Non-contact high-speed test method for pipe vibration test section load

Abstract

The present application provides a kind of pipeline vibration test section load non-contact high-speed test method, belong to measurement testing field, including the following steps: first step: test system setup;Second step: test image acquisition;Third step: deformation field calculation;Fourth step: reflection transformation calculation;Fifth step: pipeline full circumferential surface morphology reconstruction;Sixth step: deformation field measurement;From the three-dimensional point cloud of initial state in the three-dimensional point cloud of deformation state, obtain the three-dimensional displacement field of each deformation state, further calculate three-dimensional displacement field, obtain the required strain field;Seventh step: pipeline section stiffness coefficient calibration;Eighth step: based on single system multi-view pipeline full circumferential deformation test method, the deformation information under pipeline section load is collected, and section load data is calculated according to section stiffness coefficient data and strain data, complete test.The present application solves the problem of low test reliability and measurement accuracy caused by the quality of sensor and wire itself in the prior art.

Description

Technical Field

[0001] This invention belongs to the field of measurement and testing technology, specifically relating to a non-contact high-speed testing method for cross-sectional loads in pipeline vibration tests. Background Technology

[0002] Piping structures are typically used to transport fluid media such as gases and liquids, and are widely used in important fields such as aerospace and shipbuilding. Among them, delivery pipelines, pressurization pipelines, and pre-cooling reflux pipelines are common forms and important structures of aerospace rocket systems, acting like the "blood vessels" of rocket engines to provide "blood" to the core of the propulsion system.

[0003] Given that pipelines have the fundamental function of delivering designated media to their intended use, the pipeline delivery system is a crucial component of the spacecraft's propulsion system throughout its service life. The safety and reliability of the pipeline structure directly impact the overall reliability of the spacecraft. From the initial production and assembly of the spacecraft to its final launch and flight, the pipeline structure endures complex and severe mechanical environmental loads (such as vibration and shock, temperature, high pressure, and self-excited vibrations caused by fluid-solid coupling). These load factors significantly threaten the strength of the pipeline structure. Instantaneous impact loads can cause loosening or wear of clamps or pipe joints due to excessive stress peaks, and in severe cases, can even lead to pipeline deformation and breakage. Prolonged cyclic loads can cause coupled vibrations, leading to fatigue failure of the pipeline structure and consequently affecting the overall reliability of the spacecraft. Therefore, ground-based simulations of the load conditions experienced by the pipeline are necessary to verify the overall strength and reliability of the pipeline system and reduce the probability of system failure.

[0004] The purpose of pipeline cross-sectional load (including vibration load) testing and analysis is to clarify the types, values, and transmission paths of loads in the pipeline, providing a basis for pipeline structural layout and strength design. Currently, the common method for testing pipeline cross-sectional loads is the resistance strain gauge method, which is characterized by high accuracy. However, in high-magnitude vibration tests, the load influence caused by the mass of the sensor and the conductor itself will be greatly increased, affecting the interpretation of test data.

[0005] In summary, existing contact-type pipeline cross-sectional load testing methods are affected by the mass of the sensors and conductors themselves, which can impact the load during the test, especially in high-level vibration tests. It is necessary to improve these methods, develop new testing techniques, and enhance the reliability and measurement accuracy of the tests. Summary of the Invention

[0006] This invention provides a non-contact high-speed testing method for cross-sectional loads in pipeline vibration tests, aiming to solve the problems in existing technologies where the mass of the sensors and wires themselves affects the load during the test, resulting in low test reliability and measurement accuracy.

[0007] The objective of this invention is achieved through the following technical solution:

[0008] A non-contact, high-speed method for testing cross-sectional loads in pipeline vibration tests includes the following steps:

[0009] Step 1: Setting up the experimental system;

[0010] The pipeline under test is installed on the test bench. An optical measurement system is installed on one side of the pipeline, and a plane mirror group consisting of two plane mirrors is installed on the other side. Speckle patterns are prepared on the entire surface and circumference of the pipeline and at the edge of the plane mirror.

[0011] Step 2: Experimental image acquisition;

[0012] During the pipeline vibration test, a photoelectric measurement system was used to continuously acquire clear test images;

[0013] Step 3: Deformation field calculation;

[0014] The coordinate fields of all object surfaces with speckle patterns were obtained by calculating the image sequence using the optical measurement system software; all data were in the camera coordinate system of the optical measurement system.

[0015] Step 4: Calculation of reflection transformation;

[0016] To obtain the complete circumferential deformation field of the pipeline, the speckle patterns of the pipeline in two regions need to be reflected and transformed onto two mirror planes respectively. The spatial plane equation of the plane mirror is established by using the speckle coordinate field obtained by the optical measurement system, and the reflection transformation matrix of the mirror is constructed.

[0017] Step 5: Reconstruct the surface morphology of the entire pipeline circumference;

[0018] Based on the reflection transformation matrix, all the reconstructed virtual surfaces are reflected back to their real positions, thereby obtaining the morphology of multiple surface regions in the same world coordinate system. The three fields of the pipeline are spliced ​​together by the transformation matrix.

[0019] Step 6: Deformation field measurement;

[0020] Subtract the initial three-dimensional point cloud from the three-dimensional point cloud of the deformed state to obtain the three-dimensional displacement field of each deformed state. Further calculate the three-dimensional displacement field to obtain the required strain field.

[0021] Step 7: Calibration of pipe section stiffness coefficient;

[0022] One end of the pipeline is fixed, and a known load is applied to the other end. The deformation information of the pipeline section under the load is collected according to the pipeline full circumferential deformation test method from step one to step six. The section stiffness coefficient data is obtained by calculation using the load identification formula.

[0023] Step 8: Based on the single-system multi-view pipeline full-circumferential deformation test method, the deformation information of the pipeline section under load is collected, and the section load data is calculated according to the section stiffness coefficient data and strain data to complete the non-contact high-speed test of the pipeline vibration test section load.

[0024] As a preferred approach, in the pipeline full-circumference surface morphology reconstruction step, strain is calculated for each region separately, and subsequent deformation field calculations are performed directly on each real surface transformed to the same world coordinate system.

[0025] As a preferred option, the load identification formula in the pipeline section stiffness coefficient calibration step is as follows:

[0026] N=K N ε a =K N (ε1+ε2)

[0027] My = K M ε b =K M (ε1-ε2)

[0028] In the formula, N represents the axial force at the pipe cross section, and the unit is N;

[0029] My represents the bending moment of the pipe section, in N·m;

[0030] e1 and e2 are the strains measured by optical methods, and are dimensionless parameters; K N This represents the axial stiffness coefficient of the pipeline section, expressed in N, and is obtained through calibration tests.

[0031] K M This represents the bending stiffness coefficient of the pipeline section, expressed in N·m, and is obtained through calibration tests.

[0032] As a preferred option, in the experimental system setup steps, the optical measurement system is installed along the pipeline path. The entire experimental system is symmetrical about the plane containing the pipeline diameter in the direction of the optical measurement system's lens acquisition. The 120° symmetrical range on one side where the optical measurement system is installed is designated as the 0° region. Two plane mirrors are symmetrically installed on the side of the pipeline away from the optical measurement system, with an angle of 120° between the two plane mirrors. According to theoretical geometric relationships, the optical measurement system can only acquire images that meet the requirements when the distance between the intersection line of the two plane mirrors and the pipeline axis is greater than 1.16 times the pipeline diameter. In practice, the distance between the intersection line of the two plane mirrors and the pipeline axis needs to be set according to the specific capabilities of the optical measurement system.

[0033] As a preferred option, the test images acquired in the experimental image acquisition step include five speckle images: speckle in the 0° region of the pipeline, speckle in the 120° region of the pipeline as a mirror image of the plane mirror, speckle in the 240° region of the pipeline as a mirror image of the plane mirror, speckle on the 120° surface of the pipeline, and speckle on the 240° surface of the pipeline.

[0034] As a preferred solution, in the reflection transformation calculation step, the reflection transformation matrix of the mirror is obtained as follows: theoretical calculations are performed on the optical path, the optical path geometric model is analyzed, and the measured actual deformation field and the deformation field data of two virtual images are fused and unified; the relative relationship of the coordinate systems of the three data fields is established, that is, the reflection transformation matrix of each plane mirror. The reflection transformation matrix of the plane mirror is first solved by testing a finite number of points on the mirror surface and fitting the plane space coordinate equation. After reflecting the virtual image data, the multiple virtual images and the physical test data are unified.

[0035] The beneficial technical effects achieved by this invention are:

[0036] This paper presents a non-contact, high-speed testing method for cross-sectional loads in pipeline vibration tests. By employing a non-contact testing method, sensors and wires are no longer required, thus eliminating the problem of sensor and wire quality affecting the load during the test. This improves the reliability and measurement accuracy of the test, meeting the requirements for cross-sectional load testing in general pipeline vibration tests. The effect is even more significant in high-level vibration tests. The method is stable and reliable, with outstanding substantive features and significant progress. Attached Figure Description

[0037] Figure 1 This is a diagram illustrating the principle of reflection using a plane mirror.

[0038] Figure 2 This is a schematic diagram of the optical path geometric model of one actual deformation field and two virtual image deformation fields in this invention;

[0039] Figure 3 This is a schematic diagram illustrating the principle of the classic bridging method based on resistance strain gauges in this invention.

[0040] Figure 4 This is a schematic diagram of the test system layout according to one specific embodiment of the present invention;

[0041] Figure 5 This is a speckle pattern map of different regions in a test image collected according to one specific embodiment of the present invention;

[0042] Figure 6 This is a spatial distribution map of five regions obtained by the optical measurement system in one specific embodiment of the present invention;

[0043] Figure 7This is a 360-degree panoramic topographic image obtained by stitching together dispersed fields in one specific embodiment of the present invention. Detailed Implementation

[0044] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection claimed by the present invention.

[0045] To obtain the cross-sectional load of a pipeline, it is necessary to simultaneously observe the deformation at multiple locations along the circumferential direction (0°, 90°, 180°, 270°) of a specific cross-section. The cross-sectional load is calculated by analyzing the deformation data and combining it with calibration data. The principles of the single-system multi-view pipeline full-circumferential deformation testing method and the cross-sectional load calibration and data processing method are as follows:

[0046] I. Single-system multi-view pipeline full-circumferential deformation test method

[0047] The 3D digital image correlation method (3D-DIC method) is a non-contact optical measurement method that uses a dual-camera system to measure the strain field and displacement field of an object surface; it is also known as the optical measurement method. In this specific embodiment, the optical measurement method is combined with the principle of plane mirror reflection to realize the cross-sectional load testing of vibrating pipelines.

[0048] To obtain the cross-sectional load of a pipeline, it is usually necessary to construct a stiffness model of the pipeline cross-section and solve for the cross-sectional load based on the test deformation data. Therefore, the prerequisite for obtaining the cross-sectional load is to simultaneously test the deformation of the pipeline cross-section at multiple locations along the circumferential direction, such as 0°, 90°, 180°, and 270°, i.e., the deformation in the entire circumference.

[0049] Optical measurement systems offer the advantage of non-contact measurement; however, a single optical measurement system can only acquire images of a region with a circumferential wrap angle of approximately 120° on one side of the pipeline. To acquire images of the entire circumference of the pipeline, a plane mirror needs to be placed behind the pipeline, and a plane mirror device needs to be designed. A single optical measurement system can then acquire images of the front of the pipeline, as well as two rear images of the pipeline obtained through reflection from the plane mirror. The principle of plane mirror reflection is as follows... Figure 1 As shown.

[0050] In order to accurately acquire images of the pipeline in the full circumference using an optical measurement system (divided into three images with a circumferential wrap angle of approximately 120°), it is necessary to perform theoretical calculations on the optical path, analyze the optical path geometric model, and fuse and unify the measured data of one actual deformation field with the deformation field data of two virtual images.

[0051] To unify the actual deformation field and the virtual image deformation field data, it is necessary to establish the relative relationship between the coordinate systems of the three data fields (i.e., the reflection transformation matrix of each plane mirror), such as... Figure 2 The T shown r1 and T r2 Its reflection transformation matrix can be solved by first testing a finite number of points on the test mirror and fitting the plane space coordinate equation. After reflecting the virtual image data, the test data of multiple virtual images and physical objects are unified.

[0052] II. Methods for Cross-Section Load Calibration and Data Processing

[0053] For structures with two or more axes of symmetry, such as circular cross-section pipes, the classic bridging method based on resistance strain gauges is as follows: Figure 3 As shown. In this specific embodiment, a virtual bridge approach is adopted, that is, strain image test areas are set at corresponding positions in the circumferential direction. For a circular cross-section, it is subjected to both axial force and bending moment. Considering the symmetry of the structure, data measurement areas can be set at 0° and 180° of the circular cross-section of the pipeline. The influence of axial force is eliminated by bridge (a), and the bending moment load is measured; the influence of bending moment is eliminated by bridge (b), and the axial force load is measured.

[0054] Because optical methods are used to measure strain data, axial force and bending moment loads can be obtained simultaneously within the same strain testing area during the same test, improving testing efficiency compared to electrical methods. The axial force and bending moment after bridging are linearly related to the corresponding output strain values; the load identification formula is as follows:

[0055] N=K N ε a =K N (ε1+ε2) (1)

[0056] My = K M ε b =K M (ε1-ε2) (2)

[0057] The stiffness coefficient K in the formula (including K) N and K M The stiffness coefficient K is obtained through calibration tests, which involve applying known loads to one end of the pipeline, measuring the cross-sectional strain data under the loads, and calculating the stiffness coefficient K.

[0058] In the formula, N represents the axial force at the pipe cross section, and the unit is N;

[0059] My represents the bending moment of the pipe section, in N·m;

[0060] e1 and e2 are the strains measured by optical methods, and are dimensionless parameters; K N This represents the axial stiffness coefficient of the pipeline section, expressed in N, and is obtained through calibration tests.

[0061] K M This represents the bending stiffness coefficient of the pipeline section, expressed in N·m, and is obtained through calibration tests.

[0062] Since the load being measured is a unidirectional axial force load and two bending moment loads, the above strain bridge method only obtains one axial force and one bending moment. The other bending moment load needs to be tested in corresponding strain test areas at 90° and 270° positions to construct a virtual strain measurement bridge.

[0063] Based on the above principles, a specific embodiment of the non-contact high-speed testing method for cross-sectional loads in pipeline vibration testing according to the present invention includes the following steps:

[0064] Step 1: Setting up the experimental system.

[0065] First, the pipeline under test is installed on the test bench. A photoelectric measurement system is installed on one side of the pipeline, and a plane mirror assembly consisting of two plane mirrors is installed on the other side. Speckle patterns are prepared on the entire circumferential surface of the pipeline and at the edges of the plane mirrors. In this specific embodiment, the test system is arranged as follows: Figure 4 As shown, the optical measurement system is installed along the pipeline path. The entire experimental system is symmetrical about the plane containing the pipeline diameter in the direction of the optical measurement system's lens acquisition. The 0° area is defined as the 60° range to the left and right of the side where the optical measurement system is installed, i.e., within a 120° symmetrical range. Two plane mirrors are symmetrically installed on the side of the pipeline away from the optical measurement system, with an included angle of 120° between the two plane mirrors. According to theoretical geometric relationships, the optical measurement system can only acquire a satisfactory image when the distance between the intersection line of the two plane mirrors and the pipeline axis is greater than 1.16 times the pipeline diameter. In practice, the distance between the intersection line of the two plane mirrors and the pipeline axis needs to be set according to the specific capabilities of the optical measurement system.

[0066] In this specific embodiment, the camera can simultaneously acquire five speckle images: speckle in the 0° region of the pipeline, speckle in the 120° region of the pipeline as a mirror image of the plane mirror, speckle in the 240° region of the pipeline as a mirror image of the plane mirror, speckle on the 120° surface of the pipeline, and speckle on the 240° surface of the pipeline.

[0067] Step 2: Experimental Image Acquisition

[0068] During the pipeline vibration test, a photoelectric measurement system was used to continuously acquire clear test images. The images included five speckle patterns, such as... Figure 5 As shown in the figure. Speckle areas 1 and 5 are speckle patterns on the mirror surface, while speckle areas 2, 3, and 4 are speckle patterns on the pipeline.

[0069] Step 3: Deformation Field Calculation

[0070] The image sequence was calculated using the optical measurement system software to obtain the coordinate fields of all object surfaces with speckle patterns. All data were in the camera coordinate system of the optical measurement system. In this specific embodiment, the spatial distribution of the five regions obtained by the optical measurement system is as follows: Figure 6 As shown.

[0071] Step 4: Calculate the reflection transformation.

[0072] To obtain the complete circumferential deformation field of the pipeline, the A2 and A3 of the pipeline need to be reflected and transformed by the two mirror planes respectively. Based on the method introduced above, the spatial plane equation of the plane mirror is established by the speckle coordinate field of the mirror obtained by the optical measurement system, thereby constructing the reflection transformation matrix of the mirror.

[0073] Step 5: Reconstruct the surface morphology of the entire pipeline circumference.

[0074] Based on the reflection transformation matrix, all reconstructed virtual surfaces can be reflected back to their real positions, thus obtaining the topography of multiple surface regions in the same world coordinate system, such as a 360-degree panoramic topography. Finally, the three fields dispersed by the pipeline are stitched together using the transformation matrix, such as... Figure 7 As shown.

[0075] Since reflection transformation estimation inevitably contains errors, there will always be subtle rigid body translations or rotations between the reflected virtual surface regions and their actual positions. If the strain is calculated separately for each region, the rigid body translation will not affect the strain calculation for each region. If all the test surfaces are first stitched together in the overlapping region through interpolation, the deviation between the interpolated overlapping region and its true position will no longer be a rigid body displacement error, which may lead to a large strain calculation error. Therefore, in this specific embodiment, the test surfaces are not stitched together, but the subsequent deformation field calculations are performed directly on each real surface transformed to the same world coordinate system.

[0076] Step 6: Deformation field measurement.

[0077] By subtracting the initial three-dimensional point cloud from the three-dimensional point cloud of the deformed state, the three-dimensional displacement field of each deformed state can be obtained. Further calculation of the three-dimensional displacement field yields the required strain field.

[0078] Step 7: Calibration of the stiffness coefficient of the pipeline section.

[0079] One end of the pipeline is fixed, and a known load is applied to the other end. Based on the single-system multi-view pipeline full circumferential deformation test method, i.e., the first to sixth steps, the deformation information of the pipeline section under load is collected. The section stiffness coefficient data can be obtained by calculating using the load identification formula, i.e., formulas (1) and (2).

[0080] Step 8: Based on the single-system multi-view pipeline full circumferential deformation test method, i.e., steps one to six, the deformation information of the pipeline section under load is collected, and the section load data is calculated based on the section stiffness coefficient data and strain data.

[0081] Thus, the cross-sectional load data of the pipeline vibration test were obtained, realizing the non-contact high-speed test of the cross-sectional load of the pipeline vibration test.

[0082] Based on the above principles, a specific embodiment of the non-contact high-speed testing method for cross-sectional loads in pipeline vibration testing according to the present invention includes the following steps:

[0083] S1. Construct and calibrate the optical measurement system;

[0084] S1.1 Constructing a dual-camera light measurement system

[0085] A dual-camera optical measurement system is established, with both cameras taking pictures at the 0° position of the section of interest. The position of the camera at 0° along the circumference of the section of interest is taken as the front of the pipeline. Plane mirrors are set at 120° and 240° behind the pipeline, and a plane mirror device is designed. The optical measurement system acquires the image of the front of the pipeline and the two images of the rear of the pipeline obtained by reflection from the plane mirrors.

[0086] S1.2 Calibrate the dual-camera optical measurement system.

[0087] A series of calibration image pairs are acquired, and the internal parameters of the two cameras and the external parameters between the two cameras are calculated according to the calibration method of the dual-camera optical measurement system. Calibration is a necessary step before the use of the optical measurement system, and the specific operation is common knowledge that should be mastered by those skilled in the art, so it will not be described in detail here.

[0088] S2, Experimental Image Acquisition;

[0089] S2.1 First, before the experiment, a pair of images of the experimental specimen are collected as reference images;

[0090] S2.2 Subsequently, during the experiment, a pair of images were acquired for each state of interest as deformed images; each image covered the real surface region and the virtual surface region of interest; the real surface region was directly acquired by the optical measurement system, and the virtual surface region was indirectly acquired by the optical measurement system through reflection from a plane mirror;

[0091] S3, Calculation of reflection transformation;

[0092] The reflection transformation calculation is used to estimate the reflection transformation matrix; in this specific embodiment, based on the calibrated dual-camera photometry system, the spatial plane equation of the plane mirror surface is established, thereby constructing the reflection transformation matrix of the mirror surface;

[0093] S4. Reconstruction of the three-dimensional shape of the real and virtual surface regions;

[0094] S4.1 First, select the calculation region on all regions of interest in the acquired left camera reference image and specify a fixed calculation point step size to obtain the calculation points evenly distributed in each calculation region; the calculation point step size is set according to the actual situation, which is common knowledge that those skilled in the art should master, and will not be described in detail here.

[0095] S4.2 Subsequently, using a suitable photometric image matching strategy, all calculated points can be matched to all images acquired by the two cameras; in this specific embodiment, the photometric image matching strategy is the Digital Image Correlation (DIC) method.

[0096] S4.3 Finally, the triangulation principle is applied to the matched image points to reconstruct and track the three-dimensional morphology of all regions of interest in different deformation states;

[0097] S5. Full-circumference surface morphology reconstruction;

[0098] Based on the reflection transformation matrix of each mirror estimated in step S2, all reconstructed virtual surfaces can be reflected back to their real positions, thereby obtaining the morphology of multiple surface regions in the same world coordinate system, such as 360-degree panoramic morphology.

[0099] In this specific embodiment, the strain is calculated for each region separately. Its advantage is that the rigid body translation will not affect the strain calculation of each region. The surfaces to be measured are not spliced ​​together. The subsequent deformation field calculation is performed directly on each real surface transformed into the same world coordinate system.

[0100] S6. Deformation field measurement;

[0101] Subtracting the initial three-dimensional point cloud from the three-dimensional point cloud of the deformed state yields the three-dimensional displacement field for each deformed state. Further calculation of the three-dimensional displacement field yields the required strain field.

[0102] S7. Calibration of pipe section stiffness coefficient;

[0103] One end of the pipeline is fixed, and a known load is applied to the other end. Based on the single-system multi-view pipeline full circumferential deformation test method, namely steps S1 to S6, the deformation information of the pipeline section under load is collected, and the section stiffness coefficient data is obtained by calculation using the load identification formula.

[0104] S8. Based on the single-system multi-view pipeline full circumferential deformation test method, namely steps S1 to S6, the deformation information of the pipeline section under load is collected, and the section load data is calculated based on the section stiffness coefficient data and strain data to obtain the pipeline section load.

[0105] Thus, the cross-sectional load data of the pipeline vibration test were obtained, realizing the non-contact high-speed test of the cross-sectional load of the pipeline vibration test.

[0106] The beneficial technical effects achieved by this specific embodiment are:

[0107] This invention provides a non-contact, high-speed testing method for cross-sectional loads in pipeline vibration tests. By employing a non-contact testing approach, sensors and wires are eliminated, thus preventing the impact of sensor and wire mass on the load during testing. This improves both the reliability and measurement accuracy of the test, meeting the requirements for cross-sectional load testing in general pipeline vibration tests. The method is stable and reliable. This invention provides a new testing method and approach for cross-sectional load testing in pipeline vibration tests. The results have been applied in the vibration testing of pipelines for new launch vehicles in my country and can be extended to tests on other similar structures.

Claims

1. A method for non-contact high-speed testing of a pipe vibration test section load, characterized in that, The method comprises the following steps: First step: test system building; The pipeline to be tested is installed on the test bench, a light measurement system is installed on one side of the pipeline, and a plane mirror group composed of two plane mirrors is installed on the other side; speckle patterns are prepared on the full surface and full circumference of the pipeline and the edge of the plane mirror; Second step: test image acquisition; During the pipeline vibration test, clear test images are continuously acquired using the light measurement system; Third step: deformation field calculation; The image sequence is calculated using the light measurement system software to obtain the coordinate field of all the object surfaces on which the speckle patterns are prepared; all the data are in the camera coordinate system of the light measurement system; Fourth step: reflection transformation calculation; In order to obtain the full circumferential deformation field of the pipeline, the mirror speckle patterns in the two regions need to be reflected and transformed to the two mirror planes, respectively; the spatial plane equation of the mirror plane of the mirror speckle coordinate field obtained by the light measurement system is established to construct the reflection transformation matrix of the mirror; Fifth step: pipeline full circumferential surface topography reconstruction; Based on the reflection transformation matrix, all the virtual surfaces are reflected to their real positions to obtain the topography of multiple surface regions in the same world coordinate system; the three scattered fields of the pipeline are spliced together through the transformation matrix; Sixth step: deformation field measurement; The three-dimensional point cloud in the initial state is subtracted from the three-dimensional point cloud in the deformed state to obtain the three-dimensional displacement field of each deformed state; the three-dimensional displacement field is further calculated to obtain the required strain field; Seventh step: pipeline cross-section stiffness coefficient calibration; One end of the pipeline is fixed, and a known load is applied to the other end; the deformation information of the pipeline under the cross-section load is acquired according to the pipeline full circumferential deformation test method described in the first to sixth steps; the cross-section stiffness coefficient data are obtained through calculation according to the load identification formula; Eighth step: based on the single-system multi-view pipeline full circumferential deformation test method, the deformation information of the pipeline under the cross-section load is acquired, and the cross-section load data are calculated according to the cross-section stiffness coefficient data and the strain data to complete the non-contact high-speed test of the pipeline vibration test cross-section load.

2. The test method of claim 1, wherein, In the pipeline full circumferential surface topography reconstruction step, the strain of each region is calculated, and the subsequent deformation field calculation is directly performed on each real surface transformed into the same world coordinate system.

3. The test method of claim 2, wherein, In the pipeline cross-section stiffness coefficient calibration step, the load identification formula is as follows: N = K N ε a = K N (ε1+ε2) My = K M ε b = K M (ε1-ε2) In the formula, N represents the pipeline cross-section axial force, and the unit is N; My represents the pipeline cross-section bending moment, and the unit is N·m; ε1, ε2 are the strains measured by optical measurement method, which are dimensionless parameters; K N represents the axial stiffness coefficient of the pipeline cross section, with the unit of N, which is obtained through calibration test; K M represents the bending stiffness coefficient of the pipe cross section, in N-m, obtained through calibration tests.

4. The test method of claim 3, wherein, In the test system building step, the light measurement system is installed along the pipeline path; the entire test system is symmetrical to the plane in which the pipeline diameter in the lens acquisition direction of the light measurement system lies; the 0° region is within the 120° symmetrical range on the side where the light measurement system is installed; the plane mirror group composed of two plane mirrors is symmetrically installed on the side of the pipeline away from the light measurement system; the included angle between the two plane mirrors is 120°; according to the theoretical geometric relationship, when the distance between the intersection line of the two plane mirrors and the pipeline axis is greater than 1.16 times the pipeline diameter, the light measurement system can obtain images meeting the requirements; in actual situations, the distance between the intersection line of the two plane mirrors and the pipeline axis needs to be set according to the specific capability of the light measurement system.

5. The test method of claim 4, wherein, The test image acquisition step, the test image includes pipeline 0 area speckle, pipeline 120 area speckle mirror image about plane mirror, pipeline 240 area speckle mirror image about plane mirror, pipeline 120 mirror speckle, pipeline 240 mirror speckle, a total of five speckle images.

6. The test method according to any one of claims 1 to 5, characterized in that, In the reflection transformation calculation step, the reflection transformation matrix of the mirror is obtained as follows: The optical path is theoretically calculated, the optical path geometric model is analyzed, and one actual deformation field and two virtual image deformation field data are fused and unified; The relative relationship of the three data field coordinate systems is established, that is, the reflection transformation matrix of each plane mirror. The reflection transformation matrix of the plane mirror is first obtained by testing a finite number of points on the mirror and fitting the plane space coordinate equation, and then the reflection transformation matrix is solved. After reflecting the virtual image data, the multiple virtual images and the actual test data are unified.

Images