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The effect of crack growth history on fracture toughness

Research output: Chapter in Book/Report/Conference proceedingConference contribution

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The effect of crack growth history on fracture toughness. / Probert, Molly; Coules, Harry; Truman, Christopher; Hofmann, Michael.

Proceedings of the ASME 2019 Pressure Vessels & Piping Conference. 2019. 93307.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Harvard

Probert, M, Coules, H, Truman, C & Hofmann, M 2019, The effect of crack growth history on fracture toughness. in Proceedings of the ASME 2019 Pressure Vessels & Piping Conference., 93307.

APA

Probert, M., Coules, H., Truman, C., & Hofmann, M. (Accepted/In press). The effect of crack growth history on fracture toughness. In Proceedings of the ASME 2019 Pressure Vessels & Piping Conference [93307]

Vancouver

Probert M, Coules H, Truman C, Hofmann M. The effect of crack growth history on fracture toughness. In Proceedings of the ASME 2019 Pressure Vessels & Piping Conference. 2019. 93307

Author

Probert, Molly ; Coules, Harry ; Truman, Christopher ; Hofmann, Michael. / The effect of crack growth history on fracture toughness. Proceedings of the ASME 2019 Pressure Vessels & Piping Conference. 2019.

Bibtex

@inproceedings{c76d4b07b4e042f5914b6ffd818a8b0c,
title = "The effect of crack growth history on fracture toughness",
abstract = "If a crack is introduced progressively into an elastic-plastic material containing a residual stress field, the incremental relaxation of the residual stress field causes the formation of a plastic wake along the crack boundaries. This leads to the reduction in the J parameter for a crack of a given size, compared to a crack with the same dimensions which has been introduced instantaneously, having the crack faces released simultaneously along the whole length. This reduction in J is due to the dissipation of strain energy which is otherwise available for further crack extension, as in the instantaneously introduced crack. This is important for the current J-based fracture assessment common in the nuclear and petro-chemical industries such as EDF Energy’s R6 and BS7910:2013 as they currently assume instantaneous insertion of cracks as this is inherently more conservative. Although many studies demonstrating this effect in FE are available, there is little experimental evidence for this phenomenon. Especially those including rigorous comparisons with specimens that have been ‘instantaneously’ cracked. This may be due to the difficulty inherent in manufacturing such a specimen as manufacturing processes rely on the incremental removal of material. Assumption about the order in which the crack and the residual stress field are applied to the specimen are equally difficult to justify as containing an accurate example of an ‘instantaneous’ crack. The aim of this paper is to detail the current analysis that aims to replicate the deformation behavior of an instantaneously introduced crack tip in a model that has had the nodes released in a progressive manner. This will allow specimens to be machined in a way that replicates ‘instantaneous’ cracking allowing for experimental techniques to be developed to display the difference between instantaneous and progressively introduced cracks.",
author = "Molly Probert and Harry Coules and Christopher Truman and Michael Hofmann",
year = "2019",
month = "3",
day = "15",
language = "English",
booktitle = "Proceedings of the ASME 2019 Pressure Vessels & Piping Conference",

}

RIS - suitable for import to EndNote

TY - GEN

T1 - The effect of crack growth history on fracture toughness

AU - Probert, Molly

AU - Coules, Harry

AU - Truman, Christopher

AU - Hofmann, Michael

PY - 2019/3/15

Y1 - 2019/3/15

N2 - If a crack is introduced progressively into an elastic-plastic material containing a residual stress field, the incremental relaxation of the residual stress field causes the formation of a plastic wake along the crack boundaries. This leads to the reduction in the J parameter for a crack of a given size, compared to a crack with the same dimensions which has been introduced instantaneously, having the crack faces released simultaneously along the whole length. This reduction in J is due to the dissipation of strain energy which is otherwise available for further crack extension, as in the instantaneously introduced crack. This is important for the current J-based fracture assessment common in the nuclear and petro-chemical industries such as EDF Energy’s R6 and BS7910:2013 as they currently assume instantaneous insertion of cracks as this is inherently more conservative. Although many studies demonstrating this effect in FE are available, there is little experimental evidence for this phenomenon. Especially those including rigorous comparisons with specimens that have been ‘instantaneously’ cracked. This may be due to the difficulty inherent in manufacturing such a specimen as manufacturing processes rely on the incremental removal of material. Assumption about the order in which the crack and the residual stress field are applied to the specimen are equally difficult to justify as containing an accurate example of an ‘instantaneous’ crack. The aim of this paper is to detail the current analysis that aims to replicate the deformation behavior of an instantaneously introduced crack tip in a model that has had the nodes released in a progressive manner. This will allow specimens to be machined in a way that replicates ‘instantaneous’ cracking allowing for experimental techniques to be developed to display the difference between instantaneous and progressively introduced cracks.

AB - If a crack is introduced progressively into an elastic-plastic material containing a residual stress field, the incremental relaxation of the residual stress field causes the formation of a plastic wake along the crack boundaries. This leads to the reduction in the J parameter for a crack of a given size, compared to a crack with the same dimensions which has been introduced instantaneously, having the crack faces released simultaneously along the whole length. This reduction in J is due to the dissipation of strain energy which is otherwise available for further crack extension, as in the instantaneously introduced crack. This is important for the current J-based fracture assessment common in the nuclear and petro-chemical industries such as EDF Energy’s R6 and BS7910:2013 as they currently assume instantaneous insertion of cracks as this is inherently more conservative. Although many studies demonstrating this effect in FE are available, there is little experimental evidence for this phenomenon. Especially those including rigorous comparisons with specimens that have been ‘instantaneously’ cracked. This may be due to the difficulty inherent in manufacturing such a specimen as manufacturing processes rely on the incremental removal of material. Assumption about the order in which the crack and the residual stress field are applied to the specimen are equally difficult to justify as containing an accurate example of an ‘instantaneous’ crack. The aim of this paper is to detail the current analysis that aims to replicate the deformation behavior of an instantaneously introduced crack tip in a model that has had the nodes released in a progressive manner. This will allow specimens to be machined in a way that replicates ‘instantaneous’ cracking allowing for experimental techniques to be developed to display the difference between instantaneous and progressively introduced cracks.

M3 - Conference contribution

BT - Proceedings of the ASME 2019 Pressure Vessels & Piping Conference

ER -