Time dependent ductile crack extension in A533B class I steel

Garwood, S.J.

doi:10.1016/0029-5493(86)90205-0

Cited by 8 publications

(20 citation statements)

References 4 publications

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“…Together, this means that the relative importance of hold times compared to load increases is greater in small-scale yielding than under fully yielded conditions. This is just opposite to what Ingham and Moreland [7] and Garwood [8] expect.…”

Section: The Influence Of the Degree Of Yield Containmentcontrasting

confidence: 50%

“…The maximum tolerable loads are reduced by long hold times by less than 10 percent in all cases considered. In the literature, it has been claimed that time effects should become smaller under conditions of contained, or small-scale, yielding and larger under fully yielded conditions [7][8]. The idea underlying this argument is that the elastic material surrounding the plastic zone acts as a practically rigid cage suppressing time-dependent straining.…”

Section: The Influence Of the Degree Of Yield Containmentmentioning

confidence: 99%

“…Since such a drop in load-bearing capacity of cracked structures due to creep might affect the safety of light water reactors, in particular under certain postulated accident conditions, several investigations have been carried out to determine the magnitude of the hold-time effect [3][4][5][6][7][8]. The common result of these studies is that a cracked specimen does not fracture within a few days unless it is loaded to 90 to 95 percent of the maximum load achieved in a short-term constant-strain-rate test.…”

Section: Introductionmentioning

confidence: 99%

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Time-dependent deformation and fracture of steel between 20�C and 400�C

Kuhnle

Riedel

1987

Int J Fract

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A~traet. The time-dependent deformation and cracking behavior of the quenched and tempered steel 15 NiCuMoNb 5 was investigated in the temperature range 20°C to 400°C. Fracture mechanics tests were carried out under various loading conditions including load-hold times of up to three weeks. The time-dependent crack growth can be described by the crack resistance (JR-) curve. Only above 300°C, the JR-curves obtained from constant-load tests start to deviate substantially from constant-displacement-rate tests. In this temperature range, the C,-parameter, which has been developed for creep crack growth testing, can be used to describe crack growth rates. For practical purposes, it is important to note that hold-time effects reduce the load-bearing capacity of cracked specimens by less than 10 percent for the present material and testing conditions.

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Section: The Influence Of the Degree Of Yield Containmentcontrasting

confidence: 50%

Section: The Influence Of the Degree Of Yield Containmentmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Time-dependent deformation and fracture of steel between 20�C and 400�C

Kuhnle

Riedel

1987

Int J Fract

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“…Under sustained loading, time‐dependent deformation and crack growth can occur in ductile ferritic and austenitic steels at temperatures well below the conventional creep range 1–7 . However, failure is generally found to occur only if the sustained loads are close to the monotonic collapse load 7 .…”

Section: Introductionmentioning

confidence: 99%

“…In bodies containing defects, the appropriate stress is the so‐called reference stress, a measure of the overall level of plasticity within the body, which controls the crack‐tip stress and strain fields within the J ‐estimation approach 9 underlying R6. Time‐dependent plasticity or ‘cold creep’ has been attributed to the sensitivity of the material's stress–strain curve to loading rate, 1,2 and R6 advises that sustained load effects need only be considered at susceptible temperatures, currently considered to be below 200 °C in austenitic steel. The effect of limited crack extension on the integrity of a structure needs to be carefully assessed within the susceptible range.…”

Section: Introductionmentioning

confidence: 99%

Time‐dependent fracture of type 316L(N) steel at ambient temperature

Budden

Wardle

Birkett

2005

Fatigue Fract Eng Mat Struct

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A B S T R A C T Experimental data on tensile and compact geometry (CT) specimens of austenitic Type 316L(N) steel were obtained under sustained load conditions at room temperature. Timedependent crack growth, in some cases leading to failure, occurred in many of the CT specimens, dependent on the load level. However, rupture of the uniaxial specimens occurred only at stresses very close to the material's ultimate strength. The data validate the approach to assessing sustained loading effects in the R6 defect assessment procedure.In particular, sustained load effects in austenitic steel may be neglected for values of the R6 L r parameter less than unity. Uniaxial sustained load tests were also performed at 100 • C and 200 • C. The measured strain rates decreased with increasing temperature, becoming negligible at 200 • C. This is consistent with the advice in R6 that sustained load effects in austenitic steel can be neglected at temperatures between 200 • C and the high-temperature creep range.Keywords cold creep; fracture; sustained loading; 316 steel. N O M E N C L A T U R Ea = crack length, a o + a a o = initial crack length B = gross thickness B e = effective thickness, B n (2 − B n /B) B n = nett thickness E = Young's modulus E = E/(1 − ν 2 ) f (L r ) = failure assessment curve f 1 , f 2 = particular expressions for f J = crack driving force J 0 = value of J on load-up J mat ( a) = tearing resistance K = stress intensity factor K mat ( a) = fracture toughness K r = R6 parameter, K/K mat K r = modified R6 parameter, λK r L r = R6 parameter, P/P L L max r = R6 plastic collapse limit, σ f /σ y N = strain hardening exponent P = load P L = limit load t = time from start of sustained loading W = width Correspondence: P. J. Budden.

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