A Method for Calculating Internal Pressure Load by Folias Expansion Coefficient of Corroded Pipeline

A technology of expansion coefficient and pipeline, which is applied in the field of calculation of pipeline Folias expansion coefficient, and can solve the problem of single consideration factors

Active Publication Date: 2020-05-19
DALIAN UNIV OF TECH
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Problems solved by technology

[0012] It can be seen from the above formula that the calculation of the Folias expansion coefficient is mainly related to the corrosion length, and the consideration is relatively simple, and the expansion coefficient M corresponding to different corrosion lengths is also different. In order to calculate the limit internal pressure load of the corroded pipeline more accurately, it is necessary to calculate the corrosion pipeline coefficient of expansion to be studied

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  • A Method for Calculating Internal Pressure Load by Folias Expansion Coefficient of Corroded Pipeline
  • A Method for Calculating Internal Pressure Load by Folias Expansion Coefficient of Corroded Pipeline
  • A Method for Calculating Internal Pressure Load by Folias Expansion Coefficient of Corroded Pipeline

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[0113] The code ASME B31G, MB31G and RPA calculate the complete pipeline failure pressure as shown in formula (3):

[0114] The DNV RP-F101 method to calculate the complete pipeline failure pressure is shown in formula (4):

[0115]

[0116] where σ flow is the flow stress, D is the outer diameter of the pipe, and t is the wall thickness of the pipe.

[0117] For the axial projected area of ​​the actual corrosion defect of the pipeline, it presents an irregular shape. For the shape parameter α, there are three main value methods:

[0118] Corrosion with axial projection as rectangle: α = 1;

[0119] The corrosion of the axial projection as a parabola: α=2 / 3;

[0120] Axial projection as erosion of complex shapes: α = 0.85 (A = 0.55dL + 0.45(2 / 3)dL).

[0121] From the above analysis, it can be seen that the reduction ratio of the pipeline implosion failure formula is mainly determined by the corrosion length parameter and depth parameter. In order to study the relatio...

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Abstract

The invention discloses a method for calculating the internal pressure load through the Folias expansion coefficient of a corroded pipeline, and belongs to the technical field of pipeline construction. By considering the influences of the corrosion length and corrosion depth on the Folias expansion coefficient of the corroded pipeline, simulating different corrosion working conditions through finite elements and counting and fitting calculation results, the method for calculating the Folias expansion coefficient under different expansion lengths is obtained. The speed reduction ratio of the corroded pipeline is calculated through the method for calculating the expansion coefficient; in combination with the limit internal pressure load of the undamaged pipeline, the method for calculating the limit internal pressure of the corroded pipeline is obtained.

Description

technical field [0001] The invention relates to a method for calculating the Folias expansion coefficient of a pipeline, and uses the calculation method to calculate the internal pressure load of a corroded pipeline, which belongs to the technical field of pipeline structures. Background technique [0002] Volume defects refer to the loss of metal on the pipe wall. The main cause of volume defects in pipelines is corrosion. Among the many factors that endanger pipelines, corrosion is one of the most common factors. Corrosion can reduce the wall thickness of pipelines in a large area, reduce the pressure bearing capacity of pipelines, cause pipeline perforation or blasting, cause oil leakage and gas leakage accidents, and further lead to serious accidents such as fire, explosion and environmental pollution. [0003] Under normal operating conditions of submarine pipelines, the control load is generally internal pressure load, which determines the main design parameters such a...

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Application Information

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Patent Type & AuthorityPatents(China)
IPC IPC(8): G06F30/23G06F113/14
CPCG06F30/23G06F2113/14
Inventor李昕孙明明彭增利武行张杰
OwnerDALIAN UNIV OF TECH