On fracture locus in the equivalent strain and stress triaxiality space

Bao, Yuequan; Wierzbicki, Tomasz

doi:10.1016/j.ijmecsci.2004.02.006

Cited by 1,711 publications

(817 citation statements)

References 14 publications

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“…Such a drop has been reported for other alloys by e.g. Bao and Wierzbicki [7]. Here, the local failure strain to failure in the shear test was extracted from DIC measurements.…”

Section: Failure Curve Constructionsupporting

confidence: 57%

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On the fracture locus of AA7075-T651

Fourmeau

Benallal

Hopperstad³

2010

EPJ Web of Conferences

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Abstract. The overall goal of this work-in-progress is to try to establish the fracture locus (i.e. the equivalent strain to fracture as a function of the stress triaxiality factor) for the high-strength AA7075-T651 aluminium alloy. Experiments on several specimen geometries enabled us to reach stress triaxialities in the range from ı* = 0 for shear tests to ı* = 1.4 for notched specimen tensile tests. For shear tests, failure occurred by strong strain localization. However, local stresses and strains can not be deduced directly from these tests. Consequently, Digital Image Correlation (DIC) was used to extract the local strain fields to failure. In parallel, numerical simulations of the tests were run using the non-linear finite element code LS-DYNA to extract the evolution of the local stress triaxiality during straining. Based on a combination of both experimental and numerical data, the failure locus of the material can be constructed.

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“…Such a drop has been reported for other alloys by e.g. Bao and Wierzbicki [7]. Here, the local failure strain to failure in the shear test was extracted from DIC measurements.…”

Section: Failure Curve Constructionsupporting

confidence: 57%

“…Rice & Tracey [5] and Johnson & Cook [6], while more recently curves with several branches have been proposed by Bao & Wierzbicki [7]. However, these have been somewhat criticized for its phenomenological origin, and there are still a lack of understanding of the fracture mechanisms when it comes to low stress triaxiality.…”

Section: Introductionmentioning

confidence: 99%

On the fracture locus of AA7075-T651

Fourmeau

Benallal

Hopperstad³

2010

EPJ Web of Conferences

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“…The modified ASTM sample was used to reduce the tendency of buckling under the effect of additional moments in the shear zone. In pure shear test the value of hydrostatic pressure is very small or zero as compared to the equivalent stress at fracture zone [36]. As shown in Fig.…”

Section: Validation Of the Modified Gtn Model Under Tensile And Shearmentioning

confidence: 89%

Modelling of ductile fracture in single point incremental forming using a modified GTN model

Gatea

Lü

et al. 2017

Engineering Fracture Mechanics

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A note on versions:The version presented here may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher's version. Please see the repository url above for details on accessing the published version and note that access may require a subscription. t r a c tUnderstanding the deformation and failure mechanisms in single point incremental forming (SPIF) is of great importance for achieving improved formability. Furthermore, there will be added benefits for more in depth evaluation of the effect of localised deformation to the fracture mechanism in SPIF. Although extensive research has been carried out in recent years, questions still remain on the shear and particularly its effect to the formability in SPIF processes. In this work, a modified Gurson-Tvergaard-Needleman (GTN) damage model was developed with the consideration of shear to predict ductile fracture in the SPIF process due to void nucleation and coalescence with results compared with original GTN model in SPIF. A combined approach of experimental testing and SPIF processing was used to validate finite element results of the shear modified Gurson-Tvergaard-Needleman damage model. The results showed that the shear modified GTN model improved the modelling accuracy of fracture over the original GTN model under shear loading conditions. Furthermore, the shear plays a role under meridional tensile stress to accelerate fracture propagation in SPIF processes.

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“…The design of this geometry is an evolution of the geometries proposed by Tarigopula et al [13] and Bao and Wierzbicki [14]. The advantage of this geometry is that it is relatively simple to fabricate, does not require through-thickness machining and provides a uniform shear strain distribution that can be used to resolve the shear stress response of the material.…”

Section: Introductionmentioning

confidence: 99%

Effect of strain rate on shear properties and fracture characteristics of DP600 and AA5182-O sheet metal alloys

Rahmaan

Butcher

Abedini

et al. 2015

EPJ Web of Conferences

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Abstract. Shear tests were performed at strain rates ranging from quasi-static (.01 s −1 ) to 600 s −1 for DP600 steel and AA5182-O sheet metal alloys at room temperature. A miniature sized shear specimen was modified and validated in this work to perform high strain rate shear testing. Digital image correlation (DIC) techniques were employed to measure the strains in the experiments, and a criterion to detect the onset of fracture based on the hardening rate of the materials is proposed. At equivalent strains greater than 20%, the DP600 and AA5182 alloys demonstrated a reduced work hardening rate at elevated strain rates. At lower strains, the DP600 shows positive rate sensitivity while the AA5182 was not sensitive to strain rate. For both alloys, the equivalent fracture strain and elongation to failure decreased with strain rate. A conversion of the shear stress to an equivalent stress using the von Mises yield criterion provided excellent agreement with the results from tensile tests at elevated strain rates. Unlike the tensile test, the shear test is not limited by the onset of necking so the equivalent stress can be determined over a larger range of strain.

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On fracture locus in the equivalent strain and stress triaxiality space

Cited by 1,711 publications

References 14 publications

On the fracture locus of AA7075-T651

On the fracture locus of AA7075-T651

Modelling of ductile fracture in single point incremental forming using a modified GTN model

Effect of strain rate on shear properties and fracture characteristics of DP600 and AA5182-O sheet metal alloys

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