Numerical Simulation of the Effect of Pre-Strain on Fatigue Crack Growth in AA2024-T351

The objective here is to study the effect of pre-strain on fatigue crack growth (FCG) in 2024-T351 aluminum alloy. Three pre-strain conditions were considered: without pre-strain, compressive and tensile permanent pre-strains of 4%. A numerical approach based on cumulative plastic strain at the crac...

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Bibliographic Details
Main Authors: Diogo M. Neto, Edmundo Sérgio, André Agra, Fernando V. Antunes
Format: Article
Language:English
Published: MDPI AG 2025-04-01
Series:Metals
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Online Access:https://www.mdpi.com/2075-4701/15/5/481
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Summary:The objective here is to study the effect of pre-strain on fatigue crack growth (FCG) in 2024-T351 aluminum alloy. Three pre-strain conditions were considered: without pre-strain, compressive and tensile permanent pre-strains of 4%. A numerical approach based on cumulative plastic strain at the crack tip was followed to predict FCG rate. The compressive pre-strain increased FCG rate, while the tensile pre-strain reduced the <i>da</i>/<i>dN</i> relative to the situation without pre-strain. The influence of pre-strain was linked with plasticity-induced crack closure. In fact, a linear trend was obtained between <i>da</i>/<i>dN</i> and ΔK<sub>eff</sub> for three crack lengths (a = 16.184; a = 15.048 mm and a = 15.152 mm) and three pre-strain conditions. The increase in the stress ratio from R = 0.1 to R = 0.5 and the elimination of the contact of crack flanks significantly reduced the effect of pre-strain, also pointing to the huge relevance of crack closure in this context. Finally, the effect of pre-strain on <i>da</i>/<i>dN</i> after an overload was also explained by crack closure variations.
ISSN:2075-4701