Fatigue Crack Growth Calculations for Pipes Considering Subsurface to Surface Flaw Proximity Rules

2015 ◽  
Author(s):  
Genshichiro Katsumata ◽  
Yinsheng Li ◽  
Kunio Hasegawa ◽  
Valery Lacroix
Keyword(s):  
Experimental Data ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Growth Rates ◽  
Surface Flaw ◽  
Rule Based ◽  
Aspect Ratios ◽  
Inner Surface ◽  
Crack Growth Rates

If a subsurface flaw is located near a component surface, the subsurface flaw is transformed to a surface flaw in accordance with a subsurface-to-surface flaw proximity rule. The re-characterization process from subsurface to surface flaw is adopted in all fitness-for-service (FFS) codes. However, the specific criteria of the re-characterizations are different among the FFS codes. Recently, the authors have proposed a new subsurface-to-surface flaw proximity rule based on experimental data and equivalent fatigue crack growth rates. In this study, fatigue crack growth calculations were carried out for pipes with subsurface flaws, using the proposed subsurface-to-surface flaw proximity rule and the current proximity rule provided in the current JSME and ASME Section XI. Different pipe sizes, flaw aspect ratios and ligament distances from subsurface flaws to inner surface of pipes were taken into account. As the results, the current proximity rule gives less conservative fatigue lives, when the aspect ratios of the subsurface flaws are small.

Remaining Lives of Fatigue Crack Growths for Pipes With Subsurface Flaws and Subsurface-to-Surface Flaw Proximity Rules

2016 ◽  
Vol 138 (5) ◽  
Author(s):  
Genshichiro Katsumata ◽  
Yinsheng Li ◽  
Kunio Hasegawa ◽  
Valery Lacroix
Keyword(s):  
Experimental Data ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Surface Flaw ◽  
Japan Society ◽  
Rule Based ◽  
Aspect Ratios ◽  
Inner Surface ◽  
American Society

If a subsurface flaw is located near a component surface, the subsurface flaw is transformed into a surface flaw in accordance with a subsurface-to-surface flaw proximity rule. The recharacterization process from subsurface to surface flaw is adopted in all fitness-for-service (FFS) codes. However, the specific criteria of the recharacterizations are different among the FFS codes. Recently, the authors have proposed a new subsurface-to-surface flaw proximity rule based on experimental data and equivalent fatigue crack growth rate calculations. In this study, fatigue crack growth calculations were carried out for pipes with subsurface flaws, using the proximity rule provided in the current ASME (American Society of Mechanical Engineers) Section XI and JSME (The Japan Society of Mechanical Engineers) codes and the proposed subsurface-to-surface flaw proximity rule. Different pipe sizes, flaw aspect ratios, and ligament distances from subsurface flaws to inner surface of pipes were taken into account. The results indicate the current proximity rule gives less conservative fatigue lives, when the aspect ratios of the subsurface flaws are small.

Recharacterization of Subsurface Flaw to Surface Flaw Based on Equivalent Fatigue Crack Growth Rate

2015 ◽  
Vol 138 (2) ◽  
Author(s):  
Valery Lacroix ◽  
Yinsheng Li ◽  
Bohumir Strnadel ◽  
Kunio Hasegawa
Keyword(s):  
Growth Rate ◽  
Stress Intensity Factor ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Point Of View ◽  
Surface Flaw ◽  
Aspect Ratios ◽  
Crack Growth Rates ◽  
Factor Interaction

A subsurface flaw located near a component surface is transformed to a surface flaw in accordance with a flaw-to-surface proximity rule. The recharacterization process from subsurface to surface flaw is adopted in all fitness-for-service (FFS) codes. However, the criteria of the recharacterizations are different among the FFS codes. In addition, the proximity factors in the rules are generally defined by constant values, irrespective of flaw aspect ratios. This paper describes the stress intensity factor interaction between the subsurface flaw and component free surface and proposes a proximity factor from the point of view of fatigue crack growth rates.

Effect of the Thickness on Re-Characterisation of Subsurface to Surface Flaw: Application on Piping and Vessels

2016 ◽  
Author(s):  
Valéry Lacroix ◽  
Genshichiro Katsumata ◽  
Yinsheng Li ◽  
Kunio Hasegawa
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Surface Flaw ◽  
Thick Wall ◽  
Thin Wall ◽  
Rule Based ◽  
Asme Code ◽  
Crack Growth Rates ◽  
Wall Components

If a subsurface flaw is located near a component surface, the subsurface flaw is transformed to a surface flaw in accordance with a subsurface-to-surface flaw proximity rule. The re-characterization process from subsurface to surface flaw is adopted in all fitness-for-service (FFS) codes in different countries. However, the specific criteria of the recharacterizations are different among the FFS codes. The authors have proposed a new subsurface-to-surface flaw proximity rule based on experimental data and equivalent fatigue crack growth rates. Recently, the authors have highlighted through numerous fatigue crack growth calculations that, on one hand, the proximity rule provided in the current ASME Boiler and Pressure Vessel Code Section XI (ASME Code Section XI) can provide non conservative fatigue lives for thin wall components like pipes and, on the other hand, for thick wall components like vessels, the current proximity rule and the proposed one provide relatively similar fatigue lives. It appears therefore that the flaw-to-surface factor should be updated according to the thickness of the component or according to the type of component i.e. pipe or vessel. In this study, fatigue crack growth calculations were carried out on additional flaw configurations in thick wall pipes and thin wall vessels in order define the best limit for the thickness-dependence of the fatigue lives. Finally, a new subsurface to surface proximity rule depending on the thickness of the component is proposed.

An Investigation of the Effects of Microstructure on Fatigue Crack Growth in Ti-6242

2005 ◽  
Vol 127 (1) ◽  
pp. 46-57 ◽  
Author(s):  
F. McBagonluri ◽  
E. Akpan ◽  
C. Mercer ◽  
W. Shen ◽  
W. O. Soboyejo
Keyword(s):  
Growth Rate ◽  
Fatigue Crack ◽  
Crack Growth Rate ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Growth Rates ◽  
Surface Crack ◽  
Rate Data ◽  
Aspect Ratios ◽  
Crack Growth Rates

Surface and subsurface crack nucleation and growth mechanisms are elucidated for equiaxed (microstructure 1), elongated (microstructure 2), and colony (microstructure 3) microstructures of Ti6242. Prominent cleavage facets, indicative of a Stroh-type dislocation-pile phenomenon characterize the nucleation sites. Beachmarking and scanning electron microscopy (SEM) techniques are used to study fatigue crack growth rates and crack shape evolution in the short and long crack regimes. The studies reveal that surface crack growth rate data are generally comparable to the through-crack growth rate data in the long crack growth regime. However, the depth crack growth rates are somewhat slower than the through-crack growth rates. Surface crack evolution profiles are shown to exhibit a tendency towards “Preferred Propagation Paths” (PPPs). However, the magnitudes of the aspect ratios along the PPPs are different from those reported for square or rectangular cross sections subjected to cyclic tension or bending loads. Finally, the measured crack lengths and aspect ratios are compared with predictions obtained from a fracture mechanics model.

Fatigue Crack Growth Calculations for Vessels Considering Subsurface to Surface Flaw Proximity Rules

2015 ◽  
Author(s):  
Valéry Lacroix ◽  
Kunio Hasegawa ◽  
Yinsheng Li
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Surface Flaw ◽  
Thick Wall ◽  
Intensity Factors ◽  
Extended Finite Element ◽  
Rule Based ◽  
Aspect Ratios ◽  
Asme Code

If a subsurface flaw is located near a component surface, the subsurface flaw is transformed to a surface flaw in accordance with a subsurface-to-surface flaw proximity rule. The re-characterization process from subsurface to surface flaw is adopted in all fitness-for-service (FFS) codes. However, the specific criteria of the re-characterizations are different among the FFS codes. Recently, the authors have proposed a new subsurface-to-surface flaw proximity rule based on the experiments data and the interaction of stress intensity factors. In this study, extended Finite Element fatigue crack growth calculations were carried out for thick wall component like vessels with subsurface flaws, using the proposed subsurface-to-surface flaw proximity rule and the proximity rule provided in the current ASME Code Section XI. Different, flaw aspect ratios and ligament distances from subsurface flaws to inner surface of vessel were taken into account. As the results, the current proximity rule and proposed one provide relatively similar fatigue lives, whatever the aspect ratios of the initial subsurface flaws. However, when the thickness of the component decreases this similarity between both proximity rules appears not to be valid anymore.

Re-Characterization of Subsurface Flaw to Surface Flaw Based on Equivalent Fatigue Crack Growth Rate

2015 ◽  
Author(s):  
Kunio Hasegawa ◽  
Yinsheng Li ◽  
Valery Lacroix ◽  
Bohumir Strnadel
Keyword(s):  
Growth Rate ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Point Of View ◽  
Surface Flaw ◽  
Aspect Ratios ◽  
Crack Growth Rates ◽  
Factor Interaction

A subsurface flaw located near a component surface is transformed to a surface flaw in accordance with a flaw-to-surface proximity rule. The re-characterization process from subsurface to surface flaw is adopted in all fitness-for-service (FFS) codes. However, the criteria of the re-characterizations are different among the FFS codes. In addition, the proximity factors in the rules are defined by constant values, irrespective of flaw aspect ratios. This paper describes the stress intensity factor interaction between the subsurface flaw and component free surface, and proposes a proximity factor from the point of view of fatigue crack growth rates.

scholarly journals Advantageous Description of Short Fatigue Crack Growth Rates in Austenitic Stainless Steels with Distinct Properties

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 475
Author(s):  
Lukáš Trávníček ◽  
Ivo Kuběna ◽  
Veronika Mazánová ◽  
Tomáš Vojtek ◽  
Jaroslav Polák ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Stainless Steels ◽  
Growth Rates ◽  
Large Scale ◽  
J Integral ◽  
Scale Yielding ◽  
Residual Fatigue ◽  
Crack Growth Rates

In this work two approaches to the description of short fatigue crack growth rate under large-scale yielding condition were comprehensively tested: (i) plastic component of the J-integral and (ii) Polák model of crack propagation. The ability to predict residual fatigue life of bodies with short initial cracks was studied for stainless steels Sanicro 25 and 304L. Despite their coarse microstructure and very different cyclic stress–strain response, the employed continuum mechanics models were found to give satisfactory results. Finite element modeling was used to determine the J-integrals and to simulate the evolution of crack front shapes, which corresponded to the real cracks observed on the fracture surfaces of the specimens. Residual fatigue lives estimated by these models were in good agreement with the number of cycles to failure of individual test specimens strained at various total strain amplitudes. Moreover, the crack growth rates of both investigated materials fell onto the same curve that was previously obtained for other steels with different properties. Such a “master curve” was achieved using the plastic part of J-integral and it has the potential of being an advantageous tool to model the fatigue crack propagation under large-scale yielding regime without a need of any additional experimental data.

Sign in / Sign up

Export Citation Format

Share Document