Damage prediction method and device for in-service welding burn-through of pipeline

Abstract

The invention relates to the field of damage mechanics, and discloses a pipeline in-service welding burn-through damage prediction method and device, and the method comprises the steps: determining the damage parameter data of a target pipeline at different temperatures and different strain rates; constructing a Bonora damage model of the target pipeline based on the damage parameter data; solving the Bonora damage model and the constitutive parameter expression of the Bonora damage model to obtain a damage evolution equation of the target pipeline; simulating and correcting the damage evolution equation based on an in-service welding finite element of the under-pressure pipeline; and on the basis of the corrected damage evolution equation, carrying out pipeline in-service welding burn-through damage prediction. According to the method, the Bonora damage model is introduced, the distribution rule and evolution behavior of the damage in the in-service welding burn-through process are researched, the dynamic evolution process from damage evolution to burn-through in the burn-through process can be given, and the safety threshold of the in-service welding burn-through risk is given. And safe operation of the oil-gas pipeline can be guaranteed.

Description

Technical Field

[0001] The present application relates to the field of damage mechanics, and particularly relates to a method and device for predicting damage of in-service welding burn-through of pipelines. Background Art

[0002] The in-service welding repair technology is an economic, environment-friendly and efficient oil and gas pipeline repair technology, and is also an important development direction for pipeline repair. Due to the forced constraint of the pipeline and the presence of flowing high-pressure medium inside the pipe, there are mainly two technical difficulties in in-service welding repair: (1) During in-service welding, the arc heat will cause local loss of strength of the pipe wall metal, and burn-through will occur under the action of the internal medium pressure of the pipe and welding stress, etc.; (2) The flowing medium inside the pipe will increase the possibility of cold cracks in the weld and heat-affected zone. Among them, burn-through is the primary problem in in-service welding.

[0003] In view of the engineering application value of in-service welding burn-through, the research work mainly focuses on the burn-through criterion. The existing criteria are mainly proposed based on the macroscopic burn-through phenomenon of in-service welding, and mainly include the minimum wall thickness criterion, the highest inner wall temperature criterion, the remaining strength criterion and the radial deformation criterion. The above criteria lack the understanding of the mechanism, and so far, a generally recognized and quantitative mechanism-integrated safety assessment criterion has not been formed.

[0004] In-service welding burn-through is essentially a problem of high-temperature deformation and fracture under the coupling action of multi-physical fields of welding and the internal medium pressure of the pipe. Its dynamic failure process occurs inside the high-temperature metal, and goes through dynamic evolution processes such as the initiation of micro-defects, the evolution of micro-cracks, and the propagation of macro-cracks. Finding characteristic parameters that can comprehensively consider the multi-field coupling action of in-service welding and can quantitatively evaluate the risk of in-service welding burn-through is the key to the research on burn-through instability safety criteria.

[0005] Damage mechanics can give a quantitative solution for burn-through based on the welding finite element simulation results and damage theory on the premise of comprehensively considering the multi-field coupling action, which provides a new way for the research on the safety criterion of in-service welding burn-through instability. Summary of the Invention

[0006] The present application aims to solve at least one of the technical problems in the above technologies to some extent. For this purpose, the present application proposes a method for predicting damage failure of in-service welding of pipelines, including:

[0007] Determine the damage parameter data of the target pipeline at different temperatures and different strain rates;

[0008] Construct the Bonora damage model of the target pipeline based on the damage parameter data;

[0009] Solve the expression of the Bonora damage model and its corresponding constitutive parameters to obtain the damage evolution equation of the target pipeline;

[0010] Modify the damage evolution equation based on the finite element simulation of in-service welding of pressurized pipelines;

[0011] Predict the damage failure of in-service welding of pipelines based on the modified damage evolution equation.

[0012] Preferably, determine the damage parameter data of the target pipeline at different temperatures and different strain rates, including:

[0013] Prepare high-temperature tensile specimens using the material of the target pipeline;

[0014] Conduct high-temperature tensile experiments based on the high-temperature tensile specimens;

[0015] After equating the volume of the non-uniform deformation zone of the high-temperature tensile specimen to the volume of the uniform deformation zone, calculate the fracture strain values at different temperatures;

[0016] Take the strain corresponding to the highest point of the load-stroke curve as the initial damage threshold strain;

[0017] Based on the Lemaitre damage theory, calculate the critical damage value using the critical damage value calculation formula; among them, the critical damage value calculation formula includes:

[0018]

[0019] Among them, D cr represents the critical damage value of the target pipeline; σ R represents the engineering fracture stress of the target pipeline; σ u represents the peak stress of the target pipeline.

[0020] Preferably, construct the Bonora damage model of the target pipeline based on the damage parameter data, including:

[0021] Assume that the effects of temperature and strain rate on the critical damage value are not coupled, characterize and solve the flow stress, temperature and strain rate of the target pipeline based on the Arrhenius equation and the damage parameter data, determine the deformation activation energy and damage parameter expression of the target pipeline, and obtain the Bonora damage model.

[0022] Preferably, the damage evolution equation includes an initial damage threshold strain equation, a critical damage threshold strain equation, a critical damage value equation, a stress triaxiality equation and a damage dynamic evolution equation.

[0023] Preferably, modify the damage evolution equation based on the finite element simulation of in-service welding of pressurized pipelines, including:

[0024] Construct a finite element mesh model of a pressurized steel pipe according to the dimensions of the target pipeline;

[0025] Determine the boundary conditions of the finite element mesh model according to the parameters of the target pipeline, and perform numerical simulations of the temperature field and stress field on the finite element mesh model;

[0026] Compare the numerical simulation results with the actual data to judge the reliability of the numerical simulation results;

[0027] When it is determined that the numerical simulation results are reliable, embed the criterion that the absolute value of the radial stress is greater than the yield strength as the criterion for damage initiation into the Bonora damage model, and correct the damage evolution equation of the target pipeline.

[0028] Preferably, perform in-service welding damage failure prediction for the pipeline based on the corrected damage evolution equation, including: import the temperature field and stress field data simulation results of the finite element mesh model into the corrected damage evolution equation to determine the damage evolution situation during in-service welding of the target pipeline.

[0029] Preferably, performing in-service welding damage failure prediction for the pipeline based on the corrected damage evolution equation further includes:

[0030] Set the damage value of the area where the temperature is higher than the threshold in the temperature field simulation data to zero, extract the stress field numerical simulation results and the corresponding node coordinates to obtain the plastic strain, calculate the stress triaxiality, and substitute it into the corrected damage evolution equation to calculate the damage value;

[0031] Based on the corresponding node coordinates of the stress field simulation data and the calculated damage value, construct a damage evolution diagram of the target pipeline with the change of the medium pressure.

[0032] Preferably, after performing in-service welding damage failure prediction for the pipeline based on the corrected damage evolution equation, it further includes: comparing the in-service welding damage failure prediction result of the pipeline with the result of the pipeline burn-through experiment to determine the reliability of the in-service welding damage failure prediction result of the pipeline.

[0033] This application also proposes an electronic device, including a memory and a processor. A computer program or instruction is stored in the memory. When the computer program or instruction is executed by the processor, it is at least used to implement the above method.

[0034] This application also proposes a computer-readable storage medium, characterized in that a computer program or instruction is stored in the computer-readable storage medium. When the computer program or instruction is executed by a processor, it is at least used to implement the above method.

[0035] Compared with the prior art, the beneficial effects of this application are:

[0036] By introducing the Bonora damage model, this application can study the distribution law and evolution behavior of damage during in-service welding burn-through. After modifying the Bonora model based on the damage theory and the instability mechanism of in-service welding burn-through, it can give the dynamic evolution process from damage to burn-through during the burn-through process and provide the safety threshold of the in-service welding burn-through risk. This prediction method is extremely simple to calculate and convenient for engineering applications, and has important theoretical and application values for ensuring the safe operation of oil and gas pipelines and the safety of people's lives and property.

[0037] Other features and advantages of this application will be described in the following specification, and, in part, will be obvious from the specification or learned by implementing this application. The objectives and other advantages of this application can be achieved and obtained through the structures specifically pointed out in the written specification and the accompanying drawings.

[0038] The technical solutions of this application will be further described in detail below through the accompanying drawings and embodiments. Brief Description of the Drawings

[0039] The accompanying drawings are used to provide a further understanding of this application, and constitute a part of the specification. Together with the embodiments of this application, they are used to explain this application and do not constitute a limitation to this application. In the accompanying drawings:

[0040] Figure 1 is a schematic diagram of the prediction method for in-service welding burn-through damage of pipelines;

[0041] Figure 2 is a schematic diagram of the prediction method for in-service welding burn-through damage of pipelines given in the embodiment;

[0042] Figure 3 is a schematic diagram of the electronic device given in this application;

[0043] Figure 4 is a schematic diagram of the computer-readable storage medium given in this application. Detailed Description of the Preferred Embodiments

[0044] The following describes this application in conjunction with the accompanying drawings. The preferred embodiments described herein are only used to illustrate and explain this application and are not used to limit this application.

[0045] In-service welding burn-through is essentially a problem of high-temperature deformation and fracture under the coupled action of multi-physical fields in welding and the pressure of the medium inside the pipe. Its dynamic failure process occurs inside the high-temperature metal and goes through dynamic evolution processes such as micro-defect initiation, micro-crack evolution, and macro-crack propagation. Finding characteristic parameters that can comprehensively consider the multi-field coupling effect in in-service welding and quantitatively evaluate the risk of in-service welding burn-through is the key to the research on the burn-through instability safety criterion. Damage mechanics can, on the premise of comprehensively considering the multi-field coupling effect, give a quantitative solution for burn-through based on the results of welding finite element simulation and damage theory, which provides a new way for the research on the safety criterion of in-service welding burn-through instability. By introducing the Bonora damage model, the present invention can study the distribution law and evolution behavior of damage during the in-service welding burn-through process. After modifying the Bonora model based on damage theory and the in-service welding burn-through instability mechanism, it can give the dynamic evolution process from damage evolution to burn-through during the burn-through process and give the safety threshold of the in-service welding burn-through risk. This prediction method is extremely simple to calculate and convenient for engineering applications, and has important theoretical and application values for ensuring the safe operation of oil and gas pipelines and the safety of people's lives and property.

[0046] Figure 1 This application provides a damage prediction method for in-service welding burn-through of pipelines, and the method includes:

[0047] Determine the damage parameter data of the target pipeline at different temperatures and different strain rates;

[0048] Construct the Bonora damage model of the target pipeline based on the damage parameter data;

[0049] Solve the expression of the Bonora damage model and its corresponding constitutive parameters to obtain the damage evolution equation of the target pipeline;

[0050] Modify the damage evolution equation based on the finite element simulation of in-service welding of pressurized pipelines;

[0051] Predict the damage failure of in-service welding of pipelines based on the modified damage evolution equation.

[0052] According to some embodiments of this application, determining the damage parameter data of the target pipeline at different temperatures and different strain rates includes: preparing high-temperature tensile specimens using the material of the target pipeline; conducting high-temperature tensile experiments based on the high-temperature tensile specimens; after equating the volume of the non-uniform deformation zone of the high-temperature tensile specimens to the volume of the uniform deformation zone, calculating the fracture strain values at different temperatures; taking the strain corresponding to the highest point of the load-displacement curve as the initial damage threshold strain; based on the Lemaitre damage theory, calculating the critical damage value using the critical damage value calculation formula; where the critical damage value calculation formula includes:

[0053]

[0054] Among them, D cr represents the critical damage value of the target pipeline; ρ R represents the engineering fracture stress of the target pipeline; ρ u represents the peak stress of the target pipeline.

[0055] According to some embodiments of the present application, a Bonora damage model of the target pipeline is constructed based on damage parameter data, including: assuming that the effects of temperature and strain rate on the critical damage value are uncoupled, the flow stress, temperature, and strain rate of the target pipeline are characterized and solved based on the Arrhenius equation and damage parameter data to determine the deformation activation energy and damage parameter expression of the target pipeline, and the Bonora damage model is obtained.

[0056] According to some embodiments of the present application, the damage evolution equation includes an initial damage threshold strain equation, a critical damage threshold strain equation, a critical damage value equation, a stress triaxiality equation, and a damage dynamic evolution equation.

[0057] According to some embodiments of the present application, the damage evolution equation is corrected based on the finite element simulation of in-service welding of pressurized pipelines, including: constructing a finite element mesh model of a pressurized steel pipe according to the dimensions of the target pipeline; determining the boundary conditions of the finite element mesh model according to the parameters of the target pipeline, and performing numerical simulations of the temperature field and stress field on the finite element mesh model; comparing the numerical simulation results with the actual data to judge the reliability of the numerical simulation results; when it is determined that the numerical simulation results are reliable, taking the absolute value of the radial stress greater than the yield strength as the discrimination condition for damage initiation and embedding it into the Bonora damage model to correct the damage evolution equation of the target pipeline.

[0058] According to some embodiments of the present application, for the prediction of in-service welding damage failure of pipelines based on the corrected damage evolution equation, it further includes: setting the damage value of the area where the temperature is higher than the threshold in the temperature field simulation data to zero, extracting the stress field numerical simulation results and the corresponding node coordinates to obtain the plastic strain, calculating the stress triaxiality, and substituting it into the corrected damage evolution equation to calculate the damage value; based on the corresponding node coordinates of the stress field simulation data and the calculated damage value, constructing a damage evolution diagram of the target pipeline varying with the medium pressure.

[0059] According to some embodiments of the present application, after the prediction of in-service welding damage failure of pipelines, it further includes: comparing the prediction results of in-service welding damage failure of pipelines with the results of the pipeline burn-through experiment to determine the reliability of the prediction results of in-service welding damage failure of pipelines.

[0060] Figure 2 The damage prediction method for in-service welding burn-through of pipelines based on the corrected Bonora damage model given in some embodiments of the present application includes the following steps:

[0061] Step 1: Based on high-temperature tensile tests, determine and calculate the damage parameters of the material at different temperatures and different strain rates;

[0062] Step 2: According to the Bonora damage model framework, conduct mathematical modeling, solve for the deformation activation energy, and obtain the mathematical expressions for the critical damage value, initial damage threshold strain, and critical damage threshold strain at different temperatures and strain rates;

[0063] Step 3: Based on the Bonora damage constitutive model and the mathematical expressions of the corresponding constitutive parameters, solve and obtain the damage evolution equation;

[0064] Step 4: Carry out finite element simulation of in-service welding of pressurized steel pipes, and calibrate the temperature field and stress field results in combination with the in-service welding process test of pressurized steel pipes to ensure the reliability of the finite element simulation of in-service welding;

[0065] Step 5: Based on the finite element simulation of in-service welding of pressurized steel pipes, analyze the temperature field and stress field laws, and modify the damage evolution equation;

[0066] Step 6: Extract the results such as the temperature field and stress field in the finite element simulation of in-service welding, import them into the modified damage evolution equation, and analyze the damage evolution during the in-service welding process;

[0067] Step 7: Through visualization software, visualize the solution results of the damage evolution equation to obtain the damage evolution contour map;

[0068] Step 8: In combination with the in-service welding process test of pressurized steel pipes, through failure analysis, analyze the evolution behavior of defects and burn-through, verify the damage evolution contour map obtained by numerical simulation, and ensure the credibility of the numerical simulation damage evolution contour map;

[0069] Step 9: In combination with the damage evolution contour map, quantitatively predict the burn-through risk during in-service welding, obtain the burn-through threshold, and compare and verify it with the experimental burn-through threshold obtained from the in-service welding process test of pressurized steel pipes to demonstrate the reliability of the predicted burn-through threshold.

[0070] In this embodiment, the calculation of the damage parameters based on the high-temperature tensile test in Step 1 includes the following steps:

[0071] Step (1): According to the metal material tensile test standard, prepare a rod-shaped high-temperature tensile specimen with a diameter of 6 mm, and make a scale in the middle of the specimen to facilitate the accurate calculation of damage parameters in the subsequent steps; Exemplarily, the test material is X65 pipeline steel, the steel pipe specification is φ114.3 mm × 11.0 mm, and the high-temperature tensile specimen is taken along the longitudinal direction of the pipe body. The specimen size is φ6 × 121.5 mm. The width of the high-temperature heating area is generally 12 mm in the middle of the specimen. The 6 mm position in the middle of the specimen is generally not marked with a gauge length in the fracture area. Laser etching is used to mark scales on the 9 mm areas on both sides of this 6 mm area. The depth of the scale line is 0.1 mm, and the interval between the scale lines is 1 mm. The purpose of making the scale lines is to more accurately calculate the damage parameters of the material at different temperatures and different strain rates.

[0072] Step (2): Based on the principle of volume invariance, use the equivalent volume method to equivalent the volume of the non-uniform deformation zone to the volume of the uniform deformation zone, and then calculate the more accurate fracture strain value at different temperatures;

[0073] Step (3): Based on the Lemaitre damage theory, microvoids initially germinate in the necking stage. This stage is regarded as the beginning of damage, and the strain corresponding to the highest point of the load-displacement curve is used to replace the initial damage threshold strain;

[0074] Step (4): Based on the Lemaitre damage theory, use the formula to calculate the critical damage value, where ρ R represents the engineering fracture stress; ρ u represents the peak stress.

[0075] In this embodiment, for the solution of the mathematical expressions of the constitutive model parameters such as the value of the deformation activation energy, the critical damage value, the initial damage threshold strain, and the critical damage threshold strain in step 2, the following steps are included:

[0076] Step (1): Use the power function form of the Arrhenius equation to characterize the relationship between the flow stress and temperature and strain rate, and perform operations such as logarithmic transformation, partial derivative calculation, and data curve fitting on the formula to solve for the deformation activation energy;

[0077] Step (2): Assume that the effects of temperature and strain rate on the critical damage value are non-coupled, obtain the expression of the critical damage value, and perform operations such as logarithmic transformation, partial derivative calculation, and data curve fitting on the above expression to solve for the mathematical expression of the critical damage value;

[0078] Step (3): Characterize the relationship between the flow stress and temperature and strain rate using the power function form of the Arrhenius equation. Appropriately transform the formula, and through operations such as logarithmic transformation, partial derivative calculation, and data curve fitting, obtain the mathematical expression of the initial damage threshold strain;

[0079] Step (4): Refer to the solution method of the critical damage value to solve and obtain the mathematical expression of the critical damage threshold strain.

[0080] In this embodiment, the damage evolution equation in step 3 is a series of equations, including the initial damage threshold strain equation (mathematical expression), critical damage threshold strain equation, critical damage value equation, stress triaxiality equation, and damage dynamic evolution equation. This damage evolution equation mainly includes 6 parameters, namely the initial damage threshold strain ε t , critical damage fracture strain ε cr , critical damage value D cr , stress triaxiality, temperature T, and strain rate Among them, the initial damage threshold strain ε t , critical damage fracture strain ε cr , and critical damage value D cr are all functions of temperature T and strain rate . Exemplarily, the obtained series of equations are as follows:

[0081]

[0082]

[0083]

[0084]

[0085]

[0086]

[0087] In this embodiment, in step 4, finite element simulation of in-service welding of pressurized steel pipes is carried out, and the temperature field and stress field results are calibrated in combination with the in-service welding process test of pressurized steel pipes to ensure the reliability of the finite element simulation of in-service welding. Exemplarily, the in-service welding process test of pressurized steel pipes is implemented as follows. It is generally considered that the first surfacing circumferential weld in in-service welding will not burn through and subsequent weld beads will not burn through either. The X65 steel pipe is processed into a specification of φ114mm×200mm×4mm, the medium inside the pipe is water, the pressure of the medium inside the pipe can be adjusted between 0 - 10 MPa, the welding method is TIG welding, no welding wire is added, and a stable welding is carried out using an ABB welding robot. The finite element simulation of in-service welding of pressurized steel pipes includes the following steps:

[0088] Step (1): Construct a finite element mesh model of a pressurized steel pipe according to the size of the test pipeline.

[0089] Step (2): Set boundary conditions consistent with the test according to the heat dissipation, constraints, mechanical boundary conditions, etc. of the test pipeline.

[0090] Step (3): Based on the framework of the thermal-metallurgical-mechanical sequential coupling model, conduct numerical simulations of the temperature field and stress field.

[0091] Step (4): Compare with the test to check the reliability of the results of the numerical simulation temperature field and stress field.

[0092] In this embodiment, step 5 is based on the finite element simulation of in-service welding of pressurized steel pipes, analyzes the laws of the temperature field and stress field, and corrects the damage evolution equation.

[0093] When the absolute value of the radial stress is greater than the yield strength of the material at this time, the metal of the pipe wall begins to undergo radial yield and gradually produces an outward convex radial deformation. During this process, the radial strain is positive, and this deformation behavior is the key reason for burn-through instability. Based on the above research, it is necessary to introduce a radial stress judgment condition into the damage model. When the absolute value of the radial stress is greater than the yield strength value or the hydrostatic stress is greater than zero, damage begins to accumulate, otherwise damage is not accumulated. The corrected damage evolution equation is as follows:

[0094]

[0095] In the formula, D RS is the effective damage, σ 33 is the radial stress; σ s is the yield strength.

[0096] The corrected damage evolution equation in step 5 means embedding the condition that the radial stress (absolute value) is greater than the yield strength as the criterion for damage initiation into the damage model;

[0097] In this embodiment, obtaining the damage evolution cloud diagram in step 7 includes the following steps:

[0098] Step (1): Extract the results of the temperature field numerical simulation, set the damage value of the area where the temperature is higher than 1590 °C to zero, and consider this part as the molten pool. The data results of this part are not brought into the damage evolution equation for calculation;

[0099] Step (2): Extract the results of the temperature field numerical simulation, extract the results of the stress field numerical simulation and the three-dimensional coordinates of the corresponding nodes, obtain the plastic strain, calculate the stress triaxiality, and substitute it into the damage evolution equation to calculate the damage value;

[0100] Step (3): Input the three-dimensional coordinates and damage values of the nodes into the visualization software to create a damage evolution nephogram that changes with the medium pressure.

[0101] In this embodiment, the damage evolution nephogram in step 8 needs to be verified and analyzed in combination with the evolution of defects and microcracks in the burn-through test to illustrate the reliability of the numerical simulation prediction results. Exemplarily, the comparison between the predicted value of the modified Bonora model (in this application) and the test / theoretical value is shown in Table 1 below:

[0102]

[0103] In this embodiment, the burn-through threshold in step 9 is the maximum medium pressure that the pipeline can withstand under a specific welding current (or heat input).

[0104] As Figure 3 shown, this application provides an electronic device 1000, which includes a memory 1002 and a processor 1001. A computer program or instruction is stored in the memory 1002. When the computer program or instruction is executed by the processor 1001, it is at least used to implement the above method. As Figure 4 shown, this application provides a computer-readable storage medium 1100. A computer program or instruction is stored in the computer-readable storage medium 1100. When the computer program or instruction is executed by the processor, it is at least used to implement the above method.

[0105] Working principle and beneficial effects of the above technical solutions:

[0106] 1. In-service welding burn-through is essentially a high-temperature deformation and fracture problem under the coupled action of multi-physical fields of welding and the medium pressure in the pipe. Its dynamic failure process occurs inside the high-temperature metal and undergoes dynamic evolution processes such as micro-defect initiation, micro-crack evolution, and macro-crack propagation. Finding characteristic parameters that can comprehensively consider the multi-field coupling effect of in-service welding and can quantitatively evaluate the risk of in-service welding burn-through is the key to the research on burn-through instability safety criteria. Damage mechanics can give a quantitative solution for burn-through based on the results of welding finite element simulation and damage theory under the premise of comprehensively considering the multi-field coupling effect. This application introduces the Bonora damage model to study the distribution law and evolution behavior of damage during the in-service welding burn-through process, taking the damage factor as a new characteristic parameter for evaluating in-service welding burn-through, providing a new way to evaluate the risk of in-service welding burn-through.

[0107] 2. By introducing the Bonora damage model, this application can study the distribution law and evolution behavior of damage during the in-service welding burn-through process and give a dynamic evolution nephogram of the process from damage evolution to burn-through, which provides guidance for studying the evolution behavior of micro-defects and micro-cracks during the in-service welding burn-through process.

[0108] 3. After introducing the Bonora damage model in this application, considering the misjudgment phenomenon caused by the inability to distinguish between tensile and compressive stress states in the stress triaxiality term of the original Bonora model, taking the radial stress (absolute value) greater than the yield strength as the discriminant condition for damage initiation and embedding it into the damage model not only eliminates the misjudgment phenomenon, but also realizes the organic integration of the in-service welding burn-through mechanism and the prediction method, thus giving a more accurate quantitative prediction value of the burn-through risk.

[0109] Obviously, the above embodiments are only for illustrating the technical concept and features of this application, and their purpose is to enable those familiar with this technology to understand the content of this application and implement it accordingly. It is not intended to limit the protection scope of this application. Any equivalent changes or modifications made according to the spirit and essence of this application should be covered within the protection scope of this application.

Claims

1. A damage prediction method for pipeline in-service welding burn-through, characterized in that: include: Determine the damage parameter data of the target pipeline at different temperatures and different strain rates; constructing a Bonora damage model of the target pipeline based on the damage parameter data; Solving the Bonora damage model and its corresponding constitutive parameter expressions to obtain the damage evolution equation of the target pipeline; The damage evolution equation is modified based on finite element simulation of in-service welding of pressurized pipelines; In-service pipeline welding damage failure prediction is carried out based on the modified damage evolution equation.

2. The method according to claim 1, characterized in that Determine the damage parameter data of the target pipeline at different temperatures and strain rates, including: High temperature tensile specimens were prepared using target pipeline materials; Performing a high temperature tensile test based on the high temperature tensile specimen; After the volume of the non-uniform deformation zone of the high-temperature tensile specimen is equivalent to the volume of the uniform deformation zone, the fracture strain values ​​at different temperatures are calculated; The strain corresponding to the highest point of the load-stroke curve is taken as the initial damage threshold strain; Based on the Lemaitre damage theory, the critical damage value is calculated using a critical damage value calculation formula; wherein the critical damage value calculation formula includes: Among them, D cr represents the critical damage value of the target pipeline; σ R Represents the engineering fracture stress of the target pipeline; σ u Indicates the peak stress of the target pipe.

3. The method according to claim 2, characterized in that Constructing a Bonora damage model of the target pipeline based on the damage parameter data includes: Assuming that the effects of temperature and strain rate on the critical damage value are uncoupled, the rheological stress, temperature and strain rate of the target pipeline are characterized and solved based on the Arrhenius equation and the damage parameter data, the deformation activation energy and damage parameter expressions of the target pipeline are determined, and the Bonora damage model is obtained.

4. The method according to claim 3, characterized in that The damage evolution equation includes an initial damage threshold strain equation, a critical damage threshold strain equation, a critical damage value equation, a stress triaxiality equation and a damage dynamic evolution equation.

5. The method according to claim 4, characterized in that The damage evolution equation is modified based on the finite element simulation of in-service welding of pressurized pipelines, including: Construct a finite element mesh model of a pressurized steel pipe according to the size of the target pipeline; Determine the boundary conditions of the finite element mesh model according to the parameters of the target pipeline, and perform numerical simulation of the temperature field and stress field on the finite element mesh model; Compare the numerical simulation results with the actual data to determine the reliability of the numerical simulation results; When it is determined that the numerical simulation result is reliable, the absolute value of radial stress greater than the yield strength is embedded in the Bonora damage model as a judgment condition for damage initiation, and the damage evolution equation of the target pipeline is corrected.

6. The method according to claim 5, characterized in that The method predicts pipeline in-service welding damage failure based on the modified damage evolution equation, including: importing the temperature field and stress field data simulation results of the finite element mesh model into the modified damage evolution equation to determine the damage evolution of the target pipeline during in-service welding.

7. The method according to claim 6, characterized in that Based on the modified damage evolution equation, the in-service pipeline welding damage failure prediction is carried out, which also includes: The damage value of the area where the temperature is higher than the threshold in the temperature field simulation data is set to zero, the numerical simulation results of the stress field and the corresponding node coordinates are extracted, the plastic strain is obtained, and the stress triaxiality is calculated, and then substituted into the modified damage evolution equation to calculate the damage value; Based on the corresponding node coordinates of the stress field simulation data and the calculated damage values, a damage evolution diagram of the target pipeline as the medium pressure changes is constructed.

8. The method according to claim 1, characterized in that After predicting the in-service welding damage failure of the pipeline based on the modified damage evolution equation, it also includes: comparing the in-service welding damage failure prediction results of the pipeline with the pipeline burn-through test results to determine the reliability of the in-service welding damage failure prediction results of the pipeline.

9. An electronic device, characterized in that: The method comprises a memory and a processor, wherein the memory stores a computer program or instruction, and when the computer program or instruction is executed by the processor, it is used to implement at least the method described in any one of claims 1 to 8.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program or instruction, and when the computer program or instruction is executed by a processor, it is used to implement at least the method according to any one of claims 1 to 8.

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