Pipeline support risk assessment method based on multi-type detection

Abstract

The invention discloses a pipeline support risk assessment method based on multi-type detection. The method comprises the following steps: numbering pipeline supports, and carrying out ultrasonic detection on nondestructive bolts by using an ultrasonic flaw detector; the stress of the pipeline support is analyzed based on finite element simulation, and the maximum stress borne by the pipeline support and the maximum displacement generated by the pipeline support are obtained; the pipeline support picture is processed based on image recognition, and the number of cracks of the pipeline support is obtained; performing nondestructive inspection on the bolts by using an ultrasonic flaw detector to obtain the number of damaged bolts; and evaluating the risk of each pipeline bracket, and evaluating the risk of the bracket section forming the whole pipe section according to an evaluation result. By the adoption of the method, related data of the pipeline support can be obtained through multiple methods such as finite element simulation, image recognition and ultrasonic detection, the danger of the pipeline support is comprehensively evaluated, the accuracy of detection and evaluation work is improved, and potential safety hazards are eliminated.

Description

Technical Field

[0001] The invention relates to a pipeline support hazard assessment method, and in particular to a pipeline support hazard assessment method based on multi-type detection. Background Art

[0002] In the oil and gas industry, pipe supports, as supporting components of pipelines, play a very important role in the safe operation of pipelines. Since the status of pipe supports is constantly changing after they are built, the status of pipe supports should be tested and evaluated in a timely manner. At present, the detection of pipe supports relies on manual measurement, which requires a lot of manpower and material resources. Not only is the efficiency of the detection and evaluation work low, but the accuracy of the data obtained cannot be improved. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a pipeline support hazard assessment method based on multi-type detection. The method can improve the accuracy of detection and assessment work and eliminate safety hazards.

[0004] To achieve the above object, the technical solution adopted by the present invention is:

[0005] A pipeline support hazard assessment method based on multi-type detection of the present invention comprises the following steps:

[0006] Step 1: Number all pipe supports in the entire pipe section from 1 to p, and count all bolt types used in the pipe section. Use the ultrasonic detection probe of the industrial ultrasonic flaw detector to perform ultrasonic detection on all types of non-destructive bolts to obtain normal echo signals corresponding to various types of bolts.

[0007] Step 2: Establish a record table of the pipeline support information in the data software, and record the data of the pipeline support in the record table;

[0008] Step 3: Based on finite element simulation, the bearing performance of each pipe support on a pipe section is analyzed respectively, and the maximum stress and maximum displacement of each pipe support are obtained;

[0009] Step 4: Based on image recognition, use a camera to take pictures of each plane of each pipe support, and then use data processing software to process the pipe support pictures to obtain the total number of cracks of each pipe support and record it in a record table;

[0010] Step 5: Use the ultrasonic detection probe of the industrial ultrasonic flaw detector to perform nondestructive flaw detection on the bolts connected to each pipe support. The ultrasonic detection probe transmits the echo signal to the flaw detector, and the echo signal is displayed on the oscilloscope screen of the flaw detector. By comparing the difference with the non-destructive bolt echo signal, it is determined whether the bolts on each pipe support are damaged. The total number of damaged bolts on each pipe support is obtained and recorded in the record table;

[0011] Step 6: Query the allowable stress [σ] corresponding to each pipe support q and allowable displacement [Δx] q , q = 1, 2, ..., p, q represents the number of the pipe support, p represents the total number of pipe supports, and is recorded in the record table;

[0012] Step 7: Establish a pipeline support hazard rating table in the data software, wherein the pipeline support hazard rating table includes the pipeline support number, bearing capacity assessment level, surface quality assessment level, bolt damage assessment level, and support hazard assessment level, and then assess the hazard of each pipeline support and record it in the pipeline support hazard rating table;

[0013] Step 8: Set a threshold value, compare the total number of supports of different support hazard assessment levels in the pipeline support hazard rating table with the threshold value, and assess the hazard of the support segments of all pipeline supports that constitute the entire pipe section.

[0014] The beneficial effects of the present invention are: relevant data of the pipeline support can be obtained through various methods such as finite element simulation, image recognition and ultrasonic detection, and the danger of the pipeline support can be comprehensively evaluated, the accuracy of detection and evaluation work can be improved, and safety hazards can be eliminated. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 The present invention is a flowchart of a pipeline support hazard assessment method based on multi-type detection according to an embodiment of the present invention. DETAILED DESCRIPTION

[0016] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0017] like Figure 1 The present invention provides a pipeline support hazard assessment method based on multi-type detection, comprising the following steps:

[0018] Step 1: Number all pipe supports in the entire pipe section from 1 to p, and count all bolt types used in the pipe section. Use the ultrasonic detection probe of the industrial ultrasonic flaw detector to perform ultrasonic detection on all types of non-destructive bolts to obtain normal echo signals corresponding to various types of bolts.

[0019] Step 2: Establish a record table of the pipeline support information in the data software, and record the data of the pipeline support in the record table;

[0020] Step 3: Based on finite element simulation, analyze the bearing performance of each pipe support on a pipe section, and obtain the maximum stress and maximum displacement of each pipe support. The specific method is as follows:

[0021] The first step is to install a force sensor on the pipe support No. 1 and connect it to a computer, and then use the force sensor to measure the load on the pipe support over a period of time. The force sensor transmits the load data on the pipe support to the computer, and selects the maximum load value F from the measured multiple load data. max It is recorded that the period of time mentioned includes the stress conditions of the pipeline support under all working conditions; the all working conditions mentioned generally include normal and stable operation of the pipeline, pipeline start-up and stop, etc.;

[0022] The second step is to create a 3D pipe support model in the 3D software, and then import the 3D pipe support model into the finite element analysis software. Assume that the load on the pipe support is F max , simulate and analyze the pipeline support to obtain the maximum stress value σ of the pipeline support and the maximum displacement Δx generated by the pipeline support;

[0023] Step 3: Repeat steps 1 to 3 for all pipe supports with other numbers in the entire pipe section to obtain the maximum stress value σ of each pipe support. q and the maximum displacement Δx q And record it in the record table, q=1, 2, ..., p, q represents the number of the pipe support, and p represents the total number of the pipe support.

[0024] Step 4: Based on image recognition, use a camera to take pictures of each plane of each pipe support, and then use data processing software to process the pipe support pictures to obtain the total number of cracks of each pipe support and record them in the record table. The specific method is as follows:

[0025] The first step is to use a camera to take pictures of each plane of the pipe support numbered 1, and mark the pictures from 1 to n in the order in which they were taken;

[0026] Step 2: Import the first pipe support image into the data processing software. The R, G, and B values ​​of each pixel in the image are recorded as R(x, y), G(x, y), and B(x, y), respectively, where x and y represent the horizontal and vertical coordinates of the pixel in the image, respectively.

[0027] The third step is to grayscale the pipe support image. The grayscale value I (x, y) of each pixel in the pipe support image is calculated as follows:

[0028] I(x,y)=0.299R(x,y)+0.587G(x,y)+0.114B(x,y)

[0029] Let R(x, y) = G(x, y) = B(x, y) = I(x, y) for each pixel to obtain the grayscale image of the pipe support;

[0030] The fourth step is to perform binarization on the grayscale image of the pipeline support. First, the graythresh function is called in the data processing software to automatically calculate the optimal threshold I of the grayscale image of the pipeline support. 最佳 ; Then, compare the gray value of each pixel I(x, y) in the grayscale image of the road support with I 最佳 If I(x, y)>I 最佳 , then set I(x, y) to 1, otherwise, set it to 0, and you can get a binary image;

[0031] Step 5: Extract the connected domain information in the binary image. First, in the data processing software, call the bwlabel function to find the connected domain of the binary image in an 8-connected manner, that is, find the area where I(x, y) = 1 and is connected, and get the number of connected domains k; finally, call the regionprops function to obtain the information of each connected domain, which includes the length l of the circumscribed rectangle i , width b i etc., where i represents the i-th connected domain, i=1, 2,…, k;

[0032] Step 6: Reduce the noise of the binary image and filter out other noise. Since the crack is long and thin, its connected domain has the characteristics of large length and small width. Therefore, the minimum aspect ratio of the connected domain is set to T to remove the non-crack connected domain. The value of T can be adjusted according to the actual situation. Calculate the aspect ratio T of each connected domain i = l i / b i , where i represents the i-th connected domain, i = 1, 2, ..., k; compare each connected domain T i The relationship between T and i >T, the grayscale values ​​I(x, y) of all pixels in the i-th connected domain are set to 1, otherwise, the grayscale values ​​I(x, y) of all pixels in the i-th connected domain are set to 0, and finally the crack binary image after denoising is obtained;

[0033] Step 7. Repeat steps 2 to 6, and import other pictures of the pipe support No. 1 into the data processing software in sequence to obtain the crack binary pictures of the pipe support after noise reduction, and count the number of cracks in each crack binary picture, recorded as N. j, j = 1, 2, ..., n, j represents the picture number of the pipe support, n represents the total number of pictures of the pipe support, calculate the total number of cracks of the pipe support

[0034] Step 8: Repeat steps 1 to 8 for all pipe supports with other numbers in the entire pipe section to obtain the total number of cracks N for each pipe support. q , q=1, 2,…, p, q represents the number of the pipe support, p represents the total number of pipe supports, and is recorded in the record table.

[0035] Step 5. Use the ultrasonic detection probe of the industrial ultrasonic flaw detector to perform non-destructive flaw detection on the bolts connected to each pipe support. The ultrasonic detection probe transmits the echo signal to the flaw detector, and the echo signal is displayed on the oscilloscope screen of the flaw detector. By comparing the difference with the non-destructive bolt echo signal, it is determined whether the bolts on each pipe support are damaged. The total number of damaged bolts on each pipe support is obtained and recorded in the record table.

[0036] The ultrasonic detection probe in this step is used as both a transmitting device and a receiving element, and can intermittently transmit ultrasonic waves in a pulsed manner. The industrial ultrasonic flaw detector can be the NDT610 industrial ultrasonic flaw detector of Beijing Keda Keyi Technology Co., Ltd. The industrial ultrasonic flaw detector is composed of an ultrasonic detection probe and a flaw detector. The specific method of this step can be as follows:

[0037] Step 1: Number the bolts on the pipe support No. 1 from 1 to m, and use the ultrasonic detection probe to detect them in sequence. If the echo signal of the bolt is different from the normal signal, record the number of the bolt, otherwise, do not record it;

[0038] Step 2: Count the number of damaged bolts, recorded as M;

[0039] Step 3: Repeat steps 2 to 3 for all pipe supports with other numbers in the entire pipe section to obtain the total number of damaged bolts M for each pipe support. q , q=1, 2,…, p, q represents the number of the pipe support, p represents the total number of pipe supports, and is recorded in the record table.

[0040] Step 6. Query (e.g., by querying the Mechanical Design Manual, Vol. 1, edited by Cheng Daxian, 5th edition, Beijing: Chemical Industry Press, 2007.11) the allowable stress [σ] corresponding to each pipe support q and allowable displacement [Δx] q , q=1, 2,…, p, q represents the number of the pipe support, p represents the total number of pipe supports, and is recorded in the record table.

[0041] Step 7: Establish a pipe support hazard rating table in the data software. The pipe support hazard rating table includes the pipe support number, load-bearing capacity assessment level, surface quality assessment level, bolt damage assessment level, and support hazard assessment level. Then, the hazard of each pipe support is assessed and recorded in the pipe support hazard rating table. The specific assessment method is as follows:

[0042] Step 1: Evaluate the bearing capacity of the pipe support: First, query the maximum stress value σ of each pipe support in the pipe support information record table. q , maximum displacement Δx q , allowable stress value [σ] q , Allowable displacement [Δx] q ; Secondly, determine the load-bearing capacity level of each bracket. If σ q <[σ] q And Δx q <[Δx] q , then the bearing capacity of the pipeline support is rated as grade A, which means that the bearing capacity is sufficient; otherwise, the bearing capacity of the pipeline is rated as grade C, which means that the bearing capacity is insufficient; finally, the bearing capacity rating of each support is recorded in the pipeline support hazard rating table;

[0043] Step 2: Evaluate the surface quality of the pipe support: First, query the number of cracks N of each pipe support in the record table. q ; Secondly, determine the surface quality rating of each bracket. If N q <1, the surface quality is rated as grade a, which means there are no cracks on the surface of the bracket; if 1≤N q <3, the surface quality is rated as Class B, which means there are a few cracks on the surface of the bracket; if N q ≥3, it is rated as Class C, which means there are multiple cracks on the support surface; finally, the surface quality rating of each support is recorded in the Pipeline Support Hazard Rating Table;

[0044] Step 3: Assess the level of damage to the pipe support bolts: First, query the number of damaged bolts M for each pipe support in the record table. q ; Secondly, determine the damage assessment level of the bolts of each bracket. If M q <1, the bolt damage is assessed as grade a, which means the bracket bolts are not damaged; if 1≤M q <3, the bolt damage is rated as Class B, which means that a small amount of bolts have internal damage; if M q ≥3, the bolt damage is assessed as Class C, which means that multiple bolts are damaged internally; finally, the bolt damage assessment level of each bracket is recorded in the pipeline bracket hazard rating table;

[0045] Step 4: Assess the hazard level of the pipe support: For any pipe support, if the load-bearing capacity assessment level, surface quality assessment level, and bolt damage assessment level are the same, then this rating is the hazard level of the pipe support; if the load-bearing capacity assessment level, surface quality assessment level, and bolt damage assessment level are different, then the highest hazard rating is used as the hazard level of the pipe support, and the hazard levels are divided from high to low into c, b, and a; use this method to assess the hazard level of all pipe supports and record them in the pipe support hazard level table;

[0046] Step 5. If the hazard assessment of the pipe support is grade A, it means that the support has sufficient bearing capacity and is not damaged, and no further inspection is required; if the hazard assessment of the pipe support is grade B, it means that there are some problems with the support, and further inspection of the pipe support is required to determine whether measures should be taken to maintain the support; if the hazard assessment of the pipe support is grade C, it means that there are multiple problems with the support, and measures should be taken to maintain the support.

[0047] Step 8: Set a threshold value, compare the total number of supports of different support hazard assessment levels in the pipeline support hazard rating table with the threshold value, and assess the hazard of the support segments of all pipeline supports that constitute the entire pipe section. The specific method is as follows:

[0048] The first step is to count the number of pipe supports with a hazard rating of grade A in the pipe support hazard rating table, recorded as X, the number of pipe supports with grade B, recorded as Y, and the number of pipe supports with grade C, recorded as Z;

[0049] Step 2: If Z = 0 and The stent segment is rated as A; if Z = 0 and The stent segment is rated as Class B; if Z≠0 and In this case, the bracket section is rated as Class B, and in other cases, the bracket section is rated as Class C. p represents the total number of pipeline brackets;

[0050] Step 3: If the bracket segment is rated as Grade A, the overall performance of the bracket segment is good and appropriate measures may be taken for some individual brackets; Grade B: slightly lower than normal use requirements and measures should be taken for some brackets; Grade C: measures should be taken to maintain the entire bracket segment.

Claims

1. A pipeline support hazard assessment method based on multi-type detection, characterized in that The following steps are involved: Step 1: Number all pipe supports in the entire pipe section from 1 to p, and count all bolt types used in the pipe section. Use the ultrasonic detection probe of the industrial ultrasonic flaw detector to perform ultrasonic detection on all types of non-destructive bolts to obtain normal echo signals corresponding to various types of bolts. Step 2: Establish a record table of the pipeline support information in the data software, and record the data of the pipeline support in the record table; Step 3: Based on finite element simulation, the bearing performance of each pipe support on a pipe section is analyzed respectively, and the maximum stress and maximum displacement of each pipe support are obtained; Step 4: Based on image recognition, use a camera to take pictures of each plane of each pipe support, and then use data processing software to process the pipe support pictures to obtain the total number of cracks of each pipe support and record it in a record table; Step 5: Use the ultrasonic detection probe of the industrial ultrasonic flaw detector to perform nondestructive flaw detection on the bolts connected to each pipe support. The ultrasonic detection probe transmits the echo signal to the flaw detector, and the echo signal is displayed on the oscilloscope screen of the flaw detector. By comparing the difference with the non-destructive bolt echo signal, it is determined whether the bolts on each pipe support are damaged. The total number of damaged bolts on each pipe support is obtained and recorded in the record table; Step 6: Query the allowable stress [σ] corresponding to each pipe support q and allowable displacement [Δx] q , q = 1, 2, ..., p, q represents the number of the pipe support, p represents the total number of pipe supports, and is recorded in the record table; Step 7: Establish a pipeline support hazard rating table in the data software, wherein the pipeline support hazard rating table includes the pipeline support number, bearing capacity assessment level, surface quality assessment level, bolt damage assessment level, and support hazard assessment level, and then assess the hazard of each pipeline support and record it in the pipeline support hazard rating table; Step 8: Set a threshold value, compare the total number of supports of different support hazard assessment levels in the pipeline support hazard rating table with the threshold value, and assess the hazard of the support segments of all pipeline supports that constitute the entire pipe section.

2. The pipeline support hazard assessment method based on multi-type detection according to claim 1 is characterized in that: The specific method of step three is as follows: The first step is to install a force sensor on the pipe support No. 1 and connect it to a computer, and then use the force sensor to measure the load on the pipe support over a period of time. The force sensor transmits the load data on the pipe support to the computer, and selects the maximum load value F from the measured multiple load data. max It is recorded that the period of time mentioned includes the stress conditions of the pipeline support under all working conditions; the all working conditions mentioned generally include normal and stable operation of the pipeline and the start-up and shutdown conditions of the pipeline; The second step is to create a 3D pipe support model in the 3D software, and then import the 3D pipe support model into the finite element analysis software. Assume that the load on the pipe support is F max , simulate and analyze the pipeline support to obtain the maximum stress value σ of the pipeline support and the maximum displacement Δx generated by the pipeline support; Step 3: Repeat steps 1 to 3 for all pipe supports with other numbers in the entire pipe section to obtain the maximum stress value σ of each pipe support. q and the maximum displacement Δx q And record it in the record table, q=1, 2, ..., p, q represents the number of the pipe support, and p represents the total number of the pipe support.

3. The pipeline support hazard assessment method based on multi-type detection according to claim 1 is characterized in that: The specific method of step 4 is as follows: The first step is to use a camera to take pictures of each plane of the pipe support numbered 1, and mark the pictures from 1 to n in the order in which they were taken; Step 2: Import the first pipe support image into the data processing software. The R, G, and B values ​​of each pixel in the image are recorded as R(x, y), G(x, y), and B(x, y), respectively, where x and y represent the horizontal and vertical coordinates of the pixel in the image, respectively. The third step is to grayscale the pipe support image. The grayscale value I (x, y) of each pixel in the pipe support image is calculated as follows: I(x,y)=0.299R(x,y)+0.587G(x,y)+0.114B(x,y) Let R(x, y) = G(x, y) = B(x, y) = I(x, y) for each pixel to obtain the grayscale image of the pipe support; The fourth step is to perform binarization on the grayscale image of the pipeline support. First, the graythresh function is called in the data processing software to automatically calculate the optimal threshold I of the grayscale image of the pipeline support. 最佳 ; Then, compare the gray value of each pixel I(x, y) in the grayscale image of the road support with I 最佳 If I(x, y)>I 最佳 , then set I(x, y) to 1, otherwise, set it to 0, and you can get a binary image; Step 5: Extract the connected domain information in the binary image. First, in the data processing software, call the bwlabel function to find the connected domain of the binary image in an 8-connected manner, that is, find the area where I(x, y) = 1 and is connected, and get the number of connected domains k; finally, call the regionprops function to obtain the information of each connected domain, which includes the length l of the circumscribed rectangle i , width b i Information, where i represents the i-th connected domain, i = 1, 2, ..., k; Step 6: Set the minimum aspect ratio of the connected domain to T to remove the non-crack connected domains and calculate the aspect ratio T of each connected domain. i = l i / b i , where i represents the i-th connected domain, i = 1, 2, ..., k; compare each connected domain T i The relationship between T and i >T, the grayscale values ​​I(x, y) of all pixels in the i-th connected domain are set to 1, otherwise, the grayscale values ​​I(x, y) of all pixels in the i-th connected domain are set to 0, and finally the crack binary image after denoising is obtained; Step 7. Repeat steps 2 to 6, and import other pictures of the pipe support No. 1 into the data processing software in sequence to obtain the crack binary pictures of the pipe support after noise reduction, and count the number of cracks in each crack binary picture, recorded as N. j , j = 1, 2, ..., n, j represents the picture number of the pipe support, n represents the total number of pictures of the pipe support, calculate the total number of cracks of the pipe support Step 8: Repeat steps 1 to 8 for all pipe supports with other numbers in the entire pipe section to obtain the total number of cracks N for each pipe support. q , q=1, 2,…, p, q represents the number of the pipe support, p represents the total number of pipe supports, and is recorded in the record table.

4. The pipeline support hazard assessment method based on multi-type detection according to claim 1 is characterized in that: The specific method of step five is as follows: Step 1: Number the bolts on the pipe support No. 1 from 1 to m, and use the ultrasonic detection probe to detect them in sequence. If the echo signal of the bolt is different from the normal signal, record the number of the bolt, otherwise, do not record it; Step 2: Count the number of damaged bolts, recorded as M; Step 3: Repeat steps 2 to 3 for all pipe supports with other numbers in the entire pipe section to obtain the total number of damaged bolts M for each pipe support. q , q=1, 2,…, p, q represents the number of the pipe support, p represents the total number of pipe supports, and is recorded in the record table.

5. The pipeline support hazard assessment method based on multi-type detection according to claim 1 is characterized in that: The specific method of step seven is as follows: Step 1: Evaluate the bearing capacity of the pipe support: First, query the maximum stress value σ of each pipe support in the pipe support information record table. q , maximum displacement Δx q , allowable stress value [σ] q , Allowable displacement [Δx] q ; Secondly, determine the load-bearing capacity level of each bracket. If σ q <[σ] q And Δx q <[Δx] q , then the bearing capacity of the pipeline support is rated as grade A, which means that the bearing capacity is sufficient; otherwise, the bearing capacity of the pipeline is rated as grade C, which means that the bearing capacity is insufficient; finally, the bearing capacity rating of each support is recorded in the pipeline support hazard rating table; Step 2: Evaluate the surface quality of the pipe support: First, query the number of cracks N of each pipe support in the record table. q ; Secondly, determine the surface quality rating of each bracket. If N q <1, the surface quality is rated as grade a, which means there are no cracks on the surface of the bracket; if 1≤N q <3, the surface quality is rated as Grade B, which means there are a few cracks on the surface of the bracket; if N q ≥3, it is rated as Class C, which means there are multiple cracks on the support surface; finally, the surface quality rating of each support is recorded in the Pipeline Support Hazard Rating Table; Step 3: Assess the level of damage to the pipe support bolts: First, query the number of damaged bolts M for each pipe support in the record table. q ; Secondly, determine the damage assessment level of the bolts of each bracket. If M q <1, the bolt damage is assessed as grade a, which means the bracket bolts are not damaged; if 1≤M q <3, the bolt damage is rated as Class B, which means that a small amount of bolts have internal damage; if M q ≥3, the bolt damage is assessed as Class C, which means that multiple bolts are damaged internally; finally, the bolt damage assessment level of each bracket is recorded in the pipeline bracket hazard rating table; Step 4: Assess the hazard level of the pipe support: For any pipe support, if the load-bearing capacity assessment level, surface quality assessment level, and bolt damage assessment level are the same, then this rating is the hazard level of the pipe support; if the load-bearing capacity assessment level, surface quality assessment level, and bolt damage assessment level are different, then the highest hazard rating is used as the hazard level of the pipe support, and the hazard levels are divided from high to low into c, b, and a; use this method to assess the hazard level of all pipe supports and record them in the pipe support hazard level table; Step 5. If the hazard assessment of the pipe support is grade A, it means that the support has sufficient bearing capacity and is not damaged, and no further inspection is required; if the hazard assessment of the pipe support is grade B, it means that there are some problems with the support, and further inspection of the pipe support is required to determine whether measures should be taken to maintain the support; if the hazard assessment of the pipe support is grade C, it means that there are multiple problems with the support, and measures should be taken to maintain the support.

6. The pipeline support hazard assessment method based on multi-type detection according to claim 5 is characterized in that: The specific method of step eight is as follows: The first step is to count the number of pipe supports with a hazard rating of grade A in the pipe support hazard rating table, recorded as X, the number of pipe supports with grade B, recorded as Y, and the number of pipe supports with grade C, recorded as Z; Step 2: If Z = 0 and The stent segment is rated as A; if Z = 0 and The stent segment is rated as Class B; if Z≠0 and In this case, the bracket section is rated as Class B, and in other cases, the bracket section is rated as Class C. p represents the total number of pipeline brackets; Step 3: If the bracket segment is rated as Grade A, the overall performance of the bracket segment is good and appropriate measures may be taken for some individual brackets; Grade B: slightly lower than normal use requirements and measures should be taken for some brackets; Grade C: measures should be taken to maintain the entire bracket segment.

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