Calculation method of stress intensity factor for axial-radial cracks in outer wall of ultra-high pressure vessel

A technology of stress intensity factor and container cylinder, applied in the direction of applying stable tension/pressure to test material strength, strength characteristics, instruments, etc., can solve the problems that are not suitable for fast and concise calculation needs, and the calculation process is complicated and complicated, and achieve The calculation method is fast, concise and accurate, the consideration is comprehensive, and the calculation process is simple and fast.

Active Publication Date: 2022-05-31
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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  • Calculation method of stress intensity factor for axial-radial cracks in outer wall of ultra-high pressure vessel
  • Calculation method of stress intensity factor for axial-radial cracks in outer wall of ultra-high pressure vessel
  • Calculation method of stress intensity factor for axial-radial cracks in outer wall of ultra-high pressure vessel

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 , we get A' 0 , A' 1 , A' 2 , A' 3 They are: 36.27, 44.64, -28.68, 84.44.

[0096] 3. Calculate the fitti...

Embodiment 3

[0103] Assume that the internal pressure load p of an ultra-high pressure vessel i It is 130MPa and bears the 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 the general complex method, 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 Equation 1 according to Equation 6 i , we 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 fo...

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Abstract

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. The invention includes the following steps: determining the structural parameters of the ultra-high pressure vessel, measuring the shape parameters of the axial-radial cracks, and determining the load condition of the cylinder; fitting the stress distribution perpendicular to the plane where the cracks are located; calculating the required simulated Calculate another fitting coefficient under the current crack shape; calculate the crack shape coefficient at the deepest point of the current crack and near the free surface; calculate the stress intensity factor K I . While ensuring the accuracy of the calculation results, the present invention can realize the fast, concise and written calculation of the stress intensity factor of the axis-radial semi-elliptical crack on the outer wall of the cylinder only through formulas, without relying on finite elements Calculation software and professional mathematical analysis software are more suitable for engineering applications.

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 the stress intensity factor of an axial-radial crack in the outer wall of an ultra-high pressure vessel cylinder. Background technique [0002] The axial-radial surface crack on the outer wall of the cylinder is a common crack form in the manufacture and operation of ultra-high pressure vessels, mainly semi-elliptical, which is the E in the typical cracks described in GB 34019-2017 "Ultra-High Pressure Vessel" type crack. From the point of view of the damage tolerance of the pressure vessel, the stress intensity factor at the crack tip needs to be accurately calculated, because it is a key parameter for the evaluation of the residual strength of the pressure vessel with cracks and the prediction of the residual life based on fatigue crack growth. Therefore, in practical ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
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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