Bending failure evaluation method for corrosion defect contained submarine pipeline structure

A technology for submarine pipeline and failure assessment, which is applied in the direction of testing material strength, pipeline system, weather resistance/light resistance/corrosion resistance by applying a stable bending force, and can solve problems such as inaccurate evaluation results and low practical application value

Active Publication Date: 2020-02-21
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] Aiming at the problem that the traditional evaluation method is to set the corrosion defect at the maximum bending position of the pipeline to obtain the critical load limit of plastic failure of the pipeline in the corrosion sea, there are problems that the evaluation results are inaccurate and the practical application value is not high. The present invention provides a A bending failure assessment method for submarine pipeline structures with corrosion defects, which includes a calculation method for the plastic limit load-bearing bending moment of submarine pipelines at any position, not limited to the case where corrosion defects only exist at the maximum bending position of the pipeline

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  • Bending failure evaluation method for corrosion defect contained submarine pipeline structure
  • Bending failure evaluation method for corrosion defect contained submarine pipeline structure
  • Bending failure evaluation method for corrosion defect contained submarine pipeline structure

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Embodiment 1

[0063] Embodiment 1 Failure Assessment Method

[0064] An embodiment of the present invention provides a bending failure evaluation method for a submarine pipeline structure containing corrosion defects, specifically:

[0065] Step S1: Select an active pipeline as the pipeline to be tested, and detect the location and corrosion size of the largest corrosion defect of the pipeline under test;

[0066] Step S2: According to the service environment state parameters of the pipeline under test and the detection data of step S1, calculate the resultant force of the wave load and current load, determine the bending moment and the bending direction of the pipeline under test, and determine the pressure of the pipeline under test. The maximum bending moment position and maximum bending moment value;

[0067] Step S3: Deduce the plastic limit bending moment formula of the pipeline with corrosion defects, and calculate the plastic limit bending moment of the tested pipeline according to...

Embodiment 2

[0091] Calculation method of embodiment 2 plastic limit bending moment

[0092] An embodiment of the present invention provides a calculation method for the plastic limit bending moment of a submarine pipeline, specifically:

[0093] Step S1: Determine the position of the plastic neutral axis according to the location and corrosion size of the corrosion defect of the pipeline under test, and calculate the tensile zone area A of the pipeline under test according to formula (1) and formula (2) I and the compression zone area A Π :

[0094] A Ι = 2R m tβ (1)

[0095] A Π = 2R m t(π-β)-2Rhθ (2)

[0096] in: is the average radius; R is the radius of the outer wall of the pipeline; t is the thickness of the tested pipeline, t is much smaller than R; h is the corrosion depth, θ is the half angle of the corrosion width;

[0097] Step S2: According to the position and corrosion size of the corrosion defect of the detected pipeline, the angle β of the plastic neutral axis, the ...

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Abstract

The invention discloses a bending failure evaluation method for a corrosion defect contained submarine pipeline structure. The method specifically comprises the following steps: detecting the positionand size of the maximum size corrosion defect of a pipeline; calculating the wave and current load borne by the pipeline according to pipeline detection data, working conditions and environmental conditions, and determining the maximum bending moment position and the maximum bending moment value borne by the tested pipeline finally; deducing the formula of plastic ultimate bending moment for thecorrosion defect contained submarine pipeline, and calculating the plastic ultimate bearing bending moment of the tested pipeline according to the formula; comparing the calculated maximum bending moment with the plastic limit bending moment, and judging whether the tested pipeline fails on the premise of taking into account the safety factor. The method has the beneficial effects that overall bending strength calculation and evaluation can be performed on the pipeline containing the small-range long-axis corrosion defect at any position, the finite element modeling and analysis process is omitted, the calculation difficulty is reduced, calculation efficiency is improved, and the requirement of result precision is also met.

Description

technical field [0001] The invention relates to the technical field of failure assessment of submarine pipelines, in particular to a bending failure assessment method of a submarine pipeline structure containing corrosion defects. Background technique [0002] In recent years, my country's demand for oil, natural gas and other resources has been increasing. The development and utilization of oil, natural gas and other resources are also becoming more and more important. As the "lifeline" for the development, production and transportation of oil and gas resources, submarine pipelines play an extremely important role in ensuring the safety of pipeline structures. Due to the complex marine environment, submarine pipelines are often suspended due to erosion and seawater erosion. When the outer anti-corrosion layer of the submarine pipeline is damaged, the seawater will erode along the direction in which the anti-corrosion layer is damaged, and it is easy to form long corrosion...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): F17D5/02G01N3/20G01N17/00
CPCF17D5/02G01N3/20G01N17/00
Inventor 杨冬平王强郭爱洪丛军王伟斌牛更奇支景波朱丽国高莎莎马文峰
Owner CHINA PETROLEUM & CHEM CORP
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