A method and device for estimating the probability of explosion failure of a submarine pipeline with complex defects

Abstract

The present invention provides a method for estimating the probability of explosion failure of a submarine pipeline with complex defects. The estimation method includes: generating a pipeline entity model with a specified corrosion defect form in combination with Boolean operations based on the material information, geometric information, size information of corrosion defects, specific forms of corrosion defects and spacing information of the submarine pipeline; constructing and solving a finite element numerical model of the submarine pipeline using the pipeline entity model, and extracting the limit explosion pressure at the same time; coding and encapsulating the construction, solution and extraction processes of the finite element numerical model and the limit explosion pressure to obtain a finite element numerical analysis script; and performing failure simulation using the finite element numerical analysis script to determine the explosion failure probability value of the corrosion defects of the submarine pipeline. The explosion failure probability calculated by this method is more accurate, making the safety design of the pipeline more precise and avoiding potential safety risks.

Description

Technical Field

[0001] The invention relates to the technical field of submarine oil and gas pipelines, and in particular to a method and device for estimating the explosion failure probability of a submarine pipeline with complex defects. Background Art

[0002] Submarine pipelines are the "lifeline" of the marine oil and gas development industry. As a medium connecting submarine facilities and onshore terminals, they undertake the important task of transporting resources. During their service, they bear harsh environmental loads. Once a submarine pipeline fails, it will bring immeasurable economic losses and environmental pollution. Among them, corrosion is the main cause of submarine pipeline failure. The ultimate bursting pressure of the structure of pipelines with corrosion defects is weakened, and they are prone to burst failure under the action of working internal pressure, resulting in crude oil leakage and even explosion accidents. From the perspective of risk prevention and control, it is necessary to accurately estimate the failure probability of submarine pipelines with corrosion defects, so as to take reasonable protective measures to reduce the failure risk of marine oil and gas transportation systems.

[0003] At present, for submarine pipelines with a single defect form, the empirical formula in the current specification can calculate its ultimate bursting pressure more accurately, because the subsequent failure probability results are more reliable. However, there is currently no more effective solution for the failure probability of submarine pipelines with complex defects. Due to the interaction between different defects, the mechanical mechanism of pipeline structure failure becomes complicated, so the empirical formula obtained based on simplified assumptions cannot accurately estimate the ultimate bursting pressure of the structure. Therefore, for submarine pipelines with complex defect forms, it is generally necessary to estimate the ultimate bursting pressure of the structure through finite element numerical calculation, but this brings difficulties to the subsequent failure probability solution. Since the failure probability solution algorithm often requires a large number of iterative calculation processes, multiple numerical calculations are performed to obtain the ultimate bursting pressure under different conditions. The modeling process of numerical calculation is complicated and the calculation time is long, which ultimately leads to the inability to effectively calculate its failure probability. Summary of the invention

[0004] A major problem solved by the present invention is that the existing method for calculating the probability of explosion failure of a submarine pipeline with complex defect forms has large calculation amount and low calculation efficiency.

[0005] According to one aspect of the present invention, the present invention discloses a method for estimating the probability of explosion failure of a submarine pipeline with complex defects, the estimation method comprising:

[0006] According to the material information, geometric information, size information, specific form and spacing information of corrosion defects of the submarine pipeline, a pipeline entity model with the specified corrosion defect form is generated by combining Boolean operation;

[0007] The finite element numerical model of the submarine pipeline is constructed and solved by using the pipeline entity model, and the limit bursting pressure is extracted at the same time. The construction, solution and extraction process of the finite element numerical model and the limit bursting pressure are coded and packaged to obtain a finite element numerical analysis script;

[0008] The finite element numerical analysis script is used to perform failure simulation to determine the explosion failure probability value of the corrosion defect of the submarine pipeline.

[0009] Further, according to the material information, geometric information, size information, specific form of the corrosion defect and spacing information of the submarine pipeline, the pipeline entity model with the specified corrosion defect form is generated by combining Boolean operation, including the steps of:

[0010] Establish a defect-free pipeline model based on the geometric information of the submarine pipeline;

[0011] Establishing a corresponding corrosion defect entity model according to the size information of the corrosion defect of the submarine pipeline;

[0012] According to the specific form and spacing information of the corrosion defects, the defect-free pipeline model is mapped into a first entity in the assembly space, and the corrosion defect entity model is mapped into a second entity;

[0013] The position of the second entity relative to the first entity is adjusted, and the pipeline entity model having a specified corrosion defect form is generated through Boolean operation.

[0014] Furthermore, the pipeline entity model is used to construct a finite element numerical model of the submarine pipeline and solve it, and the ultimate bursting pressure is extracted at the same time. The construction, solution and ultimate bursting pressure extraction processes of the finite element numerical model are coded and packaged to obtain a finite element numerical analysis script including the following steps:

[0015] Performing regional division and mesh discretization on the pipeline entity model having the specified corrosion defect form;

[0016] Assigning material information of the submarine pipeline to the pipeline entity model after dividing the areas;

[0017] defining the analysis steps, as well as the boundary conditions and loads of the pipeline entity model after dividing the regions, solving the pipeline entity model using an arc length method solver, and calculating the ultimate bursting pressure;

[0018] The process of model construction, solution and calculation of limit bursting pressure is coded and packaged to obtain a finite element numerical analysis script.

[0019] Furthermore, adjusting the position of the second entity relative to the first entity and generating a pipeline entity model having a specified corrosion defect form through Boolean operation also includes the steps of:

[0020] If the corrosion defect is an axially distributed defect, two corrosion defect entity models are mapped in the assembly space, and through a translation operation, the distance between the two defect entities is made to be a first preset distance, and the two corrosion defect entity models are symmetrical along the central longitudinal section of the first entity;

[0021] The two translated corrosion defect entity models are subjected to Boolean operation to generate a pipeline entity model having a specified corrosion defect form and corresponding components.

[0022] Furthermore, adjusting the position of the second entity relative to the first entity and generating a pipeline entity model having a specified corrosion defect form through Boolean operation also includes the steps of:

[0023] If the corrosion defect is a circumferentially distributed defect, two corrosion defect entity models are mapped in the assembly space, and through a rotation operation, the distance between the two corrosion defect entity models is made to be a second preset distance, and the two corrosion defect entity models are symmetrical along the central cross section of the first entity;

[0024] The two rotated corrosion defect entity models are subjected to Boolean operation to generate a pipeline entity model having a specified corrosion defect form.

[0025] Furthermore, adjusting the position of the second entity relative to the first entity and generating a pipeline entity model having a specified corrosion defect form through Boolean operation also includes the steps of:

[0026] If the corrosion defect is a composite distribution defect, four corrosion defect entity models are mapped in the assembly space, and through translation and rotation operations, the spacing between two symmetrical corrosion defect entity models is 1 times the first preset distance, and the spacing between the other two symmetrical corrosion defect entity models is 2 times the second preset distance and 1 times the corrosion defect width, and the four corrosion defect entity models are symmetrical along the central longitudinal cross-section of the first entity;

[0027] The four translated and rotated corrosion defect entity models are subjected to Boolean operations to generate a pipeline entity model with a specified corrosion defect form.

[0028] Furthermore, using the finite element numerical analysis script to perform failure simulation and determine the failure probability value of the corrosion defect of the submarine pipeline includes the following steps:

[0029] Input random variables and select the initial central test point;

[0030] Based on the central test point, the central composite method is used to construct the test condition near the failure domain of the structure:

[0031] A random variable space is established with the central test point as the origin, and then for any random variable, a point on the positive and negative coordinate axes of the corresponding random variable space and the central test point are respectively taken as test points;

[0032] Calculate the response value corresponding to each test point using the finite element numerical analysis script;

[0033] Based on the test points and the response values, a least square method is used to fit the structural limit state surface;

[0034] Based on the fitted structural limit state surface, the initial design verification point is set equal to the mean value of each random variable, and the first-order second moment method is used for continuous iteration until the structural limit state surface meets the convergence condition, so as to obtain the structural design verification point and the corresponding reliability index.

[0035] Furthermore, the random variable includes a distribution type, a mean, and a coefficient of variation.

[0036] Furthermore, the convergence condition is:

[0037] The Euclidean distance between the design verification point and the central test point obtained by two iterations is less than a set threshold.

[0038] According to another aspect of the present invention, there is also disclosed a device for estimating the probability of explosion failure of a submarine pipeline with complex defects, the device being used to implement any of the above-mentioned estimation methods, the device comprising:

[0039] A data acquisition module is used to collect material information, geometric information, size information of corrosion defects, specific forms of corrosion defects and spacing information of corrosion defects of submarine pipelines;

[0040] A modeling module is used to generate a pipeline entity model with a specified corrosion defect form according to the material information, geometric information, size information, size information of the submarine pipeline, specific form of the corrosion defect and spacing information of the corrosion defect, combined with Boolean operations; calculate the ultimate bursting pressure of the submarine pipeline using the pipeline entity model, extract a script for calculating the ultimate bursting pressure, encapsulate the script after coding, and obtain a finite element numerical model;

[0041] The simulation calculation module is used to perform failure simulation based on the finite element numerical analysis script to determine the explosion failure probability value of the corrosion defect of the submarine pipeline.

[0042] The present invention couples finite element numerical calculation with failure probability algorithm through scripting language, constructs the limit state surface of the pipeline structure by setting a finite number of numerical calculations near the failure domain of the structure, and then continuously approaches the real failure probability of the structure through the failure path search algorithm, thereby making the safety design of the pipeline more accurate and avoiding potential safety risks. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The accompanying drawings, which constitute a part of the specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

[0044] Figure 1 The schematic diagram of the design of establishing a normalized model for finite element numerical calculation of a corroded pipeline in an embodiment of the present invention.

[0045] Figure 2 Schematic diagram of the coding process of numerical calculation scripts in an embodiment of the present invention.

[0046] Figure 3 In the embodiment of the present invention, the defect-free pipeline model part p and corrosion defect part d Mapped into corresponding entities in the assembly space p and ins d Schematic diagram of .

[0047] Figure 4 It is a schematic diagram of adjusting the relative position of the corrosion defect entity model in an embodiment of the present invention. DETAILED DESCRIPTION

[0048] Various exemplary embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings. It should be noted that unless otherwise specifically stated, the relative arrangement of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present invention.

[0049] At the same time, it should be understood that for the convenience of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship.

[0050] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

[0051] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

[0052] Technologies, methods, and apparatus known to ordinary technicians in the relevant field may not be discussed in detail, but where appropriate, such technologies, methods, and apparatus should be considered part of the authorization specification.

[0053] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0054] It should be noted that like reference numerals and letters refer to similar items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0055] Embodiment 1, the implementation steps of the method for estimating the explosion failure probability of a submarine pipeline with complex defects in this embodiment include two parts, namely: 1. Establishing a standardized and coded model for finite element numerical calculation of corroded pipelines; 2. Establishing a coupling model of the finite element numerical model and the failure probability search algorithm. The modeling and solution of the finite element numerical calculation in the present invention are completed based on the large-scale general finite element program Abaqus platform.

[0056] Specifically, combined Figure 1 , the establishment of the standardized and coded model of the finite element numerical calculation of the corrosion pipeline includes the following steps:

[0057] 1.1 Establish a standardized model for finite element numerical calculation of corroded pipelines. The specific steps include:

[0058] S1. Determine the geometric information and material information of the pipeline, including the outer diameter D and the wall thickness t of the pipeline. Studies have shown that the length of the pipeline model is l p =6D, the convergent numerical simulation results can be obtained; the pipeline yield strength σ y , pipeline ultimate tensile strength σ uts .

[0059] S2. Create defect-free pipeline components based on the pipeline’s geometric information p .

[0060] S3. Determine the size information of the corrosion defect, including the corrosion defect length l, the corrosion defect width w, and the corrosion defect depth d.

[0061] S4. According to the size information of the corrosion defect, Figure 1 The method shown establishes the corresponding corrosion defect entity model part d .

[0062] S5. Determine the specific form and spacing information of corrosion defects, such as Figure 3 As shown, the defect-free pipeline model part p and corrosion defect part d Mapped into corresponding entities in the assembly space p and ins dSchematic diagram: Figure 3 (a) is axially distributed corrosion, so the axial spacing s of the corrosion defects needs to be determined. l ; Figure 3 (b) For circumferential distribution, the circumferential spacing s of the corrosion defects needs to be determined c ; Figure 3 (c) For composite distribution defects, the axial spacing s of the corrosion defects must be determined at the same time. l and circumferential defects c .

[0063] S6. According to the specific form of corrosion defects and corresponding defects, the defect-free pipeline model part p and corrosion defect part d Mapped into corresponding entities in the assembly space p and ins d , adjust the relative position of the corrosion defect entity model, and perform Boolean operations to generate a pipeline entity with the specified corrosion defect form. p,d .

[0064] In some embodiments, step S6 further includes the following steps:

[0065] like Figure 4 As shown, the relative position diagram of the adjusted corrosion defect entity model.

[0066] exist Figure 4 In (a), if the corrosion defect is an axially distributed defect, then a 2× corrosion defect solid model ins is mapped in the assembly space. d,1 ,ins d,2 Through translation operation, the distance between the two corrosion defect models is s. l , and symmetrically along the central longitudinal section B-B' of the defect-free pipeline. Finally, the above two entities are Boolean operated to generate a pipeline entity ins with the specified corrosion defect form. p,d And the corresponding parts p,d ;

[0067] Figure 4 In (b), if it is a circumferentially distributed defect, the 2× corrosion defect solid model ins is mapped in the assembly space. d,1 ,ins d,2 Through the rotation operation, the distance between the two defect entities is s c , and symmetrically along the central cross section A-A' of the defect-free pipeline, and finally perform Boolean operations on the above entities to generate a pipeline entity ins with the specified corrosion defect form p,d And the corresponding parts p,d ;

[0068] Figure 4In (c), if it is a composite distribution defect, the 4× corrosion defect solid model ins is mapped in the assembly space d,1 ,ins d,2 ,ins d,3 ,ins d,4 Through translation and rotation operations, the defect entity ins d,1 ,ins d,2 The spacing is (s l ), and is symmetrical along the central longitudinal section B-B' of the defect-free pipe. d,3 ,ins d,4 The spacing is (2×s c +w), and symmetrically along the central cross section A-A' of the defect-free pipeline. Finally, the above entities are Boolean operated to generate a pipeline solid model with the specified corrosion defect form. p,d And the corresponding parts p,d .

[0069] S7. Divide the generated pipeline entity model with corrosion defects into regions.

[0070] S8. Grid division: lay out grid seeds and divide the grid.

[0071] S9. Set definition: Define the node set Set-cor for the surface inside the corrosion area, define the node set Set-end for both ends of the pipeline, and define the surface set Surf-load for the inner surface of the pipeline.

[0072] S10. Assign material properties of the pipeline to the pipeline model with corrosion defects.

[0073] S11. Define the analysis steps and use the arc length method Riks solver.

[0074] S12. Boundary condition definition: impose fixed constraints on the node sets Set-end at both ends of the pipeline.

[0075] S13. Load definition: Apply unit pressure to the surface set Surf-load on the inner surface of the pipe.

[0076] S14, calculating and solving the pipeline model in step 10.

[0077] S15. Read the calculated ultimate bursting pressure p u :Read the calculation result file (*.ODB) and obtain the variation curve of the Mises stress of the surface node set Set-cor nodes in the corrosion area with the applied internal pressure. When the Mises stress of any node in the set is equal to the ultimate tensile strength σ of the material uts When the corresponding internal pressure is the ultimate bursting pressure p of the submarine pipeline structure u .

[0078] 1.2 Numerical calculation script coding, combined with Figure 2 , the specific steps include:

[0079] S1. Script language reading: perform operations according to the model calculation process of steps S1-S15. After the operations are completed, read the replay file (*.rpy). The information recorded in the file is the script language corresponding to each of the above operations.

[0080] S2. Script coding: Arrange the above script language according to the logical relationship of steps S1-S15 to obtain the code of the entire calculation process. Modify the arranged code and encapsulate it into a function of input variables as needed. The function is the mathematical expression of the finite element numerical model. For example, if the input variables are the aforementioned pipeline geometry information, material information and corrosion defect size, the function can be expressed as p u = script(x),x = (D, t, σ y ,σ uts ,l,w,d).

[0081] 2. Establish a coupling model between the finite element numerical model and the failure probability search algorithm. The specific steps include:

[0082] S1. Determine the random variables that need to be considered and their statistical characteristics, including distribution type, mean μ, and coefficient of variation cv.

[0083] S2. According to the random variables and statistical characteristics, select the initial central test point according to formula (1):

[0084]

[0085] in, is the center point of the i-th random variable, μ i is the mean of the i-th random variable, m is the number of iterations, m=0 at the initial moment, n is the number of random variables, and i is the subscript of the current random variable.

[0086] S3. Based on the central test point, a series of test conditions are constructed near the failure domain of the submarine pipeline structure using the composite center design method: a random variable space is established with the central test point as the origin. First, its coordinate origin (central test point) is taken as the test point. Then, for each random variable x i , take each point on the positive and negative coordinate axes as the test point, and the specific expression is shown in formula (2):

[0087]

[0088] in, is the jth test point in the mth iteration process, σ iis the standard deviation of the ith random variable, and j is the subscript of the current test point.

[0089] Substitute the above test points into the finite element numerical calculation function p established in the previous step u =script(·), the response value of the corresponding test point can be obtained. The specific expression is shown in formula (3):

[0090]

[0091] in, is the ultimate bursting pressure of the pipeline corresponding to the jth test point in the mth iteration process.

[0092] S4. Select a quadratic polynomial containing cross terms as the basic form of the limit state surface of the submarine pipeline structure, as shown in formula (4). According to the test points and corresponding response information obtained above, The unknown coefficients a and b of the limit state surface of the submarine pipeline structure can be obtained by using the least squares method. i ,c i ,d i,j :

[0093]

[0094] in, is the limit state equation, is the structure function, x i is the ith random variable.

[0095] S5. Based on the fitted limit state surface, let the initial design verification point be equal to the mean value of each random variable, as shown in formula (5):

[0096] x d,i m =μ i (5)

[0097] Among them, x d,i m The component of the design verification point corresponding to the i-th random variable in the m-th iteration process;

[0098] The first-order second moment method is used to iterate continuously according to equations (6)-(8):

[0099]

[0100] in, is the equivalent normalized standard deviation of the ith random variable;

[0101]

[0102] Among them, β m is the reliability index;

[0103]

[0104] in, is the mean after normalization, is the sensitivity coefficient of the ith random variable, where

[0105] Iterate until the convergence condition of formula (9) is satisfied. The convergence condition is the two design verification points x obtained twice before and after. d m ,new and x d m,old The Euclidean distance of is less than the set threshold, and the design verification point x of the submarine pipeline structure can be obtained. d m And the corresponding reliability index β m :

[0106]

[0107] S6. Convergence judgment: Determine the design verification point x according to formula (10) d m and the central test point x d m If the condition is not met, a new central test point is obtained by interpolation according to formula (11), and then steps S2-S6 are repeated until the convergence requirement is met.

[0108]

[0109]

[0110] S7. Solving the failure probability: If the convergence condition is met, the failure probability of the submarine pipeline structure is solved according to formula (12):

[0111] P f =Φ(-β m ) (12)

[0112] Among them, P f is the calculated failure probability.

[0113] The technical effect of the present invention is further illustrated by example calculation below.

[0114] Before calculating the failure probability of the submarine pipeline, it is first necessary to verify the accuracy of the calculation results of the finite element numerical model established in Section 1.2 of Example 1.

[0115] The proposed script is used for numerical modeling and compared with the pipeline prototype test. The test parameters and comparison results are shown in Table 1.

[0116] Table 1 Comparison of ultimate bursting pressure results

[0117]

[0118] It can be seen that the results of finite element numerical calculations are very close to the experimental values ​​for both single defects and complex defects, with an average relative error of 2.09%. This comparison proves the accuracy of the finite element model established according to the proposed script and can be used for subsequent failure probability analysis.

[0119] Next, the failure probability of a high-strength submarine pipeline with corrosion defects is taken as an example to verify the applicability of the coupling algorithm proposed in the present invention. The geometric and material parameters of the pipeline are shown in Table 2:

[0120] Table 2 Geometric and material parameters of high-strength submarine pipelines

[0121]

[0122] The working pressure of the pipeline is p d =15MPa. The pipeline corrosion defects are considered to be circumferentially distributed defects, axially distributed defects, and compositely distributed defects. As a control group, the single defect is also calculated. The geometric parameters of the defects are shown in Table 3. According to the requirements of the model calculation accuracy, the pipeline model length is l = 6D:

[0123] Table 3 Corrosion defect size parameters

[0124]

[0125] In this example, the random variables considered are the pipe wall thickness t and the yield strength σ of the pipe steel material. y , the depth d of the corrosion defect, the statistical parameters of the above random variables are shown in Table 4:

[0126] Table 4 Statistical properties of random variables

[0127]

[0128] The method proposed in the present invention is used to calculate the failure probability of the pipeline under the above two defects, and the results are listed in Table 5:

[0129] Table 5 Failure probability calculation results

[0130]

[0131] Among them, for a single defect, the traditional method, namely the Monte-Carlo-DNV method, can also be used to estimate its failure probability. For a single defect, since the traditional method ignores the influence of pipeline structure nonlinearity, material nonlinearity and corrosion width when estimating structural response, there is a slight deviation in the failure probability of the two, but overall they are still very close, with a difference of 10 -8 The above results prove that the method proposed in this invention is quite reasonable. At the same time, the failure probability obtained by the two methods is 2×10 -8 This proves that the safety of the submarine pipeline structure is highly guaranteed.

[0132] For circumferentially distributed defects, the failure probability is slightly increased, about 8.08×10 -8 This result shows that the failure probability of circumferentially distributed defects is not significantly different from that of single defects, which can also be confirmed by relevant research literature. The structural bearing capacity of circumferentially distributed defects does not significantly decrease the structural bearing capacity of submarine pipelines with single defects, but as the corrosion spacing decreases, its bearing capacity will further decrease, so it is necessary to consider this factor.

[0133] As for axially distributed defects, due to the interaction between defects, the failure probability of the submarine pipeline structure is significantly greater than the results in the above two cases. -4 On the magnitude of.

[0134] At the same time, for composite distribution defects, the total area of ​​corrosion defects increases and the interaction between defects becomes more obvious, resulting in a further significant increase in the failure probability, which is about 3.71×10 -2 .

[0135] It can be seen from the above calculation results that the form of corrosion has a significant impact on the failure probability of the pipeline. If the above factors are not taken into account, it will cause potential risks to the pipeline structure.

[0136] In summary, the traditional method can only estimate the corrosion failure of pipelines with a single defect form. The method proposed in the present invention can estimate the corrosion failure probability of submarine pipelines with complex defect forms. The calculated results are more accurate and in line with the laws of objective facts, which can be fully proved by experiments and related literature, making the safety design of pipelines more accurate and avoiding potential safety risks.

[0137] 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 and improvements made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

[0138] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

Claims

1. A method for estimating the probability of explosion failure of a submarine pipeline with complex defects, characterized in that: The estimation method includes: According to the material information, geometric information, size information, specific form and spacing information of corrosion defects of the submarine pipeline, a pipeline entity model with the specified corrosion defect form is generated by combining Boolean operation; The finite element numerical model of the submarine pipeline is constructed and solved by using the pipeline entity model, and the limit bursting pressure is extracted at the same time. The construction, solution and extraction process of the finite element numerical model and the limit bursting pressure are coded and packaged to obtain a finite element numerical analysis script; Perform failure simulation using the finite element numerical analysis script to determine the explosion failure probability value of the corrosion defect of the submarine pipeline; According to the material information, geometric information, size information, specific form and spacing information of corrosion defects of the submarine pipeline, the pipeline entity model with the specified corrosion defect form is generated by combining Boolean operation, including the following steps: Establish a defect-free pipeline model based on the geometric information of the submarine pipeline; Establishing a corresponding corrosion defect entity model according to the size information of the corrosion defect of the submarine pipeline; According to the specific form and spacing information of the corrosion defects, the defect-free pipeline model is mapped into a first entity in the assembly space, and the corrosion defect entity model is mapped into a second entity; adjusting the position of the second entity relative to the first entity, and generating the pipeline entity model having a specified corrosion defect form through Boolean operation; The finite element numerical model of the submarine pipeline is constructed and solved by using the pipeline entity model, and the limit bursting pressure is extracted at the same time. The construction, solution and extraction process of the finite element numerical model and the limit bursting pressure are coded and packaged to obtain a finite element numerical analysis script, which includes the following steps: Performing regional division and mesh discretization on the pipeline entity model having the specified corrosion defect form; Assigning material information of the submarine pipeline to the pipeline entity model after dividing the areas; defining the analysis steps, as well as the boundary conditions and loads of the pipeline entity model after dividing the regions, solving the pipeline entity model using an arc length method solver, and calculating the ultimate bursting pressure; The process of model building, solving and calculating the limit bursting pressure is coded and packaged to obtain a finite element numerical analysis script; The finite element numerical analysis script is used to perform failure simulation to determine the failure probability value of the corrosion defect of the submarine pipeline, including the following steps: Input random variables and select the initial central test point; Based on the central test point, the central composite method is used to construct the test condition near the failure domain of the structure: A random variable space is established with the central test point as the origin, and then for any random variable, a point on the positive and negative coordinate axes of the corresponding random variable space and the central test point are respectively taken as test points; Calculate the response value corresponding to each test point using the finite element numerical analysis script; Based on the test points and the response values, a least square method is used to fit the structural limit state surface; Based on the fitted structural limit state surface, the initial design verification point is set equal to the mean value of each random variable, and the first-order second moment method is used for continuous iteration until the structural limit state surface meets the convergence condition, so as to obtain the structural design verification point and the corresponding reliability index.

2. The method for estimating the probability of explosion failure of a submarine pipeline with complex defects according to claim 1, characterized in that: Adjusting the position of the second entity relative to the first entity and generating a pipeline entity model with a specified corrosion defect form through Boolean operation also includes the steps of: If the corrosion defect is an axially distributed defect, two corrosion defect entity models are mapped in the assembly space, and through a translation operation, the distance between the two defect entities is made to be a first preset distance, and the two corrosion defect entity models are symmetrical along the central longitudinal section of the first entity; The two translated corrosion defect entity models are subjected to Boolean operation to generate a pipeline entity model having a specified corrosion defect form and corresponding components.

3. The method for estimating the probability of explosion failure of a submarine pipeline with complex defects according to claim 1, characterized in that: Adjusting the position of the second entity relative to the first entity and generating a pipeline entity model with a specified corrosion defect form through Boolean operation also includes the steps of: If the corrosion defect is a circumferentially distributed defect, two corrosion defect entity models are mapped in the assembly space, and through a rotation operation, the distance between the two corrosion defect entity models is made to be a second preset distance, and the two corrosion defect entity models are symmetrical along the central cross section of the first entity; The two rotated corrosion defect entity models are subjected to Boolean operation to generate a pipeline entity model having a specified corrosion defect form.

4. The method for estimating the probability of explosion failure of a submarine pipeline with complex defects according to claim 1, characterized in that: Adjusting the position of the second entity relative to the first entity and generating a pipeline entity model with a specified corrosion defect form through Boolean operation also includes the steps of: If the corrosion defect is a composite distribution defect, four corrosion defect entity models are mapped in the assembly space, and through translation and rotation operations, the spacing between two symmetrical corrosion defect entity models is 1 times the first preset distance, and the spacing between the other two symmetrical corrosion defect entity models is 2 times the second preset distance and 1 times the corrosion defect width, and the four corrosion defect entity models are symmetrical along the central longitudinal cross-section of the first entity; The four translated and rotated corrosion defect entity models are subjected to Boolean operations to generate a pipeline entity model with a specified corrosion defect form.

5. The method for estimating the probability of explosion failure of a submarine pipeline with complex defects according to claim 1, characterized in that: The random variable includes distribution type, mean and coefficient of variation.

6. The method for estimating the probability of explosion failure of a submarine pipeline with complex defects as claimed in claim 1, characterized in that: The convergence condition is: The Euclidean distance between the design verification point and the central test point obtained by two iterations is less than a set threshold.

7. An estimation device for the probability of explosion failure of a submarine pipeline with complex defects, characterized in that: The estimation device is used to implement the estimation method according to any one of claims 1 to 6, and the estimation device includes: A data acquisition module is used to collect material information, geometric information, size information of corrosion defects, specific forms of corrosion defects and spacing information of corrosion defects of submarine pipelines; A modeling module is used to generate a pipeline entity model with a specified corrosion defect form according to the material information, geometric information, size information, size information of the submarine pipeline, specific form of the corrosion defect and spacing information of the corrosion defect, combined with Boolean operations; calculate the ultimate bursting pressure of the submarine pipeline using the pipeline entity model, extract a script for calculating the ultimate bursting pressure, encapsulate the script after coding, and obtain a finite element numerical model; The simulation calculation module is used to perform failure simulation based on the finite element numerical analysis script to determine the explosion failure probability value of the corrosion defect of the submarine pipeline.

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