Yield criterion and finite strain behavior of random porous isotropic materials
Résumé
The mechanical response of isotropic elastoplastic materials containing random distributions of initially spherical voids is investigated
computationally based on Fast Fourier Transform simulations. Numerical limit-analysis simulations at constant stress
triaxiality allow to determine the yield surfaces, leading in particular to the determination of a Representative Volume Element
size for the onset of coalescence / inhomogeneous yielding. Moreover, two different coalescence regimes are observed that differ
by the presence of shearing. The yield surfaces are found to be consistent with the combination of two models proposed in the
literature, a GTN-type model calibrated for homogeneous yielding of random porous materials and an inhomogeneous yielding
model accounting for both coalescence with or without shear. Finite strain simulations performed for different hardening moduli
and stress triaxialities under axisymmetric loading conditions confirm the existence of a RVE up to the onset of inhomogeneous
yielding. Coalescence strains are found to be significantly smaller for random porous materials than for periodic distribution of
voids. A homogenized model is finally proposed that reproduces quantitatively the behavior of isotropic elastoplastic materials
containing random distributions of voids under finite strains.
Domaines
MatériauxOrigine | Fichiers produits par l'(les) auteur(s) |
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