On the Use of Side-Grooves in Estimating JIc Fracture Toughness With Charpy-Size Specimens

Server, W.L.; Wullaert, R.A.; Ritchie, R.O.

doi:10.1115/1.3224796

Cited by 31 publications

(3 citation statements)

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“…In general, the tilt,, ratios were greater than 0.50. This is in conformity with the reported suggestion that with precracking and/or side-grooving and/or using embrittled specimens, the point of crack initiation approaches the point of maximum load [40,45]. The Ej/ET ratio (where ET is the total impact energy) was mostly 20% or higher in the present case.…”

Section: Estimates Of N M D and Gydsupporting

confidence: 94%

MEASUREMENT OF STRETCH ZONE HEIGHT AND ITS RELATIONSHIP TO CRACK TIP OPENING DISPLACEMENT AND INITIATION J‐VALUE IN AN AISI 316 STAINLESS STEEL

Sreenivasan¹,

Ray

Vaidyanathan³

et al. 1996

Fatigue Fract Eng Mat Struct

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An accurate method using SEM for the measurement of stretch zone height (SZH) on fracture surfaces has been established This method does not make any assumption regarding crack blunting angle S, and for 316 stainless steel in the present investigation 6 was in the range of 50 to 67", contrary to the common assumption of 45". The semi-empirical equations, SZH(T) = 2.5 SZW (stretch zone width) and SZW=89(J/fi), reported in the literature were found to give very conservative predictions of initiation toughness Ji for an AISI 316 stainless steel. Lowerbound values of the coefficient m in the equation, J = ma,& relating J to CTOD, 6, is found to be 1.5-1.7 for the 316 SS used in this investigation; the upperbound value for m is found to be 2.6. The plastic CTOD values (6,)corresponding to the maximum load-point on the instrumented impact test traces are not sensitive to the aging conditions and as they incorporate significant crack growth effects they cannot be used for predicting Ji by a procedure similar to that discussed above. The ratio tiltT, where ti is the time to crack initiation and tT is the time to total fracture, in precracked Charpy tests of unaged and aged 316 SS used in this investigation (a/"= 0.55 to 0.8) corresponds to 0.15 to 0.17.Keywords-Stretch zone height; Crack tip opening displacement; J-integral; AISI 316 stainless steel NOMENCLATURE a, a, = crack length and initial length b, b, = remaining ligament ( W-a) and initial ligament ( W -%) B = specimen thickness CVN = Charpy V-notch CTOD = crack tip opening displacement d,, = factor relating CTOD to 3-integral; d: = Ea,/d,, E = Youngs' modulus Ei = energy under the load(P) -time(t) trace up to crack initiation ET = total impact energy h = SZH on one half of the fracture surface Ji = value of J integral at the point of crack initiation J,, = critical value of mode-I 3-integral satisfying ASTM E813 validity criteria m = J/ay 6 n = work-hardening index P, = load on the instrumented impact test load-time trace corresponding to crack LPD = load-point displacement PGy = general yield load on the instrumented impact test load-time trace initiation PmaX = maximum load on the instrumented test load-time trace r = rotation constant used in the expression relating CTOD to LPD for three-pointbend specimens SZD, SZH, SZW = stretch zone depth, height and width SZH(T) = sum of the SZH values (h) from the two halves of the specimen (= CTOD) ti = time to crack initiation (from the load-time trace) t,, = time to maximum load (from the load-time trace) t, = time to total (complete) fracture 855 856 P. R. SREENIVASAN et al. u = Poisson's ratio W = specimen width a = angle of rotation of the specimen in the SEM with respect to the electron beam 6 = CTOD Ssl, 6, = elastic and plastic parts of 6 diva, Bi,pl = elastic and plastic parts of 6, 6, = CTOD at maximum load Anb = blunting crack extensions evaluated by different procedures E,, = uniform true strain in the tensile test B = crack blunting angle uo = reference stress in the power law fit to the true stress-true str...

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Section: Estimates Of N M D and Gydsupporting

confidence: 94%

MEASUREMENT OF STRETCH ZONE HEIGHT AND ITS RELATIONSHIP TO CRACK TIP OPENING DISPLACEMENT AND INITIATION J‐VALUE IN AN AISI 316 STAINLESS STEEL

Sreenivasan¹,

Ray

Vaidyanathan³

et al. 1996

Fatigue Fract Eng Mat Struct

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“…Prior investigations [I [13][14][15][16] have indicated that side-grooves can promote plane strain fractirre in thin sections which usually exhibit ductile behavior. Other studies show that side-grooves may also affect fatigue crack growth by lowering closure loads [ 171 and slightly decreasing thick specimen retardation [18].…”

Section: Introductionmentioning

confidence: 99%

Effect of Side‐grooves on Fatigue Crack Retardation

Hess¹,

Grandt²,

Dumanis³

1983

Fatigue Fract Eng Mat Struct

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This paper describes results of an experimental program conducted to determine the influence of deep side-grooves on fatigue crack retardation. The results indicate that side-grooves significantly reduce the delay in fatigue crack growth caused by single peak overloads. It is suggested that the decreased retardation is due to simulation of plane strain conditions in the "thin" test sections by the stress field at the root of the side-groove. NOMENCLATURE a = crack length B = specimen thickness B, = net thickness after side-grooving B = stress intensity factor coefficient da/dN = fatigue crack growth rate cXSC = u-component of strain in side-grooved specimen cXUT = x-component of strain in uniform thickness specimen AK = stress intensity factor range during load cycle K,,, = maximum stress intensity factor during load cycle Kpeak = peak stress intensity factor during overload K,,,, = actual stress intensity factor for side-groove specimen K * = stress intensity factor computed for side-groove specimen assuming uniform thickness B, N , = delay cycles caused by overload 11 = empirical exponent P = applied force R = minimum/maximum load (J = root radius of side-groove notch 0 = side-groove flank angle W = specimen width.

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“…5). Bei seitengekerbten Proben ist es mo Èglich, aus der Maximalkraft einen angena Èherten Wert fu Èr die Risseinleitungsza Èhigkeit zu bestimmen [53].…”

Section: Der Konventionelle Kerbschlagbiegeversuchunclassified

100 Jahre Kerbschlagbiegeversuch nach Charpy

Blumenauer

2001

Mat.-wiss. u. Werkstofftech.

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On the Use of Side-Grooves in Estimating JIc Fracture Toughness With Charpy-Size Specimens

Cited by 31 publications

References 0 publications

MEASUREMENT OF STRETCH ZONE HEIGHT AND ITS RELATIONSHIP TO CRACK TIP OPENING DISPLACEMENT AND INITIATION J‐VALUE IN AN AISI 316 STAINLESS STEEL

MEASUREMENT OF STRETCH ZONE HEIGHT AND ITS RELATIONSHIP TO CRACK TIP OPENING DISPLACEMENT AND INITIATION J‐VALUE IN AN AISI 316 STAINLESS STEEL

Effect of Side‐grooves on Fatigue Crack Retardation

100 Jahre Kerbschlagbiegeversuch nach Charpy

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