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Assessment of structural integrity of structures often requires investigating the combination of ... more Assessment of structural integrity of structures often requires investigating the combination of tensile (Mode I) and shearing (Mode II) or tearing (Mode III) loadings. The purpose of the this study is to shed some light on the ductile mixed-mode fracture process and its underlying mechanics. Ductile rupture of a 2024 Al Alloy thin sheet is investigated under mixed-mode loading. Mechanical tests are carried out on smooth and specific mixed-mode Arcan specimens. Test data on smooth samples are used to identify the parameters of constitutive equations describing plastic anisotropy. Digital image correlation (DIC) technique is used to measure the local displacement in the vicinity of the V-notch. Using these measurements an analysis of the effect of mixed-mode loading on ductile crack initiation is performed. Failure mechanisms are investigated using scanning electron microscope (SEM). Results are finally interpreted and modeled using a simple local approach based on the Rice and Trace...
Mechanics & Industry, 2014
ABSTRACT
Procedia Materials Science, 2014
Brittle out-of-plane cracking (by delamination or brittle tilted fracture) affects the impact tou... more Brittle out-of-plane cracking (by delamination or brittle tilted fracture) affects the impact toughness of pipeline steels. It has been investigated on notched tensile specimens using a local approach to fracture. Smooth and notched bars taken along four directions (including the short transverse direction, ND) have been tested in tension at temperatures between 20°C and -196°C. Delamination partly results from the lower value of the critical cleavage stress along ND, linked to the microtexture anisotropy, but also from the presence of ductile microcracks acting as stress concentrators triggering fracture along the rolling plane. Brittle tilted fracture was associated to a relatively lower value of the critical cleavage stress in that plane, but prior delamination was necessary to trigger it. The relevance of a macroscopic critical stress criterion for delamination is finally discussed.
Assessment of structural integrity of structures often requires investigating the combination of ... more Assessment of structural integrity of structures often requires investigating the combination of tensile (Mode I) and shearing (Mode II) or tearing (Mode III) loadings. The purpose of the this study is to shed some light on the ductile mixed-mode fracture process and its underlying mechanics. Ductile rupture of a 2024 Al Alloy thin sheet is investigated under mixed-mode loading. Mechanical tests are carried out on smooth and specific mixed-mode Arcan specimens. Test data on smooth samples are used to identify the parameters of constitutive equations describing plastic anisotropy. Digital image correlation (DIC) technique is used to measure the local displacement in the vicinity of the V-notch. Using these measurements an analysis of the effect of mixed-mode loading on ductile crack initiation is performed. Failure mechanisms are investigated using scanning electron microscope (SEM). Results are finally interpreted and modeled using a simple local approach based on the Rice and Trace...
Mechanics & Industry, 2014
ABSTRACT
Procedia Materials Science, 2014
Brittle out-of-plane cracking (by delamination or brittle tilted fracture) affects the impact tou... more Brittle out-of-plane cracking (by delamination or brittle tilted fracture) affects the impact toughness of pipeline steels. It has been investigated on notched tensile specimens using a local approach to fracture. Smooth and notched bars taken along four directions (including the short transverse direction, ND) have been tested in tension at temperatures between 20°C and -196°C. Delamination partly results from the lower value of the critical cleavage stress along ND, linked to the microtexture anisotropy, but also from the presence of ductile microcracks acting as stress concentrators triggering fracture along the rolling plane. Brittle tilted fracture was associated to a relatively lower value of the critical cleavage stress in that plane, but prior delamination was necessary to trigger it. The relevance of a macroscopic critical stress criterion for delamination is finally discussed.