating degradation process of welding stud connecting piece of composite beam bridge

Abstract

The invention discloses a method and system for calculating the degradation process of a welding stud connecting piece of a composite beam bridge. The method comprises the steps that an experimental device is built, a concrete test piece provided with the welding stud connecting piece is placed in the experimental device, a tomography test is conducted on the concrete test piece, and the degradation process of the experimental device is obtained; based on a corrosion generation stage, a corrosion propagation stage and a corrosion expansion cracking stage of the welding stud connecting piece, a degradation model of the welding stud connecting piece is constructed, the degradation model is applied to the experimental device, and parameter calibration of the experimental device is updated; and monitoring the failure degree of the concrete test piece according to the degradation stage of the welding stud connecting piece, and determining the failure time of the welding stud connecting piece. The calculation method can be directly applied to durability evaluation of the welding stud connecting piece in the hogging moment area of the steel-concrete composite beam bridge, core parameters are provided for long-term rigidity prediction of the composite beam, then the durability and reliability of the steel-concrete composite beam bridge are improved, and the method has wide engineering application prospects.

Description

Technical Field

[0001] This invention relates to the field of durability assessment technology for steel-concrete composite beam bridge structures, specifically to a method and system for calculating the deterioration process of welded stud connectors in composite beam bridges. Background Technology

[0002] With the rapid development of the steel structure industry and the promotion of related policies, steel-concrete composite beam bridges have been widely used due to their many advantages. However, during long-term service, the problem of deterioration in the negative bending moment zone has become increasingly prominent.

[0003] Unlike traditional reinforced concrete (RC) beam bridges, steel-concrete composite beam bridges are prone to steel-concrete interface delamination and bridge deck cracking. Chloride ions can easily penetrate through gaps and cracks, leading to corrosion of welded stud connectors in the negative bending moment zone. Corrosion of these connectors reduces the steel-concrete connection strength, thereby weakening the bending stiffness of the composite beam and severely impacting the structural performance and lifespan. The stiffness in the negative bending moment zone of a steel-concrete composite beam bridge is determined by the moments of the concrete slab and steel web about the neutral axis. Cracks in the bridge deck cannot penetrate the beam structure; damage is concentrated at the connection between the bridge deck and the steel-concrete layer, ultimately resulting in the loss of the steel-concrete composite effect and a significant decrease in bending stiffness. Therefore, accurate assessment and prediction of the stiffness in the negative bending moment zone are urgently needed.

[0004] However, under the coupled effects of corrosion and fatigue, steel-concrete composite beam bridges experience coordinated degradation of multiple key load-bearing components, including concrete panel cracking and decreased steel-concrete connection strength. The degradation mechanism is complex, making traditional methods for calculating the post-deterioration stiffness of reinforced concrete (RC) beam bridges inapplicable. Existing research indicates that the failure mode of welded stud shear connectors is concrete shear-compression cracking → increased displacement → connector deformation (failure), which is completely different from the failure mechanism of tensile reinforcement in RC beam bridges. Furthermore, domestic and international standards lack calculation methods for the durability of key load-bearing components in steel-concrete composite beam bridges under the coupled effects of corrosion and fatigue, and there is a lack of computational models that can accurately describe the time-varying degradation process of welded stud connectors. This makes it difficult to meet the practical engineering needs for long-term stiffness assessment and prediction of composite beams. Summary of the Invention

[0005] Based on this, the purpose of this invention is to provide a method and system for calculating the deterioration process of welded stud connectors in composite beam bridges. This aims to solve the technical problem that the existing technology lacks a time-varying model calculation method for welded stud connector deterioration that considers the coupling effect of environmental corrosion and vehicle load, which cannot accurately describe the entire process of welded stud connectors from corrosion initiation to failure, thus affecting the durability and safety assessment of steel-concrete composite beam bridges.

[0006] To achieve the above objectives, this invention proposes a method for calculating the deterioration process of welded stud connectors in composite beam bridges. The method includes: An experimental setup was constructed, and a concrete specimen with welded stud connectors was placed inside the setup. A tomographic scan was performed on the concrete specimen to obtain the deterioration process of the setup. Based on the corrosion initiation stage, corrosion propagation stage, and rust expansion cracking stage of weld stud connectors, a degradation model of weld stud connectors is constructed. The degradation model is then applied to the experimental setup to update the parameter calibration of the experimental setup. Based on the deterioration stage of the welded stud connector, the failure degree of the concrete specimen is monitored to determine the failure time of the welded stud connector.

[0007] According to one aspect of the above technical solution, in the step of constructing the experimental apparatus, placing a concrete specimen with welded stud connectors inside the experimental apparatus, and performing a tomographic scanning test on the concrete specimen to obtain the deterioration process of the experimental apparatus: The experimental apparatus includes at least a sodium chloride solution, a copper sheet, a DC regulated power supply, and a steel beam. A concrete specimen with welded studs is placed between the sodium chloride solution and the steel beam. The copper sheet is placed inside the sodium chloride solution. The concrete specimen has initial cracks. The two poles of the DC regulated power supply are connected to the copper sheet and the steel beam, respectively. The sodium chloride solution penetrates into the concrete specimen through the initial cracks.

[0008] According to one aspect of the above technical solution, in the step of performing a tomographic scanning test on the concrete specimen to obtain the deterioration process of the experimental device: The concrete specimens were subjected to omnidirectional scanning using an X-ray emitter, X-ray detector, rotating stage, and low-density support to obtain the corrosion status of the welded stud joints at different times, the crack propagation morphology of the concrete specimens, and the steel-concrete bond condition.

[0009] According to one aspect of the above technical solution, the steps for constructing a degradation model of the weld stud connector based on the corrosion generation stage, corrosion propagation stage, and rust expansion cracking stage are as follows: Based on the stages of corrosion formation, the thickness of the concrete overburden, the chloride ion diffusion rate, and the width and depth of fatigue cracks were selected as key parameters to establish a chloride ion penetration and diffusion sub-model:

[0010] in, The time of initial rust formation. The thickness of the concrete cover layer. This represents the chloride ion diffusion rate. The width of the fatigue crack. This represents the fatigue crack depth. , , , The coefficients of fit for the experiment; Based on the corrosion propagation stages, a pitting corrosion diffusion sub-model was established, selecting weld stud size and concrete water-cement ratio as key parameters. Based on Faraday's law, the mapping relationship between the current flowing per unit area in the weld stud joint and the corrosion rate was derived, and the corrosion rate was calculated at any given time. Pitting depth:

[0011] in, For a moment The pitting depth, The corrosion current efficiency coefficient is... The corrosion current density per unit area, The density of rust, It is Faraday's constant; Based on the stages of rust expansion and cracking, and using crack width as the control index, the model parameters were calibrated based on X-ray tomography test results, and a crack growth sub-model was constructed to show the crack width changing over time.

[0012] in, For a moment The width of the crack, The initial crack width, , calibrate the parameters for the model; Statistical analysis was performed on the deterioration model composed of the chloride ion penetration diffusion sub-model, the pitting corrosion diffusion sub-model, and the crack growth sub-model. Based on the results of accelerated corrosion and X-ray tomography tests, the random distribution parameters in the three stages were updated and calibrated to determine the random probability distribution type and parameters of each parameter. The random distribution parameters include at least the chloride ion diffusion rate, corrosion current density, and model fitting coefficient.

[0013] According to one aspect of the above technical solution, the step of monitoring the failure degree of the concrete specimen and determining the failure time of the welded stud connector based on the deterioration stage of the welded stud connector includes: Based on the stages of corrosion formation and the characteristics of initial cracks caused by fatigue loading, the upper boundary of the time for the corrosion formation stages is determined as the initial corrosion formation time. The first lower boundary is the moment when the pitting depth reaches the preset depth. ; The pitting growth rate was calculated based on the stages of rust propagation, and the fatigue crack propagation rate was calculated based on the Paris formula:

[0014] in, This represents the fatigue crack propagation rate. , For material constants, K is the stress intensity factor amplitude, representing the moment when the pitting depth reaches the critical value for crack nucleation. This is the lower boundary of the second time.

[0015] According to one aspect of the above technical solution, based on the rust expansion cracking stage, when the width of the concrete crack reaches the critical value for steel-concrete bond failure, the failure time boundary of the steel-concrete bond is determined as the first lower time boundary. When the weld stud connector deteriorates and fails, the failure time boundary is determined as the second lower time boundary. ,Pick and The smaller value is used to determine the final failure time of the weld stud connector.

[0016] This invention also proposes a calculation system for the deterioration process of welded stud connectors in composite beam bridges. This system is used to implement the aforementioned calculation method for the deterioration process of welded stud connectors in composite beam bridges. The system includes: The degradation scanning module is used to build an experimental device, place a concrete specimen with welded stud connectors into the experimental device, perform a tomographic scanning test on the concrete specimen, and obtain the degradation process of the experimental device. The model building module is used to build a deterioration model of the weld stud connector based on the corrosion generation stage, corrosion propagation stage, and rust expansion cracking stage, and to apply the deterioration model to the experimental device to update the parameter calibration of the experimental device. The failure monitoring module is used to monitor the degree of failure of concrete specimens based on the deterioration stage of the weld stud connectors and determine the failure time of the weld stud connectors.

[0017] The present invention also proposes a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described method for calculating the deterioration process of weld stud connectors in composite beam bridges.

[0018] The present invention also proposes an electronic device, including a memory, a processor, and a computer program stored in the memory and running on the processor, wherein the processor executes the computer program to implement the above-described method for calculating the deterioration process of weld stud connectors in composite beam bridges.

[0019] In summary, the method for calculating the degradation process of welded stud connectors in composite beam bridges provided by this invention, through a combination of accelerated corrosion testing and X-ray tomography, systematically elucidates for the first time the complete degradation mechanism of welded stud connectors under corrosion-fatigue coupling, providing solid experimental support for model construction and solving the problem of unclear degradation mechanisms in existing studies. Furthermore, the entire corrosion degradation process of welded studs is divided into three stages, and targeted numerical models are established for each stage, achieving accurate simulation of the time-varying processes of corrosion initiation, propagation, and rust expansion cracking, overcoming the deficiency of traditional models in not being able to subdivide degradation stages. Simultaneously, a three-stage failure model considering corrosion-fatigue coupling is constructed, combining the EIFS model and the Paris formula, to accurately describe the entire life-cycle time-varying degradation process of welded stud connectors from corrosion initiation to final failure, solving the problem of large calculation deviations caused by neglecting coupling effects in existing methods. The calculation method of this invention can be directly applied to the durability assessment of welded stud connections in the negative bending moment zone of steel-concrete composite beam bridges, providing core parameters for the prediction of long-term stiffness of composite beams, thereby improving the durability and reliability of steel-concrete composite beam bridges, and has broad engineering application prospects.

[0020] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0021] Figure 1 This is a flowchart of the calculation method for the deterioration process of weld stud connectors in composite beam bridges in Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the experimental apparatus in Embodiment 1 of the present invention; Figure 3 This is a schematic diagram of an all-around scan in Embodiment 1 of the present invention; Figure 4 This is a schematic diagram of the structure of the calculation system for the deterioration process of weld stud connectors in a composite beam bridge in Embodiment 2 of the present invention; Figure 5 This is a structural block diagram of the electronic device in Embodiment 4 of the present invention. Detailed Implementation

[0022] To make the objectives, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Several embodiments of the present invention are shown in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of the present invention will be more thorough and complete.

[0023] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "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," "upper," "lower," and similar expressions used herein are for illustrative purposes only and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the invention.

[0024] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances. The term "and / or" as used herein includes any and all combinations of one or more of the related listed items.

[0025] Example 1 like Figure 1 The diagram shows a flowchart of a method for calculating the deterioration process of weld stud connectors in a composite beam bridge according to Embodiment 1 of the present invention. The method for calculating the deterioration process of weld stud connectors in a composite beam bridge includes the following steps S01-S03, wherein: S01. Set up an experimental device, place a concrete specimen with welded stud connectors into the experimental device, and perform a tomographic scanning test on the concrete specimen to obtain the deterioration process of the experimental device. S02. Based on the corrosion generation stage, corrosion propagation stage, and rust expansion cracking stage of the weld stud connector, a degradation model of the weld stud connector is constructed, and the degradation model is applied to the experimental device to update the parameter calibration of the experimental device. S03. Based on the deterioration stage of the welded stud connector, monitor the failure degree of the concrete specimen and determine the failure time of the welded stud connector.

[0026] An electrochemical accelerated corrosion test method was used to construct an experimental setup (such as...). Figure 2 As shown, the device includes a sodium chloride solution, a copper sheet, a DC regulated power supply, and a steel beam. The copper sheet is placed in the sodium chloride solution. A concrete specimen with welded studs is placed between the sodium chloride solution and the steel beam. The concrete specimen has initial cracks. The two poles of the DC regulated power supply are connected to the copper sheet and the steel beam, respectively. The sodium chloride solution permeates into the concrete specimen through the initial cracks.

[0027] Experimental variables were set, including initial crack parameters (width, depth), chloride ion concentration, concrete overburden thickness, and weld stud size. A stable current was applied via a DC regulated power supply to simulate the corrosion process of the weld stud connectors in the service environment. Simultaneous X-ray tomography (XCT) tests were conducted. Figure 3 As shown in the figure, the specimen was scanned from all directions using an X-ray emitter, X-ray detector, rotating stage and low-density support. The corrosion state of the weld studs (rust location, rust area, pitting depth), the expansion morphology of concrete cracks (crack width, length, expansion direction) and the bond condition of steel-concrete (degree of delamination of the bond surface, range of delamination) were quantitatively observed at different times during the test. Finally, the complete deterioration mechanism of weld stud joints under corrosion-fatigue coupling, from pitting rust, rust diffusion, crack formation to steel-concrete connection failure, was explored, providing an experimental basis for subsequent model construction.

[0028] The entire process of corrosion and deterioration of welded stud connectors is divided into three stages: corrosion generation, corrosion propagation, and corrosion expansion and cracking. Numerical models for each stage are established based on corrosion propagation theory.

[0029] Based on the stages of corrosion formation, the thickness of the concrete overburden, the chloride ion diffusion rate, and the width and depth of fatigue cracks were selected as key parameters to establish a chloride ion penetration and diffusion sub-model to simulate the time-varying process of corrosion initiation in the connectors:

[0030] in, The time of initial rust formation. The thickness of the concrete cover layer. This represents the chloride ion diffusion rate. The width of the fatigue crack. This represents the fatigue crack depth. , , , The coefficients are the experimental fit coefficients.

[0031] Based on the corrosion propagation stages, a pitting corrosion diffusion sub-model is established to simulate the time-varying process of corrosion propagation from the initial location to the surrounding area and the growth of pitting pits. Weld stud size and concrete water-cement ratio are selected as key parameters. Assuming the initial corrosion location is the weak area at the weld stud-concrete interface, the mapping relationship between the current flowing per unit area in the weld stud connector and the corrosion rate is derived based on Faraday's law. The model is then used to calculate the corrosion rate at any given time. Pitting depth:

[0032] in, For a moment The pitting depth, The corrosion current efficiency coefficient is... The corrosion current density per unit area, The density of rust, is Faraday's constant.

[0033] Based on the stages of rust expansion and cracking, and using crack width as the control index, the model parameters were calibrated based on X-ray tomography test results. A crack growth sub-model was constructed to simulate the time-varying process of crack formation and propagation in concrete due to rust expansion.

[0034] Where ω(t) is the crack width at time t, ω0 is the initial crack width, and m and n are model calibration parameters; Statistical analysis was performed on the deterioration model composed of the chloride ion penetration diffusion sub-model, the pitting corrosion diffusion sub-model, and the crack growth sub-model. Based on the results of accelerated corrosion and X-ray tomography tests, the random distribution parameters in the three stages were updated and calibrated to determine the random probability distribution type and parameters of each parameter. The random distribution parameters include at least the chloride ion diffusion rate, corrosion current density, and model fitting coefficient.

[0035] Combining the degradation model, the EIFS model (Equivalent Initial Defect Size Model), and the Paris formula, the degradation and failure process of weld stud connectors under corrosion-fatigue coupling is divided into three stages: corrosion initiation and pit formation, pit growth and fatigue crack propagation rate competition, and weld stud cross-section degradation failure or steel-concrete connection failure.

[0036] In the stages of corrosion initiation and pitting formation, based on the rust formation stage and the characteristics of initial cracks caused by fatigue loading, the upper boundary of the rust formation stage is determined as the initial rust formation time. The first lower boundary is the moment when the pitting depth reaches the preset depth. .

[0037] In the competition between pitting growth and fatigue crack propagation rate, after pitting forms, stress concentration occurs at its root, inducing fatigue crack generation and propagation in weld studs. The pitting growth rate is calculated based on the corrosion propagation stages, and the fatigue crack propagation rate is calculated based on the Paris formula.

[0038] in, This represents the fatigue crack propagation rate. , For material constants, K is the stress intensity factor amplitude, representing the moment when the pitting depth reaches the critical value for crack nucleation. This is the lower boundary of the second time.

[0039] During the stage of weld stud cross-section deterioration failure or steel-concrete joint failure, when the width of the concrete crack reaches the critical value for steel-concrete joint failure... The time (usually 0.3~0.5mm according to specifications) is used to determine the failure time boundary of the steel-concrete connection as the lower boundary of the first time. Simultaneously, based on the EIFS model to simulate the fatigue crack propagation process, and combined with the specification regarding the crack width of weld stud failure (usually 10% of the weld stud diameter) in the standard, the failure time boundary was determined as the second lower time boundary. ,Pick and The smaller value is used to determine the final failure time of the weld stud connector.

[0040] Furthermore, taking the welded stud connector in the negative bending moment zone of a steel-concrete composite beam bridge for a highway as the research object, the welded stud diameter is 16mm and the length is 80mm, the concrete strength grade is C50, the water-cement ratio is 0.45, the concrete overburden thickness is 30mm, the initial crack width is 0.1mm and the depth is 5mm, the chloride ion concentration in the service environment is 0.05mol / L, and the fatigue load stress amplitude is 100MPa. The time-varying process of the deterioration of the welded stud connector and the final failure time are calculated using the method of this invention. The specific steps are as follows: Concrete specimens with initial cracks (150mm×150mm×300mm) were prepared. Welded stud connectors were embedded in the center of the specimens to ensure reliable connection between the studs and the steel beams. An electrochemical accelerated corrosion test apparatus was constructed, in which the specimens were immersed in a 5% sodium chloride solution. Copper sheets were used as auxiliary electrodes, and the welded studs were used as working electrodes. A constant current of 0.5mA / cm² was applied through a DC regulated power supply. X-ray tomography was performed on the specimens every 7 days to obtain quantitative data on the corrosion state of the welded studs, the crack propagation morphology of the concrete, and the bond condition between the steel and concrete. The test lasted for 60 days to explore the degradation mechanism.

[0041] Rust formation stage: Based on experimental data fitting, a linear relationship between the initial rust formation time and key parameters was obtained. Substituting these parameters, the following calculations were performed. The corrosion propagation stage was 14.3 days. The formula for calculating pitting depth was derived based on Faraday's law, taking k=0.85 and ρ=5.2 g / cm³. 3 F = 96500 C / mol, calculated at any time Pitting depth Rust expansion and cracking stage: Based on experimental data, the crack growth model parameters m=0.12 and n=0.08 were calibrated, and the crack width variation over time was expressed as follows: Statistical analysis was used to determine that the chloride ion diffusion rate follows a log-normal distribution (mean 1.2 × 10⁻⁶). - ¹²m² / s, coefficient of variation 0.3), corrosion current density follows a normal distribution (mean 0.5mA / cm², coefficient of variation 0.2).

[0042] During the stages of corrosion initiation and pitting formation, It is 14.3. It took 21.5 days (the pitting depth reached 10 μm); In the competition stage between pitting growth and fatigue crack propagation rate, taking the critical value for pitting crack nucleation δc = 1.0 mm, the following calculations were performed. =39.7 days; Paris formula parameter C=6.5×10 12. Given m=3.2, calculate the fatigue crack propagation rate; During the stage of weld stud cross-section deterioration failure or steel-concrete joint failure, the critical crack width for steel-concrete joint failure is... =0.3mm, calculated as follows =52.8 days; the critical crack width for weld stud failure is 1.6 mm, calculated as follows: =48.3 days; the final expiration time is 48.3 days.

[0043] In summary, the method for calculating the degradation process of welded stud connectors in composite beam bridges provided by this invention, through a combination of accelerated corrosion testing and X-ray tomography, systematically elucidates for the first time the complete degradation mechanism of welded stud connectors under corrosion-fatigue coupling, providing solid experimental support for model construction and solving the problem of unclear degradation mechanisms in existing studies. Furthermore, the entire corrosion degradation process of welded studs is divided into three stages, and targeted numerical models are established for each stage, achieving accurate simulation of the time-varying processes of corrosion initiation, propagation, and rust expansion cracking, overcoming the deficiency of traditional models in not being able to subdivide degradation stages. Simultaneously, a three-stage failure model considering corrosion-fatigue coupling is constructed, combining the EIFS model and the Paris formula, to accurately describe the entire life-cycle time-varying degradation process of welded stud connectors from corrosion initiation to final failure, solving the problem of large calculation deviations caused by neglecting coupling effects in existing methods. The calculation method of this invention can be directly applied to the durability assessment of welded stud connections in the negative bending moment zone of steel-concrete composite beam bridges, providing core parameters for the prediction of long-term stiffness of composite beams, thereby improving the durability and reliability of steel-concrete composite beam bridges, and has broad engineering application prospects.

[0044] Example 2 In another aspect, this invention provides a calculation system for the deterioration process of weld stud connectors in composite beam bridges. Please refer to [link / reference needed]. Figure 4The diagram shows a structural schematic of the deterioration process calculation system for welded stud connectors in a composite beam bridge according to Embodiment 2 of the present invention. The composite beam bridge welded stud connector deterioration process calculation system includes: The degradation scanning module 11 is used to set up an experimental device, place a concrete specimen with welded stud connectors into the experimental device, perform a tomographic scanning test on the concrete specimen, and obtain the degradation process of the experimental device. The model building module 12 is used to build a deterioration model of the weld stud connector based on the corrosion generation stage, corrosion propagation stage, and corrosion expansion cracking stage, and to apply the deterioration model to the experimental device to update the parameter calibration of the experimental device. The failure monitoring module 13 is used to monitor the degree of failure of the concrete specimen according to the deterioration stage of the weld stud connector and determine the failure time of the weld stud connector.

[0045] Example 3 In another aspect, the present invention provides a computer-readable storage medium having stored thereon one or more computer programs that, when executed by a processor, implement the above-described method for calculating the deterioration process of weld stud connectors in composite beam bridges.

[0046] Those skilled in the art will understand that the logic or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable storage medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable storage medium" can mean any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device.

[0047] More specific examples (a non-exhaustive list) of computer-readable storage media include: electrical connections (electronic devices) having one or more wires, portable computer disk drives (magnetic devices), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Furthermore, computer-readable storage media can even be paper or other suitable media on which the program can be printed, since the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in computer memory.

[0048] Example 4 Figure 5 This is a structural block diagram of an electronic device provided in Embodiment 4. The electronic device includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, it implements the method for calculating the deterioration process of the weld stud connectors of the composite beam bridge described in the above embodiments. Figure 5 The electronic device 30 shown is merely an example and should not impose any limitation on the functionality and scope of use of the embodiments of the present invention.

[0049] like Figure 5 As shown, the electronic device 30 can be manifested as a general-purpose computing device, such as a server device. The components of the electronic device 30 may include, but are not limited to: at least one processor 31, at least one memory 32, and a bus 33 connecting different system components (including memory 32 and processor 31).

[0050] Bus 33 includes a data bus, an address bus, and a control bus.

[0051] The memory 32 may include volatile memory, such as RAM 321 (random access memory), and / or cache memory 322, and may further include ROM 323 (read-only memory).

[0052] The memory 32 may also include a program tool 325 having a set (at least one) of program modules 324, including but not limited to: an operating system, one or more application programs, other program modules, and program data, each or some combination of these examples may include an implementation of a network environment.

[0053] The processor 31 executes various functional applications and data processing by running computer programs stored in the memory 32, such as the method for calculating the deterioration process of weld stud connectors in composite beam bridges as described above.

[0054] Electronic device 30 can also communicate with one or more external devices 34 (e.g., keyboard, pointing device, etc.). This communication can be performed via I / O interface 35 (input / output interface). Furthermore, electronic device 30 can also communicate with one or more networks (e.g., local area network (LAN), wide area network (WAN), and / or public network, such as the Internet) via network adapter 36. Figure 3 As shown, network adapter 36 communicates with other modules of the model-generated electronic device 30 via bus 33. It should be understood that, although not shown in the figure, other hardware and / or software modules can be used in conjunction with the model-generated electronic device 30, including but not limited to: microcode, device drivers, redundant processors, disk drive arrays, RAID (disk array) systems, tape drives, and data backup storage systems.

[0055] It should be noted that although several units / modules or sub-units / modules of the electronic device have been mentioned in the detailed description above, this division is merely exemplary and not mandatory. In fact, according to embodiments of the present invention, the features and functions of two or more units / modules described above can be embodied in one unit / module. Conversely, the features and functions of one unit / module described above can be further divided and embodied by multiple units / modules.

[0056] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0057] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this patent should be determined by the appended claims.

Claims

1. A method for calculating deterioration process of a welded connector of a composite girder bridge, characterized by, The calculation method for the deterioration process of weld stud connectors in the composite beam bridge includes: An experimental setup was constructed, and a concrete specimen with welded stud connectors was placed inside the setup. A tomographic scan was performed on the concrete specimen to obtain the deterioration process of the setup. Based on the corrosion initiation stage, corrosion propagation stage, and rust expansion cracking stage of weld stud connectors, a degradation model of weld stud connectors is constructed. The degradation model is then applied to the experimental setup to update the parameter calibration of the experimental setup. Based on the deterioration stage of the welded stud connector, the failure degree of the concrete specimen is monitored to determine the failure time of the welded stud connector.

2. The method for calculating the deterioration process of welded stud connectors in composite beam bridges according to claim 1, characterized in that, The step of setting up the experimental apparatus, placing a concrete specimen with welded stud connectors inside the apparatus, and performing a tomographic scan on the concrete specimen to obtain the deterioration process of the experimental apparatus includes: The experimental apparatus includes at least a sodium chloride solution, a copper sheet, a DC regulated power supply, and a steel beam. A concrete specimen with welded studs is placed between the sodium chloride solution and the steel beam. The copper sheet is placed inside the sodium chloride solution. The concrete specimen has initial cracks. The two poles of the DC regulated power supply are connected to the copper sheet and the steel beam, respectively. The sodium chloride solution penetrates into the concrete specimen through the initial cracks.

3. The method for calculating the deterioration process of welded stud connectors in composite beam bridges according to claim 2, characterized in that, In the step of performing a tomographic scanning test on the concrete specimen to obtain the deterioration process of the experimental device: The concrete specimens were subjected to omnidirectional scanning using an X-ray emitter, X-ray detector, rotating stage, and low-density support to obtain the corrosion status of the welded stud joints at different times, the crack propagation morphology of the concrete specimens, and the steel-concrete bond condition.

4. The method for calculating the deterioration process of welded stud connectors in composite beam bridges according to claim 1, characterized in that, The steps for constructing a degradation model for welded stud connectors based on the corrosion initiation stage, corrosion propagation stage, and rust expansion cracking stage are as follows: Based on the stages of corrosion formation, the thickness of the concrete overburden, the chloride ion diffusion rate, and the width and depth of fatigue cracks were selected as key parameters to establish a chloride ion penetration and diffusion sub-model: in, The time of initial rust formation. The thickness of the concrete cover layer. This represents the chloride ion diffusion rate. The width of the fatigue crack. This represents the fatigue crack depth. , , , The coefficients of fit for the experiment; Based on the corrosion propagation stages, a pitting corrosion diffusion sub-model was established, selecting weld stud size and concrete water-cement ratio as key parameters. Based on Faraday's law, the mapping relationship between the current flowing per unit area in the weld stud joint and the corrosion rate was derived, and the corrosion rate was calculated at any given time. Pitting depth: in, For a moment The pitting depth, The corrosion current efficiency coefficient is... The corrosion current density per unit area, The density of rust, It is Faraday's constant; Based on the stages of rust expansion and cracking, and using crack width as the control index, the model parameters were calibrated based on X-ray tomography test results, and a crack growth sub-model was constructed to show the crack width changing over time. in, For a moment The width of the crack, The initial crack width, , calibrate the parameters for the model; Statistical analysis was performed on the deterioration model composed of the chloride ion penetration diffusion sub-model, the pitting corrosion diffusion sub-model, and the crack growth sub-model. Based on the results of accelerated corrosion and X-ray tomography tests, the random distribution parameters in the three stages were updated and calibrated to determine the random probability distribution type and parameters of each parameter. The random distribution parameters include at least the chloride ion diffusion rate, corrosion current density, and model fitting coefficient.

5. The method for calculating the deterioration process of welded stud connectors in composite beam bridges according to claim 1, characterized in that, The step of monitoring the failure degree of concrete specimens and determining the failure time of welded stud connectors based on the deterioration stage of the welded stud connectors includes: Based on the stages of corrosion formation and the characteristics of initial cracks caused by fatigue loading, the upper boundary of the time for the corrosion formation stages is determined as the initial corrosion formation time. The first lower boundary is the moment when the pitting depth reaches the preset depth. ; The pitting growth rate was calculated based on the stages of rust propagation, and the fatigue crack propagation rate was calculated based on the Paris formula: in, This represents the fatigue crack propagation rate. , For material constants, K is the stress intensity factor amplitude, representing the moment when the pitting depth reaches the critical value for crack nucleation. This is the lower boundary of the second time.

6. The method for calculating the deterioration process of welded stud connectors in composite beam bridges according to claim 5, characterized in that, Based on the rust expansion cracking stage, when the width of the concrete crack reaches the critical value for steel-concrete bond failure, the time boundary for steel-concrete bond failure is determined as the first lower time boundary. When the weld stud connector deteriorates and fails, the failure time boundary is determined as the second lower time boundary. ,Pick and The smaller value is used to determine the final failure time of the weld stud connector.

7. A system, characterized in that, The composite beam bridge weld stud connector deterioration process calculation system is used to implement the composite beam bridge weld stud connector deterioration process calculation method according to any one of claims 1-6, the system comprising: The degradation scanning module is used to build an experimental device, place a concrete specimen with welded stud connectors into the experimental device, perform a tomographic scanning test on the concrete specimen, and obtain the degradation process of the experimental device. The model building module is used to build a deterioration model of the weld stud connector based on the corrosion generation stage, corrosion propagation stage, and rust expansion cracking stage, and to apply the deterioration model to the experimental device to update the parameter calibration of the experimental device. The failure monitoring module is used to monitor the degree of failure of concrete specimens based on the deterioration stage of the weld stud connectors and determine the failure time of the weld stud connectors.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by the processor, the program implements the method for calculating the deterioration process of weld stud connectors in composite beam bridges as described in any one of claims 1-6.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that, When the processor executes the computer program, it implements the method for calculating the deterioration process of weld stud connectors in composite beam bridges as described in any one of claims 1-6.

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