On the connection between mode II and mode III effective thresholds in metals

Closure-free long cracks under the remote mode III loading grow in a more complicated way than those under the remote mode II. For bcc metals, a coplanar in-plane spreading of tongues driven by the local mode II loading components at crack-front asperities prevails while twisting of crack-front segm...

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Main Authors: Tomas Vojtek, Stanislav Zak, Jaroslav Pokluda
Format: Article
Language:English
Published: Gruppo Italiano Frattura 2017-06-01
Series:Fracture and Structural Integrity
Subjects:
Online Access:https://www.fracturae.com/index.php/fis/article/view/1888
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author Tomas Vojtek
Stanislav Zak
Jaroslav Pokluda
author_facet Tomas Vojtek
Stanislav Zak
Jaroslav Pokluda
author_sort Tomas Vojtek
collection DOAJ
description Closure-free long cracks under the remote mode III loading grow in a more complicated way than those under the remote mode II. For bcc metals, a coplanar in-plane spreading of tongues driven by the local mode II loading components at crack-front asperities prevails while twisting of crack-front segments to mode I, often leading to factory-roof morphology, is typical for other materials. In bcc metals, therefore, the formulation of a quantitative relationship connecting effective thresholds in modes II and III demands to calculate the local mode II components of stress intensity factors at typical asperities of a crack front loaded in the remote mode III. Therefore, a numerical model of a serrated crack front was created and the results were compared with experimentally determined ratio of mode II and III effective thresholds for the ARMCO iron. Although the calculated crack-front roughness needs an experimental verification, the preliminary results indicate that the model can provide a quantitative explanation of the experimentally observed ratio of mode II and mode III effective thresholds in bcc metals.
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series Fracture and Structural Integrity
spelling doaj-art-d222d9d056d14d1887f8ec3d50c5332e2024-12-02T05:42:33ZengGruppo Italiano FratturaFracture and Structural Integrity1971-89932017-06-011141On the connection between mode II and mode III effective thresholds in metalsTomas VojtekStanislav ZakJaroslav PokludaClosure-free long cracks under the remote mode III loading grow in a more complicated way than those under the remote mode II. For bcc metals, a coplanar in-plane spreading of tongues driven by the local mode II loading components at crack-front asperities prevails while twisting of crack-front segments to mode I, often leading to factory-roof morphology, is typical for other materials. In bcc metals, therefore, the formulation of a quantitative relationship connecting effective thresholds in modes II and III demands to calculate the local mode II components of stress intensity factors at typical asperities of a crack front loaded in the remote mode III. Therefore, a numerical model of a serrated crack front was created and the results were compared with experimentally determined ratio of mode II and III effective thresholds for the ARMCO iron. Although the calculated crack-front roughness needs an experimental verification, the preliminary results indicate that the model can provide a quantitative explanation of the experimentally observed ratio of mode II and mode III effective thresholds in bcc metals.https://www.fracturae.com/index.php/fis/article/view/1888Modes II and IIIEffective thresholdMicromechanismFinite element methodARMCO iron
spellingShingle Tomas Vojtek
Stanislav Zak
Jaroslav Pokluda
On the connection between mode II and mode III effective thresholds in metals
Fracture and Structural Integrity
Modes II and III
Effective threshold
Micromechanism
Finite element method
ARMCO iron
title On the connection between mode II and mode III effective thresholds in metals
title_full On the connection between mode II and mode III effective thresholds in metals
title_fullStr On the connection between mode II and mode III effective thresholds in metals
title_full_unstemmed On the connection between mode II and mode III effective thresholds in metals
title_short On the connection between mode II and mode III effective thresholds in metals
title_sort on the connection between mode ii and mode iii effective thresholds in metals
topic Modes II and III
Effective threshold
Micromechanism
Finite element method
ARMCO iron
url https://www.fracturae.com/index.php/fis/article/view/1888
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