Failure of AA6022-T4 sheets in hole-expansion after uniaxial prestrain

Ha, Jinjin; Dirian, Moritz; Dunn, Christopher T.; Korkolis, Yannis P.

doi:10.1063/1.5112743

Cited by 7 publications

(2 citation statements)

References 6 publications

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“…As the last plasticity characterization test, the plastic strain ratio of the RD and TD at the equibiaxial stress state, termed

, i.e.,

, is determined using the disk compression experiment [ 27 , 69 ]. A well-lubricated, coin-shaped specimen of 8 mm diameter is compressed in the thickness direction using an Instron 1350 servo-hydraulic testing machine (Norwood, MA, USA) [ 66 , 67 , 70 , 71 ]. The experiment is interrupted at several levels of compressive thickness strain and in each step, the lengths along the RD and TD are measured manually using a micrometer.…”

Section: Plastic Anisotropymentioning

confidence: 99%

Plasticity and Formability of Annealed, Commercially-Pure Aluminum: Experiments and Modeling

Fones

Kinsey

et al. 2020

Materials

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The plasticity and formability of a commercially-pure aluminum sheet (AA1100-O) is assessed by experiments and analyses. Plastic anisotropy of this material is characterized by uniaxial and plane-strain tension along with disk compression experiments, and is found to be non-negligible (e.g., the r-values vary between 0.445 and 1.18). On the other hand, the strain-rate sensitivity of the material is negligible at quasistatic rates. These results are used to calibrate constitutive models, i.e., the Yld2000-2d anisotropic yield criterion as the plastic potential and the Voce isotropic hardening law. Marciniak-type experiments on a fully-instrumented hydraulic press are performed to determine the Forming Limit Curve of this material. Stereo-type Digital Image Correlation is used, which confirms the proportional strain paths induced during stretching. From these experiments, limit strains, i.e., the onset of necking, are determined by the method proposed by ISO, as well as two methods based on the second derivative. To identify the exact instant of necking, a criterion based on a statistical analysis of the noise that the strain signals have during uniform deformation versus the systematic deviations that necking induces is proposed. Finite element simulation for the Marciniak-type experiment is conducted and the results show good agreement with the experiment.

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“…As the last plasticity characterization test, the plastic strain ratio of the RD and TD at the equibiaxial stress state, termed

, i.e.,

Section: Plastic Anisotropymentioning

confidence: 99%

Plasticity and Formability of Annealed, Commercially-Pure Aluminum: Experiments and Modeling

Fones

Kinsey

et al. 2020

Materials

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“…Beyond these works, a variety of anisotropic yield criteria, e.g., Hill '48 [14], Barlat '89 [15], and Yld2000-2D [16], or crystal plasticity, have been used in numerical simulations of HE [3,[17][18][19][20][21][22][23][24]. In some of these works, anisotropy was calibrated based on uniaxial tension tests at angles to the rolling direction (RD).…”

Section: Introductionmentioning

confidence: 99%

Hole-Expansion: Sensitivity of Failure Prediction on Plastic Anisotropy Modeling

Korkolis

2021

JMMP

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The influence of yield function parameters on hole-expansion (HE) predictions are investigated for an anisotropic AA6022-T4 aluminum sheet. The HE experiment is performed in a fully-instrumented double-action hydraulic press with a flat-headed punch. Full strain fields are measured by a stereo-type digital image correlation (DIC) system. The stress state gradually changes from uniaxial to plane-strain tension to biaxial tension in the radial direction. Besides HE, the plastic anisotropy of AA6022-T4 is characterized by uniaxial tension and plane-strain tension experiments. Uniaxial tension is considered as the most important, since it is the stress state along the hoop direction in the hole. For the finite element (FE) simulation, the Yld2000-2d non-quadratic anisotropic yield function is used with two different parameter sets, calibrated by: (1) uniaxial tension only (termed Calib1) and, (2) both uniaxial and plane-strain tension (Calib2). The strain field predictions show a good agreement with the experiments only for Calib2, which takes into account plane-strain as well uniaxial tension. This indicates the importance of biaxial modes, and in particular plane-strain tension, for the adopted yield function to produce accurate HE simulations.

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Sensitivity Study of Plastic Anisotropy on Failure Prediction in Hole-Expansion

Korkolis

2022

The Minerals, Metals &Amp; Materials Series

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Failure of AA6022-T4 sheets in hole-expansion after uniaxial prestrain

Cited by 7 publications

References 6 publications

Plasticity and Formability of Annealed, Commercially-Pure Aluminum: Experiments and Modeling

Plasticity and Formability of Annealed, Commercially-Pure Aluminum: Experiments and Modeling

Hole-Expansion: Sensitivity of Failure Prediction on Plastic Anisotropy Modeling

Sensitivity Study of Plastic Anisotropy on Failure Prediction in Hole-Expansion

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