Pipeline structure tension recognition method based on tension coefficient matrix correction

Abstract

According to the pipeline structure tension identification method based on tension coefficient matrix correction, tension distribution in the pipeline service process can be identified, data support is provided for real-time monitoring and evaluation of the pipeline service state, and therefore the pipeline service safety and stability are improved. The method comprises the steps that a pipeline coordinate system is constructed, pipeline tension function parameters are determined according to the relative positions between pipeline constraint ends, and then a tension function model is constructed. On the basis, a tension recognition equation when the pipeline is subjected to the concentrated force effect is deduced. And a gravity constraint iteration method is introduced, and a tension recognition equation when the pipeline is not subjected to the effect of concentrated force is solved. Meanwhile, strain sensing information of the optical fiber sensor integrated in the pipeline is extracted, and a tension characteristic correction coefficient matrix is constructed, so that the tension recognition precision is remarkably improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of pipeline structure monitoring, and in particular relates to a pipeline structure tension identification method based on tension coefficient matrix correction. Background Art

[0002] Modern industry, urban lifelines, and aviation (such as aerial refueling hoses) rely heavily on various pipeline systems. These pipeline structures often operate under complex load environments. Pipeline tension, a core safety and performance indicator, directly impacts their buckling resistance, fatigue life, overall stability, and reliability. However, existing detection technologies primarily target pipeline structural defects and are ill-suited for long-distance, continuous, and real-time monitoring. Therefore, the development of high-precision, intelligent tension identification methods is urgently needed. These methods provide a scientific basis for assessing the condition of pipelines in extreme environments, dynamic service, and aging, optimizing maintenance and operational decisions, extending asset lifespans and improving mission success rates. These methods are also strategic requirements for meeting increasingly stringent safety regulations and implementing lean management of pipeline integrity. This research is of irreplaceable importance for building quality and safety, improving economic efficiency, and enhancing national defense effectiveness.

[0003] In recent years, strain sensing technology based on fiber optic sensors has been increasingly applied to structural health monitoring. Fiber optic sensors offer advantages such as high precision, immunity to electromagnetic interference, lightweight, and corrosion resistance, enabling real-time monitoring of structural strain distribution. However, a mature, universal, and effective strain identification method that can effectively utilize the rich strain data obtained by fiber optic sensors is currently lacking, making it difficult to establish a mapping between distributed strain and the tension distribution of pipeline structures under complex operating conditions. Summary of the Invention

[0004] Purpose of the invention: The technical problem to be solved by the present invention is to address the deficiencies of the existing technology and provide a pipeline structure tension identification method based on tension coefficient matrix correction, comprising the following steps: Step 1: Establish a rectangular coordinate system with the lower end of the pipeline as the origin to determine the length of the pipeline l , the height difference between the two restrained ends of the pipe h 0, the angle between the two ends of the pipe θ , the gravity load p on the pipeline; Step 2: Based on the tension function theory, derive the corresponding tension identification equation when the pipeline is subjected to a vertical downward concentrated force; Step 3: Using the gravity constraint iteration method, numerically solve the key parameters of the tension identification equation when the pipeline is not subjected to the vertical downward concentrated force; Step 4: Attach fiber optic sensors to the pipeline surface to obtain the strain distribution data on the pipeline surface during service. Construct a tension characteristic correction coefficient matrix based on the measured strain raw data matrix and the first-order derivative matrix. Substitute the tension characteristic correction coefficient matrix into the tension identification equation to correct the tension identification error caused by not including the detailed material coefficient characteristics of the pipeline.

[0005] In step 1, define the pipeline AB The horizontal length is l , the gravity load p acting on the pipeline is solved by the pipeline density.

[0006] Step 2 includes: Step 2.1, take any infinitesimal segment on the pipeline ds , set the pipe to be under tension T The horizontal component of force is H , the vertical component is V , then the static equilibrium equation of the pipeline during service is obtained by static analysis: (1), in d is the differential symbol; y is the pipeline infinitesimal segment Y axis coordinates; x Pipeline micro-segment X axis coordinates; Solve the equation (1) by quadratic integration, and according to the boundary conditions: the horizontal coordinate of the starting point of the pipeline x 1=0, vertical coordinate y 1=0; horizontal coordinate of the pipeline end point x 2=l, vertical coordinate y 2=l, and the linear equation of the pipeline in the free state is obtained: (2), in 、 is an arbitrary constant generated by the integration process, which is determined by formula (3): (3), in arsinh represents the inverse hyperbolic sine function; Step 2.2: Let point C be the lowest point of the pipeline, take the derivative of equation (3) and take the extreme point to obtain the horizontal coordinate of the lowest point C. for: (4), Substituting equation (4) into equation (2), we can obtain the pipeline linear function under the condition of known lowest point: y ( x ): (5), Set pipeline at any position Q ( x , y ) point tension is T , the vertical component of tension is V , the pipeline tension identification equation is obtained from static analysis: (6), (7), According to formula (7), the pipeline is at the lowest point The tension value at the lowest point is The tension value gradually increases towards both ends and reaches the maximum at the higher end point B. Therefore, the maximum tension of the pipeline and minimum value for: (8), in is the vertical component of the tension at point B; Step 2.3, when the pipeline is subjected to a vertical downward concentrated force, the pipeline shape can be summarized into two types. One concentrated force is applied at the center of the pipeline, called pipeline line type I, and the other concentrated force is applied near the two ends of the pipeline, called pipeline line type II.

[0007] In step 2.3, when the pipeline shape is linear type I, the simultaneous equations (2), (6), and (7) are obtained: (9), When the pipeline shape is linear II, the simultaneous equations (2), (6), and (7) are: (10), Where: (11), in Position for concentrated force application X Axis coordinates, for Y Axis coordinates, is the concentrated load on the pipeline; By numerically solving equations (9) and (10), we can obtain The value of Substituting into equations (6) and (7) we can obtain the distribution characteristics of pipeline tension when the pipeline is subjected to a vertical downward concentrated force.

[0008] Step 3 includes: Step 3.1, based on the known horizontal coordinate of the lowest point of the pipeline , vertical coordinate , get the parameters The constraint equation is: (12), Step 3.2: Use gravity constraint iteration method to solve numerically and construct iteration function : (13), Step 3.3, use gravity constraint iteration method to solve the parameters Calculate the derivative of the iterative function when : (14), in: (15), Step 3.4, the format of gravity constraint iteration method is: (16), in, Indicates the parameters obtained at the nth iteration ; is the convergence factor; Indicates parameter value The function, that is, the function M and N ; The convergence condition is , is the set convergence accuracy; Step 3.5, use the gravity constraint equation to verify the calculation results, set the pipeline A The vertical component of tension at V A ,pipeline B The vertical component of tension at V B ,but: (17), According to the gravity constraint equation ps = V A + V B , the calculation results must satisfy: (18), in s Indicates the arc length of the pipe.

[0009] Step 4 includes: Step 4.1: Arrange three optical fibers along the circumference of the pipe at 0°, 120°, and 240°. Bragg Grating sensor strain sensing path; by optical fiber Bragg Actual tensile and compressive strains of the pipeline collected by the grating sensor ; In step 4.2, the strains obtained at each discrete measuring point are: , then the measurement strain matrix E is defined as: (19), in Indicates the n The strain measured at discrete measuring points; The first-order derivative matrix of the measured strain matrix is calculated using the central difference method : (20), in For the i Strain value of each optical fiber measuring point; For the i -1 optical fiber measuring point strain value; For the i Fiber measurement points X Axis coordinate values; i Value 1~ n ; Calculate the first-order derivative matrix of the measured strain matrix for: (twenty one), Step 4.3: Based on the measured strain matrix and the first-order derivative of the measured strain matrix obtained by the optical fiber sensing system, the tension characteristic correction coefficient matrix is obtained. K : (twenty two), Step 4.4: Establish the pipeline tension identification equation based on the tension correction coefficient matrix.

[0010] In step 4.1, the actual tensile and compressive strains of the pipeline The calculation formula is: (twenty three), in, 、 、 0°, 120°, and 240° optical fibers Bragg The strain is measured by the grating sensor.

[0011] In step 4.1, the pipeline tension identification equation based on the tension correction coefficient matrix is: (twenty four), (25), in Y ( x ) represents the pipeline linear function based on the tension correction coefficient matrix; Represents the pipeline structure tension identification function based on the tension correction coefficient matrix.

[0012] The present invention also provides an electronic device, comprising a processor and a memory, wherein the memory stores program code, and when the program code is executed by the processor, the processor executes the steps of the method.

[0013] The present invention also provides a storage medium storing a computer program or instruction, which executes the steps of the method when the computer program or instruction is run on a computer.

[0014] The method proposed in this paper constructs a pipeline-specific tension function model by determining the pipeline's coordinate system and combining the spatial positional relationship between the pipeline's two constrained ends. Furthermore, a gravity-constrained numerical iteration method is proposed to solve the tension distribution of the pipeline under deadweight conditions, resolving the difficulty associated with the tension function being a transcendental equation. Furthermore, by extracting strain information from fiber optic sensors integrated with the pipeline and constructing a tension characteristic correction coefficient matrix, the accuracy of tension identification is significantly improved.

[0015] The present invention aims to provide data support for real-time monitoring and evaluation of pipeline service status, thereby improving pipeline service safety and stability.

[0016] Beneficial effects: This invention combines optical fiber sensors with innovative tension recognition models, significantly improving pipeline monitoring. It has the following beneficial effects: By correlating the pipeline linear function with the load on the pipeline, the tension identification equation of the pipeline under different stress conditions is derived, breaking through the limitation that the pipeline tension function only contains the pipeline gravity parameters; a gravity-constrained numerical iteration method is proposed to solve the tension distribution of the pipeline under the condition of only its own weight, which solves the problem of equation solving difficulty caused by the tension function being a transcendental equation; at the same time, by extracting the strain information of the optical fiber sensor integrated with the pipeline, a tension characteristic correction coefficient matrix is constructed, which significantly improves the accuracy of tension identification. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, and the above and / or other advantages of the present invention will become more apparent.

[0018] Figure 1 It is a flow chart of the method of the present invention.

[0019] Figure 2 It is a schematic diagram of the simulation constraint application obtained in an implementation case of the present invention.

[0020] Figure 3 This is a comparison diagram of the tension distribution obtained by the method of the present invention and the simulation.

[0021] Figure 4 It is a schematic diagram of the relative error of tension obtained by identification and simulation using the method of the present invention. DETAILED DESCRIPTION

[0022] like Figure 1 As shown, this embodiment provides a pipeline structure tension identification method based on tension coefficient matrix correction, including the following steps: Step 1: Establish a rectangular coordinate system with the lower end of the pipeline as the coordinate origin to determine the horizontal length of the pipeline l , the height difference between the two restrained ends of the pipe h 0, the angle between the two ends of the pipe θ , the gravity load p on the pipeline; Step 2: Based on the tension function theory, derive the tension identification equation when the pipeline is subjected to a vertical downward concentrated force; Step 3: Use the gravity constraint iteration method to numerically solve the key parameters of the tension identification equation when the pipeline is not subjected to the vertical downward concentrated force; Step 4: Attach fiber optic sensors to the pipeline surface to obtain surface strain distribution data during service. Based on the measured strain raw data matrix and its first-order derivative matrix, a tension characteristic correction coefficient matrix is constructed. Substituting the tension characteristic correction coefficient matrix into the tension identification equation corrects for tension identification errors caused by not including detailed pipe material coefficient characteristics.

[0023] Step 2 includes: Step 2.1, take any infinitesimal segment on the pipeline ds Assume the pipe is under tension T The horizontal component of force is H , the vertical component is V , then the static equilibrium equation of the pipeline in the process is obtained by static analysis: (1), Where, d is the differential symbol; y is the pipeline infinitesimal segment Y axis coordinates; x Pipeline micro-segment X Axis coordinates.

[0024] Solve the equation (1) by quadratic integration, and according to the boundary conditions: the horizontal coordinate of the starting point of the pipeline x 1=0, vertical coordinate y 1=0; horizontal coordinate of the pipeline end point x 2=l, vertical coordinate y 2=l, and the linear equation of the pipeline in the free state is obtained: (2), in 、 is an arbitrary constant generated by the integration process, which is determined by formula (3): (3), in arsinh represents the inverse hyperbolic sine function; Step 2.2: Let point C be the lowest point of the pipeline, take the derivative of equation (3) and take the extreme point to obtain the horizontal coordinate of the lowest point C. for: (4), Substituting equation (4) into equation (2), we can obtain the pipeline linear function under the condition of known lowest point: y ( x ): (5), Set pipeline at any position Q ( x , y ) point tension is T , the vertical component of tension is V , the pipeline tension identification equation is obtained from static analysis: (6), (7), According to formula (7), the pipeline is at the lowest point The tension value at the lowest point is The tension value gradually increases towards both ends and reaches the maximum at the higher end point B. Therefore, the maximum tension of the pipeline and minimum value for: (8), in is the vertical component of the tension at point B; Step 2.3, when the pipeline is subjected to a vertical downward concentrated force, the pipeline shape can be summarized into two types. One concentrated force is applied at the center of the pipeline, called pipeline line type I, and the other concentrated force is applied near the two ends of the pipeline, called pipeline line type II.

[0025] In step 2.3, when the pipeline shape is linear type I, the simultaneous equations (2), (6), and (7) are obtained: (9), When the pipeline shape is linear II, the simultaneous equations (2), (6), and (7) are: (10), Where: (11), in Position for concentrated force application X Axis coordinates, for Y Axis coordinates, is the concentrated load on the pipeline; By numerically solving equations (9) and (10), we can obtain The value of Substituting into equations (6) and (7) we can obtain the distribution characteristics of pipeline tension when the pipeline is subjected to a vertical downward concentrated force.

[0026] Step 3 includes: Step 3.1, based on the known horizontal coordinate of the lowest point of the pipeline , vertical coordinate , get the parameters The constraint equation is: (12), Step 3.2: Use gravity constraint iteration method to solve numerically and construct iteration function : (13), Step 3.3, use gravity constraint iteration method to solve the parameters Calculate the derivative of the iterative function when : (14), in: (15), Step 3.4, the format of gravity constraint iteration method is: (16), in, Indicates the parameters obtained at the nth iteration ; is the convergence factor; to ensure , It can be halved based on the previous iteration. Indicates parameter value The function, that is, the function M and N ; The convergence condition is , is the set convergence accuracy; Step 3.5, use the gravity constraint equation to verify the calculation results, set the pipeline A The vertical component of tension at V A ,pipeline B The vertical component of tension at V B ,but: (17), According to the gravity constraint equation ps = V A + V B , the calculation results must satisfy: (18), in s Indicates the arc length of the pipe.

[0027] Step 4 includes: Step 4.1: Arrange three optical fibers along the circumference of the pipe at 0°, 120°, and 240°. Bragg Grating sensor strain sensing path; by optical fiber Bragg Actual tensile and compressive strains of the pipeline collected by the grating sensor ; In step 4.2, the strains obtained at each discrete measuring point are: , then the measurement strain matrix E is defined as: (19), in Indicates the n The strain measured at discrete measuring points; The first-order derivative matrix of the measured strain matrix is calculated using the central difference method : (20), in For the i Strain value of each optical fiber measuring point; For the i -1 optical fiber measuring point strain value; For the i Fiber measurement points X Axis coordinate values; i Value 1~ n ; Calculate the first-order derivative matrix of the measured strain matrix for: (twenty one), Step 4.3: Based on the measured strain matrix and the first-order derivative of the measured strain matrix obtained by the optical fiber sensing system, the tension characteristic correction coefficient matrix is obtained. K : (twenty two), Step 4.4: Establish the pipeline tension identification equation based on the tension correction coefficient matrix.

[0028] In step 4.1, the actual tensile and compressive strains of the pipeline The calculation formula is: (twenty three), in, 、 、 0°, 120°, and 240° optical fibers Bragg The strain is measured by the grating sensor.

[0029] In step 4.1, the pipeline tension identification equation based on the tension correction coefficient matrix is: (twenty four), (25), in Y ( x ) represents the pipeline linear function based on the tension correction coefficient matrix; Represents the pipeline structure tension identification function based on the tension correction coefficient matrix.

[0030] In a specific embodiment of the present invention, a pipeline structure tension identification method based on tension coefficient matrix correction is provided, comprising: Firstly, based on the tension function theory, the tension identification equation when the pipeline is subjected to a vertical downward concentrated force is derived to solve the tension identification problem when the pipeline is subjected to an external force. Secondly, the gravity-constrained iteration method is used to numerically solve the key parameters of the tension identification equation when the pipeline is not subjected to a vertical downward concentrated force, so as to solve the tension identification problem when the pipeline is only subjected to its own gravity. Next, fiber optic sensors are attached to the pipeline surface to acquire surface strain data. A tension correction coefficient matrix is constructed from the raw strain data matrix and its first-order derivative matrix. Substituting this matrix into the tension identification equation corrects for tension identification errors caused by not including detailed pipeline material coefficient characteristics.

[0031] Finally, the pipeline model was established using Ansys Workbench simulation software, and fixed constraints were applied to both ends of the pipeline. At the same time, the pipeline's own gravity load was applied to the pipeline, as shown in the following example: Figure 2 As shown; extract pipeline simulation tension data and strain data, substitute the strain data into the method of the present invention to obtain the tension data identified by the method of the present invention, and compare the two tension data, as shown Figure 3 As shown. The relative error between the tension data of this method and the simulated tension data is calculated, as shown Figure 4 shown.

[0032] The present invention provides a method for identifying pipeline structural tension based on tension coefficient matrix correction. There are numerous methods and approaches for implementing this technical solution. The above is merely a preferred embodiment of the present invention. It should be noted that those skilled in the art may make various improvements and modifications without departing from the principles of the present invention, and such improvements and modifications are also within the scope of protection of the present invention. Components not specified in this embodiment may be implemented using existing technologies.

Claims

1. A pipeline structure tension identification method based on tension coefficient matrix correction is characterized by: The following steps are involved: Step 1: Establish a rectangular coordinate system with the lower end of the pipeline as the origin to determine the length of the pipeline l , the height difference between the two restrained ends of the pipe h 0, the angle between the two ends of the pipe θ , the gravity load p on the pipeline; Step 2: Based on the tension function theory, derive the corresponding tension identification equation when the pipeline is subjected to a vertical downward concentrated force; Step 3: Using the gravity constraint iteration method, numerically solve the key parameters of the tension identification equation when the pipeline is not subjected to the vertical downward concentrated force; Step 4: Attach fiber optic sensors to the pipeline surface to obtain the strain distribution data on the pipeline surface during service. Construct a tension characteristic correction coefficient matrix based on the measured strain raw data matrix and the first-order derivative matrix. Substitute the tension characteristic correction coefficient matrix into the tension identification equation to correct the tension identification error caused by not including the detailed material coefficient characteristics of the pipeline.

2. The method according to claim 1, characterized in that In step 1, the horizontal length of pipe AB is defined as l , the gravity load p acting on the pipeline is solved by the pipeline density.

3. The method according to claim 2, characterized in that Step 2 includes: Step 2.1, take any infinitesimal segment on the pipeline ds , set the pipe to be under tension T The horizontal component of force is H , the vertical component is V , then the static equilibrium equation of the pipeline during service is obtained by static analysis: （1）， in d is the differential symbol; y is the pipeline infinitesimal segment Y Axis coordinate; x is the pipeline microelement segment X axis coordinates; Solve the equation (1) by quadratic integration, and according to the boundary conditions: the horizontal coordinate of the starting point of the pipeline x 1=0, vertical coordinate y 1=0; horizontal coordinate of the pipeline end point x 2=l, vertical coordinate y 2=l, and the linear equation of the pipeline in the free state is obtained: （2）， in 、 is an arbitrary constant generated by the integration process, which is determined by formula (3): （3）， in arsinh represents the inverse hyperbolic sine function; Step 2.2: Let point C be the lowest point of the pipeline, take the derivative of equation (3) and take the extreme point to obtain the horizontal coordinate of the lowest point C. for: （4）， Substituting equation (4) into equation (2), we can obtain the pipeline linear function under the condition of known lowest point: y ( x ): （5）， Set pipeline at any position Q ( x , y ) point tension is T , the vertical component of tension is V , the pipeline tension identification equation is obtained from static analysis: （6）， （7）， According to formula (7), the pipeline is at the lowest point The tension value at the lowest point is The tension value gradually increases towards both ends and reaches the maximum at the higher end point B. Therefore, the maximum tension of the pipeline and minimum value for: （8）， in is the vertical component of the tension at point B; Step 2.3, when the pipeline is subjected to a vertical downward concentrated force, the pipeline shape can be summarized into two types. One concentrated force is applied at the center of the pipeline, called pipeline line type I, and the other concentrated force is applied near the two ends of the pipeline, called pipeline line type II.

4. The method according to claim 3, characterized in that In step 2.3, when the pipeline shape is linear type I, the simultaneous equations (2), (6), and (7) are obtained: （9）， When the pipeline shape is linear II, the simultaneous equations (2), (6), and (7) are: （10）， Where: （11）， in Position for concentrated force application X Axis coordinates, for Y Axis coordinates, is the concentrated load on the pipeline; By numerically solving equations (9) and (10), we can obtain The value of Substituting into equations (6) and (7) we can obtain the distribution characteristics of pipeline tension when the pipeline is subjected to a vertical downward concentrated force.

5. The method according to claim 4, characterized in that Step 3 includes: Step 3.1, based on the known horizontal coordinate of the lowest point of the pipeline , vertical coordinate , get the parameters The constraint equation is: （12）， Step 3.2: Use gravity constraint iteration method to solve numerically and construct iteration function : （13）， Step 3.3, use gravity constraint iteration method to solve the parameters Calculate the derivative of the iterative function when : （14）， in: （15）， Step 3.4, the format of gravity constraint iteration method is: （16）， in, Indicates the parameters obtained at the nth iteration ; is the convergence factor; Indicates parameter value The function, that is, the function M and N ; The convergence condition is , is the set convergence accuracy; Step 3.5, use the gravity constraint equation to verify the calculation results, set the pipeline A The vertical component of tension at V A ,pipeline B The vertical component of tension at V B ,but: （17）， According to the gravity constraint equation ps = V A + V B , the calculation results must satisfy: （18）， in s Indicates the arc length of the pipe.

6. The method according to claim 5, characterized in that Step 4 includes: Step 4.1: Arrange three optical fibers along the circumference of the pipe at 0°, 120°, and 240°. Bragg Grating sensor strain sensing path; by optical fiber Bragg Actual tensile and compressive strains of the pipeline collected by the grating sensor ; In step 4.2, the strains obtained at each discrete measuring point are: , then the measurement strain matrix E is defined as: （19）， in Indicates the n The strain measured at discrete measuring points; The first-order derivative matrix of the measured strain matrix is calculated using the central difference method : （20）， in For the i Strain value of each optical fiber measuring point; For the i -1 strain value of optical fiber measuring point; For the i Fiber measurement points X Axis coordinate values; i Value 1~ n ; Calculate the first-order derivative matrix of the measured strain matrix for: （21）， Step 4.3: Based on the measured strain matrix and the first-order derivative of the measured strain matrix obtained by the optical fiber sensing system, the tension characteristic correction coefficient matrix is obtained. K : （22）， Step 4.4: Establish the pipeline tension identification equation based on the tension correction coefficient matrix.

7. The method according to claim 6, characterized in that In step 4.1, the actual tensile and compressive strains of the pipeline The calculation formula is: （23）， in, 、 、 0°, 120°, and 240° optical fibers Bragg The strain is measured by the grating sensor.

8. The method according to claim 7, characterized in that In step 4.1, the pipeline tension identification equation based on the tension correction coefficient matrix is: （24）， （25）， in Y ( x ) represents the pipeline linear function based on the tension correction coefficient matrix; Represents the pipeline structure tension identification function based on the tension correction coefficient matrix.

9. An electronic device, characterized in that: The method comprises a processor and a memory, wherein the memory stores program codes, and when the program codes are executed by the processor, the processor is caused to perform the steps of the method according to any one of claims 1 to 8.

10. A storage medium, characterized in that: A computer program or instruction is stored, and when the computer program or instruction is run on a computer, the steps of the method according to any one of claims 1 to 8 are executed.

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