Three-dimensional numerical simulation method for ultrasonic internal detection of pipeline cracks

Abstract

The invention discloses a three-dimensional numerical simulation method for ultrasonic internal detection of pipeline cracks. The method comprises the following steps: S1, establishing a three-dimensional geometric model according to an ultrasonic propagation process; s2, adding material attributes corresponding to all the parts; s3, setting a propagation process and boundary conditions of the geometric model by using pressure acoustics, transient state, solid mechanics, static electricity and a circuit; s4, coupling a liquid-solid boundary by using a multi-physical field acoustic-structure boundary, and coupling static electricity and a solid mechanical physical field by using a piezoelectric effect; s5, setting a crack defect in the detected pipeline; s6, performing entity unit grid division by using free triangles, sweeping and free tetrahedrons; and S7, adding a research, and setting a solver type to carry out analog calculation. The method can be used for ultrasonic internal detection of crack defects, the development of only two-dimensional plane model detection for crack detection is promoted, and the ultrasonic propagation process can be visually observed.

Description

Technical Field

[0001] The invention relates to the technical field of ultrasonic nondestructive testing, and in particular to a three-dimensional numerical simulation method for ultrasonic internal detection of pipeline cracks. Background Art

[0002] As the global demand for energy continues to grow, the safe operation of oil and gas pipelines, as the main way to transport oil and natural gas over long distances, is of vital importance. Once a pipeline leaks or is damaged, it will not only cause huge economic losses, but may also cause environmental pollution and safety accidents. During the long-term operation of oil and gas pipelines, various defects such as corrosion, cracks, and deformation may occur. If these defects are not discovered and handled in time, they may cause pipeline failure or even cause serious leakage accidents. In order to ensure the safe operation of pipelines, a variety of non-destructive testing technologies have been developed.

[0003] In the field of online detection technology for oil and gas pipelines in my country, we have successfully achieved breakthroughs in the research and development of magnetic flux leakage internal detectors and realized the localization of industrial-grade detection equipment. However, the existing magnetic flux leakage internal detectors have certain limitations in detection accuracy and produce a significant magnetization effect on steel pipelines during use. Therefore, it is particularly necessary to continue to research and develop ultrasonic online internal detectors with higher detection accuracy and harmless detection process. Ultrasonic detection technology has been widely used in pipeline detection due to its advantages such as fast detection speed, high accuracy and portable equipment. However, due to the difficulty in developing special equipment, my country is still in the stage of tackling key technologies and no mature products have yet appeared.

[0004] Existing simulations are mainly aimed at planar structures such as plates and rails. The simulation models are two-dimensional planar structures. There are few studies on the sound field characteristics of ultrasound in complex structures. A three-dimensional simulation model is established for crack-type defects. The acquired detection signals can be used to determine the impact of crack-type defects on echo signals, and the connection between sound field characteristics and detection signals can be established. Then, defect information can be determined based on the detection signals, thereby promoting the development of ultrasonic internal detectors. Summary of the invention

[0005] The purpose of the present invention is to provide a three-dimensional numerical simulation method for ultrasonic internal detection of pipeline cracks, so as to solve the technical problem of how to detect crack-type defects closer to the actual situation.

[0006] The present invention is implemented by adopting the following technical scheme: a three-dimensional numerical simulation method for ultrasonic internal detection of pipeline cracks, comprising the following steps: S1: Establish a three-dimensional geometric model based on the ultrasonic propagation process; S2: Add the corresponding material properties of each part; S3: Use pressure acoustics, transients, solid mechanics, electrostatics, and circuits to set boundary conditions for propagation processes and geometric models; S4: Use multiphysics acoustic-structure boundary coupling to liquid-solid boundary, and use piezoelectric effect to couple electrostatics and solid mechanics physics; S5: Set a crack defect inside the tested pipe; S6: Solid element meshing using free triangles, sweeps, and free tetrahedrons; S7: Add a study and set the solver type for simulation calculations.

[0007] Furthermore, the components of the three-dimensional geometric model include an ultrasonic probe, a water area, a measured pipeline and a crack, wherein the ultrasonic probe includes a piezoelectric chip, a matching layer and a backing layer.

[0008] Furthermore, the material properties include the materials of the piezoelectric wafer, the matching layer and the backing layer in the ultrasonic probe, as well as the water area and the steel of the pipeline as the coupling fluid.

[0009] Furthermore, step S3 is specifically as follows: Pressure acoustics, the transient physical field corresponds to the water area as the coupling fluid, simulating the propagation of ultrasound in the liquid; Solid mechanics corresponds to the ultrasonic probe and pipeline, simulating the propagation of ultrasonic waves in solids; The electrostatic corresponding piezoelectric chip simulates the generation and reception of ultrasonic waves, that is, the positive and negative piezoelectric effects realize the conversion between ultrasonic waves and electrical signals; The circuit corresponds to an excitation load that causes the piezoelectric chip to vibrate and generate ultrasonic waves.

[0010] Furthermore, step S4 is specifically as follows: Two solid-liquid interfaces, namely the interface between the ultrasonic probe and water, and the interface between water and the pipe, are coupled through the acoustic-structure boundary. Apply piezoelectric effect multiphysics to a piezoelectric wafer to couple electrostatics with solid mechanics.

[0011] Furthermore, step S5 specifically includes: adding a geometric shape of a crack in the pipeline, and setting the crack with the help of a preset crack boundary condition in the solid mechanics physical field.

[0012] Furthermore, step S6 is specifically as follows: free triangle, sweep, and free tetrahedron mesh division methods correspond to the contact surface between the piezoelectric chip and the matching layer, the piezoelectric chip and the matching layer, the pipeline, the water area, and the backing layer, respectively.

[0013] The beneficial effects of the present invention are as follows: the present invention can be used for ultrasonic internal detection of crack defects, promoting the development of only two-dimensional plane model detection for crack detection, and can intuitively observe the process of ultrasonic wave propagation. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0015] Figure 1 It is a flow chart of the present invention; Figure 2 It is a schematic diagram of the geometric model; Figure 3 for Figure 2 Schematic diagram of the ultrasonic probe geometric model shown; Figure 4 for Figure 2 Schematic diagram of meshing of the geometric model shown; In the figure, 1-pipeline, 2-ultrasonic probe, 3-water area, 4-matching layer, 5-piezoelectric wafer, 6-backing layer. DETAILED DESCRIPTION

[0016] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0017] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0018] Some embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0019] See also Figure 1 A three-dimensional numerical simulation method for ultrasonic internal detection of pipeline cracks includes the following steps: S1: Establish a three-dimensional geometric model based on the ultrasonic propagation process; S2: Add the corresponding material properties of each part; S3: Use pressure acoustics, transients, solid mechanics, electrostatics, and circuits to set boundary conditions for propagation processes and geometric models; S4: Use multiphysics acoustic-structure boundary coupling to liquid-solid boundary, and use piezoelectric effect to couple electrostatics and solid mechanics physics; S5: Set a crack defect inside the tested pipe; S6: Solid element meshing using free triangles, sweeps, and free tetrahedrons; S7: Add a study and set the solver type for simulation calculations.

[0020] In this embodiment, step S1 specifically includes: establishing a three-dimensional geometric model including a piezoelectric chip 5, a matching layer 4, a backing layer 6 constituting an ultrasonic probe, a water area 3 as a coupling liquid, a pipeline to be detected 1 and a crack according to an actual ultrasonic internal detection test system, such as Figure 2 , Figure 3 shown.

[0021] In this embodiment, step S2 is specifically as follows: add the material properties corresponding to each part: the material of the piezoelectric chip 5 in the ultrasonic probe is selected as Lead Zirconate Titanate (PZT-5H), the matching layer 4 and the backing layer 6 are first added with empty materials, and the density, pressure wave and shear wave velocities are set accordingly. The water area 3 as the coupling liquid is selected as Water, liquid, and the steel corresponding to the pipeline 1 is Structural steel.

[0022] In this embodiment, step S3 is specifically as follows: using pressure acoustics, transient, solid mechanics, electrostatics, circuits and other physical fields to set the boundary conditions of the propagation process and the geometric model: pressure acoustics, transient physical fields correspond to the water area 3 as the coupling liquid; solid mechanics corresponds to the piezoelectric chip 5, matching layer 4, backing layer 6 and pipeline 1; electrostatics corresponds to the piezoelectric chip 5, simulating the generation and reception of ultrasonic waves, that is, the positive and negative piezoelectric effects realize the conversion between ultrasonic waves and electrical signals; the circuit corresponds to the excitation load that causes the piezoelectric chip to vibrate and generate ultrasonic waves.

[0023] In this embodiment, step S4 is specifically as follows: after being generated by the probe, the ultrasonic wave propagates to the water area 3, then propagates to the pipe 1, is reflected and refracted in the pipe 1, and finally returns to the probe to be converted into an electrical signal. The acoustic-structure boundary couples two solid-liquid interfaces, namely the interface between the ultrasonic probe and the water, and the interface between the water and the pipe. The surface of the piezoelectric chip 5 is wrapped by the backing layer 6 and the matching layer 4. After being excited by the excitation load, it vibrates and converts the electrical signal into an ultrasonic wave through the inverse positive piezoelectric effect. After propagation, the ultrasonic wave returns to the piezoelectric chip 5 and is converted into an electrical signal by the positive piezoelectric effect. Therefore, the piezoelectric effect multi-physics field is applied to the piezoelectric chip 5 for coupling between electrostatics and solid mechanics.

[0024] In this embodiment, step S5 is specifically as follows: setting a crack defect inside the tested pipeline 1: setting an axial crack inside the pipeline 1, and the setting of the crack is set by the boundary conditions provided in solid mechanics. The size of the crack inside the pipeline needs to be set according to the actual engineering practice and the requirements of the national standards.

[0025] In this embodiment, step S6 is specifically as follows: using free triangle, sweep, and free tetrahedron to perform entity unit meshing: the contact surface between the piezoelectric chip 5 and the matching layer 4 is meshed using the free triangle type; the piezoelectric chip 5 and the matching layer 4 are meshed using the sweeping method; the pipeline 1, the water area 3, and the backing layer 6 are meshed using the free tetrahedron method. The meshing results are shown in FIG. Figure 4 shown.

[0026] In this embodiment, step S7 specifically includes: adding a study and setting the solver type to perform simulation calculations.

[0027] When performing online detection of pipeline crack defects, the circuit of the present invention provides an excitation load to be applied to the piezoelectric chip, causing it to vibrate and generate ultrasonic waves. The ultrasonic waves propagate into the water and continue to propagate forward, and are reflected and refracted on the inner wall of the pipeline. The ultrasonic waves refracted into the pipeline are reflected by the outer wall of the pipeline, propagate to the crack and are reflected by the crack, and the ultrasonic waves propagate to the probe surface in the opposite direction of the original propagation path and are converted into electrical signals, thereby completing a detection.

[0028] For the aforementioned embodiments, for the sake of simplicity, they are all described as a series of action combinations, but those skilled in the art should be aware that the present application is not limited by the order of the actions described, because according to the present application, some steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are preferred embodiments, and the actions involved are not necessarily required by the present application.

[0029] The above embodiments describe the basic principles and main features of the present invention and the advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the changes and modifications made by those skilled in the art shall be within the scope of protection of the appended claims of the present invention without departing from the spirit and scope of the present invention.

Claims

1. A three-dimensional numerical simulation method for ultrasonic internal detection of pipeline cracks, characterized in that: The steps include: S1: Establish a three-dimensional geometric model based on the ultrasonic propagation process; S2: Add the corresponding material properties of each part; S3: Use pressure acoustics, transients, solid mechanics, electrostatics, and circuits to set boundary conditions for propagation processes and geometric models; S4: Use multiphysics acoustic-structure boundary coupling to liquid-solid boundary, and use piezoelectric effect to couple electrostatics and solid mechanics physics; S5: Set a crack defect inside the tested pipe; S6: Solid element meshing using free triangles, sweeps, and free tetrahedrons; S7: Add a study and set the solver type for simulation calculations.

2. A three-dimensional numerical simulation method for ultrasonic internal detection of pipeline cracks according to claim 1, characterized in that: The components of the three-dimensional geometric model include an ultrasonic probe, a water area, a pipeline to be tested and a crack, wherein the ultrasonic probe includes a piezoelectric chip, a matching layer and a backing layer.

3. A three-dimensional numerical simulation method for ultrasonic internal detection of pipeline cracks according to claim 2, characterized in that: The material properties include the materials of the piezoelectric wafer, matching layer, and backing layer in the ultrasonic probe, as well as the water area and steel of the pipe as the coupling fluid.

4. A three-dimensional numerical simulation method for ultrasonic internal detection of pipeline cracks according to claim 3, characterized in that: Step S3 is specifically as follows: Pressure acoustics, the transient physical field corresponds to the water area as the coupling fluid, simulating the propagation of ultrasound in the liquid; Solid mechanics corresponds to the ultrasonic probe and pipeline, simulating the propagation of ultrasonic waves in solids; The electrostatic corresponding piezoelectric chip simulates the generation and reception of ultrasonic waves, that is, the positive and negative piezoelectric effects realize the conversion between ultrasonic waves and electrical signals; The circuit corresponds to an excitation load that causes the piezoelectric chip to vibrate and generate ultrasonic waves.

5. A three-dimensional numerical simulation method for ultrasonic internal detection of pipeline cracks according to claim 4, characterized in that: Step S4 is specifically as follows: Two solid-liquid interfaces, namely the interface between the ultrasonic probe and water, and the interface between water and the pipe, are coupled through the acoustic-structure boundary. Apply piezoelectric effect multiphysics to a piezoelectric wafer to couple electrostatics with solid mechanics.

6. A three-dimensional numerical simulation method for ultrasonic internal detection of pipeline cracks according to claim 5, characterized in that: Step S5 specifically includes: adding the geometric shape of the crack in the pipeline, and setting the crack with the help of the preset crack boundary conditions in the solid mechanics physical field.

7. A three-dimensional numerical simulation method for ultrasonic internal detection of pipeline cracks according to claim 6, characterized in that: Step S6 specifically includes: using free triangle, sweep, and free tetrahedron mesh division methods to correspond to the contact surface between the piezoelectric chip and the matching layer, the piezoelectric chip and the matching layer, the pipeline, the water area, and the backing layer, respectively.

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