scholarly journals Improved Formula for the Stress Intensity Factor of Semi-Elliptical Surface Cracks in Welded Joints under Bending Stress

Materials ◽  
2017 ◽  
Vol 10 (2) ◽  
pp. 166 ◽  
Author(s):  
Yang Peng ◽  
Chao Wu ◽  
Yifu Zheng ◽  
Jun Dong
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Welded Joints ◽  
Surface Cracks ◽  
Bending Stress

Stress Intensity Factors for Circular-Arc Cracks in Plates

2018 ◽  
Author(s):  
D. J. Shim ◽  
S. Tang ◽  
T. J. Kim ◽  
N. S. Huh
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Stress Intensity Factors ◽  
Crack Model ◽  
Surface Cracks ◽  
Intensity Factors ◽  
Element Analysis ◽  
Crack Face ◽  
Circular Arc

Stress intensity factor solutions are readily available for flaws found in pipe to pipe welds or shell to shell welds (i.e., circumferential/axial crack in cylinder). In some situations, flaws can be detected in locations where an appropriate crack model is not readily available. For instance, there are no practical stress intensity factor solutions for circular-arc cracks which can form in circular welds (e.g., nozzle to vessel shell welds and storage cask closure welds). In this paper, stress intensity factors for circular-arc cracks in finite plates were calculated using finite element analysis. As a first step, stress intensity factors for circular-arc through-wall crack under uniform tension and crack face pressure were calculated. These results were compared with the analytical solutions which showed reasonable agreement. Then, stress intensity factors were calculated for circular-arc semi-elliptical surface cracks under the lateral and crack face pressure loading conditions. Lastly, to investigate the applicability of straight crack solutions for circular-arc cracks, stress intensity factors for circular-arc and straight cracks (both through-wall and surface cracks) were compared.

Closed-Form Stress Intensity Factor Solutions for Surface Cracks With Large Aspect Ratios in Plates

2019 ◽  
Vol 142 (2) ◽  
Author(s):  
Kisaburo Azuma ◽  
Yinsheng Li ◽  
Steven Xu
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Closed Form ◽  
Influence Coefficient ◽  
Maximum Point ◽  
Surface Cracks ◽  
Fourth Degree ◽  
Aspect Ratios ◽  
Influence Coefficients

Abstract Alloy 82/182/600, which is used in light-water reactors, is known to be susceptible to stress-corrosion cracking. The depth of some of these cracks may exceed the value of half-length on the surface. Although the stress intensity factor (SIF) for cracks plays an important role in predicting crack propagation and failure, Section XI of the ASME Boiler and Pressure Vessel Code does not provide SIF solutions for such deep cracks. In this study, closed-form SIF solutions for deep surface cracks in plates are discussed using an influence coefficient approach. The stress distribution at the crack location is represented by a fourth-degree-polynomial equation. Tables for influence coefficients obtained by finite element analysis in the previous studies are used for curve fitting. The closed-form solutions for the influence coefficients were developed at the surface point, the deepest point, and the maximum point of a crack with an aspect ratio a/c ranging from 1.0 to 8.0, where a is the crack depth and c is one-half of the crack length. The maximum point of a crack refers to the location on the crack front where the SIF reaches a maximum value.

Fatigue Growth Behaviour for Surface Crack in Welded Joints Under Combined Tension and Bending Stresses

2006 ◽  
Author(s):  
Jian-Ping Zhao ◽  
Wen-Long Huang
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Crack Growth ◽  
Surface Crack ◽  
Welded Joints ◽  
Stress Intensity Factor Range ◽  
Growth Behaviour ◽  
Bending Stresses ◽  
The Relationship

The fatigue growth behaviour for surface crack in welded joints under combined tension and bending stresses is studied by fatigue crack growth tests of 16MnR steel in bow specimens. In this present paper the Newman-Raju empirical equation was used for the stress intensity factor of a surface crack. The experimental results show that the Paris’ relationship between crack growth rate and stress intensity factor range under tension and bending fatigue stresses is still valid, and the relationship between the Paris’ coefficients Ca and Cc can be represented as Cc = (0.89)mCa.

Analytical Solutions and Tools for Assessment of Surface Cracks in Cylindrical Components

2008 ◽  
Author(s):  
Igor Varfolomeyev ◽  
Dieter Beukelmann
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Fatigue Loading ◽  
Complex Stress ◽  
Radial Coordinate ◽  
Cylinder Wall ◽  
Crack Plane ◽  
Surface Cracks ◽  
Inner Radius

The paper reviews some advanced stress intensity factor solutions derived for analyses of axial and circumferential surface cracks in cylindrical components subjected to variable stress fields. The solutions are examined considering their validity ranges with respect to the crack and cylinder geometry, ability to account for a complex stress distribution in the pipe wall, as well as their accuracy. A method for estimating errors in numerical stress intensity factor solutions is introduced and applied to a particular set of data. Examples of a leak-before-break assessment and crack growth calculations under thermal fatigue loading are included to demonstrate the solutions performance. The considered analytical stress intensity factor solutions yield close results provided that the stress field in the prospective crack plane is described by a smooth function of the radial coordinate. For two-dimensional stress profiles as well as for variable ratios of the cylinder wall thickness to the inner radius, a selective use of the solutions is recommended considering their specific features and validity ranges.

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