A method for analyzing a fracture propagation process of a carbon dioxide transport pipeline based on a fluid-solid coupling technology
By utilizing the fluid-structure interaction technology in ABAQUS simulation software, an analytical method for the fracture process of carbon dioxide transportation pipelines was established. This method solved the problem of difficulties in full-scale fracture testing, achieved accurate simulation of pipeline fracture and fluid decompression, and improved the accuracy of safety design and evaluation.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- DALIAN UNIV OF TECH
- Filing Date
- 2023-11-16
- Publication Date
- 2026-07-24
AI Technical Summary
Existing technologies cannot effectively simulate the full-scale fracture process of carbon dioxide transport pipelines, which limits the development of safety design and evaluation systems. Furthermore, existing numerical analysis methods have discrepancies between the results and experimental values, and cannot truly reflect the coupling process between pipeline fracture and fluid decompression.
By employing fluid-structure interaction technology based on ABAQUS simulation software, a coupled simulation analysis of pipe fracture and fluid decompression is achieved by establishing a three-dimensional analysis model, testing material property parameters, using the GTN fracture model and the Peng-Robison equation of state, and combining mesh generation and solver.
It enables accurate simulation of pipeline fracture propagation process under different materials and initial pressures, improves the accuracy of fracture failure prediction, and guides safe design and extended operation cycle.
Smart Images
Figure CN117610450B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the research field of safe carbon dioxide transportation, specifically involving a method for analyzing the fracture propagation process of carbon dioxide transportation pipelines based on fluid-structure interaction technology. Background Technology
[0002] As global carbon emissions increase year by year, global temperatures are gradually rising. Carbon capture, utilization, and storage (CCUS), as a favorable measure to mitigate global warming, has been incorporated into the national development plans of various countries around the world. Pipelines, as the optimal method for continuous, long-distance, and high-flow-rate transport of carbon dioxide, have always received considerable attention and research regarding their safety design. Carbon dioxide transport pipelines operate in high-temperature, high-pressure, and corrosive environments for extended periods, inevitably leading to performance degradation, damage, cracking, and even failure. For example, long-term operation can result in corrosion, leakage, and cracking. Due to the strong Joule-Thomson coefficient of carbon dioxide, localized leaks can cause a sudden drop in temperature at the leak point, resulting in a sharp decrease in the toughness of the pipeline material. Under high pressure within the pipe, this leads to failure, and subsequently, driven by the internal pressure, ductile fracture propagation occurs.
[0003] However, the long preparation period, high cost, high technical threshold, high risk factor, and high uncertainty of full-scale fracture tests for carbon dioxide transportation pipelines limit the development of pipeline safety design and evaluation systems. Currently, countries / teams mastering full-scale fracture testing of carbon dioxide are concentrated in Europe and other countries, and are not allowed to conduct full-scale fracture tests arbitrarily due to various limitations. The analytical results of numerical simulation methods are now recognized by researchers worldwide. Therefore, conducting numerical simulation research using simulation analysis software can compensate for the inability to conduct specific tests.
[0004] Current research on ductile fracture in pipelines often uses functional relationships, atmospheric pressure values, and the ideal gas law to define the pressure inside the pipe. However, this method oversimplifies the handling of pressure changes within the pipe, neglecting the changes in the properties of carbon dioxide. Consequently, the numerical analysis results differ significantly from experimental values. Therefore, there is an urgent need for a numerical analysis method that can realistically simulate the pipeline fracture process to analyze pipeline fracture and fluid decompression behavior.
[0005] To address the aforementioned research bottlenecks, this invention proposes a method for analyzing the fracture process of carbon dioxide transport pipelines based on fluid-structure interaction technology, using the ABAQUS simulation software analysis environment. This method features high computational accuracy, vivid analysis results, and the ability to simultaneously describe the coupled process of pipeline fracture and fluid decompression during pipeline failure. Summary of the Invention
[0006] This invention aims to address the limitations of existing technologies in conducting full-scale fracture tests. It provides a method for analyzing the fracture process of carbon dioxide transport pipelines based on fluid-structure interaction (FSI) technology, enabling simultaneous simulation of pipeline fracture and carbon dioxide decompression using simulation software. This method realistically simulates the ductile-propagation fracture process of a carbon dioxide pipeline under the influence of high-pressure gas, guiding pipeline parameter design and extending the safe operating life of carbon dioxide transport pipelines. This method can be applied to pipelines of varying diameters and wall thicknesses made of different materials, and to pipeline transport scenarios with different initial pressures. It has advantages such as wide applicability, strong targeting, and short testing cycles, enabling safety evaluation of pipelines with different materials and initial pressures.
[0007] The present invention achieves its objective by employing the following technical solution:
[0008] A method for analyzing the fracture process of carbon dioxide transport pipelines based on fluid-structure interaction technology includes the following steps:
[0009] S1. A three-dimensional analysis model of the carbon dioxide transport pipeline was established using three-dimensional software;
[0010] S2. Obtain material property parameters by physical testing using a universal testing machine, establish constitutive and fracture models of the test materials, and adopt the GTN (Gurson-Tvergaard-Needleman) fracture model for the fracture model, and set the boundary conditions of the solid domain according to the simulation analysis to be carried out.
[0011] S3. Based on the Peng-Robison equation of state, generate fluid parameters and input the fluid parameters into the material definition function *EOS,TYPE=TABULAR of the fluid domain in the ABAQUS software, and set the boundary conditions of the fluid domain.
[0012] S4. Select an appropriate mesh generation strategy to generate meshes for the solid domain and fluid domain, and select an appropriate solver to perform fluid-structure interaction analysis and calculation.
[0013] S5. Process the simulation results in ABAQUS software to obtain the pipe fracture velocity and the propagation velocity of the carbon dioxide decompression wave inside the pipe.
[0014] Furthermore, in S2, the constitutive model establishment process for the test material is as follows: the test material is subjected to quasi-static uniaxial tension using a universal testing machine at a tension rate of 0.1 mm / min to 5 mm / min. Tensile force values at different strain rates are obtained through tensile testing, and the true stress-strain curve of the test material is calculated.
[0015] Furthermore, in S2, the function of the GTN fracture model, i.e., the constitutive equation, is expressed as:
[0016]
[0017] In the formula, Φ is the yield strength; R eq For macroscopic Mises equivalent effects; R el R represents the yield strength of the test material. H The stress is the macroscopic hydrostatic stress; q1, q2, and q3 are the damage parameters; f * f is the volume fraction of the voids; c f0 represents the critical void volume fraction; f0 represents the initial void volume fraction.
[0018] Furthermore, in S2, the process of establishing the GTN fracture model of the test material is as follows: In ABAQUS software, the same geometric model and tensile parameters as those used in the material tensile test are established; by adjusting the *Damage evolution keyword... c The values of f0 and f0 are chosen to ensure that the simulation results generated by the material constitutive equation match the actual stress-strain curves obtained from the material tensile test to the greatest extent.
[0019] Furthermore, in step S3, the Peng-Robison equation of state is used to calculate the density values of the carbon dioxide medium at different pressure values. The pressure-density correspondence is set using the keyword *EOS,TYPE=TABULAR in the ABAQUS software. The relationship between pressure and density in this operation is as follows:
[0020] P=f1(ε vol )+ρ0f2(ε vol E m
[0021] In the formula, P is the pressure value; f1 and f2 are functions of the exponential volumetric strain rate ε(vol); the expression for ε(vol) is ε(vol) = ln(ρ0 / ρ), where ρ0 is the reference density; E m It is the internal energy of the fluid.
[0022] Furthermore, in step S4, a suitable meshing strategy is selected to mesh the pipes in the solid domain and to mesh the carbon dioxide in the fluid domain; solvers with different step increments are selected to set up the solvers; and a calculation example is submitted in the ABAQUS software until the calculation of the calculation example is completed.
[0023] Furthermore, in step S5, the fluid-structure interaction calculation results are processed in ABAQUS software to obtain the pipe fracture velocity and carbon dioxide decompression velocity.
[0024] In summary, the beneficial effects of adopting the technical solution proposed in this invention are as follows:
[0025] This invention establishes a reasonable and comprehensive constitutive model, fracture model, and fluid property model for simulating full-scale fracture of carbon dioxide transport pipelines. It can satisfy the fracture propagation rate requirements of pipelines with different performance materials, diameters, and wall thicknesses under different initial pressures of carbon dioxide, fully considering the interaction between pipeline material properties and fluid characteristics. Comparative evaluation with actual experimental data fully demonstrates the accuracy of the method in conducting ductile fracture analysis of carbon dioxide transport pipelines, greatly improving the prediction accuracy of fracture failure in carbon dioxide pipelines under different pressures. This has significant implications for the safety design and evaluation of pipelines in the global CCUS (Carbon Dioxide, Carbon Fiber, and Gas) field. Attached Figure Description
[0026] Figure 1 This is a schematic diagram of the calculation process of the method of the present invention;
[0027] Figure 2 It is a schematic diagram of the actual stress-strain curve of the test material;
[0028] Figure 3 It is a pressure-density relationship established based on the Peng-Robison equation of state;
[0029] Figure 4 This is a diagram of a fluid-structure interaction model;
[0030] Figure 5 This is a diagram of the solid domain morphology after the pipeline fractures.
[0031] Figure 6 This is a diagram of the fluid domain morphology after a pipe rupture.
[0032] Figure 7 This is a diagram showing the rate of pipe fracture.
[0033] Figure 8 This is a velocity diagram of carbon dioxide decompression waves. Detailed Implementation
[0034] The technical solution of the present invention will be further described below with reference to specific embodiments and accompanying drawings.
[0035] Example 1
[0036] like Figure 1 As shown, a method for analyzing the fracture propagation process of carbon dioxide transportation pipelines based on fluid-structure interaction technology is presented. The method includes the following steps:
[0037] S1. Use 3D software (ABAQUS, UG, Solidworks, etc.) to establish a 3D analysis model of the carbon dioxide transport pipeline;
[0038] S2. Obtain material property parameters by physical testing using a universal testing machine, establish constitutive and fracture models of the test materials, and adopt the GTN (Gurson-Tvergaard-Needleman) fracture model for the fracture model, and set the boundary conditions of the solid domain according to the simulation analysis to be carried out.
[0039] S3. Based on the Peng-Robison equation of state, generate fluid parameters and input the fluid parameters into the material definition function *EOS,TYPE=TABULAR of the fluid domain in the ABAQUS software, and set the boundary conditions of the fluid domain.
[0040] S4. Select an appropriate mesh generation strategy to generate meshes for the solid domain and fluid domain, and select an appropriate solver to perform fluid-structure interaction analysis and calculation.
[0041] S5. Process the simulation results in ABAQUS software to obtain the pipe fracture velocity and the propagation velocity of the carbon dioxide decompression wave inside the pipe.
[0042] In this experimental example, the experimental material is X80 steel, the pressure of the carbon dioxide to be transported is 25 MPa, the pipe diameter OD = 1454 mm, and the wall thickness t = 12 mm. The simulation software used in the experimental example of the X80 steel pipeline containing carbon dioxide for model establishment, determination of material property constitutive equations, loading of fluid properties in the fluid domain, and fluid-structure interaction simulation is ABAQUS.
[0043] This example will detail the constitutive model of the experimental material, the establishment of fluid properties, and the fluid-structure interaction simulation method.
[0044] First, the experimental conditions for the solid domain constitutive model are described. Quasi-static tensile tests were conducted on X80 material using a Wancheng quasi-static universal tensile testing machine. The loading rate was 1 mm / min, and a 20 mm extensometer was used. The engineering stress-strain curves under quasi-static conditions were obtained, and after transformation, the true stress-strain curves were obtained, as shown below. Figure 2 As shown.
[0045] In ABAQUS software, the same material and boundary conditions as X80 were constructed. After meshing and setting the GTN parameters, the stress-strain curves of the material in the simulation software were obtained. The f parameter in the *Damage evolution keyword was adjusted. c The values of f0 and f0 are chosen to ensure that the simulation results generated by the material constitutive equation match the actual stress-strain curves obtained from the material tensile test to the greatest extent.
[0046] Using the Peng-Robison equation of state in REFPROP software, the isentropic method was employed to derive the relationship between pressure and density for the specific carbon dioxide under study. In this example, the carbon dioxide pressure was 25 MPa, corresponding to a density of 626.3 kg / m³. 3 (This value is also the reference density ρ0 for constructing the fluid domain). The pressure-density relationship of carbon dioxide at 25 MPa is as follows: Figure 3 As shown. The pressure and density in this relationship are set using the keyword *EOS,TYPE=TABULAR in the ABAQUS software. In this mode, the pressure-density relationship is: P = f1(ε vol )+ρ0f2(ε vol E m Here, we set Em to 0, then P = f1(ε) vol Therefore, the material properties of the fluid domain can be set.
[0047] The fluid-structure interaction analysis model constructed in this example is as follows: Figure 4 As shown, the pipe length is L. F =12OD, initial crack length is F int =1OD, in the solid domain only the crack initiation site is GTN material with damage evolution, the other materials are the pipe body material. To save power consumption and shorten the calculation cycle, this example uses a 1 / 2 model. The outer layer of the pipe is P a,0 =0.1MPa air, air is assigned material properties according to the ideal gas law, and the dimensions of air are: height H a =1.5OD, width E a =2OD, length L a =12OD. BC s,z The model is symmetrical about the analysis surface along the Z-axis, BC s,y This refers to the model being symmetrical about the analysis surface along the Y-axis. ⊥ =0 means that the velocity vector of this analysis surface is 0.
[0048] In the mesh generation strategy, the solid domain is a C3D8R mesh, which is a three-dimensional 8-node reduced integration element; the fluid domain (air and carbon dioxide) is an E3D8R mesh, which is a three-dimensional 8-node reduced integration element with Euler behavior.
[0049] This example uses an explicit dynamic analysis step with a calculation time of 0.5s and employs an automatic control incremental step calculation strategy.
[0050] After setting the parameters and boundary conditions for both the solid and fluid domains, the calculation example was submitted, and the computer was allowed to complete the calculation. This calculation example was completed on a Z8G4 workstation equipped with two Platinum 6133 CPUs, two 32GB DR2133ECC memory modules, and one 2TB mechanical hard drive. The calculation example took a total of 35.5 hours.
[0051] After the calculation is completed, the output results of the example are organized in the ABAQUS result post-processing interface. The fracture mode of the pipeline is as follows: Figure 5 As shown; the fluid decompression and jet patterns are as follows Figure 6 As shown; the speed at which the pipe breaks is as follows Figure 7 As shown; the propagation speed of the carbon dioxide decompression wave inside the pipe is as follows: Figure 8 As shown.
[0052] After the comprehensive application of the method in this embodiment and the comparison and verification with the results of the full-scale fracture experiment, it can be clearly seen that the method proposed in this embodiment, a method for analyzing the fracture propagation process of carbon dioxide transportation pipelines based on fluid-structure interaction technology, can realistically simulate the coupled analysis of pipeline fracture and carbon dioxide decompression characteristics during the actual fracture propagation process of carbon dioxide transportation pipelines. This method fully considers the fracture process under the coupling effect of pipeline and carbon dioxide, and therefore has high calculation accuracy.
Claims
1. A method for analyzing the fracture propagation process of carbon dioxide transport pipelines based on fluid-structure interaction technology, characterized in that, Includes the following steps: S1. A three-dimensional analysis model of the carbon dioxide transport pipeline was established using three-dimensional software; S2. Obtain material property parameters by physical testing using a universal testing machine, establish constitutive and fracture models of the test materials, with the fracture model adopting the GTN fracture model, and set the boundary conditions of the solid domain according to the simulation analysis to be carried out. S3. Generate fluid parameters based on the Peng-Robinson equation of state, and input the fluid parameters into the material definition function of the fluid domain in ABAQUS software. In TYPE=TABULAR, set the boundary conditions for the fluid domain; S4. Select an appropriate mesh generation strategy to generate meshes for the solid domain and fluid domain, and select an appropriate solver to perform fluid-structure interaction analysis and calculation. S5. Process the simulation results in ABAQUS software to obtain the pipe fracture velocity and the propagation velocity of the carbon dioxide decompression wave inside the pipe.
2. The method for analyzing the fracture propagation process of a carbon dioxide transport pipeline based on fluid-structure interaction technology according to claim 1, characterized in that, In S2, the constitutive model establishment process of the test material is as follows: the test material is subjected to quasi-static uniaxial tension using a universal testing machine at a tension rate of 0.1 mm / min to 5 mm / min; the tensile force values at different strain rates are obtained through tensile testing, and the true stress-strain curve of the test material is obtained through calculation.
3. The method for analyzing the fracture propagation process of a carbon dioxide transport pipeline based on fluid-structure interaction technology according to claim 1, characterized in that, In S2, the function of the GTN fracture model, i.e., the constitutive equation, is expressed as: In the formula, R is the yield strength. eq For macroscopic Mises equivalent effects; R el R represents the yield strength of the test material. H The stress is the macroscopic hydrostatic stress; q1, q2, and q3 are the damage parameters. This represents the volume fraction of voids.
4. The method for analyzing the fracture propagation process of a carbon dioxide transport pipeline based on fluid-structure interaction technology according to claim 1, characterized in that, In S2, the process of establishing the GTN fracture model of the test material is as follows: A geometric model and tensile parameters identical to those used in the material tensile test are established in ABAQUS software; by adjusting... Critical void volume fraction f in keywords c The value of the initial pore volume fraction f0 is used to ensure that the simulation results generated by the material constitutive equation match the actual stress-strain curves obtained from the material tensile test to the greatest extent.
5. The method for analyzing the fracture propagation process of a carbon dioxide transport pipeline based on fluid-structure interaction technology according to claim 1, characterized in that, In step S3, the Peng-Robinson equation of state is used to calculate the density values of the carbon dioxide medium at different pressure values. The pressure-density correspondence is then converted into the material definition function of the fluid domain in ABAQUS software. ,TYPE=TABULAR completes the setting. The relationship between pressure and density in this operating mode is as follows: In the formula, P is the pressure value; f1 and f2 are the exponential volumetric strain rates ε. vol The function; ε vol The expression for ε is vol =ln(ρ0 / ρ), where ρ0 is the reference density; E m It is the internal energy of the fluid.
6. The method for analyzing the fracture propagation process of a carbon dioxide transport pipeline based on fluid-structure interaction technology according to claim 1, characterized in that, In step S4, a suitable meshing strategy is selected to mesh the pipes in the solid domain and the carbon dioxide in the fluid domain; solvers with different step increments are selected to set up the solvers; and a calculation example is submitted in the ABAQUS software until the calculation of the calculation example is completed.
7. The method for analyzing the fracture propagation process of a carbon dioxide transport pipeline based on fluid-structure interaction technology according to claim 1, characterized in that, In step S5, the fluid-structure interaction calculation results are processed in ABAQUS software to obtain the pipe fracture velocity and carbon dioxide decompression velocity.