Large conveying pipeline stress and strain field state testing device and testing method thereof

Abstract

The application discloses a large-scale conveying pipeline stress and strain field state testing device and testing method, a strain rosette and a strain gauge. The strain rosette is arranged on a pipeline inner wall testing point. The strain rosette leads out a wire which is inserted into the strain gauge. The strain gauge is electrically connected with a network signaler. The network signaler is electrically connected with a terminal and an alarm. The terminal includes a data acquisition system and a post-processing system. The terminal is used for receiving the data collected by the strain gauge at any time, analyzing the overall stress and strain field state of the pipeline and monitoring the pipeline strength change during construction. When the pipeline approaches the strength limit, the terminal can receive the corresponding feedback and send a signal. The network signaler receives the signal and transmits it to the alarm. The construction is timely stopped, the safety of the construction is improved and the safety guarantee is provided for the pipeline transportation.

Description

Technical Field

[0001] This invention relates to the technical field of pipeline stress testing methods, and in particular to a testing device and method for testing the stress and strain field state of a large-scale transport pipeline. Background Technology

[0002] Large-scale pipelines are widely used, and their strength is crucial to their reliability. However, most pipeline construction takes place deep underground, often employing pipe jacking methods, which hinders data collection and strength verification. Furthermore, construction sometimes encounters extreme environments, significantly impacting strength testing. Moreover, existing testing methods are cumbersome in the data acquisition phase, particularly when large datasets are required, making on-site data collection impractical. Current measurement methods also necessitate subsequent calculations after data collection, reducing the timeliness of data acquisition and the accuracy of strength verification. Therefore, an efficient and simple method is needed to test the stress and strain field state of pipelines to determine their ultimate bearing capacity and strength, ensuring safe pipeline operation. Summary of the Invention

[0003] One objective of this invention is to provide a testing device and method for testing the stress and strain field state of large-scale pipelines. When the pipeline is about to reach its strength limit, the terminal can immediately receive corresponding feedback and send a signal. The network signaler receives the signal and transmits it to the alarm, so the construction can be stopped in time, improving the safety of construction and providing safety assurance for pipeline transportation.

[0004] A testing device for stress and strain field state of a large-scale conveying pipeline according to an embodiment of the present invention includes:

[0005] The strain gauge is installed at test points on the inner wall of the pipeline to sense and transmit the stress and strain response generated by the pipeline. By using the stress and strain field state of a finite number of test points and applying the inverse problem method, the stress and strain field state of the entire pipeline is calculated, and the strength verification result is given before an early warning is issued.

[0006] A strain gauge, with strain gauge lead wires inserted into the strain gauge, the strain gauge being electrically connected to a network signaler, used to sense and transmit strain and send data;

[0007] A network signaler, which is electrically connected to a terminal and an alarm, is used to receive a warning from the terminal and trigger the alarm.

[0008] The terminal includes a data acquisition system and a post-processing system, which are used to receive data collected by the strain gauge at any time, analyze the overall stress-strain field state of the pipeline, and monitor changes in pipeline strength during construction.

[0009] Optionally, the pipeline inner wall test points are 8-12, and each pipeline inner wall test point corresponds to a strain gauge.

[0010] Optionally, the power supply is connected with the strain gauge, the network signaler and the alarm.

[0011] Optionally, the terminal data acquisition module has an acquisition interface, and the acquisition time, the acquisition frequency and the automatic processing of the acquisition data can be controlled.

[0012] The terminal post-processing system contains finite element software, which automatically processes the acquisition data, calculates the stress and strain field state of a limited number of test points by the inverse problem method, and obtains the stress and strain field state of the whole pipeline.

[0013] The testing method of the stress and strain field state testing device for a large conveying pipeline comprises the following steps:

[0014] S1, sticking strain gauges on a limited number of points inside the conveying pipeline;

[0015] S2, collecting strain data and transmitting the strain data to a terminal in time;

[0016] S3, simulating the stress and strain field of the whole pipeline by the inverse problem method and calculating the stress value;

[0017] S4, issuing a pre-warning when the stress and strain field state of the pipeline reaches the strength limit, transmitting a signal to the construction site and triggering the alarm.

[0018] Optionally, S1 further comprises the following steps:

[0019] S11, each strain gauge is composed of three single strain gauges and a substrate, the three single strain gauges are collectively stuck on a 12mm*12mm substrate, and each single strain gauge needs to lead out two thin wires, that is, each strain gauge will lead out six wires;

[0020] S12, sticking strain gauges on the pipeline inner wall test points, and then connecting the wires and the wires of each strain gauge by welding;

[0021] S13, protective treatment of the strain gauges, and coating protective glue on the strain gauges stuck on the pipeline inner wall test points.

[0022] Optionally, S2 further comprises the following steps:

[0023] S21, inserting all the wires into the corresponding ports of the strain gauge before the pipeline is buried to the specified position;

[0024] S22, the lead wire introduced by the strain gauge is connected to the corresponding strain gauge port respectively;

[0025] S23, the six lead wires introduced by the strain gauge are inserted into the corresponding strain gauge ports respectively.

[0026] Optionally, the strain gauge in S23 is measured by 1 / 4 bridge method to form a corresponding 1 / 4 bridge measurement resistance circuit.

[0027] Optionally, S3 further comprises:

[0028] S31, one end of the network cable is inserted into the corresponding strain gauge network port, the other end is connected with the network signaler, the power supply is connected to the strain gauge and the computer, and the computer is connected with the strain gauge device in advance and is adjusted;

[0029] S32, the computer needs to be adjusted when connected for the first time, and each subsequent connection can be connected with the strain gauge through the network;

[0030] S33, the data collected by the strain gauge is received remotely after the pipeline is buried, and the corresponding data is obtained according to the pipeline construction period.

[0031] Optionally, S4 further comprises:

[0032] S41, the terminal is loaded in advance before collecting data for the first time, when the terminal receives the strain data collected by the strain gauge, the finite element software automatically analyzes the collection points and the corresponding data, obtains the overall stress and strain field state distribution by using the inverse problem method according to the stress distribution of part of the collection points, finds out the dangerous point of the pipeline, calculates the stress value of the dangerous point, and thus checks the strength of the pipeline;

[0033] S42, in the construction process, the terminal detects the stress and strain field state of the pipeline in real time, if the stress value of the dangerous point of the pipeline exceeds the limit bearing stress of the pipeline, the terminal will feedback to the network signaler, and then the alarm receiver receives the early warning signal and alarms.

[0034] The beneficial effects of the present application are:

[0035] The present application comprehensively detects the strength of the pipeline in all aspects, not only can the strain value transmitted by the strain gauge be remotely collected, but also the pipeline as a whole can be analyzed by using the inverse problem method of the finite element software, and the construction process can be monitored at any time whether there is a problem, when the pipeline approaches the strength limit during the construction process, the terminal can obtain the corresponding feedback and send a signal, the network signaler receives the signal and transmits it to the alarm, the construction is stopped in time, the safety of the construction is improved, and the safety of the pipeline transportation is provided. BRIEF DESCRIPTION OF DRAWINGS

[0036] In the drawings:

[0037] Figure 1 The pipeline measuring point distribution plan view of a large conveying pipeline stress and strain field state testing device and testing method proposed by the present application;

[0038] Figure 2 The data remote acquisition and processing system of a large conveying pipeline stress and strain field state testing device and testing method proposed by the present application;

[0039] Figure 3 The terminal module system of a large conveying pipeline stress and strain field state testing device and testing method proposed by the present application;

[0040] Figure 4 The axial normal stress-time relationship graph in embodiment one of a large conveying pipeline stress and strain field state testing device and testing method proposed by the present application;

[0041] Figure 5 The radial normal stress-time relationship graph in embodiment one of a large conveying pipeline stress and strain field state testing device and testing method proposed by the present application;

[0042] Figure 6 The shear stress-time relationship graph in embodiment one of a large conveying pipeline stress and strain field state testing device and testing method proposed by the present application;

[0043] Figure 7 The stress distribution graph when the pipeline reaches the maximum stress in embodiment one of a large conveying pipeline stress and strain field state testing device and testing method proposed by the present application;

[0044] Figure 8 The axial normal stress-time relationship graph in embodiment two of a large conveying pipeline stress and strain field state testing device and testing method proposed by the present application;

[0045] Figure 9 The radial normal stress-time relationship graph in embodiment two of a large conveying pipeline stress and strain field state testing device and testing method proposed by the present application;

[0046] Figure 10 The shear stress-time relationship graph in embodiment two of a large conveying pipeline stress and strain field state testing device and testing method proposed by the present application;

[0047] Figure 11 The stress distribution graph when the pipeline reaches the maximum stress in embodiment two of a large conveying pipeline stress and strain field state testing device and testing method proposed by the present application. DETAILED DESCRIPTION

[0048] Reference Figures 1-2 A large conveying pipeline stress and strain field state testing device, comprising:

[0049] Strain flowers are arranged on the pipeline inner wall test points, the pipeline inner wall test points are 8-12, one strain flower is pasted on each pipeline inner wall test point, preferably 10 in the embodiment, each strain flower has 6 lead wires, the strain gauges are measured by 1 / 4 bridge method, form a corresponding 1 / 4 bridge measurement resistance circuit, used to sense the stress and strain response generated by the conveying pipeline, and the stress and strain field state of the whole pipeline is calculated by using the inverse problem method of a limited number of measuring points, and the strength checking result is given to give a warning;

[0050] Strain gauges, strain flower lead wires, lead wires are inserted into strain gauges, strain gauges are electrically connected with network signalers, used to sense and transmit strain and send data;

[0051] Network signalers, network signalers are electrically connected with terminals, network signalers are electrically connected with alarms, used to receive terminal early warning triggering alarms;

[0052] Terminals, terminals include data acquisition systems and post-processing systems, used to receive data collected by strain gauges at any time, analyze the overall stress and strain field state of the pipeline, and monitor the strength change of the pipeline during construction.

[0053] In the embodiment, it can be understood that the driving mode of the strain gauge, the network signaler and the alarm in the application can be driven by an external power supply, the control of the strain gauge, the network signaler and the alarm can be programmed by the main control system, and the control principle is realized by existing control technology. The type of strain gauge, network signaler and alarm is not limited to a single type and can be the existing type suitable for the application in the market.

[0054] In the embodiment, the terminal data acquisition module has an acquisition interface which can control the acquisition time, acquisition frequency and automatically process the collected data;

[0055] The finite element software in the terminal post-processing system automatically processes the collected data, calculates the stress and strain field state of a limited number of measuring points by the inverse problem method to obtain the stress and strain field state of the whole pipeline, and the terminal post-processing system solves by the positive problem method by using known geometric dimensions, material parameters and boundary conditions to obtain the numerical simulation result.

[0056] Before receiving the signal in the terminal system, the material parameters of the pipeline, such as the inner diameter, the outer diameter, the length, the Poisson's ratio and the elastic modulus of the pipeline, i.e. the geometric size and the material parameters, need to be input in the finite element simulation software of the terminal.

[0057] A testing method of a large-scale pipeline stress and strain field state testing device, comprising:

[0058] S1, sticking strain gauges on a limited number of points inside the pipeline;

[0059] In the embodiment, S1 further comprises:

[0060] S11, each strain gauge is composed of three single strain gauges and a substrate, the three single strain gauges are collectively stuck on a 12mm*12mm substrate, and each single strain gauge needs to lead out two thin wires, i.e. each strain gauge will lead out six wires;

[0061] S12, sticking the strain gauges on the test points on the inner wall of the pipeline. Then, the wires are welded with the wires of each strain gauge after the wire connection;

[0062] S13, protective treatment of the strain gauges, i.e. applying protective glue to the strain gauges stuck on the test points on the inner wall of the pipeline.

[0063] S2, collecting strain data and transmitting to the terminal in time;

[0064] In the embodiment, S2 further comprises:

[0065] S21, inserting all the wires into the corresponding ports of the strain gauges before the pipeline is buried to the specified position;

[0066] S22, connecting the wires led out by the strain gauges into the corresponding ports of the strain gauges;

[0067] S23, inserting the six wires led out by the strain gauges into the corresponding ports of the strain gauges.

[0068] S3, simulating the stress and strain field of the entire pipeline by using the inverse problem method and calculating the stress value;

[0069] In the embodiment, S3 further comprises:

[0070] S31, inserting one end of the network cable into the corresponding network port of the strain gauge, connecting the other end with the network signal, connecting the power supply to the strain gauge and the computer, and connecting the computer with the strain gauge device in advance and adjusting;

[0071] S32, the computer needs to be adjusted during the first connection, and each subsequent connection can be connected with the strain gauge through the network;

[0072] S33, after the pipeline is buried, the data collected by the strain gauge is received remotely, and the corresponding data is obtained according to the pipeline construction period.

[0073] S4, when the stress-strain field state of the pipeline is about to reach the strength limit, a pre-warning is given, a signal is transmitted to the construction site and an alarm is triggered.

[0074] In this embodiment, S4 further includes:

[0075] S41, before collecting data for the first time, the terminal is loaded in advance, when the terminal receives the strain data collected by the strain gauge, the finite element software automatically analyzes the collection points and the corresponding data, obtains the overall stress-strain field state distribution by using the inverse problem method according to the stress distribution of part of the collection points, finds out the dangerous points of the pipeline, calculates the stress value of the dangerous points, and thus checks the strength of the pipeline;

[0076] S42, during the construction process, the terminal detects the stress-strain field state of the pipeline in real time, if the stress value at the dangerous point of the pipeline exceeds the limit bearing stress of the pipeline, the terminal will feedback to the network signaler, and then the alarm receives the pre-warning signal and alarms.

[0077] Example 1

[0078] A test was conducted on a pipeline under construction, 10 strain flowers were pasted on a sewage pipeline with a buried depth of 18 m, and the positions of the strain flowers were as shown in Figure 1 Each strain flower was connected with 6 wires, and each two wires were connected to a channel of the strain gauge according to the 1 / 4 bridge method, so that one group of strain flowers corresponded to three channels at the same time, and all the strain flower groups corresponded to 30 channels in total. The strain gauge was connected with a temperature compensation sheet, that is, a small piece of material sample.

[0079] One channel of the strain gauge can output one strain value, and three values output by one strain flower are: ε0, ε 45 , and ε 90 . The three values will be sent to the terminal in real time through the signaler. By using the three values through the following strain relationship, ε x , ε y , and γ xy can be obtained:

[0080]

[0081] Referring to Figures 3-6 , the known parameters are substituted into the following four equations, and σ x , σ y , and τ xyThe seven equations have been written in the terminal in advance, so when testing, only the relevant parameters of the material need to be input to directly obtain the results. The terminal is set to collect data in real time, with a sampling frequency of 1 Hz, i.e. collecting data once per second. Since the strain gauges are always measuring data in real time, the terminal can directly obtain the values of σ x , σ y , τ xy with respect to time, i.e. the changes in the principal stresses with respect to time, and the changes in the principal stresses with respect to time at site 1 and site 2 are listed. At the same time, the finite element software establishes a corresponding pipeline model by inputting the geometric dimensions and material parameters.

[0082] Referring to Figure 7 , in this embodiment, the elastic modulus of the pipeline is E = 8.9 Gpa, the Poisson's ratio is v = 0.2, and the shear modulus is G = 1.8 Gpa. The finite element software reads the collected data in real time and analyzes to obtain the corresponding stress and strain field. The finite element software uses the stress values on the inner wall of the top end to obtain the stress values at the actual dangerous points of the pipeline. When the pipeline reaches the maximum stress, the maximum stress of the pipeline does not exceed the allowable stress value during construction, so the alarm does not issue a warning, thereby ensuring the safety of the construction process.

[0083]

[0084]

[0085]

[0086]

[0087] Referring to Figures 8-11 , in embodiment two, testing is performed on a section of underground sewage pipeline with a buried depth of 14 m, and the same strain gauge pasting method as in embodiment one is used. The terminal collects data transmitted by the strain gauges in real time, and the finite element simultaneously establishes a corresponding pipeline model. The finite element analyzes in real time using the strain data transmitted by the strain gauges and obtains the actual stress of the pipeline using the inverse problem method. Similarly, the changes in the axial normal stress, radial normal stress and shear stress with respect to time at site 1 and site 2 are listed.

[0088] In this embodiment, the material parameters of the pipeline are: the elastic modulus E = 8.9 Gpa, the Poisson's ratio v = 0.2 and the shear modulus G = 1.8 Gpa. The finite element software reads the collected data in real time and analyzes to obtain the corresponding stress and strain field. When the stress of the pipeline reaches the maximum, the finite element software draws the corresponding stress distribution diagram.

[0089] The application comprehensively detects the strength of the pipeline in all aspects, can not only remotely collect the strain value transmitted by the strain gauge, analyze the whole pipeline by using the inverse problem method of the finite element software, but also can monitor whether problems appear in the construction link at any time, when the pipeline approaches the strength limit in the construction process, the terminal can immediately obtain the corresponding feedback and send a signal, the network signaler receives the signal and transmits it to the alarm, the construction is timely stopped, the safety of the construction is improved, and the safety is provided for the pipeline transportation.

Claims

1. A device for testing the state of stress and strain field in large scale conveying pipelines, characterized by, It comprises: Strain flowers are arranged on the pipeline inner wall test points to sense the stress strain response of the pipeline caused by the stress and use the finite point stress strain field state to calculate the stress strain field state of the whole pipeline to give the strength checking results and then give the early warning; Strain gauges, the strain flower lead wires, the lead wires are inserted into the strain gauges, the strain gauges are electrically connected with the network signaler to sense and transmit the strain and send data; The network signaler is electrically connected with the terminal and the alarm, and is used for receiving the terminal early warning trigger alarm; The terminal comprises a data acquisition system and a post-processing system, which is used for receiving the data collected by the strain gauge at any time, analyzing the overall stress strain field state of the pipeline, and monitoring the strength change of the pipeline during construction; The terminal data acquisition module has a collection interface which can control the collection time, collection frequency and automatic processing of the collected data; The terminal post-processing system contains finite element software which automatically processes the collected data, calculates the stress strain field state of the finite points by the inverse problem method to obtain the stress strain field state of the whole pipeline, and solves by the direct problem method to obtain the numerical simulation results by using the known geometric size, material parameters and boundary conditions; When the terminal receives the strain data collected by the strain gauge, the finite element software automatically analyzes the collection points and the corresponding data, obtains the overall stress strain field state distribution by using the inverse problem method according to the stress distribution of part of the collection points, finds out the dangerous points of the pipeline, calculates the stress value of the dangerous points, and thus checks the strength of the pipeline; During the construction process, the terminal detects and calculates the stress strain field state of the pipeline in real time, and if the stress value of the dangerous point of the pipeline exceeds the limit bearing stress of the pipeline, the terminal will feedback to the network signaler, and then the alarm receives the early warning signal and alarms.

2. The apparatus for testing the stress and strain field state of a large-scale conveying pipeline according to claim 1, characterized in that, The pipeline inner wall test points are 8-12, and each pipeline inner wall test point corresponds to a strain flower.

3. The apparatus for testing the stress and strain field state of a large-scale conveying pipeline according to claim 1, characterized in that, It also comprises a power supply which is connected with the strain gauge, the network signaler and the alarm.

4. A method of testing a large-scale pipe stress and strain field state testing apparatus according to any one of claims 1 to 3, characterized by, It comprises: S1, paste strain flowers on the inner side of the pipeline at a finite number of points; S2, collect strain data and transfer to the terminal in time; S3, simulate the stress strain field of the whole pipeline by using the inverse problem method and calculate the stress value; S4, give early warning when the stress strain field state of the pipeline reaches the strength limit, and transfer the signal to the construction site and trigger the alarm.

5. A method of testing the state of stress and strain field in a large conveying pipeline according to claim 4, characterized in that, The S1 further comprises: S11, each strain flower is composed of three single strain gauges and a substrate, the three single strain gauges are collectively pasted on a 12mm*12mm substrate, and each single strain gauge needs to lead out two thin wires, that is, each strain flower will lead out six wires; S12, paste strain flowers on the pipeline inner wall test points, then connect the wires, and weld the wires with the wires of each strain flower; S13, protective treatment of the strain flowers, and the strain flowers pasted on the pipeline inner wall test points are coated with protective glue.

6. The method of claim 4, wherein, The S2 further comprises: S21, before the pipeline is buried to the designated position, insert all the wires into the corresponding ports of the strain gauge; S22, the wires led out by the strain gauge are respectively connected to the corresponding strain gauge ports; S23, the six wires led out by the strain gauge are respectively inserted into the corresponding strain gauge ports.

7. A method of testing the state of stress and strain field in a large conveying pipeline according to claim 6, characterized in that, In S23, the strain gauges will all use 1 / 4 bridge method for measurement, and form a corresponding 1 / 4 bridge method measurement resistance circuit.

8. The method of testing the stress and strain field conditions of a large conveying pipeline according to claim 4, wherein, S3 further comprises: S31, insert one end of the network cable into the corresponding network port of the strain gauge, and connect the other end to the network signaler; connect the power supply to the strain gauge and the computer, and use the computer to connect to the strain gauge device in advance and adjust; S32, the computer needs to be adjusted when connected for the first time, and each subsequent connection can be connected to the strain gauge through the network; S33, after the pipeline is buried, remotely receive the data collected by the strain gauge, and obtain the corresponding data according to the pipeline construction period.

9. The method of testing the stress and strain field conditions of a large conveying pipeline according to claim 4, wherein, S4 further comprises: S41, load the terminal in advance before collecting data for the first time, when the terminal receives the strain data collected by the strain gauge, the finite element software will automatically analyze the collection points and their corresponding data, use the inverse problem method to obtain the overall stress-strain field state distribution according to the stress distribution of part of the collection points, find out the dangerous points of the pipeline, calculate the stress value of the dangerous points, and thus check the strength of the pipeline; S42, during the construction process, the terminal real-time detects the stress-strain field state of the pipeline, if the stress value at the dangerous point of the pipeline exceeds the limit bearing stress of the pipeline, the terminal will feedback to the network signaler, and then the alarm receiver receives the early warning signal and alarms.

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