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A Velocity Product-Based Method for Characterizing the Safety Margin of Crack Defects in Pressure Vessels

A technology of safety margin and pressure vessel, which is applied in the field of pressure vessel to achieve the effect of intuitive time-varying safety margin

Active Publication Date: 2020-07-14
SICHUAN UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

This method is only suitable for safety assessments where the ultimate stress is used as the failure criterion

Method used

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  • A Velocity Product-Based Method for Characterizing the Safety Margin of Crack Defects in Pressure Vessels
  • A Velocity Product-Based Method for Characterizing the Safety Margin of Crack Defects in Pressure Vessels
  • A Velocity Product-Based Method for Characterizing the Safety Margin of Crack Defects in Pressure Vessels

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Embodiment Construction

[0022] The specific technical method of the present invention is illustrated in conjunction with accompanying drawings.

[0023] (1) According to the applied load and the length and depth of the corresponding crack, calculate the Kr and Lr values ​​required for the evaluation point.

[0024] (2) Under a certain crack growth length-to-depth ratio, calculate the corresponding evaluation point value when the crack growth increment of each step is △a, such as figure 1 As shown, a pressure vessel crack defect decay path is obtained until the evaluation point exceeds the safe zone.

[0025] (3) if figure 2 As shown, calculate the distance from the evaluation point to the critical point, and use the paris formula to calculate the time-varying failure velocity dN at each point on the attenuation path according to the crack size corresponding to each point on the attenuation path, and obtain the path distance and failure velocity The S-V power function relationship, such as image ...

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Abstract

The invention belongs to the technical field of pressure vessels, and in particular relates to a method for characterizing the safety margin of crack defects in pressure vessels based on velocity products. According to the evaluation process of safety evaluation standards for pressure vessels containing defects in use, the pressure vessel crack defects in the R6 diagram are obtained. The safe attenuation path of the attenuation path; determine the failure speed at each point of the attenuation path, da / dN, according to the relationship between the attenuation path and the failure velocity, use the speed integral to obtain the safety margin at the evaluation point; finally obtain the points on the entire attenuation path time-varying safety margin. The beneficial effect of the present invention is that, through the model, an accurate characterization model of the time-varying attenuation of the safety margin of the crack defect of the pressure vessel is obtained, which can more intuitively reflect the time-varying safety margin of the pressure vessel containing the crack defect.

Description

technical field [0001] The invention belongs to the technical field of pressure vessels, and in particular relates to a velocity product-based method for characterizing the safety margin of crack defects in pressure vessels. Background technique [0002] Pressure vessels are widely used in important fields such as electric power, petroleum, chemical industry, and metallurgy. At the same time, these fields often have harsh working environments and are prone to leakage and explosion accidents. However, analysis and research have pointed out that the reason for many sudden safety accidents is not that there is any problem with the technical means of defect safety assessment using existing standards, but that the existing technical standards can only evaluate the safety of defects, that is, It can only give the conclusion of whether the defect is safe, but not the safety degree of the defect, and most of the pressure vessels with long service time in actual engineering appear to...

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G06F30/20
CPCG06F30/20
Inventor 龙伟刘华国岳建平
Owner SICHUAN UNIV