Pipeline specimen design and production method and urban gas pipeline stress and deformation test tube

Abstract

The invention discloses a pipeline sample design and production method and a town gas pipeline stress and deformation test tube. The design method comprises determining pipeline information, multiple defect information, rolling vehicle information and test site environmental parameters; using modeling language commands to establish a rolling stress analysis model for a town gas pipeline containing defects, comprising: setting a single-defect town gas pipeline stress analysis model with a head end defect, and calculating the stress distribution when a vehicle rolls over the pipeline; on the basis of the single-defect town gas pipeline stress analysis model, setting a multi-defect town gas pipeline stress analysis model containing a middle section defect and a tail end defect that are sequentially arranged, calculating the stress of the vehicle rolling over the pipeline, and if there is no influence, determining the distance between defects, and if there is a stress influence, increasing the distance between defects and recalculating; and determining a pipeline sample diagram of stress and deformation of the multi-defect town gas pipeline according to the calculation result. The invention can improve the utilization rate of test materials.

Description

Technical Field

[0001] The invention relates to the technical field of pipeline detection, and in particular to a pipeline sample design and production method and a town gas pipeline stress and deformation test tube. Background Art

[0002] As the urbanization process continues to accelerate, the contradiction between urban gas and road construction continues to become prominent. How to ensure the safety of urban gas pipelines has become a key work direction for gas operation companies and researchers. Researchers obtained strain and deformation data when urban gas was crushed by vehicles through field tests. However, in conventional experiments, the test pipeline is small. Larger pipelines require more test costs and larger sites, which are difficult to meet under test conditions; or only single-defect pipeline crushing simulation tests can be carried out. The single defect here refers to a section of the experimental pipeline with only one defect and one size. This leads to problems such as the test research not being consistent with the actual situation on site and waste of test materials. Therefore, establishing a set of design methods for making defective sample pipelines suitable for vehicle crushing tests is the key to solving such problems.

[0003] In the prior art, the invention patent with the patent publication number CN117129416A discloses a step-by-step constant load full-scale test system and method for defective steel pipes. The reference document processes one or more surface defects on the test steel pipe according to the experimental requirements to prefabricate cracks in the middle of the steel pipe. However, the reference document does not take into account the mutual influence between multiple surface defects during actual testing, resulting in inaccurate subsequent deformation data. Summary of the invention

[0004] The technical problem to be solved by the present invention is to solve the problem of making and simulating multiple corrosion thinning defects of different sizes on the same test pipe and ensuring that the measurement results of each defect do not interfere with each other when performing a rolling test.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0006] A method for designing a multi-defect pipeline specimen comprises the following steps:

[0007] S10, determining pipeline information, multiple defect information, rolling vehicle information and test site environmental parameters;

[0008] S20, using modeling language commands, establishes a stress analysis model for rolled defective town gas pipelines, including:

[0009] S21, set the single defect town gas pipeline stress analysis model with head end defect to calculate the stress distribution when the vehicle runs over the pipeline;

[0010] S22, on the basis of the single-defect town gas pipeline stress analysis model, a multi-defect town gas pipeline stress analysis model including a middle section defect and a tail end defect arranged in sequence is set, and the stress of the pipeline crushed by a vehicle is calculated. If there is no influence, the distance between defects is determined; if there is a stress influence, the distance between defects is increased and recalculated;

[0011] S30, determining a pipeline sample diagram of stress and deformation of a multi-defect town gas pipeline according to the calculation results.

[0012] Advantages: Here is a method for determining the distance between defects. The head boundary distance is determined by the outer diameter of the pipe, the middle boundary distance, the edge-middle boundary distance and the tail boundary distance are obtained from the finite element analysis results, and need to meet the basic restrictions specified in this section at the same time. The distance between defects in the middle section is determined by the simulated stress state of each defect.

[0013] The pipeline sample can contain multiple defects of different sizes at the same time, and the measurement results of each defect will not interfere with each other when the rolling test is carried out, thus avoiding waste of test materials and improving the efficiency of data collection in vehicle rolling pipeline tests.

[0014] In one embodiment of the present invention, in step S21: according to the determined size of the head end defect, the single defect town gas pipeline stress analysis model is input, and the head end boundary distance l between the axial edge of the head end defect and the edge of the pipeline is determined. 1 Not less than 1.5 times the pipe diameter D.

[0015] In one embodiment of the present invention, the head end boundary distance l 1 Perform stress calculation and analysis to determine the first interval boundary distance l between the head end defect and the middle section defect without stress influence when the vehicle is rolling over. 12 .

[0016] In one embodiment of the present invention, the size of the determined defects at the middle section is input into the stress analysis model of a multi-defect town gas pipeline; the number of defects at the middle section is N;

[0017] Define the middle section position defect closest to the head end defect as the first middle section position defect. When setting the position parameters of the first middle section position defect:

[0018] The middle boundary distance l of the first middle section defect 2 Greater than the first interval boundary distance l when the head end defect is rolled without stress effect 12 , and the middle boundary distance l 2 Greater than 1.5 times the pipe diameter D;

[0019] And the middle boundary distance l 2Perform stress calculation analysis to determine the second spacing boundary distance between the first middle section position defect and the second middle section position defect without stress influence when the vehicle is running over;

[0020] The interval boundary distance between multiple mid-section defects is determined according to the following method:

[0021] The interval boundary distance between the Nth middle position defect and the N+1th middle position defect is taken as: the interval boundary distance between the N-1th middle position defect and the Nth middle position defect.

[0022] In one embodiment of the present invention, the position parameter of the first middle position defect is the first interval boundary distance l 12 As the minimum setting basis, if the first interval boundary distance l 12 Less than 1.5 times the pipe diameter D, the middle boundary distance l 2 The value is 1.5 times the pipe diameter D.

[0023] In one embodiment of the present invention, the size of the determined tail end defect is input into the stress analysis model of a multi-defect town gas pipeline, and when the tail end defect position parameter is set:

[0024] The distance between the edge and the middle boundary between the tail defect and the middle defect l 3 The value is: the interval boundary distance between the two middle defects closest to the tail end defect, and the tail end boundary distance l of the tail end defect from the edge of the pipe 4 The distance should not be less than 1.5 times the pipe diameter D.

[0025] In one embodiment of the present invention, the edge-middle boundary distance l 3 Perform stress calculation and analysis, apply rolling load to the defect in the middle section closest to the tail defect to determine whether the tail defect is affected. If the tail defect is affected, redetermine the edge-middle boundary distance l 3 The value of the tail boundary distance l 4 The value should not be less than 1.5 times the pipe diameter D. If it is less than 1.5 times the pipe diameter D, the tail end defect cannot be processed on the pipe.

[0026] In one embodiment of the present invention, the head end defect, the plurality of defects at the middle section and the tail end defect are arranged in sequence according to the pipeline axis, and the axial center lines of the defects are on the same axis.

[0027] The present invention also provides a method for preparing a multi-defect pipeline sample, which is prepared by using the pipeline sample diagram obtained by the multi-defect pipeline sample design method described above.

[0028] The present invention also provides a test tube for stress and deformation of a town gas pipeline, which is manufactured using the above-mentioned method for manufacturing a multi-defect pipeline sample.

[0029] Compared with the prior art, the beneficial effects of the present invention are: it can measure the multiple defects of the gas pipeline when a heavy vehicle rolls over a defective urban gas pipeline, improve the utilization rate of test materials, and also improve the efficiency of test data collection. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The present invention is a flowchart of a method for designing a multi-defect pipeline specimen according to an embodiment of the present invention.

[0031] Figure 2 A schematic diagram of establishing a stress analysis model for a defective pipeline according to an embodiment of the present invention.

[0032] Figure 3 This is a schematic diagram of a single-defect pipeline design sample diagram according to an embodiment of the present invention.

[0033] Figure 4 This is a schematic diagram of a multi-defect pipeline design sample diagram according to an embodiment of the present invention.

[0034] Figure 5 Schematic diagram of the displacement field of the pipeline and soil according to an embodiment of the present invention.

[0035] Figure 6 This is a schematic diagram of the pipeline stress field under vehicle load at the first section defect of an embodiment of the present invention.

[0036] Figure 7 This is a design drawing of a defective pipeline sample according to an embodiment of the present invention.

[0037] Figure 8 This is a diagram showing an example of processing a defective pipe sample according to an embodiment of the present invention. DETAILED DESCRIPTION

[0038] In order to facilitate those skilled in the art to understand the technical solution of the present invention, the technical solution of the present invention is further described in conjunction with the accompanying drawings of the specification.

[0039] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0040] See also Figure 1 As shown, the present invention provides a method for designing a multi-defect pipeline specimen, comprising the following steps:

[0041] S10, determining pipeline information, multiple defect information, rolling vehicle information and test site environmental parameters.

[0042] In one embodiment of the present invention, the pipeline information includes the pipeline diameter, which is not less than 300 mm, the total length of the pipeline, which is not less than 8 m, the pipeline wall thickness and the pipeline mechanical properties, the defect information includes the number of defects, the defect length, the defect width and the defect depth, the rolling vehicle information includes vehicle information including vehicle weight, vehicle tire width, vehicle tire number and vehicle axle number, and the test site environmental parameters include temperature, maximum temperature difference within one day, soil cohesion, effective bulk density, friction angle, elastic modulus and Poisson's ratio.

[0043] Specifically, the test pipe is a spiral welded steel pipe made according to GB / T3091-2015 standard. Its material is Q235B, the diameter is 720mm, the pipe length is 12m, the wall thickness is 7.5mm, the mechanical properties are 235Mpa, the tensile strength is 390Mpa, the vehicle weight is 44490kg, the overall dimensions (length × width × height) are 14390×2800×3800, the tire width is 315mm, the rear is a double-row double-tire type and the front is a double-row single-wheel model. The experimental temperature is 20℃, the cohesion of hard clay is 28kPa, the effective bulk density is 23000N / m3, the friction angle is 33°, the elastic modulus is 28GPa, and the Poisson's ratio is 0.32. The defect information is shown in Table 1:

[0044] Table 1 Defect information

[0045]

[0046] S20, using modeling language commands, establish a stress analysis model for compacted defective urban gas pipelines.

[0047] The stress analysis model of the rolled defective town gas pipeline is established by using APDL language commands. Both the pipeline and the soil are solid unit components, and the 170 contact unit and 173 target unit in the APDL language are used to establish the constraints of the inner surface of the soil and the outer surface of the pipeline. In view of the limited extension of the buried pipeline in actual working conditions, in order to restore the actual service process of the buried pipeline, the present invention uses symmetric boundary constraints to constrain the section of Z=0 (i.e., the extension surface of the pipeline and the soil), and at the same time, the end surface away from the symmetry plane constrains the axial displacement of the soil and the pipeline.

[0048] S21, set the single defect urban gas pipeline stress analysis model with head end defect to calculate the stress distribution when the vehicle runs over the pipeline.

[0049] See also Figures 1 to 3 As shown, in one embodiment of the present invention, the vehicle load is applied by applying pressure at the corresponding node position above the head end defect, such as Figure 2 .

[0050] In this embodiment, the size of the determined head end defect is input into the single defect town gas pipeline stress analysis model, and the head end boundary distance l between the axial edge of the head end defect and the edge of the pipeline is determined. 1 Not less than 1.5 times the pipe diameter D, and the distance from the head end to the boundary l 1 Perform stress calculation and analysis to determine the first interval boundary distance l between the head end defect and the middle section defect without stress influence when the vehicle is rolling over. 12 .See Figure 3 shown.

[0051] S22, based on the single-defect urban gas pipeline stress analysis model, a multi-defect urban gas pipeline stress analysis model containing a middle position defect and a tail end defect set in sequence is set to calculate the stress of the pipeline when the vehicle runs over it. If there is no impact, the distance between defects is determined. If there is stress impact, the distance between defects is increased and recalculated.

[0052] See also Figures 1 to 4 As shown, in one embodiment of the present invention, the size of the determined middle section position defect is input into the multi-defect town gas pipeline stress analysis model. The number of middle section position defects is N, and the middle section position defect closest to the head end defect is defined as the first middle section position defect. When setting the position parameters of the first middle section position defect:

[0053] The middle boundary distance l of the first middle section defect 2 Greater than the first interval boundary distance l when the head end defect is rolled without stress effect 12 , and the middle boundary distance l 2 Greater than 1.5 times the pipe diameter D, such as Figure 4 shown.

[0054] And the middle boundary distance l 2 Stress calculation analysis is performed to determine the second interval boundary distance between the first middle section position defect and the second middle section position defect without stress influence when the vehicle is rolling over. There is no doubt that if the middle boundary distance l 2 The forward stress calculation and analysis affects the next middle section position defect, that is, affects the second middle section position defect, then increases the middle boundary distance l at this time 2 .

[0055] Among them, the position parameter of the first middle position defect is the first interval boundary distance l 12 As the minimum setting basis, if the first interval boundary distance l 12 Less than 1.5 times the pipe diameter D, the middle boundary distance l 2 The value is 1.5 times the pipe diameter D.

[0056] And, the interval boundary distance between multiple mid-section position defects is determined according to the following method:

[0057] The interval boundary distance between the Nth middle position defect and the N+1th middle position defect is taken as: the interval boundary distance between the N-1th middle position defect and the Nth middle position defect.

[0058] In one embodiment of the present invention, the head end defect, the plurality of defects at the middle section and the tail end defect are arranged in sequence according to the pipeline axis, and the axial center lines of the defects are on the same axis.

[0059] In one embodiment of the present invention, the size of the determined tail end defect is input into the stress analysis model of the multi-defect town gas pipeline. At this time, the stress analysis model of the multi-defect town gas pipeline is based on the model of setting the head end defect and the middle section position defect, and continues to load the tail end defect. When setting the tail end defect position parameters:

[0060] The distance between the edge and the middle boundary between the tail defect and the middle defect l 3 The value is: the interval boundary distance between the two middle defects closest to the tail end defect, and the tail end boundary distance l of the tail end defect from the edge of the pipe 4 The distance should not be less than 1.5 times the pipe diameter D.

[0061] The distance between edge and middle boundary is l 3 Perform stress calculation and analysis, apply rolling load to the defect in the middle section closest to the tail defect to determine whether the tail defect is affected. If the tail defect is affected, redetermine the edge-middle boundary distance l 3 The value of the tail boundary distance l 4 The value should not be less than 1.5 times the pipe diameter D. If it is less than 1.5 times the pipe diameter D, the tail end defect cannot be processed on the pipe.

[0062] See also Figure 5 to Figure 6 As shown, in one embodiment of the present invention, a vehicle load of 7200KN is applied to the defect at the head end, and the overall displacement deformation of the town gas pipeline is as follows Figure 5 As shown. Figure 5 It can be seen from the figure that the parameter model of the single-defect town gas pipeline stress analysis model established by the present invention can well simulate the influence of vehicle load on the stress and displacement field of the buried pipeline. Figure 5 The results of the buried pipeline and soil displacement field show that the defects on the surface of the urban gas pipeline are independent of each other, and only the soil and pipeline at the head end defect are affected by the vehicle load. When the load reaches 7200KN, the maximum deformation at the pipeline defect reaches 29.18mm, and the pipeline strain value is 1.03% at this time.

[0063] In order to analyze the stress of defective urban gas pipelines, the corresponding stress field distribution of urban gas pipelines is extracted as follows: Figure 6 As shown. Figure 6 It can be seen that the maximum von Mises equivalent stress of the pipeline at the head end defect reaches 205.813MPa, while the von Mises equivalent stress at the middle section defect and the tail end defect is distributed in [1.28MPa, 24MPa], indicating that the vehicle load has no effect on the pipeline at the middle section defect and the tail end defect.

[0064] S30, determining a pipeline sample diagram of stress and deformation of a multi-defect town gas pipeline according to the calculation results.

[0065] In one embodiment of the present invention, the spacing between defects can be determined based on the finite element analysis results, and the final pipeline sample diagram is as follows: Figure 7 shown.

[0066] See also Figure 1 and Figure 8 As shown, the present invention also provides a method for making a multi-defect pipeline sample, using the pipeline sample diagram obtained by the multi-defect pipeline sample design method described above to process the pipeline, and finally obtain the test pipeline sample required for the test, such as Figure 8 shown.

[0067] See also Figure 1 and Figure 8 As shown, the present invention also provides a test tube for stress and deformation of urban gas pipelines, which is made by applying the above-mentioned method for making a multi-defect pipeline sample. Figure 8 shown.

[0068] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be regarded as exemplary and non-limiting from any point of view, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention, and any reference numerals in the claims should not be regarded as limiting the claims involved.

[0069] The embodiments described above only represent implementation methods of the invention. The protection scope of the present invention is not limited to the embodiments described above. For those skilled in the art, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A method for designing a multi-defect pipeline specimen, characterized in that: The following steps are involved: S10, determining pipeline information, multiple defect information, rolling vehicle information and test site environmental parameters; wherein the defect information includes defect quantity, defect length, defect width and defect depth; S20, using modeling language commands, establishes a stress analysis model for rolled defective town gas pipelines, including: S21, set the single defect town gas pipeline stress analysis model with head end defect to calculate the stress distribution when the vehicle runs over the pipeline; S22, on the basis of the single-defect town gas pipeline stress analysis model, a multi-defect town gas pipeline stress analysis model including a middle section defect and a tail end defect arranged in sequence is set, and the stress of the pipeline crushed by a vehicle is calculated. If there is no influence, the distance between defects is determined; if there is a stress influence, the distance between defects is increased and recalculated; S30, determining a pipeline sample diagram of stress and deformation of a multi-defective town gas pipeline according to the calculation results; Wherein, in step S21: input the determined size of the head end defect into the single defect town gas pipeline stress analysis model, and determine that the head end boundary distance l1 between the axial edge of the head end defect and the edge of the pipeline is not less than 1.5 times the pipeline diameter D; The stress calculation and analysis is performed with the front end boundary distance l1 to determine the first interval boundary distance l between the front end defect and the middle section defect without stress influence when the vehicle is rolling over. 12 ; According to the determined size of the middle section defect, input it into the multi-defect town gas pipeline stress analysis model; wherein, the number of the middle section defects is N, and the middle section defect closest to the head end defect is defined as the first middle section defect. When setting the position parameters of the first middle section defect: The middle boundary distance l2 of the first middle section defect is greater than the first interval boundary distance l when the head end defect is rolled without stress 12 , and the intermediate boundary distance l2 is greater than 1.5 times the pipe diameter D; According to the determined size of the tail end defect, input it into the stress analysis model of multi-defect town gas pipeline, and set the tail end defect position parameters: A stress calculation analysis is performed on the edge-middle boundary distance l3 between the tail end defect and the middle section defect, and a rolling load is applied to the middle section defect closest to the tail end defect to determine whether the tail end defect is affected. If the tail end defect is affected, the value of the edge-middle boundary distance l3 is re-determined, and the value of the tail end boundary distance l4 is not less than 1.5 times the pipe diameter D. If it is less than 1.5 times the pipe diameter D, the tail end defect cannot be processed on the pipe; and l4 is the tail end boundary distance from the tail end defect to the pipe edge.

2. The method for designing a multi-defect pipeline specimen according to claim 1, characterized in that: According to the determined size of the defects at the middle section, the defects are input into the stress analysis model of multi-defect town gas pipeline; the number of defects at the middle section is N; Define the middle section position defect closest to the head end defect as the first middle section position defect. When setting the position parameters of the first middle section position defect: The middle boundary distance l2 of the first middle section defect is greater than the first interval boundary distance l when the head end defect is rolled without stress 12 , and the intermediate boundary distance l2 is greater than 1.5 times the pipe diameter D; A stress calculation analysis is performed with the middle boundary distance l2 to determine the second interval boundary distance between the first middle section position defect and the second middle section position defect without stress influence when the vehicle is rolling over; The interval boundary distance between multiple mid-section defects is determined according to the following method: The interval boundary distance between the Nth middle position defect and the N+1th middle position defect is taken as: the interval boundary distance between the N-1th middle position defect and the Nth middle position defect.

3. The method for designing a multi-defect pipeline specimen according to claim 2, characterized in that: The position parameter of the first middle position defect is the first interval boundary distance l 12 As the minimum setting basis, if the first interval boundary distance l 12 If the intermediate boundary distance l2 is less than 1.5 times the pipe diameter D, the value of the intermediate boundary distance l2 is 1.5 times the pipe diameter D.

4. The method for designing a multi-defect pipeline specimen according to claim 1, characterized in that: The edge-middle boundary distance l3 is taken as: the interval boundary distance between the two middle defects closest to the tail end defect, and the distance between the tail end defect and the tail end boundary distance l4 of the pipe edge is not less than 1.5 times the pipe diameter D.

5. The method for designing a multi-defect pipeline specimen according to claim 1, characterized in that: The head end defect, multiple middle section position defects and tail end defect are arranged in sequence according to the pipeline axis, and the axial center lines of the defects are on the same axis.

6. A method for preparing a multi-defect pipeline sample, characterized in that: The pipeline sample diagram is obtained by using the multi-defect pipeline sample design method described in any one of claims 1 to 5 for production.

7. A test tube for stress and deformation of town gas pipelines, characterized in that: The multi-defect pipeline sample is manufactured using the method for manufacturing a multi-defect pipeline sample as described in claim 6.

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