Effects of ferrite grain size, notch acuity and notch length on brittle fracture stress of notched specimens of low carbon steel

Yokobori, Takeo; Konosu, Shinji

doi:10.1016/0013-7944(77)90006-6

Cited by 39 publications

(13 citation statements)

References 9 publications

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“…-L values seem to be very low, but the same order of magnitude has been reported [11] [11,28,29] presents similar results in other steels. Wilshaw [28] found that L and d are equal, whereas for Yokobori [29] the relation gave L=1.2d for the same material subjected to different heat treatments, and then, presenting different grain sizes.…”

Section: Finite Elements Modelling and Calibration Of The Critical DIsupporting

confidence: 84%

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Analysis of notch effect in the apparent fracture toughness and the fracture micromechanisms of ferritic–pearlitic steels operating within their lower shelf

Cicero

Madrazo

García

2014

Engineering Failure Analysis

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The fracture resistance of materials is generally higher in notched conditions that in cracked conditions. In other words, when the notch radius increases there is also an increase in the apparent fracture toughness, which is that exhibited in notched conditions. This paper presents an analysis of the notch effect on two ferritic-pearlitic steels operating within their corresponding lower shelf, and develops an experimental The research is completed with the analysis of the evolution of fracture micromechanisms when the notch radius increases, revealing a direct relation between this evolution and the apparent fracture toughness observations.

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Section: Finite Elements Modelling and Calibration Of The Critical DIsupporting

confidence: 84%

“…Wilshaw [28] found that L and d are equal, whereas for Yokobori [29] the relation gave L=1.2d for the same material subjected to different heat treatments, and then, presenting different grain sizes.…”

Section: Finite Elements Modelling and Calibration Of The Critical DImentioning

confidence: 99%

Analysis of notch effect in the apparent fracture toughness and the fracture micromechanisms of ferritic–pearlitic steels operating within their lower shelf

Cicero

Madrazo

García

2014

Engineering Failure Analysis

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“…Miller [10] obtained a best-fit equation to the micro structural short crack growth data for medium carbon steels in the form of a fatigue crack growth parameter da/dN proportional to the stress range raised an exponent times the difference of the grain diameter and the crack length. The grain diameter is very close to the material parameter for metals as evident in the studies of Wilshaw et al [16] and that of Yokobori and Konusu [17]. In this work, therefore, the grain diameter "D" is the same as the distance parameter "l 0 " from the studies of El Haddad et al [5], which is also twice the distance parameter "d" of Roche [6].…”

Section: Introductionsupporting

confidence: 49%

“…This is valid for medium carbon steels and will be assumed to apply for the material considered in this analysis. In the above equation the grain diameter "D" appearing in the work of Miller [10] is assumed identical to the material parameter "l 0 " based on the results appearing in [16] and [17].…”

Section: S K a Th Thmentioning

confidence: 99%

High Cycle Fatigue of Structural Components Using Critical Distance Methods

Chattopadhyay

2011

Experimental and Applied Mechanics, Volume 6

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This study explores the high cycle fatigue strength of crack-like discontinuities in metallic structures as well as those made from powder metals using approaches that are based on theory of critical distances (TCD). The methods used in this study consist of (a) the point method, (b) the line method, and (c) the imaginary crack method. The effective parameter for the methods (a), (b), and (c) is the distance 'd' from the material surface, which is a material property and the reference parameter is the fatigue limit. The imaginary crack method involves introduction of a sharp crack at the root of a notch and the length of the crack, 'l o ' assumed a material constant. In the imaginary crack method, the effective crack length is taken as the sum of the actual crack and the material parameter 'l o '. It is concluded that the high cycle fatigue has a volumetric character and the proposed methods introduce the volume effect in the determination of stress and strain fields as well as the fatigue life. Using the material parameters from the various approaches, the number of cycles to initiate a fatigue has been determined for a number of materials and compared with experimental results. NOMENCLATURE a: crack length, m a th : threshold crack size, m d: distance parameter due to Roche [6], m D: grain diameter, m E: modulus of elasticity, GPa K: stress intensity factor, MPa √m ΔK th : threshold stress intensity factor range, MPa √m ΔK th l : long crack threshold stress intensity factor range, MPa √m l 0 : distance parameter due to El Haddad et al [5], m N: number of cycles to initiate a crack ΔS : stress range, MPa (remote from crack) Δσ : stress range, MPa Δσ e : endurance limit stress range, MPa

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“…This has led to a study of the effects of notch acuity on the fracture toughness of S2 fresh-water ice. The dependence of the frature toughness on the notch-tip radius is well known for other materials, such as H-ll steel (Irwin, 1964), mild or low-carbon steel at low temperatures (Wilshaw and others, 1968;Yokobori and Konosu, 1977), ceramic materials (Bertolotti, 1973;Pabst, 1974) and aluminum metal matrix composites (Manoharan and Lewandowski, 1989). In this study, tests were conducted on six groups of single-edgenotched-bend (SENB) specimens with cracks fabricated by six different methods, viz, drilling a small hole at the crack tip, a band saw, a wire saw, pressing and freezing a razor blade at the crack tip , using a hand-held razor to sharpen the crack and pre-cracking.…”

Section: Introductionmentioning

confidence: 98%

Crack-fabrication techniques and their effects on the fracture toughness and CTOD for fresh-water columnar ice

1991

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ABSTRACT. The effects of notch acuity (crack-tip sharpness) on the fracture toughness of S2 ice were investigated using six groups of single-edge-notched-bend (SENB) specimens with different crack (or notch) root radii fabricated by six different methods. The mean value and standard deviations of the apparent fracturetoughness values KQ of the specimens with blunt notches were significantly higher than those of the specimens with sharp cracks. The results presented in a plot of fracture toughness versus p~, where p is the crack-tip radius, provide an estimate of the required notch acuity for fracture-toughness testing. The microstructural features in the immediate vicinity of the crack tip and the crack-tip geometry govern the magnitude of the apparent fracture toughness of the ice. The crack-tipopening-displacement (CTOD) measured in this study indicates the existence of microplastic deformation in the vicinity of the crack tip at the initiation of unstable fracture. INTRODUCTIO N

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Effects of ferrite grain size, notch acuity and notch length on brittle fracture stress of notched specimens of low carbon steel

Cited by 39 publications

References 9 publications

Analysis of notch effect in the apparent fracture toughness and the fracture micromechanisms of ferritic–pearlitic steels operating within their lower shelf

Analysis of notch effect in the apparent fracture toughness and the fracture micromechanisms of ferritic–pearlitic steels operating within their lower shelf

High Cycle Fatigue of Structural Components Using Critical Distance Methods

Crack-fabrication techniques and their effects on the fracture toughness and CTOD for fresh-water columnar ice

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