A Procedure for Estimating the Stress Intensity Factor of a Flattened Surface Crack at a Nozzle Corner

A flattened surface crack at a nozzle corner is modeled by a segment of a semi-elliptical crack in a finite thickness plate with matching crack contour and crack pressure corresponding to the normal stresses in the uncracked nozzle corner. Lacking other solutions for comparison, a qualitative comparison was made between nondimensionalized stress intensity factors at the deepest crack penetration with those obtained experimentally for similar corner cracks in epoxy models.

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Stress Intensity Factors for Internal Straight and Curved-Fronted Cracks in Thick Cylinders

Journal of Pressure Vessel Technology ◽

10.1115/1.2172618 ◽

2006 ◽

Vol 128 (2) ◽

pp. 227-232 ◽

Cited By ~ 5

Author(s):

Anthony P. Parker ◽

Choon-Lai Tan

Keyword(s):

Stress Intensity Factor ◽

Stress Intensity ◽

Intensity Factor ◽

Surface Crack ◽

Pressure Vessel ◽

Worked Examples ◽

Covering Radius ◽

Intensity Factors ◽

Thick Cylinder ◽

Leak Before Break

Fatigue and leak-before-break calculations for a pressure vessel require knowledge of the stress intensity factor at the deepest point of a straight- or curved-fronted (semi-elliptical) surface crack emanating from the bore of an internally pressurized, autofrettaged thick cylinder. A limited number of available solutions is curve fitted. The concept of a tube equivalent plate (TEP), which exhibits crack-constraint characteristics matching those of a thick cylinder, is developed, and the resulting equations are curve fitted. Ratios of the TEP stress intensity factor results are then used to interpolate between certain existing solutions. This provides wide-ranging solutions covering radius ratios from 1.8 to 3.0, autofrettage overstrain from 0 to 100% and crack shapes from straight fronted to semi-circular. The calculation procedure is described using worked examples.

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Stress Intensity Factor for Corner Cracks of Pressurized Tees

Journal of Pressure Vessel Technology ◽

10.1115/1.3263291 ◽

1980 ◽

Vol 102 (1) ◽

pp. 121-123 ◽

Cited By ~ 2

Author(s):

M. A. Mohamed ◽

J. Schroeder

Keyword(s):

Stress Intensity Factor ◽

Stress Intensity ◽

Stress Concentration ◽

Intensity Factor ◽

Local Stress ◽

Numerical Techniques ◽

Intensity Factors ◽

Local Stress Concentration ◽

Corner Cracks ◽

Good Agreement

A method based on local stress concentration is employed to estimate stress intensity factors for corner cracks at the crotch corner of pressurized tees. The method yields results which are in good agreement with data obtained using other advanced numerical techniques.

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Stress-Intensity Factors for a Surface Crack in a Finite Solid

Journal of Applied Mechanics ◽

10.1115/1.3422611 ◽

1972 ◽

Vol 39 (1) ◽

pp. 195-200 ◽

Cited By ~ 30

Author(s):

R. W. Thresher ◽

F. W. Smith

Keyword(s):

Experimental Data ◽

Stress Intensity Factor ◽

Stress Intensity ◽

Intensity Factor ◽

Brittle Material ◽

Crack Front ◽

Finite Thickness ◽

Circular Crack ◽

Intensity Factors ◽

Iteration Technique

A solution to the problem of a circular crack partially embedded in a solid of finite thickness is presented. A superposition and iteration technique is used to determine the stress-intensity factor numerically. The stress-intensity factor is determined as a function of position around the crack front for a variety of crack depths. The results of this study are compared with experimental data for a semielliptical surface flaw in a brittle material.

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Stress Intensity Factors for Reactor Vessel Nozzle Cracks

Journal of Pressure Vessel Technology ◽

10.1115/1.3454444 ◽

1978 ◽

Vol 100 (2) ◽

pp. 141-149 ◽

Cited By ~ 7

Author(s):

C. W. Smith ◽

W. H. Peters ◽

M. I. Jolles

Keyword(s):

Stress Intensity Factor ◽

Data Analysis ◽

Stress Intensity ◽

Intensity Factor ◽

Three Dimensional ◽

Reactor Vessel ◽

Intensity Factors ◽

Independent Estimate ◽

Self Similar ◽

Corner Cracks

A method consisting of a marriage between frozen stress photoelasticity and a computerized least-squares data analysis for extracting stress intensity factor (SIF) distributions in three-dimensional cracked body problems is reviewed. Results from the application of the method to three programs dealing with nozzle corner cracks are discussed. The importance of using actual flaw shapes in analysis is stressed. It is concluded that the flaw growth in such problems is generally not self-similar due to the complexity and variety of boundary shapes. The experimental technique described appears to offer a viable independent estimate of SIF distributions for such problems.

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Numerical Study on 3D Surface Crack Growth

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.90-93.744 ◽

2011 ◽

Vol 90-93 ◽

pp. 744-747

Author(s):

Ming Tian Li ◽

Shu Cai Li ◽

Jun Lian He

Keyword(s):

Stress Intensity Factor ◽

Stress Intensity ◽

Intensity Factor ◽

Inclination Angle ◽

Stress Intensity Factors ◽

Surface Crack ◽

Orientation Angle ◽

Intensity Factors ◽

Mode Stress ◽

Surface Crack Growth

The inclined surface cracks are under the mixed mode I，II，III loading conditions. In order to study the surface crack growth the stress intensity factors of the front of half-circular surface crack are calculated according to fracture analysis code-3D(FRANC3D). And the influences of inclination angle of the surface crack and the orientation angle on I，II，III mode stress intensity factors were analyzed. I mode stress intensity factor increases along the crack front with increasing inclination angle. And I mode stress intensity factor of the same inclination angle is symmetrical with respect to the orientation angle of 90 degree. II，III mode stress intensity factors are the maximum when the inclination angle is equal to 45 degree. And the behavior of II，III mode stress intensity factors along crack front for the inclination angle of 15 and 30 degree is identical with that of inclination angle of 75 and 60 degree, respectively.

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Evaluation on an Internal Surface Crack in a Compound Tube

Journal of Pressure Vessel Technology ◽

10.1115/1.4000346 ◽

2009 ◽

Vol 131 (6) ◽

Author(s):

A. A. Ali ◽

J. Purbolaksono ◽

A. Khinani ◽

A. Z. Rashid ◽

F. Tarlochan

Keyword(s):

Stress Intensity Factor ◽

Stress Intensity ◽

Intensity Factor ◽

Stress Intensity Factors ◽

Surface Crack ◽

Modulus Of Elasticity ◽

Outer Part ◽

Internal Surface ◽

Intensity Factors ◽

Inner Region

In this paper stress intensity factors of a longitudinal semielliptical surface crack on the inner surface in a compound tube subjected to internal pressure are presented. Variations of modulus of elasticity and thickness for the inner part of the tube are used in order to evaluate their effects on the normalized stress intensity factors. The boundary element method is used to analyze the problems. The increasing of thickness of the inner region causes decreasing values of the normalized stress intensity factor, as the modulus of elasticity for the inner part is greater than that of the outer part. Conversely, if the modulus of elasticity for the inner region is smaller, the increasing of thickness of the inner part would give increasing values of the normalized stress intensity factor. A larger inner radius and smaller thickness of the tube gives a higher normalized stress intensity factor.

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The Effects of Residual Stress Distribution and Geometry of Component on the Stress Intensity Factor of Surface Crack

Volume 6: Materials and Fabrication ◽

10.1115/pvp2005-71462 ◽

2005 ◽

Author(s):

Katsumasa Miyazaki ◽

Masahito Mochizuki

Keyword(s):

Residual Stress ◽

Stress Intensity Factor ◽

Stress Intensity ◽

Stress Distribution ◽

Intensity Factor ◽

Stress Field ◽

Crack Growth ◽

Surface Crack ◽

Residual Stress Distribution ◽

Intensity Factors

The stress intensity factor estimated by using the appropriate modeling of components is essential for evaluation of crack growth behavior in stress corrosion cracking. For the appropriate modeling of welded components with a crack, it is important to understand the effects of residual stress distribution and geometry of component on the stress intensity factor of surface crack. In this study, the stress intensity factors of surface crack under two assumed residual stress fields were calculated. As residual stress field, the bending type stress field (tension-compression) and the self-equilibrating stress field (tension-compression-tension) through the thickness were assumed. The geometries of components were plate and piping. The assumed surface cracks for evaluations were long crack in surface direction and semi-elliptical surface crack. Furthermore, the crack growth evaluations were conducted to understand the effects of residual stress distribution and geometry of component. Here, the crack growth evaluation means the simulation of increments of crack depth and length by using the crack growth property and stress intensity factors. From the comparison of stress intensity factors and crack growth evaluation for surface crack under residual stress field, the effects of residual stress distribution and geometry of component on the stress intensity factor of surface crack and appropriate modeling of cracked components were discussed.

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