A statistical investigation of microcrack formation

Kaeghele, L.E; Tetelman, A. S.

doi:10.1016/0001-6160(69)90028-5

Cited by 49 publications

(19 citation statements)

References 2 publications

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“…A number of studies (see, e.g. Kaechele and Tetelman, 1969) have shown that the number of nucleated microcracks was an increasing function of plastic strain and increased when the temperature was lowered. From this observation one should be tempted to include in the expression of the Weibull stress a function increasing with plastic strain and decreasing with temperature.…”

Section: Models Of Cleavage Fracturementioning

confidence: 99%

Development of the Local Approach to Fracture over the Past 25 years: Theory and Applications

Pineau

2006

Int J Fract

171

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This review paper is devoted to the local approach to fracture (LAF) for the prediction of the fracture toughness of structural steels. The LAF has been considerably developed over the past two decades, not only to provide a better understanding of the fracture behaviour of materials, in particular the failure micromechanisms, but also to deal with loading conditions which cannot easily be handled with the conventional linear elastic fracture mechanics and elastic-plastic fracture mechanics global approaches. The bases of this relatively newly developed methodology are first presented. Both ductile rupture and brittle cleavage fracture micromechanisms are considered. The ductile-to-brittle transition observed in ferritic steels is also briefly reviewed. Two types of LAF methods are presented: (i) those assuming that the material behaviour is not affected by damage (e.g. cleavage fracture), (ii) those using a coupling effect between damage and constitutive equations (e.g. ductile fracture). The micromechanisms of brittle and ductile fracture investigated in elementary volume elements are briefly presented. The emphasis is laid on cleavage fracture in ferritic steels. The role of second phase particles (carbides or inclusions) and grain boundaries is more thoroughly discussed. The distinction between nucleation and growth controlled fracture is made. Recent developments in the theory of cleavage fracture incorporating both the effect of stress state and that of plastic strain are presented. These theoretical results are applied to the crack tip situation to predict the fracture toughness. It is shown that the ductile-to-brittle transition curve can reasonably be well predicted using the LAF approach. Additional applications of the LAF approach methods are also shown, including: (i) the effect of loading rate and prestressing; (ii) the influence of residual stresses in welds; (iii) the mismatch effects in welds; (iv) the warm-prestressing effect. An attempt is also made to delineate research areas where large improvements should be made for a better understanding of the failure behaviour of structural materials.

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Section: Models Of Cleavage Fracturementioning

confidence: 99%

Development of the Local Approach to Fracture over the Past 25 years: Theory and Applications

Pineau

2006

Int J Fract

171

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“…Kaechele and Tetelman measured also the crack angle distribution 15 . They found no effect of temperature on the crack angles 15 .…”

Section: Fracture Of Grains (Step 2)mentioning

confidence: 98%

“…The subsequent fracture of grains must also occur. Kaechele and Tetelman examined the fracture of grains in polycrystalline iron with grain boundary carbide films 15 . Based on some preliminary tests, three temperatures were selected for more detailed examination.…”

Section: Fracture Of Grains (Step 2)mentioning

confidence: 99%

Aspects of cleavage fracture initiation – relative influence of stress and strain

Wallin¹,

Laukkanen²

2006

Fatigue Fract Eng Mat Struct

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A B S T R A C T Cleavage fracture initiation has generally been assumed to be controlled mainly by matrix stress. Recently, several different cleavage fracture models have been proposed, where also strain is included in the failure criterion. However, the proposals have been rather crude and unable to provide clearly improved fracture estimates. Here, the first two steps of cleavage fracture (particle failure and grain fracture) are examined in more detail. It is shown that both stress and strain are important for cleavage fracture initiation, but that strain mainly affects particle failure, whereas grain fracture is controlled by a pure Griffith criterion. The findings are important for the development of new cleavage fracture models and to the proper way of accounting for constraint. B = specimen thickness d = particle diameter d c = critical particle diameter d N = normalization diameter d = mean particle diameter d f = mean fractured particle diameter E = Young's modulus f = volume fraction of particles f (σ ) = stress function K I = stress intensity factor m = Weibull exponent N = number of initiators in volume element N V = average number of initiators in volume element V n = number of volume elements or strain hardening exponent P{d ≥ d 0 } = cumulative particle size distribution P {d /d } = particle size distribution P f = cumulative failure probability P{f} = proportion of fractured particles P{fd} = cumulative fracture probability of a spherical brittle particle of diameter d Pr{I} = cleavage initiation probability Pr{I/0} = conditional probability of cleavage initiation with no prior void initiation Pr{V/0} = probability of not having void initiation P{α} = crack plane angle distribution P{θ} = surface trace angle distribution

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“…Some experimental investigations thus were conducted to understand the mechanism of the crack nucleation in the past [18][19][20]. We employ a probability of crack nucleation at cementite particle as the condition of Stage I, which was quantified by the author's recent study [21].…”

Section: Nucleation Of Crack At a Cementite Particle (Stage I)mentioning

confidence: 99%

Prediction model on cleavage fracture initiation in steels having ferrite–cementite microstructures – Part I: Model presentation

Shibanuma

Aihara

Suzuki

2016

Engineering Fracture Mechanics

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A statistical investigation of microcrack formation

Cited by 49 publications

References 2 publications

Development of the Local Approach to Fracture over the Past 25 years: Theory and Applications

Development of the Local Approach to Fracture over the Past 25 years: Theory and Applications

Aspects of cleavage fracture initiation – relative influence of stress and strain

Prediction model on cleavage fracture initiation in steels having ferrite–cementite microstructures – Part I: Model presentation

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