Closed-Form Stress Intensity Factor Solutions for Deep Surface Cracks in Plates

2017 ◽  
Author(s):  
Kisaburo Azuma ◽  
Yinsheng Li ◽  
Kunio Hasegawa ◽  
Steven Xu
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Stress Corrosion ◽  
Closed Form ◽  
Stress Corrosion Cracking ◽  
Corrosion Cracking ◽  
Influence Coefficient ◽  
Surface Cracks ◽  
Deep Surface

Materials made of Alloy 82/182/600 used in light-water reactors are known to be susceptible to stress corrosion cracking. It is known that the depth a of some cracks due to primary water stress corrosion cracking is larger than the half-length c. The stress intensity factor solution for cracks plays an important role to predict crack propagation and failure. However, Section XI of the ASME Boiler and Pressure Vessel Code does not provide the solutions for cracks with large aspect ratios a/c. In this study, closed-form stress intensity factor influence coefficients for deep surface cracks in plates are discussed. The crack tip stress distribution is represented by a fourth degree polynomial equation. Influence coefficient tables obtained by using finite element analysis in previous studies are used for curve fitting. The closed-form solutions for the coefficient were developed at the surface points and the deepest points of the cracks with aspect ratio a/c ranged from 1.0 to 8.0. The solutions for the points where the stress intensity factor reaches maximum were also investigated.

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.

Closed-Form Stress Intensity Factor Solutions for Deep Surface Cracks in Cylinders Subjected to Global Bending

2017 ◽  
Author(s):  
Kisaburo Azuma ◽  
Yinsheng Li ◽  
Kunio Hasegawa ◽  
Do Jun Shim
Keyword(s):  
Stress Intensity Factor ◽  
Water Stress ◽  
Stress Intensity ◽  
Aspect Ratio ◽  
Intensity Factor ◽  
Closed Form ◽  
Stress Corrosion Cracking ◽  
Surface Cracks ◽  
Aspect Ratios ◽  
Primary Water

Materials made of alloy 82/182/600 used in pressurized water reactors are known to be susceptible to primary water stress corrosion cracking. The depth, a, of flaws due to primary water stress corrosion cracking can be larger than half of the crack length c, which is referred to as cracks with large aspect ratios. The stress intensity factor solution for cracks plays an important role to predict crack propagation and failure. However, Section XI of the ASME Boiler and Pressure Vessel Code does not provide the solutions for cracks with large aspect ratio. This paper presents the stress intensity factor solutions for circumferential surface cracks with large aspect ratios in cylinders under global bending loads. Finite element solutions were used to fit closed-form equations with influence coefficients Ggb. The closed-form solutions for coefficient Ggb were developed at the deepest points and the surface points of the cracks with aspect ratio a/c ranged from 1.0 to 8.0.

Effects of Overloads on the Incubation Time for Stress Corrosion Cracking of 7075 Aluminum

CORROSION ◽  
1982 ◽  
Vol 38 (6) ◽  
pp. 330-335 ◽  
Author(s):  
A. H. Hanisch ◽  
L. H. Burck
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Incubation Time ◽  
High Strength ◽  
Critical Stress Intensity Factor ◽  
Corrosion Cracking ◽  
Cracking Behavior

Abstract A series of tests was conducted on precracked high strength aluminum alloy 7075-T651 plate to determine the effects of overstressing on the short-transverse stress corrosion cracking behavior. Fatigue precracked wedge-opening-loading specimens were preloaded in air to various percentages of the critical stress intensity factor, unloaded, and reloaded statically to lower stress intensity factor levels. The samples were then alternately immersed in an aqueous 3.5% sodium chlorine solution for stress corrosion testing. The incubation time which preceded crack extension by stress corrosion cracking was found to increase substantially for higher percentages of preloading. Furthermore, for a given percentage of prestress overload, greater effects were observed for higher applied stress intensity factor levels. The increase in incubation period produced by stress overloading is attributed primarily to the effects of residual compressive stresses at the crack tips.

Stress-Corrosion Cracking in Unidirectional GFRP Composites

2010 ◽  
Vol 430 ◽  
pp. 101-113
Author(s):  
Hideki Sekine ◽  
Peter W.R. Beaumont
Keyword(s):  
Growth Rate ◽  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Crack Growth Rate ◽  
Intensity Factor ◽  
Glass Fiber ◽  
Stress Corrosion ◽  
Crack Growth ◽  
Stress Corrosion Cracking ◽  
Matrix Crack

A micromechanical theory of macroscopic stress-corrosion cracking in unidirectional glass fiber-reinforced polymer composites is proposed. It is based on the premise that under tensile loading, the time-dependent failure of the composites is controlled by the initiation and growth of a crack from a pre-existing inherent surface flaw in a glass fiber. A physical model is constructed and an equation is derived for the macroscopic crack growth rate as a function of the apparent crack tip stress intensity factor for mode I. Emphasis is placed on the significance of the size of inherent surface flaw and the existence of matrix crack bridging in the crack wake. There exists a threshold value of the stress intensity factor below which matrix cracking does not occur. For the limiting case, where the glass fiber is free of inherent surface flaws and matrix crack bridging is negligible, the relationship between the macroscopic crack growth rate and the apparent crack tip stress intensity factor is given by a simple power law to the power of two.

Prevention of Stress Corrosion Cracking of SUS304 by Tensile Overload

2010 ◽  
Author(s):  
Hayato Sano ◽  
Koji Takahashi ◽  
Kotoji Ando
Keyword(s):  
Stress Intensity Factor ◽  
Stainless Steel ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Threshold Stress ◽  
Threshold Stress Intensity ◽  
Threshold Stress Intensity Factor ◽  
Tensile Overload

The effects of overload on the threshold stress intensity factor (KISCC) for stress corrosion cracks (SCC) in stainless steel were studied. Tensile overload was applied to a wedge opening loaded specimen of SUS304, and SCC tests were carried out to determine the resultant KISCC. The value of KISCC was found to increase with increasing stress intensity caused by tensile overload. Comparison of the effects of tensile overload on KISCC of SUS304 and SUS316 revealed that the effect on KISCC of SUS304 was smaller than that of SUS316.

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