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Method for calculating stress axial-radial crack stress intensity factor of outer wall of ultrahigh pressure vessel cylinder

A technology of stress intensity factor and container cylinder, which is applied in the direction of applying stable tension/pressure to test material strength, strength characteristics, instruments, etc. Consider comprehensively, the calculation method is fast, concise and accurate, and the calculation process is simple and fast.

Active Publication Date: 2021-07-27
HEFEI GENERAL MACHINERY RES INST +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

It can be seen that these calculation processes are too complicated and not suitable for fast and concise calculation needs in engineering.
[0005] In addition, the existing calculation methods generally only consider the working condition of the vessel under internal pressure load

Method used

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  • Method for calculating stress axial-radial crack stress intensity factor of outer wall of ultrahigh pressure vessel cylinder
  • Method for calculating stress axial-radial crack stress intensity factor of outer wall of ultrahigh pressure vessel cylinder
  • Method for calculating stress axial-radial crack stress intensity factor of outer wall of ultrahigh pressure vessel cylinder

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0085] Assume that a certain ultra-high pressure vessel only bears the internal pressure load p i is 130MPa, the design temperature is normal temperature, and the material selected is 35CrNi3MoVR; the outer radius of the cylinder is r o is 400mm, the inner radius of the cylinder is r i is 200mm, the crack depth a obtained by measuring the oval crack is 15.5mm, and the crack length l is 46.5mm. Carry out the stress intensity factor K at the deepest point of the crack and at the free surface by the calculation method described in the present invention I The specific implementation steps include:

[0086] 1. According to the outer radius and inner radius of the cylinder, the diameter ratio K value of the cylinder is 2, which meets the requirements in formula 6.

[0087] 2. Calculate the required A' in formula 1 according to formula 6 i , get A' 0 , A' 1 , A' 2 , A' 3 They are: 86.15, 58.03, -37.28, 109.77.

[0088] 3. Calculate according to formula 3 to obtain the fittin...

Embodiment 2

[0093] Assume that the internal pressure load p of a certain ultra-high pressure vessel i 130MPa, bearing external pressure load p o is 30MPa, the design temperature is normal temperature, and the material selected is 35CrNi3MoVR; the outer radius of the cylinder is r o is 400mm, the inner radius of the cylinder is r i is 200mm, the crack depth a obtained by measuring the oval crack is 15.5mm, and the crack length l is 46.5mm. Carry out the stress intensity factor K at the deepest point of the crack and at the free surface by the calculation method proposed by the present invention I The specific implementation steps include:

[0094] 1. According to the outer radius and inner radius of the cylinder, the diameter ratio K value of the cylinder is 2, which meets the requirements in formula 6;

[0095] 2. Calculate the required A' in formula 1 according to formula 6i , get A' 0 , A' 1 , A' 2 , A' 3 They are: 36.27, 44.64, -28.68, 84.44.

[0096] 3. Calculate the fitting ...

Embodiment 3

[0103] Assume that the internal pressure load p of a certain ultra-high pressure vessel i 130MPa, bearing external pressure load p o is 30MPa; the outer radius of the cylinder is r o is 400mm, the inner radius of the cylinder is r i is 200mm. The fitting curve calculated by the present invention is compared with the curve obtained by the general complex method, and the stress intensity factor K is calculated by the method of the present invention I Compared with the calculation results obtained by general complex methods, the specific implementation steps include:

[0104] 1. According to the outer radius and inner radius of the cylinder, the diameter ratio K value of the cylinder is 2, which is between 1.2 and 3.0, which meets the requirements in formula 6;

[0105] 2. Calculate the required A' in formula 1 according to formula 6 i , get A' 0 , A' 1 , A' 2 , A' 3 They are: 36.27, 44.64, -28.68, 84.44.

[0106] 3. Draw the stress distribution curve of formula 1 and t...

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Abstract

The invention relates to the technical field of ultrahigh pressure vessel design and development and fatigue failure evaluation calculation, in particular to a method for calculating an axial-radial crack stress intensity factor of the outer wall of an ultrahigh pressure vessel cylinder. The method comprises the following steps: determining structural parameters of an ultrahigh pressure vessel, measuring shape parameters of axial-radial cracks, and determining a load working condition of a cylinder; fitting stress distribution perpendicular to a plane where the crack is located; calculating a required fitting coefficient; calculating another fitting coefficient under the current crack shape; calculating crack shape coefficients at the deepest point of the current crack and the position close to the free surface; and calculating a stress intensity factor KI. According to the method, the accuracy of a calculation result can be ensured, meanwhile, rapid, concise and written calculation of the axial-radial semi-elliptical crack stress intensity factor of the outer wall of the cylinder can be achieved only through a formula, finite element calculation software and professional mathematical analysis software do not need to be relied on, and the method is more suitable for engineering application.

Description

technical field [0001] The invention relates to the technical field of ultra-high pressure vessel design and development and fatigue failure assessment calculation, in particular to a method for calculating stress intensity factors of axial-radial cracks on the outer wall of an ultra-high pressure vessel. Background technique [0002] Axial-radial surface cracks on the outer wall of the cylinder are a common form of cracks in the manufacture and operation of ultra-high pressure vessels. type crack. From the perspective of damage tolerance of pressure vessels, it is necessary to accurately calculate the stress intensity factor of the crack tip, because it is a key parameter for the evaluation of the remaining strength of cracked pressure vessels and the prediction of remaining life based on fatigue crack growth. Therefore, in practical engineering applications, it is particularly important to find a fast and concise calculation method for the stress intensity factor of axial...

Claims

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Application Information

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IPC IPC(8): G01N3/08
CPCG01N3/08G01N2203/0676G01N2203/006G01N2203/0075G01N2203/0216Y02E30/30
Inventor 汪志福秦宗川周煜朱金花危书涛戴兴旺汪兵董杰
Owner HEFEI GENERAL MACHINERY RES INST
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