A method and system for evaluating the failure of a flexible composite pipe structure in a complex beach environment

Abstract

This invention provides a method and system for evaluating the failure of flexible composite pipe structures in complex coastal environments, relating to the field of flexible composite pipe failure evaluation technology. The method includes the following steps: S1, creating a model and parameters based on pipe-soil coupling; S2, calculating coastal environmental load parameters; S3, creating a mechanical model of the flexible composite pipe and performing three-dimensional numerical calculations to extract the deformation and stress of the flexible composite pipe; S4, designing multi-parameter combination schemes and analyzing the failure influence law; S5, creating a failure index evaluation model. The system includes a pipe-soil coupling calculation module, a coastal environmental load calculation module, a mechanical calculation and analysis module, a failure factor influence module, and a failure index evaluation module. The beneficial effects of this invention are: considering the influence of multiple parameters and environmental factors, the failure evaluation results are close to reality, and the accuracy and analysis efficiency are high.

Description

Technical Field

[0001] This invention relates to the field of failure evaluation technology for flexible composite pipes, and in particular to a method and system for failure evaluation of flexible composite pipe structures in complex coastal environments. Background Technology

[0002] The Shengli Beach Oilfield has various development modes, including shallow sea oilfield, open beach oilfield, and closed / semi-closed beach oilfield. Beach oilfields are characterized by harsh operating environments, complex geological conditions, and large pollution areas after pipeline leaks.

[0003] With the long-term large-scale development of oil fields, the water cut, chloride ion content, and salinity have increased year by year, leading to intensified corrosion within gathering and transportation pipelines. This is particularly pronounced in the alternating wet and dry, high-salt environment of the intertidal zone in offshore oilfields, where external corrosion is even more severe. Flexible composite pipelines possess excellent corrosion resistance and low hydraulic friction, are lightweight, can withstand high pressure, are not prone to scaling, and have a long service life. In recent years, they have been widely used in surface engineering construction for oil and gas field development, playing a crucial role in mitigating steel pipeline corrosion, saving on surface investment, and reducing maintenance costs. However, in the application of flexible composite gathering and transportation pipelines in offshore areas, extreme conditions such as ocean current scouring, hollowing out and exposure, floating deformation, sea ice impact, and storm surge damage occur, causing fracture and buckling failures of the flexible composite pipes. However, due to the complex environment of offshore oilfields, the evaluation methods for the structural failure of flexible composite pipes are unclear, and there is a lack of corresponding evaluation criteria, limiting the research and widespread application of the applicability of flexible composite pipes.

[0004] How to solve the above-mentioned technical problems is the challenge facing this invention. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a failure evaluation method for flexible composite pipe structures in complex coastal environments that considers multiple parameters and environmental factors, yields failure evaluation results that closely approximate reality, and offers high accuracy and analytical efficiency.

[0006] The technical solution adopted by this invention to solve its technical problem is as follows: On the one hand, this invention provides a failure evaluation method for flexible composite pipe structures in complex coastal environments, including the following steps:

[0007] S1. Based on the design objectives and design scenario, create a model based on pipe-soil coupling;

[0008] S2. Determine the type of marine environmental load and calculate the marine environmental load;

[0009] S3. Create a mechanical model of the flexible composite pipe and perform three-dimensional numerical calculations to extract the deformation and stress of the flexible composite pipe.

[0010] S4. Design multi-parameter combination schemes and analyze the failure impact patterns;

[0011] S5. Based on the influence of each parameter on the failure of the flexible composite pipe, create a failure index evaluation model;

[0012] S6. Input the parameters of the flexible composite pipe into the failure index evaluation model to determine whether it has failed.

[0013] Preferably, step S1 specifically involves: inputting the design objective and design scenario into the pipe-soil coupling calculation module, and creating a model based on pipe-soil coupling, including a flexible composite pipe geometric model, a material model, a surrounding soil spring model, and a boundary equivalent spring model.

[0014] Preferably, in step S1, the boundary equivalent spring model of the flexible composite pipe is determined based on the sliding friction between the flexible composite pipe and the surrounding soil spring model, the area of ​​the flexible composite pipe, the elastic modulus of the flexible composite pipe material, and the equivalent spring elongation of the flexible composite pipe. The calculation method is as follows:

[0015]

[0016] In the formula, F is the external force on the boundary equivalent spring; f S ΔL is the sliding friction force between the flexible composite pipe per unit length and the soil; A is the cross-sectional area of ​​the flexible composite pipe; E is the elastic modulus of the flexible composite pipe; ΔL is the equivalent spring elongation at the boundary.

[0017] Preferably, the types of marine environmental loads in step S2 include sea ice loads, ocean current loads, and ocean wave loads, wherein,

[0018] The method for calculating sea ice load is as follows:

[0019] F = αWhσ C

[0020] In the formula, F is the sea ice breaking pressure / the ultimate force of sea ice acting on the flexible composite pipe; W is the width of the sea ice extrusion surface; h is the sea ice thickness; σ c denoted as uniaxial compressive strength of sea ice; α is a correction factor for various factors affecting sea ice force, with a value of 0.9.

[0021] The calculation method for ocean current load is as follows:

[0022]

[0023] In the formula, f C C represents the ocean current load per unit length of the flexible composite pipe. D This is the drag coefficient; ρ is the maximum possible velocity of the ocean current; g is the acceleration due to gravity; wD is the density of seawater; D is the diameter of the flexible composite pipe.

[0024] The method for calculating wave load is as follows:

[0025]

[0026] In the formula, f wy ρ is the wave force per unit length acting perpendicularly on the flexible composite pipe. W D is the density of seawater; D is the diameter of the flexible composite pipe; μ is the horizontal velocity of a water particle at the axis of the flexible composite pipe; C D C is the drag coefficient; M This is the inertial force coefficient.

[0027] Preferably, the ocean current load and the ocean wave load adopt a fully turbulent model.

[0028] Preferably, step S3 specifically includes:

[0029] S30, the model mesh generation module of the mechanical calculation and analysis module divides the geometric model and material model of the flexible composite pipe into a numerical calculation mesh model;

[0030] S31. The load and boundary application module obtains the boundary equivalent spring model and beach environment load of the flexible composite pipe and applies the boundary equivalent spring model and beach environment load to the numerical calculation mesh model.

[0031] S32. The tube-soil elastoplastic analysis module selects the large deformation nonlinear analysis algorithm for the flexible composite tube and surrounding soil spring model, and determines the number of load calculation steps and iteration time.

[0032] S33. The mechanical calculation module creates a mechanical model of the flexible composite pipe and performs three-dimensional numerical calculations based on the numerical calculation mesh model with applied boundary equivalent spring model and beach and sea environment load, the large deformation nonlinear analysis algorithm of flexible composite pipe and surrounding soil spring model, load calculation steps and iteration time.

[0033] S34, Deformation and Stress Analysis Module, extracts the deformation and stress of the flexible composite pipe from the three-dimensional numerical calculation results.

[0034] Preferably, the three-dimensional numerical calculation in step S33 adopts the progressive damage model NP criterion.

[0035] Preferably, step S4 specifically includes:

[0036] S40, the failure factor influence module designs a multi-parameter combination scheme of flexible composite pipe geometric model parameters, material model parameters, boundary equivalent spring model parameters, surrounding soil spring model parameters and beach and sea environment load parameters through orthogonal experimental methods;

[0037] S41. Based on the deformation and stress of the flexible composite pipe under multiple parameter combinations, the influence of the geometric model parameters, material model parameters, boundary equivalent spring model parameters, surrounding soil spring model parameters, and beach and sea environment load parameters of the flexible composite pipe on the failure of the flexible composite pipe structure is analyzed using data analysis software.

[0038] Preferably, in step S5, a data fitting method is used to create a failure index evaluation model for flexible composite pipes.

[0039] On the other hand, the present invention provides a failure evaluation system for flexible composite pipe structures in complex beach and sea environments, including a pipe-soil coupling calculation module, which creates a flexible composite pipe geometric model, material model, boundary equivalent spring model and surrounding soil spring model based on pipe-soil coupling.

[0040] A beach and sea environmental load calculation module, which determines the type of beach and sea environmental load and calculates the beach and sea environmental load;

[0041] The mechanical calculation and analysis module includes a model mesh generation module, a load and boundary application module, a soil-tube elastoplastic analysis module, a mechanical calculation module, and a deformation and stress analysis module.

[0042] The model mesh generation module divides the geometric and material models of the flexible composite pipe into numerical computation meshes; the load and boundary application module obtains the boundary equivalent spring model and marine environmental load of the flexible composite pipe and applies them to the numerical computation mesh; the pipe-soil elastoplastic analysis module selects a large deformation nonlinear analysis algorithm for the flexible composite pipe and surrounding soil spring model, and determines the number of load calculation steps and iteration time; the mechanical calculation module performs three-dimensional numerical calculations on the numerical computation mesh; and the deformation and stress analysis module extracts the deformation and stress conditions of the flexible composite pipe from the calculation results of the numerical computation mesh.

[0043] The failure factor influence module designs a multi-parameter combination scheme through orthogonal experimental methods and analyzes the influence of each parameter on the failure of the flexible composite pipe structure.

[0044] The failure index evaluation module creates a failure index evaluation model for flexible composite pipes through data fitting.

[0045] The beneficial effects of this invention are as follows: It provides a quantitative standard for the failure evaluation of flexible composite pipes. Considering the influence of multiple parameters and environmental factors, the failure evaluation results are close to reality, with high accuracy and analysis efficiency. By comprehensively considering the interaction between the flexible composite pipe and its surrounding environment, a fully turbulent flow model is used for ocean currents and waves, and the NP principle of the progressive damage model is employed for three-dimensional numerical calculations, greatly improving the accuracy of the calculations and making the failure evaluation results closer to reality. A multi-parameter combination scheme is designed using orthogonal experimental methods, and the influence of each parameter on the failure of the flexible composite pipe under the multi-parameter combination scheme is analyzed using SPSSAU data analysis software, effectively improving analysis efficiency. A failure index evaluation model is created using data fitting methods, providing a quantitative standard for whether the flexible composite pipe has failed. This helps to take timely measures to prevent fracture and buckling failure of the flexible composite pipe, reduce environmental pollution and production interruptions caused by pipeline failure, and ensure the safe production and stable operation of the coastal oilfield. Attached Figure Description

[0046] Figure 1 This is a diagram illustrating the method steps of the present invention.

[0047] Figure 2 This is a system architecture diagram of the present invention.

[0048] Figure 3 This is a schematic diagram of the numerical computation grid model of the present invention.

[0049] Figure 4 This is a schematic diagram of the mechanical model of the present invention.

[0050] The attached figures are labeled as follows: 1. Surrounding soil spring; 2. Boundary equivalent spring; 3. Buried section flexible composite pipe; 4. Exposed section flexible composite pipe; 5. Beach and sea environment load. Detailed Implementation

[0051] To clearly illustrate the technical features of this solution, the following detailed implementation method will be used to explain the solution.

[0052] Example 1:

[0053] See Figure 1-4 As shown, this embodiment provides a failure evaluation method for flexible composite pipe structures in complex coastal environments, including the following steps: S1. Based on the design objectives and design scenario, create a model based on pipe-soil coupling: Input the design objectives and design scenario into the pipe-soil coupling calculation module, and the pipe-soil coupling calculation module generates a geometric model, material model, boundary equivalent spring model, and surrounding soil spring model of the flexible composite pipe based on pipe-soil coupling. The boundary equivalent spring model of the flexible composite pipe is determined based on the sliding friction between the flexible composite pipe and the surrounding soil spring model, the area of ​​the flexible composite pipe, the elastic modulus of the flexible composite pipe material, and the elongation of the boundary equivalent spring. The calculation method is as follows:

[0054]

[0055] In the formula, F is the external force on the boundary equivalent spring; f S ΔL is the sliding friction force between the flexible composite pipe per unit length and the soil; A is the cross-sectional area of ​​the flexible composite pipe; E is the elastic modulus of the flexible composite pipe; ΔL is the equivalent spring elongation at the boundary.

[0056] Table 1 below shows the parameter values ​​for the geometric model, material model, boundary equivalent spring model, and surrounding soil spring model of the flexible composite pipe in this embodiment.

[0057] Table 1. Partial Parameter Values

[0058]

[0059]

[0060] S2. Determine the types of beach and sea environmental loads and calculate the beach and sea environmental loads: In step S2, the types of beach and sea environmental loads include sea ice loads, ocean current loads, and ocean wave loads.

[0061] The method for calculating sea ice load is as follows:

[0062] F = αWhσ C

[0063] In the formula, F is the sea ice breaking pressure / the ultimate force of sea ice acting on the flexible composite pipe; W is the width of the sea ice extrusion surface; h is the sea ice thickness; σ c denoted as uniaxial compressive strength of sea ice; α is a correction factor for various factors affecting sea ice force, with a value of 0.9.

[0064] The calculation method for ocean current load is as follows:

[0065]

[0066] In the formula, f C C represents the ocean current load per unit length of the flexible composite pipe. D This is the drag coefficient; ρ is the maximum possible velocity of the ocean current; g is the acceleration due to gravity; w D is the density of seawater; D is the diameter of the flexible composite pipe.

[0067] The method for calculating wave load is as follows:

[0068]

[0069] In the formula, f wy ρ is the wave force per unit length acting perpendicularly on the flexible composite pipe. WD is the density of seawater; D is the diameter of the flexible composite pipe; μ is the horizontal velocity of a water particle at the axis of the flexible composite pipe; C D C is the drag coefficient; M This is the inertial force coefficient.

[0070] The ocean current load and wave load are modeled using a fully turbulent flow model.

[0071] S3. Create a mechanical model of the flexible composite pipe and perform three-dimensional numerical calculations to extract the deformation and stress of the flexible composite pipe:

[0072] S30, the model mesh generation module of the mechanical calculation and analysis module divides the geometric model and material model of the flexible composite pipe into a numerical calculation mesh model;

[0073] S31. The load and boundary application module obtains the boundary equivalent spring model and beach environment load of the flexible composite pipe and applies the boundary equivalent spring model and beach environment load to the numerical calculation mesh model.

[0074] S32. The tube-soil elastoplastic analysis module selects the large deformation nonlinear analysis algorithm for the flexible composite tube and surrounding soil spring model, and determines the number of load calculation steps and iteration time.

[0075] The deformation of the surrounding soil spring model includes the elastic deformation stage, the elastoplastic deformation stage, and the plastic deformation stage.

[0076] S33. The mechanical calculation module creates a mechanical model of the flexible composite pipe based on the numerical calculation mesh model with applied boundary equivalent spring model and beach and sea environment load, the large deformation nonlinear analysis algorithm of the flexible composite pipe and surrounding soil spring model, the load calculation steps and iteration time, and performs three-dimensional numerical calculation using the NP criterion of the progressive damage model.

[0077] like Figure 4 As shown, in the mechanical model of the flexible composite pipe, the flexible composite pipe is divided into a buried section flexible composite pipe 3 and a bare section flexible composite pipe 4. The buried section flexible composite pipe 3 is subjected to the force of the surrounding soil spring 1 and the force of the boundary equivalent spring 2, while the bare section flexible composite pipe 4 is subjected to the force of the beach and sea environment load 5.

[0078] S34. The deformation and stress analysis module extracts the deformation and stress of the flexible composite pipe from the three-dimensional numerical calculation results.

[0079] S4. Design multi-parameter combination schemes and analyze the failure impact patterns:

[0080] S40, the failure factor influence module designs a multi-parameter combination scheme of flexible composite pipe geometric model parameters, material model parameters, boundary equivalent spring model parameters, surrounding soil spring model parameters and beach and sea environment load parameters through orthogonal experimental methods;

[0081] S41. Based on the deformation and stress of the flexible composite pipe under multiple parameter combinations, the influence of the geometric model parameters, material model parameters, boundary equivalent spring model parameters, surrounding soil spring model parameters, and beach and sea environment load parameters on the failure of the flexible composite pipe structure is analyzed using SPSSAU data analysis software. Taking the inner wall thickness, pipe diameter-to-thickness ratio, and pipe working pressure as examples, Table 2 shows the influence range of these parameters on the failure evaluation index under different values; Table 3 shows the influence weight of beach and sea environment load on the failure evaluation index.

[0082] Table 2 shows the range of influence of different parameter values ​​on failure evaluation indicators.

[0083]

[0084] Table 3. Weights of the Influence of Beach and Marine Environmental Loads on the Failure Evaluation Indicators of Flexible Composite Pipes

[0085]

[0086] S5. Create Failure Index Evaluation Model: The failure index evaluation module creates evaluation models for three failure indices of the flexible composite pipe structure based on the influence of the geometric model parameters, material model parameters, boundary equivalent spring model parameters, surrounding soil spring model parameters, and beach and sea environment load parameters on the failure of the flexible composite pipe structure. The module uses data fitting to create evaluation models for the buckling deformation, shear stress, and yield stress of the flexible composite pipe.

[0087] S6. Input the parameters of the flexible composite pipe into the failure index evaluation model to determine whether it has failed.

[0088] This embodiment also provides a failure evaluation system for flexible composite pipe structures in complex beach and sea environments, including a pipe-soil coupling calculation module, which is used to create a flexible composite pipe geometric model, material model, boundary equivalent spring model and surrounding soil spring model based on pipe-soil coupling.

[0089] The beach and sea environmental load calculation module is used to determine the type of beach and sea environmental load and calculate the beach and sea environmental load.

[0090] The mechanical calculation and analysis module includes a model mesh generation module, used to divide the geometric and material models of the flexible composite pipe into numerical calculation meshes; a load and boundary application module, used to obtain the boundary equivalent spring model and marine environmental load of the flexible composite pipe and apply the boundary equivalent spring model and marine environmental load to the numerical calculation mesh; a pipe-soil elastoplastic analysis module, used to select a large deformation nonlinear analysis algorithm for the flexible composite pipe and surrounding soil spring model, and determine the load calculation steps and iteration time; a mechanical calculation module, used to perform three-dimensional numerical calculations on the numerical calculation mesh; and a deformation and stress analysis module, used to extract the deformation and stress of the flexible composite pipe from the calculation results of the numerical calculation mesh.

[0091] The failure factor influence module is used to design multi-parameter combination schemes through orthogonal experimental methods and analyze the influence of each parameter on the failure of flexible composite pipe structures.

[0092] The failure index evaluation module is used to create evaluation models for three failure indices: buckling deformation, shear stress, and yield stress.

[0093] Example 2:

[0094] See Figure 1 , Figure 3 , Figure 4 As shown in the figure, this embodiment provides a failure evaluation method for flexible composite pipe structures in complex coastal environments, including the following steps:

[0095] S1. Based on the design goals and design scenario, create a model and parameters based on pipe-soil coupling: Input the design goals and design scenario into the pipe-soil coupling calculation module, and the pipe-soil coupling calculation module will generate a flexible composite pipe geometric model, material model, boundary equivalent spring model and surrounding soil spring model based on pipe-soil coupling.

[0096] S2. Determine the type of beach and sea environmental load and calculate the beach and sea environmental load: Based on the design objectives of the beach and sea environment, the beach and sea environmental load calculation module determines the type of beach and sea environmental load and calculates the beach and sea environmental load.

[0097] S3. Create a mechanical model of the flexible composite pipe and perform three-dimensional numerical calculations to extract the deformation and stress of the flexible composite pipe:

[0098] S30, the model mesh generation module of the mechanical calculation and analysis module divides the geometric model and material model of the flexible composite pipe into a numerical calculation mesh model;

[0099] S31. The load and boundary application module obtains the boundary equivalent spring model and beach environment load of the flexible composite pipe and applies the boundary equivalent spring model and beach environment load to the numerical calculation mesh model.

[0100] S32. The tube-soil elastoplastic analysis module selects the large deformation nonlinear analysis algorithm for the flexible composite tube and surrounding soil spring model, and determines the number of load calculation steps and iteration time.

[0101] S33. The mechanical calculation module creates a mechanical model of the flexible composite pipe and performs three-dimensional numerical calculations based on the numerical calculation mesh model with applied boundary equivalent spring model and beach and sea environment load, the large deformation nonlinear analysis algorithm of flexible composite pipe and surrounding soil spring model, load calculation steps and iteration time.

[0102] like Figure 4 As shown, in the mechanical model of the flexible composite pipe, the flexible composite pipe is divided into a buried section flexible composite pipe 3 and a bare section flexible composite pipe 4. The buried section flexible composite pipe 3 is subjected to the force of the surrounding soil spring 1 and the force of the boundary equivalent spring 2, while the bare section flexible composite pipe 4 is subjected to the force of the beach and sea environment load 5.

[0103] S34. The deformation and stress analysis module extracts the deformation and stress of the flexible composite pipe from the three-dimensional numerical calculation results.

[0104] S4. Design multi-parameter combination schemes and analyze the failure impact patterns:

[0105] S40, the failure factor influence module designs a multi-parameter combination scheme of flexible composite pipe geometric model parameters, material model parameters, boundary equivalent spring model parameters, surrounding soil spring model parameters and beach and sea environment load parameters through orthogonal experimental methods;

[0106] S41. Based on the deformation and stress of the flexible composite pipe under multiple parameter combinations, analyze the influence of the geometric model parameters, material model parameters, boundary equivalent spring model parameters, surrounding soil spring model parameters and beach and sea environment load parameters of the flexible composite pipe on the failure of the flexible composite pipe structure.

[0107] S5. Create Failure Index Evaluation Model: The failure index evaluation module creates evaluation models for three failure indices of the flexible composite pipe structure based on the influence of the geometric model parameters, material model parameters, boundary equivalent spring model parameters, surrounding soil spring model parameters, and beach and sea environment load parameters on the failure of the flexible composite pipe structure. The module uses data fitting to create evaluation models for the buckling deformation, shear stress, and yield stress of the flexible composite pipe.

[0108] S6. Input the parameters of the flexible composite pipe into the failure index evaluation model to determine whether it has failed.

[0109] In step S1, the boundary equivalent spring model of the flexible composite pipe is determined based on the sliding friction between the flexible composite pipe and the surrounding soil spring model, the area of ​​the flexible composite pipe, the elastic modulus of the flexible composite pipe material, and the elongation of the boundary equivalent spring. The calculation method is as follows:

[0110]

[0111] In the formula, F is the external force on the boundary equivalent spring; f S ΔL is the sliding friction force between the flexible composite pipe per unit length and the soil; A is the cross-sectional area of ​​the flexible composite pipe; E is the elastic modulus of the flexible composite pipe; ΔL is the equivalent spring elongation at the boundary.

[0112] Example 3:

[0113] See Figure 1 , Figure 3 , Figure 4 As shown in the figure, this embodiment provides a failure evaluation method for flexible composite pipe structures in complex coastal environments, including the following steps:

[0114] S1. Based on the design goals and design scenario, create a model and parameters based on pipe-soil coupling: Input the design goals and design scenario into the pipe-soil coupling calculation module, and the pipe-soil coupling calculation module will generate a flexible composite pipe geometric model, material model, boundary equivalent spring model and surrounding soil spring model based on pipe-soil coupling.

[0115] S2. Determine the type of beach and sea environmental load and calculate the beach and sea environmental load: Based on the design objectives of the beach and sea environment, the beach and sea environmental load calculation module determines the type of beach and sea environmental load and calculates the beach and sea environmental load.

[0116] S3. Create a mechanical model of the flexible composite pipe and perform three-dimensional numerical calculations to extract the deformation and stress of the flexible composite pipe:

[0117] S30, the model mesh generation module of the mechanical calculation and analysis module divides the geometric model and material model of the flexible composite pipe into a numerical calculation mesh model;

[0118] S31. The load and boundary application module obtains the boundary equivalent spring model and beach environment load of the flexible composite pipe and applies the boundary equivalent spring model and beach environment load to the numerical calculation mesh model.

[0119] S32. The tube-soil elastoplastic analysis module selects the large deformation nonlinear analysis algorithm for the flexible composite tube and surrounding soil spring model, and determines the number of load calculation steps and iteration time.

[0120] S33. The mechanical calculation module creates a mechanical model of the flexible composite pipe and performs three-dimensional numerical calculations based on the numerical calculation mesh model with applied boundary equivalent spring model and beach and sea environment load, the large deformation nonlinear analysis algorithm of flexible composite pipe and surrounding soil spring model, load calculation steps and iteration time.

[0121] like Figure 4As shown, in the mechanical model of the flexible composite pipe, the flexible composite pipe is divided into a buried section flexible composite pipe 3 and a bare section flexible composite pipe 4. The buried section flexible composite pipe 3 is subjected to the force of the surrounding soil spring 1 and the force of the boundary equivalent spring 2, while the bare section flexible composite pipe 4 is subjected to the force of the beach and sea environment load 5.

[0122] S34. The deformation and stress analysis module extracts the deformation and stress of the flexible composite pipe from the three-dimensional numerical calculation results.

[0123] S4. Design multi-parameter combination schemes and analyze the failure impact patterns:

[0124] S40, the failure factor influence module designs a multi-parameter combination scheme of flexible composite pipe geometric model parameters, material model parameters, boundary equivalent spring model parameters, surrounding soil spring model parameters and beach and sea environment load parameters through orthogonal experimental methods;

[0125] S41. Based on the deformation and stress of the flexible composite pipe under multiple parameter combinations, analyze the influence of the geometric model parameters, material model parameters, boundary equivalent spring model parameters, surrounding soil spring model parameters and beach and sea environment load parameters of the flexible composite pipe on the failure of the flexible composite pipe structure.

[0126] S5. Create Failure Index Evaluation Model: The failure index evaluation module creates evaluation models for three failure indices of the flexible composite pipe structure based on the influence of the geometric model parameters, material model parameters, boundary equivalent spring model parameters, surrounding soil spring model parameters, and beach and sea environment load parameters on the failure of the flexible composite pipe structure. The module uses data fitting to create evaluation models for the buckling deformation, shear stress, and yield stress of the flexible composite pipe.

[0127] S6. Input the parameters of the flexible composite pipe into the failure index evaluation model to determine whether it has failed.

[0128] In step S33, the NP criterion of the progressive damage model is used for the three-dimensional numerical calculation.

[0129] Example 4:

[0130] See Figure 1 , Figure 3 , Figure 4 As shown in the figure, this embodiment provides a failure evaluation method for flexible composite pipe structures in complex coastal environments, including the following steps:

[0131] S1. Based on the design goals and design scenario, create a model and parameters based on pipe-soil coupling: Input the design goals and design scenario into the pipe-soil coupling calculation module, and the pipe-soil coupling calculation module will generate a flexible composite pipe geometric model, material model, boundary equivalent spring model and surrounding soil spring model based on pipe-soil coupling.

[0132] S2. Determine the type of beach and sea environmental load and calculate the beach and sea environmental load: Based on the design objectives of the beach and sea environment, the beach and sea environmental load calculation module determines the type of beach and sea environmental load and calculates the beach and sea environmental load.

[0133] S3. Create a mechanical model of the flexible composite pipe and perform three-dimensional numerical calculations to extract the deformation and stress of the flexible composite pipe:

[0134] S30, the model mesh generation module of the mechanical calculation and analysis module divides the geometric model and material model of the flexible composite pipe into a numerical calculation mesh model;

[0135] S31. The load and boundary application module obtains the boundary equivalent spring model and beach environment load of the flexible composite pipe and applies the boundary equivalent spring model and beach environment load to the numerical calculation mesh model.

[0136] S32. The tube-soil elastoplastic analysis module selects the large deformation nonlinear analysis algorithm for the flexible composite tube and surrounding soil spring model, and determines the number of load calculation steps and iteration time.

[0137] S33. The mechanical calculation module creates a mechanical model of the flexible composite pipe and performs three-dimensional numerical calculations based on the numerical calculation mesh model with applied boundary equivalent spring model and beach and sea environment load, the large deformation nonlinear analysis algorithm of flexible composite pipe and surrounding soil spring model, load calculation steps and iteration time.

[0138] like Figure 4 As shown, in the mechanical model of the flexible composite pipe, the flexible composite pipe is divided into a buried section flexible composite pipe 3 and a bare section flexible composite pipe 4. The buried section flexible composite pipe 3 is subjected to the force of the surrounding soil spring 1 and the force of the boundary equivalent spring 2, while the bare section flexible composite pipe 4 is subjected to the force of the beach and sea environment load 5.

[0139] S34. The deformation and stress analysis module extracts the deformation and stress of the flexible composite pipe from the three-dimensional numerical calculation results.

[0140] S4. Design multi-parameter combination schemes and analyze the failure impact patterns:

[0141] S40, the failure factor influence module designs a multi-parameter combination scheme of flexible composite pipe geometric model parameters, material model parameters, boundary equivalent spring model parameters, surrounding soil spring model parameters and beach and sea environment load parameters through orthogonal experimental methods;

[0142] S41. Based on the deformation and stress of the flexible composite pipe under multiple parameter combinations, analyze the influence of the geometric model parameters, material model parameters, boundary equivalent spring model parameters, surrounding soil spring model parameters and beach and sea environment load parameters of the flexible composite pipe on the failure of the flexible composite pipe structure.

[0143] S5. Create Failure Index Evaluation Model: The failure index evaluation module creates evaluation models for three failure indices of the flexible composite pipe structure based on the influence of the geometric model parameters, material model parameters, boundary equivalent spring model parameters, surrounding soil spring model parameters, and beach and sea environment load parameters on the failure of the flexible composite pipe structure. The module uses data fitting to create evaluation models for the buckling deformation, shear stress, and yield stress of the flexible composite pipe.

[0144] S6. Input the parameters of the flexible composite pipe into the failure index evaluation model to determine whether it has failed.

[0145] The types of marine environmental loads in step S2 include sea ice loads, ocean current loads, and ocean wave loads.

[0146] The method for calculating sea ice load is as follows:

[0147] F = αWhσ C

[0148] In the formula, F is the sea ice breaking pressure / the ultimate force of sea ice acting on the flexible composite pipe; W is the width of the sea ice extrusion surface; h is the sea ice thickness; σ c denoted as uniaxial compressive strength of sea ice; α is a correction factor for various factors affecting sea ice force, with a value of 0.9.

[0149] The calculation method for ocean current load is as follows:

[0150]

[0151] In the formula, f C C represents the ocean current load per unit length of the flexible composite pipe. D This is the drag coefficient; ρ is the maximum possible velocity of the ocean current; g is the acceleration due to gravity; w D is the density of seawater; D is the diameter of the flexible composite pipe.

[0152] The method for calculating wave load is as follows:

[0153]

[0154] In the formula, f wy ρ is the wave force per unit length acting perpendicularly on the flexible composite pipe. W D is the density of seawater; D is the diameter of the flexible composite pipe; μ is the horizontal velocity of a water particle at the axis of the flexible composite pipe; C D C is the drag coefficient; M This is the inertial force coefficient.

[0155] The ocean current load and wave load are modeled using a fully turbulent flow model.

[0156] The technical features of this invention not described can be implemented by or using existing technology, and will not be repeated here. Of course, the above description is not a limitation of this invention, and this invention is not limited to the examples above. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of this invention should also be within the protection scope of this invention.

Claims

1. A failure evaluation method for flexible composite pipe structures in complex coastal environments, characterized in that, Includes the following steps: S1. Based on the design objectives and design scenario, create a model based on pipe-soil coupling; S2. Determine the type of marine environmental load and calculate the marine environmental load; S3. Create a mechanical model of the flexible composite pipe and perform three-dimensional numerical calculations to extract the deformation and stress of the flexible composite pipe. S4. Design multi-parameter combination schemes and analyze the failure impact patterns; S5. Based on the influence of each parameter on the failure of the flexible composite pipe, create a failure index evaluation model; S6. Input the parameters of the flexible composite pipe into the failure index evaluation model to determine whether it has failed.

2. The failure evaluation method for flexible composite pipe structures in complex coastal environments according to claim 1, characterized in that, Step S1 specifically involves: inputting the design objective and design scenario into the pipe-soil coupling calculation module, and creating a model based on pipe-soil coupling, including a flexible composite pipe geometric model, a material model, a surrounding soil spring model, and a boundary equivalent spring model.

3. The failure evaluation method for flexible composite pipe structures in complex coastal environments according to claim 2, characterized in that, The boundary equivalent spring model is determined based on the sliding friction between the flexible composite tube and the surrounding soil spring model, the area of ​​the flexible composite tube, the elastic modulus of the flexible composite tube material, and the elongation of the boundary equivalent spring. The calculation method is as follows: In the formula, F is the external force on the boundary equivalent spring; f S ΔL is the sliding friction force between the flexible composite pipe per unit length and the soil; A is the cross-sectional area of ​​the flexible composite pipe; E is the elastic modulus of the flexible composite pipe; ΔL is the equivalent spring elongation at the boundary.

4. The failure evaluation method for flexible composite pipe structures in complex coastal environments according to claim 1, characterized in that, The types of marine environmental loads in step S2 include sea ice load, ocean current load, and ocean wave load, among which... The method for calculating sea ice load is as follows: F=ɑWhσ C In the formula, F is the sea ice breaking pressure / the ultimate force of sea ice acting on the flexible composite pipe; W is the width of the sea ice extrusion surface; h is the sea ice thickness; σ c denoted as uniaxial compressive strength of sea ice; α is a correction factor for various factors affecting sea ice force, with a value of 0.

9. The calculation method for ocean current load is as follows: In the formula, f C C represents the ocean current load per unit length of the flexible composite pipe. D This is the drag coefficient; ρ is the maximum possible velocity of the ocean current; g is the acceleration due to gravity; w D is the density of seawater; D is the diameter of the flexible composite pipe. The method for calculating wave load is as follows: In the formula, f wy ρ is the wave force per unit length acting perpendicularly on the flexible composite pipe. W D is the density of seawater; D is the diameter of the flexible composite pipe; μ is the horizontal velocity of a water particle at the axis of the flexible composite pipe; C D C is the drag coefficient; M This is the inertial force coefficient.

5. The failure evaluation method for flexible composite pipe structures in complex coastal environments according to claim 4, characterized in that, The ocean current load and the ocean wave load are modeled using a fully turbulent flow model.

6. The failure evaluation method for flexible composite pipe structures in complex coastal environments according to claim 1, characterized in that, Step S3 specifically includes: S30, the model mesh generation module of the mechanical calculation and analysis module divides the geometric model and material model of the flexible composite pipe into a numerical calculation mesh model; S31. The load and boundary application module obtains the boundary equivalent spring model and beach environment load of the flexible composite pipe and applies the boundary equivalent spring model and beach environment load to the numerical calculation mesh model. S32. The tube-soil elastoplastic analysis module selects a large deformation nonlinear analysis algorithm for the flexible composite tube and surrounding soil spring model, and determines the number of load calculation steps and iteration time. S33. The mechanical calculation module creates a mechanical model of the flexible composite pipe and performs three-dimensional numerical calculations based on the numerical calculation mesh model with applied boundary equivalent spring model and beach and sea environment load, the large deformation nonlinear analysis algorithm of flexible composite pipe and surrounding soil spring model, the load calculation steps and iteration time. S34, Deformation and Stress Analysis Module, extracts the deformation and stress of the flexible composite pipe from the three-dimensional numerical calculation results.

7. The failure evaluation method for flexible composite pipe structures in complex coastal environments according to claim 6, characterized in that, In step S33, the progressive damage model NP criterion is used during the three-dimensional numerical calculation.

8. The failure evaluation method for flexible composite pipe structures in complex coastal environments according to claim 1, characterized in that, Step S4 specifically includes: S40, the failure factor influence module designs a multi-parameter combination scheme for the geometric model parameters, material model parameters, boundary equivalent spring model parameters, surrounding soil spring model parameters, and beach and sea environment load parameters of the flexible composite pipe through orthogonal experimental methods. S41. Based on the deformation and stress of the flexible composite pipe under multiple parameter combinations, the influence of the geometric model parameters, material model parameters, boundary equivalent spring model parameters, surrounding soil spring model parameters, and beach and sea environment load parameters of the flexible composite pipe on the failure of the flexible composite pipe structure is analyzed using data analysis software.

9. The failure evaluation method for flexible composite pipe structures in complex coastal environments according to claim 1, characterized in that, In step S5, a data fitting method is used to create a failure index evaluation model for flexible composite pipes.

10. A failure evaluation system for flexible composite pipe structures in complex coastal environments, characterized in that, include: The pipe-soil coupling calculation module creates a flexible composite pipe geometric model, material model, boundary equivalent spring model, and surrounding soil spring model based on pipe-soil coupling. A beach and sea environmental load calculation module, which determines the type of beach and sea environmental load and calculates the beach and sea environmental load; The mechanical calculation and analysis module includes a model mesh generation module, a load and boundary application module, a soil-tube elastoplastic analysis module, a mechanical calculation module, and a deformation and stress analysis module. The model mesh generation module divides the geometric and material models of the flexible composite pipe into numerical computation meshes; the load and boundary application module obtains the boundary equivalent spring model and marine environmental load of the flexible composite pipe and applies them to the numerical computation mesh; the pipe-soil elastoplastic analysis module selects a large deformation nonlinear analysis algorithm for the flexible composite pipe and surrounding soil springs, and determines the number of load calculation steps and iteration time; the mechanical calculation module performs three-dimensional numerical calculations on the numerical computation mesh; and the deformation and stress analysis module extracts the deformation and stress conditions of the flexible composite pipe from the calculation results of the numerical computation mesh. The failure factor influence module designs a multi-parameter combination scheme through orthogonal experimental methods and analyzes the influence of each parameter on the failure of the flexible composite pipe structure. The failure index evaluation module creates a failure index evaluation model for flexible composite pipes through data fitting.

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