Post yield fracture mechanics

Heald, P. T.; Spink, G. M.; Worthington, P.J.

doi:10.1016/0025-5416(72)90077-8

Cited by 135 publications

(10 citation statements)

References 11 publications

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“…The Dugdale model concept has been used with center-cracktension specimens in several fracture analyses [2][3][4] and in the developmentof fatigue crack-closuremodels [5,6] for cracked metallic materials. Currently,the compact specimen is the most widely used specimen for fatigue crack growth rate and fracture toughnesstesting.…”

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confidence: 99%

The Dugdale Model for Compact Specimen

Mall

Newman

1985

Fracture Mechanics: Sixteenth Symposium

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The purpose of this paper is to develop the Dugdale model for compact specimen. In particular, plastic-zone size and crack-tip-opening displacement (CTOD) equations are developed. Boundary-collocation analyses are used to analyze the compact specimen subjected to various loading conditions (pin loads, concentrated forces, and uniform pressure acting on the crack surface). Stress intensity factor and crack surface displacement equations for some of these loadings are developed and used to obtain the Dugdale model. The results from the equations for plastic-zone size and CTOD agreed well with numerical values calculated by Terada for crack-length-to-width ratios greater than 0.4.

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confidence: 99%

The Dugdale Model for Compact Specimen

Mall

Newman

1985

Fracture Mechanics: Sixteenth Symposium

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“…Equation (24) gives correct results for elastic fracture mechanics and low applied stresses (~r/tr~ ~ 1) when ~b-K2/3Gtr~. It is equivalent to the interpolation formulae for the post-yield fracture mechanics regime proposed by Heald, Spink and Worthington [12] and by Dowling and Townley [13]. On tracing the algebra through, it will be seen that the Eqns.…”

Section: B N -B -Y~ + • • ( 2 0 )mentioning

confidence: 91%

“…Accordingly, the critical-strain hypothesis was rejected after a brief examination. The strip yield model applies rigorously only to thin perfectly-plastic plates in plane stress (Dugdale [9]) but has been applied successfully to correlate a large amount of fracture data in plane strain (Heald, Spink and Worthington [12]; Dowling and Townley [13]). According to this model, yielding is assumed to be confined to the line of the crack (Fig.…”

Section: Strip Yield Models Of Creep Crack Incubation and Growthmentioning

confidence: 99%

Strip yield models of creep crack incubation and growth

Ewing

1978

Int J Fract

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The strip yield model of Dugdale and Bilby, CottreU and Swinden is applied to analyse the incubation and growth of creep cracks. This extends previous work by Vitek (on incubation) and by Heaton and Chan (following To) on growth.Following both Vitek and Heaton and Chan, the main criterion of crack growth used is a COD-based one. The crack is assumed to grow at constant crack opening displacement (COD) 4' = ~b,, and the creep strain ~ at the crack tip is assumed to be dplh, where the gauge length is a material constant.The COD-based theory indicates that the incubation and failure times t~, t I are controlled by the stress intensity factor K at large stresses, but by the net stress at very low stresses. A weakness of the theory is that it neglects primary-creep effects: these have to be absorbed by modifying the secondary-creep index. If this is done, then comparison with two independent experiments shows moderately good agreement with the COD-based theory for both t~ and t t.

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“…

To use the Dugdale model with the compact specimen (see Figure l(a)), equations for stress intensity factor K and crack surface displacement V must be obtained for the two loading cases shown in Figure l(b)--a pair of pin loads P and a uniform stress o^ acting on a segment p of the crack surunit thickness.)

…”

mentioning

confidence: 99%

“…The Dugdale model concept [i] has been used with center crack tension specimens in several fracture analyses [2] and in the development of simple crack closure models [3] for cracked metallic materials. Currently, the compact specimen is the most widely used specimen for fracture toughness and fatigue crack growth rate testing.…”

mentioning

confidence: 99%

Dugdale plastic zone size and CTOD equations for the compact specimen

Newman

Mall

1984

Int J Fract

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The Dugdale model concept [i] has been used with center crack tension specimens in several fracture analyses [2] and in the development of simple crack closure models [3] for cracked metallic materials. Currently, the compact specimen is the most widely used specimen for fracture toughness and fatigue crack growth rate testing.To use the Dugdale model with the compact specimen (see Figure l(a)), equations for stress intensity factor K and crack surface displacement V must be obtained for the two loading cases shown in Figure l(b)--a pair of pin loads P and a uniform stress o^ acting on a segment p of the crack surunit thickness.) face.(P is load per oThe pin-loaded case was previously analyzed [4] to obtain stress intensity factors and crack surface displacements.Srawley [5] fitted the results from [4] with a power series to obtain an equation for K. The boundary collocation method [4] is used herein to analyze the case for uniform stress.Both stress intensity factors and crack surface displacements, under plane stress conditions (~ = 0.3), were calculated.The Dugdale model for the compact specimen requires that the "finiteness" condition of Dugdale be satisfied.This condition states that the K at the tip of the plastic zone (at d = a + p) is zero. From this condition, the plastic zone size (p) was calculated for various a/w and P/wo 0 ) ratios.An equation was then fitted to these results and was p/a = (~w/8a)(PF/WOo)2F 0 where (l) F = (2 + ~)(0.886 + 4.64a -13.32~ 2 + 14.72a 3 -5.6a 4)/(I -a)~2(2) F 0 = i + fl(P/WOo) + f2(P/WOo)2fl = -2.687(1 -~) + 0.167/~ 2 (4) Int Journ of Fracture 24 (1984)

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Post yield fracture mechanics

Cited by 135 publications

References 11 publications

The Dugdale Model for Compact Specimen

The Dugdale Model for Compact Specimen

Strip yield models of creep crack incubation and growth

Dugdale plastic zone size and CTOD equations for the compact specimen

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