Real-time dynamic health monitoring method for pipeline
Through the inverse finite element method and strain mode differential method, non-invasive sensors are used to realize real-time dynamic health monitoring of spacecraft propulsion system pipelines, solving the problem of pipeline health monitoring under complex loads, improving monitoring accuracy and computing efficiency, and ensuring Promote the safety of the propulsion system.
Patent Information
- Application Number
- CN202411310179.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-19
- Publication Date
- 2024-12-27
AI Technical Summary
The spacecraft propulsion system pipeline is easily damaged under complex vibration and impact loads, resulting in the impact of safety and working capacity. Due to the special environment of the spacecraft, there are many difficulties in pipeline health monitoring, such as limited number of sensors and invasive sensors working on the system. It is difficult to achieve accurate health monitoring.
The inverse finite element method and strain mode differential method are used, and a small number of non-invasive strain sensors are used to reconstruct the pipeline structure state through the inverse finite element model, and the strain mode information is obtained for damage detection, real-time dynamic health monitoring of the pipeline is realized.
It improves the accuracy of pipeline health monitoring and reduces the impact of complex loads on monitoring. It is suitable for pipeline structures with any boundary conditions, has high computing efficiency, can realize damage detection in real time, and improves the safety and reliability of the propulsion system.
Smart Images
Figure CN119203674A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of pipeline health monitoring of a propulsion system, and in particular to a pipeline real-time dynamic health monitoring method. Background Art
[0002] In recent years, the propulsion power system of spacecraft attitude and orbit control has made breakthroughs in various key technologies and has developed in the direction of miniaturization, fast response, and high performance. The aerospace propulsion system provides control force and thrust for the spacecraft to complete orbital maneuvers, attitude control, and rendezvous and docking tasks. The structure of the spacecraft propulsion system is complex, and the propellant pipeline is responsible for connecting various components and transporting propellant. However, it is often damaged by severe vibration and impact loads caused by pump and valve operation or external excitation during operation, which seriously affects the safety and working function of the propulsion system.
[0003] Due to the special working environment of spacecraft, there are many difficulties in health monitoring of its pipeline structure. For example, spacecraft are in the complex and uncertain environment of space for a long time, and the probability of component failure is greatly increased; there are many potential sources of failure and they are very harmful; the limited number of aerospace products leads to limited monitoring times and little prior information for fault diagnosis; the resources on the spacecraft and the degree of human intervention are limited. Considering the working requirements of the spacecraft, the number of sensors that can be configured is limited, and some invasive sensors will affect the system operation, which brings great challenges to the health monitoring of the spacecraft propulsion system.
[0004] In actual situations, the loads borne by the propulsion system pipeline are very complex, and the interaction between the pipeline and the transported fluid causes coupling and mutual interference. How to ensure that the monitoring accuracy is not affected by the complex load and realize the health monitoring of the pipeline under the working state based on a limited number of non-invasive sensors is a key technical problem in this field.
[0005] Therefore, it is necessary to provide a pipeline real-time dynamic health monitoring method to solve the above problems. Summary of the invention
[0006] The present invention provides a pipeline real-time dynamic health monitoring method, which adopts the inverse finite element method and the strain modal difference method, uses a small number of non-invasive strain sensors to realize the shape sensing of the pipeline structure in a complex stress environment, and uses the strain modal information to detect pipeline damage, providing technical means for the real-time dynamic health monitoring of the pipeline structure of the propulsion system in service, so as to solve the existing actual situation that the load borne by the pipeline of the propulsion system is very complex, and the interaction between the pipeline and the conveying fluid causes coupling and mutual interference. The monitoring accuracy is affected by the complex load, and it is difficult to realize the health monitoring of the pipeline in the working state.
[0007] A pipeline real-time dynamic health monitoring method of the present invention adopts the following technical solution, including: Construct an inverse finite element model of the pipeline structure based on the inverse finite element method; Obtain the surface strain of the inverse beam unit in the inverse finite element model; derive the theoretical strain and theoretical curvature of the inverse beam unit in the inverse finite element model based on the inverse finite element method, and obtain the measured strain and measured curvature of each inverse beam unit according to the theoretical strain and surface strain of the inverse beam unit; According to the measured strain, measured curvature, theoretical strain and theoretical curvature of each inverse beam element, a weighted least square error functional of the inverse beam element is constructed, and the weighted least square error functional is minimized to obtain the inverse finite element equation of the inverse beam element; According to the conversion matrix between the local coordinate system of the inverse beam unit and the global coordinate system of the inverse finite element model of the pipeline structure, the inverse finite element equation is converted to the global coordinate system and the overall inverse finite element equation of the pipeline structure is obtained; the overall inverse finite element equation of the pipeline structure is solved to obtain the global displacement field of the inverse finite element model; Based on the global displacement field and using the modal superposition method, the strain mode of the pipeline structure is obtained, and the differential curves of each order of strain mode are obtained; the damage location index is constructed according to the effective extreme points and effective zero points of the differential curve, and the damage location is obtained according to the mutation position and damage location index in the differential curve.
[0008] Preferably, the steps of constructing an inverse finite element model of the pipeline structure based on the inverse finite element method are: Construct inverse beam element based on Euler-Bernoulli beam theory; The inverse beam unit is used to discretize the pipeline structure and an inverse finite element model of the pipeline structure is constructed.
[0009] Preferably, the step of obtaining the surface strain of the inverse finite element model is: symmetrically arranging strain sensors on the upper and lower surfaces of the inverse finite element model of the pipeline structure, and obtaining the surface strain of the inverse finite element model of the pipeline structure through the strain sensors.
[0010] Preferably, the expression of the measured strain of each inverse beam element is:
[0011] In the formula, represents the first The measured strain at each measuring point; The first Surface strain at each measuring point; The first Surface strain at each measuring point.
[0012] Preferably, the expression of the measured curvature of each inverse beam element is:
[0013] In the formula, represents the first The measured curvature of each measuring point; The first Surface strain at each measuring point; The first Surface strain at each measuring point; Indicates the outside diameter of the pipe structure.
[0014] Preferably, the expression of the weighted least squares error functional of the inverse beam element is:
[0015] In the formula, represents the first i The weighted least squares error functional between the measured strain and the theoretical strain of an inverse beam element; represents the regularized strain weighting coefficient; represents the first i Theoretical strain of an inverse beam element; represents the first i The measured strain of the inverse beam element; represents the regularized curvature weighting coefficient; represents the first i Theoretical curvature of an inverse beam element; represents the first i The measured curvature of an inverse beam element.
[0016] Preferably, the inverse finite element equation of the inverse beam unit is expressed as:
[0017] In the formula, represents the first i The solution of the inverse finite element equations for an inverse beam element; represents the first i The pseudo-stiffness matrix of the inverse beam element; represents the first i Pseudo load matrix for an inverse beam element.
[0018] Preferably, the inverse finite element equation of each inverse beam unit is converted to the global coordinate system, and the inverse finite element equation is assembled into the overall inverse finite element equation of the pipeline structure according to the standard finite element program. In combination with the constraint method of the pipeline structure, the pseudo-stiffness matrix and pseudo-load matrix of the overall inverse finite element equation are deleted and processed to obtain the target inverse finite element equation. The target inverse finite element equation is inverted and inverted once to obtain the global displacement field of the inverse finite element model of the pipeline structure.
[0019] Preferably, the steps of obtaining the differential curves of each order strain mode are: Taylor expansion is performed on the strain mode function, and the cubic and higher-order power terms are ignored to obtain an equally spaced difference format; The strain mode difference curve is fitted according to the equally spaced difference format.
[0020] Preferably, the expression of the damage index is:
[0021] In the formula, It represents the damage location index at the sth effective zero value point in the strain modal difference curve; Represents the extreme value of the effective extreme point to the right of the sth effective zero point; Represents the extreme value of the effective extreme point on the left side of the sth effective zero point; Represents the x-coordinate of the effective extreme point to the right of the sth effective zero point; Represents the x-coordinate of the effective extreme point to the left of the sth effective zero point; Indicates the difference curve The effective extreme value of the effective extreme point; Represents the span length of the pipeline structure; t represents the number of effective extreme points.
[0022] The beneficial effects of the present invention are: By obtaining the surface strain of the pipeline structure, the impact on the working state of the pipeline is reduced. When the inverse finite element method is used to reconstruct the pipeline structure state, only the strain data of a limited number of measuring points are used to obtain the strain mode of the pipeline measurement. The inverse finite element method is sufficiently versatile when performing shape sensing of the pipeline structure and is suitable for pipeline structures with any boundary conditions. It has high calculation efficiency, fast speed, and can be implemented in real time. Further, according to the real-time inverted structural state, the damage index constructed based on the damage strain modal difference principle can be used to detect pipeline damage using only the strain modal data after damage, thereby improving the accuracy of pipeline health monitoring. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] 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 these drawings without paying creative work.
[0024] Figure 1 A flow chart of a pipeline real-time dynamic health monitoring method of the present invention; Figure 2 A detailed flow chart of an embodiment of a pipeline real-time dynamic health monitoring method of the present invention; Figure 3 Schematic diagram of the arrangement position of sensors in an embodiment of the present invention; Figure 4 A schematic diagram of a local coordinate system of an inverted beam unit and a global coordinate system of a pipeline structure of the present invention; Figure 5 It is a differential curve diagram of the strain modal differential of the present invention. DETAILED DESCRIPTION
[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0026] An embodiment of a pipeline real-time dynamic health monitoring method of the present invention is as follows: Figure 1 and Figure 2 As shown, including: S1. Construct an inverse finite element model of the pipeline structure; Specifically, an inverse finite element model of the pipeline structure is constructed based on the inverse finite element method. In this embodiment, since the pipeline structure is tubular, an inverse beam unit is used to discretize it according to the actual pipeline structure form; that is, an inverse beam unit is constructed based on the Euler-Bernoulli beam theory, and the inverse beam unit is used to discretize the pipeline structure. Generally speaking, the more inverse beam units are divided, the higher the accuracy of shape sensing using the inverse finite element method. However, when the number reaches a certain level, increasing the number of inverse beam units will not significantly improve the reconstruction accuracy, and will cause a substantial increase in computational and economic costs. Therefore, considering the monitoring accuracy requirements and budget costs of the pipeline, it is sufficient to select an inverse beam unit with a suitable density to discretize the actual structure.
[0027] S2, obtaining the measured strain and measured curvature of each inverse beam element; Specifically, the surface strain of the inverse beam unit in the inverse finite element model is obtained; the theoretical strain and theoretical curvature of the inverse beam unit in the inverse finite element model are derived based on the inverse finite element method, and the measured strain and measured curvature of each inverse beam unit are obtained according to the theoretical strain and surface strain of the inverse beam unit.
[0028] Step 21: The steps for obtaining the surface strain of the inverse beam element in the inverse finite element model are: like Figure 3 As shown, in this embodiment, strain sensors are arranged on the upper and lower surfaces of the inverse finite element model of the pipeline structure, and sensor measuring points are not arranged inside, thereby reducing the influence of the existence of the strain sensors on the working state of the pipeline structure. The arrangement position of the sensor is closely related to the discrete mode of the pipeline structure in step S1. According to actual needs, 1 to n strain sensors can be arranged on the same inverse beam unit, and the positions of the strain sensors on the upper and lower surfaces of the inverse finite element model of the pipeline structure are symmetrical. Sensor measuring points can be added to the key parts of the pipeline structure, and as many sensor measuring points as possible can be arranged within the budget.
[0029] Step 22: The steps for obtaining the theoretical strain and theoretical curvature of each inverse beam element are: Based on the Euler-Bernoulli beam theory, each inverse beam element in the constructed inverse finite element model has two nodes, each node has three degrees of freedom, and a local coordinate system is constructed on the inverse beam element, such as Figure 4 As shown, the origin of the local coordinate system is located at the left node, the left node points to the right node as the x direction of the local coordinate system, and the vertical direction perpendicular to the axis of the beam is the y direction of the local coordinate system. The displacement component of the node of the inverse beam element can be expressed as: (1) In the formula, is the displacement along the x-axis of the local coordinate system; is the displacement along the y-axis of the local coordinate system; It is in the local coordinate system z The rotation angle with the axis direction as the normal direction; is the displacement of any point on the inverse beam element along the x-axis; is the displacement of any point on the inverse beam element along the y-axis.
[0030] Select appropriate shape functions to interpolate the displacement components in the inverse beam element, and then substitute the above kinematic relationship (1) into the strain-displacement relationship It can be obtained that the theoretical surface strain can be written as a linear combination of the measured strain and the bending curvature, using the displacement vector of the node of the inverse beam element in the local coordinate system It represents the cross-sectional strain of the inverse beam element. The specific form is as follows: , i = 1, 2,…, ne(2) In the formula, is the first i The displacement vector of the node of the inverse beam unit; ne represents the total number of inverse beam units divided into the pipeline structure; That is, the first i The theoretical strain of an inverse beam element, is the first i The theoretical curvature, theoretical strain and theoretical curvature of the inverse beam element are all in the local coordinate system. i The functions of the displacement vectors of the nodes of the inverse beam element are expressed as and , is the matrix of shape function derivatives of cross-sectional strain; is the matrix of shape function derivatives of bending curvature; is the surface strain of the inverse beam element.
[0031] Step 23: Obtain the measured strain and measured curvature of each inverse beam element as follows: At the same time, according to the relationship between the surface strain and the measured strain and the measured curvature, the surface strain corresponding to the upper and lower surfaces of the pipeline measured by the strain sensor is used to deduce the corresponding measured strain of the inverse beam unit: , j = 0, 1, 2,…, n (3) In the formula, represents the first The measured strain at each measuring point; The first Surface strain at each measuring point; The first Surface strain at each measuring point.
[0032] The measured curvature is: , j = 0, 1, 2,…, n (4) In the formula, represents the first The measured curvature of each measuring point; The first Surface strain at each measuring point; The first Surface strain at each measuring point; Indicates the outer diameter of the pipe structure, the superscript + indicates the upper surface and the superscript - indicates the lower surface. In this embodiment, a total of n measuring points.
[0033] So far, the theoretical strain, theoretical curvature, measured strain, and measured curvature of the pipeline structure of the inverse finite element model have been obtained.
[0034] S3, obtaining the inverse finite element equation of the inverse beam element; Specifically, according to the measured strain, measured curvature, theoretical strain and theoretical curvature of each inverse beam element, a weighted least squares error functional of the inverse beam element is constructed, and the weighted least squares error functional is minimized to obtain the inverse finite element equation of the inverse beam element.
[0035] Step 31, the expression of the weighted least squares error functional of the inverse beam element is: (5) In the formula, represents the first i The weighted least squares error functional between the measured strain and the theoretical strain of an inverse beam element; represents the regularized strain weighting coefficient; represents the first i Theoretical strain of an inverse beam element; represents the first i The measured strain of the inverse beam element; represents the regularized curvature weighting coefficient; represents the first i Theoretical curvature of an inverse beam element; represents the first i The measured curvature of an inverse beam element.
[0036] Step 32, i The inverse finite element equation of an inverse beam element is expressed as: , i = 1, 2,…, ne (6) In the formula, represents the first i The solution of the inverse finite element equations for an inverse beam element; represents the first i The pseudo-stiffness matrix of the inverse beam element; represents the first iThe pseudo load matrix of the inverse beam elements is ne, and ne represents the total number of inverse beam elements into which the pipeline structure is divided.
[0037] Among them, the expression of the pseudo stiffness matrix is: (7) The expression of the pseudo load matrix is: (8) In the formula, le is the axial length of the inverse beam element; For the i Unit j The measured strain obtained at each measuring point; For the i Unit j The measured curvature obtained at each measuring point; is the matrix of shape function derivatives of cross-sectional strain; is the matrix of the shape function derivatives of the bending curvature.
[0038] S4, obtaining the global displacement field of the inverse finite element model; The inverse finite element equation of each inverse beam unit is converted to the global coordinate system, and the inverse finite element equations are assembled into the overall inverse finite element equation of the pipeline structure according to the standard finite element program. Combined with the constraint method of the pipeline structure, the pseudo-stiffness matrix and pseudo-load matrix of the overall inverse finite element equation are deleted and processed. The processed equations are inverted and inverted to obtain the global displacement field of the inverse finite element model of the pipeline structure.
[0039] Step 41, the step of obtaining the overall inverse finite element equation of the pipeline structure is as follows: In this embodiment, the inverse finite element equation of the inverse beam unit in step S3 is transformed from the local coordinate system to the global coordinate system through the conversion matrix, and then assembled according to the standard finite element program to obtain the linear inverse finite element equation group of the overall structure, and further considering the constraint form of the actual pipeline structure, the pseudo-stiffness matrix and pseudo-load vector of the overall equation are deleted to obtain the overall inverse finite element equation of the processed pipeline structure, that is, the overall inverse finite element equation obtained by finite element integration and summation is: (9) Where K is the pseudo-stiffness matrix of the overall inverse finite element equation; is the pseudo load matrix of the overall inverse finite element equation; is the solution of the overall inverse finite element equation, that is, the global displacement of the inverse finite element model; the global displacement field can be obtained based on the global displacement.
[0040] S5. Obtain the damage location; Specifically, based on the global displacement field and using the modal superposition method to obtain the strain mode of the pipeline structure, the differential curves of each order of strain mode are obtained; the damage location index is constructed according to the effective extreme points and effective zero points of the differential curve, and the damage location is obtained according to the mutation position and damage location index in the differential curve.
[0041] Step 51, the step of obtaining the strain mode of the pipeline structure is: Taylor expansion of the variable mode function, and ignoring the cubic power term and higher-order power terms to obtain an equally spaced difference format; fitting the difference curve of the strain mode according to the equally spaced difference format.
[0042] Among them, the inverse finite element method is used to invert the global displacement field of the pipeline through limited sensor data, and the strain mode is further derived by the mode superposition method, that is: (10) In the formula, is the deformation of the pipe in the x direction; is the modal coordinate; is the displacement mode; For the r Strain mode.
[0043] right r Taylor expansion of the first-order strain modal function, ignoring the cubic and higher-order power terms, can obtain the equally spaced difference format: (11) In the formula, k Indicates k nodes; l Represents the distance between two adjacent nodes; x k-1 For Node k A coordinate value of -1, x k+1 For Node k +1 x Coordinate value.
[0044] Similarly, the second-order difference values at the two nodes used for differential curve interpolation are obtained through Taylor expansion: (12) (13) In the formula, nn is the total number of nodes of all inverse beam elements in the inverse finite element model; is the horizontal coordinate of node nn-2; is the horizontal coordinate of node nn; is the horizontal coordinate of node 3; is the horizontal coordinate of node 2; is the horizontal coordinate of node 1; Step 52: The steps of constructing the damage location index are: According to the difference curve, any two adjacent extreme values have different signs, and there is only one zero point between them, which is defined as a valid extreme point, that is, Figure 5 The horizontal coordinate is x 1, x 2, x 3 and x 4 corresponding to the effective extreme point, the corresponding effective extreme value is y 1, y 2, y 3 and y 4. Ignore zero points near the supports (such as Figure 4 shown l’ ) is a valid zero point, that is l 1, l 2, l 3. l 4, thus constructing the damage location index as:
[0045] In the formula, It represents the damage location index at the sth effective zero value point in the strain modal difference curve; Represents the extreme value of the effective extreme point to the right of the sth effective zero point; Represents the extreme value of the effective extreme point on the left side of the sth effective zero point; Represents the x-coordinate of the effective extreme point to the right of the sth effective zero point; Represents the x-coordinate of the effective extreme point to the left of the sth effective zero point; Indicates the difference curve The effective extreme value of the effective extreme point; Represents the span length of the pipeline structure; t represents the number of effective extreme points.
[0046] Finally, the damage location of the pipeline structure can be determined by the mutation in the strain modal difference curve and the values of the above damage indicators. The larger the value of the damage location indicator, the greater the possibility of damage. Figure 5 The position of the peak in the difference curve can be used to determine the damage position, that is, in this embodiment, the effective zero value point corresponding to the value of the maximum damage position indicator is used as the damage position.
[0047] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims
1. A pipeline real-time dynamic health monitoring method, characterized in that: include: Construct an inverse finite element model of the pipeline structure based on the inverse finite element method; Obtain the surface strain of the inverse beam unit in the inverse finite element model; derive the theoretical strain and theoretical curvature of the inverse beam unit in the inverse finite element model based on the inverse finite element method, and obtain the measured strain and measured curvature of each inverse beam unit according to the theoretical strain and surface strain of the inverse beam unit; According to the measured strain, measured curvature, theoretical strain and theoretical curvature of each inverse beam element, a weighted least square error functional of the inverse beam element is constructed, and the weighted least square error functional is minimized to obtain the inverse finite element equation of the inverse beam element; According to the conversion matrix between the local coordinate system of the inverse beam unit and the global coordinate system of the inverse finite element model of the pipeline structure, the inverse finite element equation is converted to the global coordinate system and the overall inverse finite element equation of the pipeline structure is obtained; the overall inverse finite element equation of the pipeline structure is solved to obtain the global displacement field of the inverse finite element model; Based on the global displacement field and using the modal superposition method, the strain mode of the pipeline structure is obtained, and the differential curves of each order of strain mode are obtained; the damage location index is constructed according to the effective extreme points and effective zero points of the differential curve corresponding to each order of strain mode, and the damage location is obtained according to the mutation position and damage location index in the differential curve corresponding to each order of strain mode.
2. A pipeline real-time dynamic health monitoring method according to claim 1, characterized in that: The steps of constructing the inverse finite element model of the pipeline structure based on the inverse finite element method are as follows: Construct inverse beam element based on Euler-Bernoulli beam theory; The inverse beam unit is used to discretize the pipeline structure and an inverse finite element model of the pipeline structure is constructed.
3. A pipeline real-time dynamic health monitoring method according to claim 1, characterized in that: The step of obtaining the surface strain of the inverse finite element model is: symmetrically arranging strain sensors on the upper surface and the lower surface of the inverse finite element model of the pipeline structure, and obtaining the surface strain of the inverse finite element model of the pipeline structure through the strain sensors.
4. A pipeline real-time dynamic health monitoring method according to claim 1, characterized in that: The expression for the measured strain of each inverse beam element is: In the formula, represents the first The measured strain at each measuring point; The first Surface strain at each measuring point; The first The surface strain at each measuring point.
5. A pipeline real-time dynamic health monitoring method according to claim 1, characterized in that: The expression for the measured curvature of each inverse beam element is: In the formula, represents the first The measured curvature of each measuring point; The first Surface strain at each measuring point; The first Surface strain at each measuring point; Indicates the outside diameter of the pipe structure.
6. A pipeline real-time dynamic health monitoring method according to claim 1, characterized in that: The expression of the weighted least squares error functional of the inverse beam element is: In the formula, represents the first i The weighted least squares error functional between the measured strain and the theoretical strain of an inverse beam element; represents the regularized strain weighting coefficient; represents the first i Theoretical strain of an inverse beam element; represents the first i The measured strain of the inverse beam element; represents the regularized curvature weighting coefficient; represents the first i Theoretical curvature of an inverse beam element; represents the first i The measured curvature of an inverse beam element.
7. A pipeline real-time dynamic health monitoring method according to claim 1, characterized in that: The inverse finite element equation of the inverse beam element is expressed as: In the formula, represents the first i The solution of the inverse finite element equations for an inverse beam element; represents the first i The pseudo-stiffness matrix of the inverse beam element; represents the first i Pseudo load matrix for an inverse beam element.
8. A pipeline real-time dynamic health monitoring method according to claim 7, characterized in that: The inverse finite element equation of each inverse beam unit is converted to the global coordinate system, and the inverse finite element equations are assembled into the overall inverse finite element equation of the pipeline structure according to the standard finite element program. Combined with the constraint method of the pipeline structure, the pseudo-stiffness matrix and pseudo-load matrix of the overall inverse finite element equation are deleted, and the processed equations are inverted and inverted to obtain the global displacement field of the inverse finite element model of the pipeline structure.
9. A pipeline real-time dynamic health monitoring method according to claim 1, characterized in that: The steps to obtain the differential curves of each order strain mode are: Taylor expansion is performed on the strain mode function, and the cubic and higher-order power terms are ignored to obtain an equally spaced difference format; The strain mode difference curve is fitted according to the equally spaced difference format.
10. A pipeline real-time dynamic health monitoring method according to claim 1, characterized in that: The expression of damage index is: In the formula, It represents the damage location index at the sth effective zero value point in the strain modal difference curve; Represents the extreme value of the effective extreme point to the right of the sth effective zero point; Represents the extreme value of the effective extreme point on the left side of the sth effective zero point; Represents the x-coordinate of the effective extreme point to the right of the sth effective zero point; Represents the x-coordinate of the effective extreme point to the left of the sth effective zero point; Indicates the difference curve The effective extreme value of the effective extreme point; Represents the span length of the pipeline structure; t represents the number of effective extreme points.