The effect of overload cycles on fatigue crack propagation in two structural steels

Drew, M.; Thompson, Katherine

doi:10.1016/0013-7944(88)90152-x

Cited by 8 publications

(6 citation statements)

References 19 publications

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“…seen in each data set are in good agreement with the literature [3,5,10], but it is less clear as to why the a,/do, ratio varies with temperature ( Fig. 5).…”

Section: Dependence Of Retardation On Temperature the Relationships Asupporting

confidence: 88%

“…If the build-up of residual stresses at 525°C is restricted because thermally-activated stress relaxation mechanisms operate, it is feasible that the resulting retardation would be less severe. Further, if a stress relief mechanism operates at 525°C (as seems likely from the findings of other researchers [10,23]), the residual stresses formed in the overload plastic zone may be partially cancelled out before they can become effective, because the crack takes some time to propagate through the overloaded region. This effect will be discussed further in Part 11.…”

Section: -6mentioning

confidence: 87%

“…Only then can the large residual stresses in the zone cause premature contact of the crack faces. This explanation of delayed retardation has been put forward by many [1,4,5,10, to account for their experimental observations, and it has an advantage over the crack branching mechanism in that the rough fracture surfaces required by the latter are not always seen.…”

Section: Part I the Influence Of Degree Of Overloading And Test Tempementioning

confidence: 94%

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OVERLOAD RETARDATION OF FATIGUE CRACK GROWTH IN A 9%Cr 1%Mo STEEL AT ELEVATED TEMPERATURES

Cotterill

Knott

1993

Fatigue Fract Eng Mat Struct

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This paper describes an investigation into the effects of a single-peak tensile overload on fatigue crack propagation in a 9%Cr 1 %Mo steel. Overloads were applied during cycling at a constant stress intensity range (AK), and any consequent transients in growth rate were recorded. The severity of retardation rises as the magnitude of the applied overload is increased. The effect of temperature is complex, but a 525°C retardation is significantly less marked than at 25 or 225°C. Signs of crack face contact are seen on post-overload fracture surfaces, but there is little crack branching. The dominant cause of overload retardation in this steel appears to be plasticity-induced closure. At 525"C, post-overload dwell periods significantly reduce the severity of retardations. This is not observed at lower temperatures, indicating that the residual clamping stresses that lead to closure are gradually relieved at 525°C. NOMENCLATURE aR = length of subsequent crack growth over which growth rates are affected by an overload do, = size of monotonic plastic zone resulting from an overload da/dN = crack growth increment per cycle AK = stress intensity range AKef = effective stress intensity range experienced at the crack tip when a closure mechanism is operating AK,,, = threshold stress intensity range, below which there is negligible crack growth K,,, = maximum stress intensity during the baseline fatigue cycle KO, = peak stress intensity applied during an overload Nd = number of cycles by which an overload delays crack growth N: = Nd normalised with respect to the number of cycles a crack would normally take to grow the distance aR during constant amplitude loading if no overload were imposed cry = uniaxial yield stress

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“…seen in each data set are in good agreement with the literature [3,5,10], but it is less clear as to why the a,/do, ratio varies with temperature ( Fig. 5).…”

Section: Dependence Of Retardation On Temperature the Relationships Asupporting

confidence: 88%

Section: -6mentioning

confidence: 87%

Section: Part I the Influence Of Degree Of Overloading And Test Tempementioning

confidence: 94%

See 1 more Smart Citation

OVERLOAD RETARDATION OF FATIGUE CRACK GROWTH IN A 9%Cr 1%Mo STEEL AT ELEVATED TEMPERATURES

Cotterill

Knott

1993

Fatigue Fract Eng Mat Struct

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“…The initiation site is minute, never extending for more than 2-5 grains around the origin. The location of the initiation is at a stress concentration [6][7][8][9]. It is believed that thermowell neck that acts as local stress raiser played a remarkable role in fatigue failure.…”

Section: Discussionmentioning

confidence: 99%

Fatigue failure of thermowells in feed gas supply downstream pipeline at a natural gas production plant

El-Batahgy

Fathy²

2013

Case Studies in Engineering Failure Analysis

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“…4 Such approaches, however, do not include the effect of a single overloading event, which often occurs in the service life of a realistic structure, exemplified by an offshore platform subjected to the impact of a small or medium size ship or a bridge under an unexpected environmental action. 5 Past research evidences [6][7][8][9][10][11] have confirmed the retardation in the fatigue crack propagation caused by a single overloading event through experimental investigations on small-scale fatigue specimens, e.g. the compact tension, C(T) specimen or the single edgenotched bend, SE(B) specimen.…”

Section: Introductionmentioning

confidence: 90%

Overload effect on the fatigue crack propagation in large‐scale tubular joints

Qian

Swaddiwudhipong

Nguyen

et al. 2012

Fatigue Fract Eng Mat Struct

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This paper examines the overloading effect on the fatigue crack propagations monitored in a large‐scale tubular X‐joint specimen under two separate cyclic tests. The first cyclic test applies a constant‐amplitude brace in‐plane bending to the joint, with a single cycle of 150% overload before the crack depth reaches the mid‐thickness of the chord. The second fatigue test applies two batches of cyclic loads, with the amplitude of the second batch at 66% of the former. The X‐joint specimen experiences a 150% overload cycle during the first batch of loading, followed by the second batch after it has recovered from the overload effect. The experimental results reveal that deep surface cracks experience more significant overload retardation than does a shallow fatigue crack. The Paris law estimation indicates that the single overload cycle applied in the first specimen leads to a 7% increase in the fatigue life of the X‐joint.

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The effect of overload cycles on fatigue crack propagation in two structural steels

Cited by 8 publications

References 19 publications

OVERLOAD RETARDATION OF FATIGUE CRACK GROWTH IN A 9%Cr 1%Mo STEEL AT ELEVATED TEMPERATURES

OVERLOAD RETARDATION OF FATIGUE CRACK GROWTH IN A 9%Cr 1%Mo STEEL AT ELEVATED TEMPERATURES

Fatigue failure of thermowells in feed gas supply downstream pipeline at a natural gas production plant

Overload effect on the fatigue crack propagation in large‐scale tubular joints

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