Fatigue crack growth in notched specimens: a numerical analysis

Fatigue crack growth (FCG) is linked to irreversible and non-linear processes happening at the crack tip, which explains different problems observed in the use of da/dN-DK curves. The replacement of DK by non-linear crack tip parameters, namely the crack tip opening displacement (CTOD) is an interes...

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Main Authors: Fernando Ventura Antunes, Ricardo Branco, Pedro Prates, José Domingos Costa
Format: Article
Language:English
Published: Gruppo Italiano Frattura 2019-03-01
Series:Fracture and Structural Integrity
Subjects:
Online Access:https://www.fracturae.com/index.php/fis/article/view/2195
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author Fernando Ventura Antunes
Ricardo Branco
Pedro Prates
José Domingos Costa
author_facet Fernando Ventura Antunes
Ricardo Branco
Pedro Prates
José Domingos Costa
author_sort Fernando Ventura Antunes
collection DOAJ
description Fatigue crack growth (FCG) is linked to irreversible and non-linear processes happening at the crack tip, which explains different problems observed in the use of da/dN-DK curves. The replacement of DK by non-linear crack tip parameters, namely the crack tip opening displacement (CTOD) is an interesting alternative. The objective in here is to study the effect of notches on FCG using the plastic CTOD range, dp. M(T) specimens with lateral notches of different radius (1, 2 4 and 8 mm were analysed numerically, keeping the total depth constant (8 mm). The increase of crack length increases dp and therefore FCG rate. For plane stress state, the formation of the residual plastic wake with crack propagation produces crack closure which compensates the effect of crack length and there is a stabilization of dp. The reduction of notch radius increases dp for all crack lengths, particularly for the shortest ones. For plane strain state there is almost no crack closure therefore dp is higher than for plane stress state, and the effect of crack length produces a relatively fast increase of dp
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spelling doaj-art-d46dc8f4fc194be4a9166ccb3a412c702025-08-20T02:51:45ZengGruppo Italiano FratturaFracture and Structural Integrity1971-89932019-03-011348Fatigue crack growth in notched specimens: a numerical analysisFernando Ventura Antunes0Ricardo Branco1Pedro Prates2José Domingos CostaDepartment of Mechanical Engineering, University of Coimbra, PortugalDepartment of Mechanical Engineering, University of Coimbra, PortugalDepartment of Mechanical Engineering, University of Coimbra, PortugalFatigue crack growth (FCG) is linked to irreversible and non-linear processes happening at the crack tip, which explains different problems observed in the use of da/dN-DK curves. The replacement of DK by non-linear crack tip parameters, namely the crack tip opening displacement (CTOD) is an interesting alternative. The objective in here is to study the effect of notches on FCG using the plastic CTOD range, dp. M(T) specimens with lateral notches of different radius (1, 2 4 and 8 mm were analysed numerically, keeping the total depth constant (8 mm). The increase of crack length increases dp and therefore FCG rate. For plane stress state, the formation of the residual plastic wake with crack propagation produces crack closure which compensates the effect of crack length and there is a stabilization of dp. The reduction of notch radius increases dp for all crack lengths, particularly for the shortest ones. For plane strain state there is almost no crack closure therefore dp is higher than for plane stress state, and the effect of crack length produces a relatively fast increase of dphttps://www.fracturae.com/index.php/fis/article/view/2195Fatigue crack growthNotchesPlastic CTODCrack closure
spellingShingle Fernando Ventura Antunes
Ricardo Branco
Pedro Prates
José Domingos Costa
Fatigue crack growth in notched specimens: a numerical analysis
Fracture and Structural Integrity
Fatigue crack growth
Notches
Plastic CTOD
Crack closure
title Fatigue crack growth in notched specimens: a numerical analysis
title_full Fatigue crack growth in notched specimens: a numerical analysis
title_fullStr Fatigue crack growth in notched specimens: a numerical analysis
title_full_unstemmed Fatigue crack growth in notched specimens: a numerical analysis
title_short Fatigue crack growth in notched specimens: a numerical analysis
title_sort fatigue crack growth in notched specimens a numerical analysis
topic Fatigue crack growth
Notches
Plastic CTOD
Crack closure
url https://www.fracturae.com/index.php/fis/article/view/2195
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