Subcycle Fatigue Crack Growth and Equivalent Initial Flaw Size Model for Fatigue Life Assessment under Arbitrary Loadings for Al-7075

A typical procedure for a remnant fatigue life (RFL) assessment is stated in the BS-7910 standard. The aforementioned standard provides two different methodologies for estimating RFL; these are: the S-N curve approach and the crack growth laws (i.e. using Linear Elastic Fracture Mechanics (LEFM) principles) approach. Due to its higher accuracy, the latter approach is more commonly used for RFL assessment in the offshore industry. Nevertheless, accurate prediction of RFL using the deterministic LEFM approach (stated in BS-7910) is a challenging task, as RFL prediction is afflicted with a high number of uncertainties. Furthermore, BS-7910 does not provide any recommendation in regard to handling the uncertainty in the deterministic RFL assessment process. The most common way of dealing with the aforementioned uncertainty is to employ Probabilistic Crack Growth (PCG) models for estimating the RFL. This manuscript explains the procedure for addressing the uncertainty in the RFL assessment of process piping with the help of a numerical example. The numerically obtained RFL estimate is used to demonstrate a calculation of inspection interval.

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Fatigue crack growth of a railway wheel steel and fatigue life prediction under spectrum loading conditions

International Journal of Fatigue ◽

10.1016/j.ijfatigue.2022.106722 ◽

2022 ◽

pp. 106722

Author(s):

Reza Masoudi Nejad ◽

Filippo Berto

Keyword(s):

Fatigue Crack ◽

Fatigue Life ◽

Fatigue Crack Growth ◽

Crack Growth ◽

Life Prediction ◽

Fatigue Life Prediction ◽

Wheel Steel ◽

Loading Conditions ◽

Railway Wheel ◽

Railway Wheel Steel

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OBSERVATIONS ON FATIGUE CRACK GROWTH AND FATIGUE LIFE OF RIVETED LAP JOINTS

Mechanics and Control ◽

10.7494/mech.2012.31.3.108 ◽

2012 ◽

Vol 31 (3) ◽

pp. 108

Author(s):

Andrzej SKORUPA ◽

Małgorzata SKORUPA ◽

Tomasz MACHNIEWICZ ◽

Andrzej KORBEL

Keyword(s):

Fatigue Crack ◽

Fatigue Life ◽

Fatigue Crack Growth ◽

Crack Growth ◽

Lap Joints ◽

Riveted Lap Joints

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Initial fatigue crack growth behaviour in a notched component. V: Assessment of initial defect to fatigue life in a notched componentCho, S.-M. and Horikawa, K. Q. J. Jpn. Weld. Soc. Feb. 1989 7, (1), 111–117 (in Japanese)

International Journal of Fatigue ◽

10.1016/0142-1123(89)90220-x ◽

1989 ◽

Vol 11 (6) ◽

pp. 450-450

Keyword(s):

Fatigue Crack ◽

Fatigue Life ◽

Fatigue Crack Growth ◽

Crack Growth ◽

Growth Behaviour ◽

Crack Growth Behaviour ◽

Initial Defect

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Influence of Pre-Stress Magnitude on Fatigue Crack Growth Behavior of Al-Alloy

Materials ◽

10.3390/ma11081267 ◽

2018 ◽

Vol 11 (8) ◽

pp. 1267

Author(s):

Chunguo Zhang ◽

Weizhen Song ◽

Qitao Wang ◽

Wen Liu

Keyword(s):

Fatigue Crack ◽

Fatigue Life ◽

Fatigue Crack Growth ◽

Crack Growth ◽

Shot Peening ◽

Fatigue Property ◽

Growth Behavior ◽

Crack Growth Behavior ◽

Al Alloy ◽

Fatigue Crack Growth Behavior

From tensile overload to shot peening, there have been many attempts to extend the fatigue properties of metals. A key challenge with the cold work processes is that it is hard to avoid generation of harmful effects (e.g., the increase of surface roughness caused by shot peening). Pre-stress has a positive effect on improving the fatigue property of metals, and it is expected to strength Al-alloy without introducing adverse factors. Four pre-stresses ranged from 120 to 183 MPa were incorporated in four cracked extended-compact tension specimens by application of different load based on the measured stress–strain curve. Fatigue crack growth behavior and fractured characteristic of the pre-stressed specimens were investigated systematically and were compared with those of an as-received specimen. The results show that the pre-stress ranged from 120 to 183 MPa significantly improved the fatigue resistance of Al-alloy by comparison with that of the as-received specimen. With increasing pre-stress, the fatigue life first increases, then decrease, and the specimen with pre-stress of 158 MPa has the longest fatigue life. For the manner of pre-stress, no adverse factor was observed for increasing fatigue property, and the induced pre-stress reduced gradually till to disappear during subsequent fatigue cycling.

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A Flaw Tolerance Concept for Plant Maintenance Using Virtual Fatigue Crack Growth Curve

Volume 1A: Codes and Standards ◽

10.1115/pvp2013-97851 ◽

2013 ◽

Cited By ~ 7

Author(s):

Masayuki Kamaya ◽

Takao Nakamura

Keyword(s):

Fatigue Crack ◽

Fatigue Life ◽

Fatigue Crack Growth ◽

Crack Growth ◽

Growth Curve ◽

Growth Behavior ◽

Plant Design ◽

Flaw Tolerance ◽

Plant Maintenance ◽

Crack Growth Curve

Incorporation of the flaw tolerance concept in plant design and maintenance is discussed in order to consider the reduction in fatigue life due to the high-temperature water environment of class 1 components of NPPs. The flaw tolerance concept has been included in Section XI of the ASME BPVC. The structural factor (safety factor) for the flaw evaluation is considered in the stress, whereas it was considered in the design fatigue curve in Section III of the ASME BPVC. In order to apply the flaw tolerance concept to plant design and maintenance, it is necessary to assume the crack initiation and growth behavior. In this study, first, crack initiation and growth behavior during fatigue tests was reviewed and a relationship between the crack growth and fatigue life was quantified. Then, the safety factor was considered in the crack growth curve. It was shown that the crack size could be correlated to the usage factor and the flaw tolerance concept was reasonably considered in the plant maintenance by using the proposed virtual fatigue crack growth curve.

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