Naila Hfaiedh

@article{zhang_1406,

title = {Failure prediction of magnesium alloys based on improved CDM model},

author = {Kai Zhang and Houssem Badreddine and Naila Hfaiedh and Khemais Saanouni and Jianlin Liu},

url = {https://www.sciencedirect.com/science/article/abs/pii/S0020768321000214?via%3Dihub},

year  = {2021},

date = {2021-01-01},

journal = {International Journal Of Solids And Structures},

volume = {217-218},

pages = {155-177},

abstract = {The aim of this contribution is to improve the behavior and failure prediction accuracy for magnesium alloy sheet forming simulation by using advanced fully coupled Continuum Damage Mechanics (CDM) model. Starting from known fully coupled constitutive equations at large inelastic (plastic or viscoplastic) strains, three aspects are enhanced on the CDM model developed by Saanouni (2012). The first one concerns the accurate description of tension-compression asymmetry in yielding and hardening of magnesium alloys induced by combined slip and twinning deformations. The second concerns introducing the stress state dependence in damage evolution to improve the fracture prediction under various loading paths. The third deals with temperature and strain rate (viscosity) effects for metal forming processes at elevated temperatures. The improved fully coupled constitutive equations were implemented into finite element code ABAQUS/Explicit via user subroutine VUMAT including the specific local integration scheme to compute the state variables at each quadrature point. Various kinds of tensile tests at different temperatures and strain rates are used to determine the material parameters, and the complete identification procedure is given in details. As validation, the improved model is applied to simulate the three-point bending and circular cup deep drawing tests, the predicted results show good agreements with the experimental observations.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{zhang_1270,

title = {Enhanced CDM model accounting of stress triaxiality and Lode angle for ductile damage prediction in metal forming},

author = {Kai Zhang and Houssem Badreddine and Naila Hfaiedh and Khemais Saanouni and Jianlin Liu},

url = {https://journals.sagepub.com/doi/full/10.1177/1056789520958045},

year  = {2020},

date = {2020-09-01},

journal = {International Journal Of Damage Mechanics},

volume = {30},

number = {2},

pages = {260-282},

abstract = {This paper deals with the prediction of ductile damage based on CDM approach fully coupled with advanced elastoplastic constitutive equations. This fully coupled damage model is developed based on the total energy equivalence assumption under the thermodynamics of irreversible processes framework with state variables. In this model, the damage evolution is enhanced by accounting for both stress triaxiality and Lode angle. The proposed constitutive equations are implemented into Finite Element (FE) code ABAQUS/Explicit through a user material subroutine (VUMAT). The material parameters are determined by the hybrid experimental-numerical method using various tensile and shear tests. Validation of the proposed model has been done using different tests of two aluminum alloys (Al6061-T6 and Al6014-T4). Through comparisons of numerical simulations with experimental results for different loading paths, the predictive capabilities of the proposed model have been shown. The model is found to be able to capture the initiation as well as propagation of macro-crack in sheet and bulk metals during their forming processes},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{hfaiedh_505,

title = {Interaction between ductile damage and texture evolution in finite polycrystalline elastoplasticity},

author = {Naila Hfaiedh and A. Roos and Houssem Badreddine and Khemais Saanouni},

url = {https://journals.sagepub.com/doi/10.1177/1056789518775179},

year  = {2019},

date = {2019-04-01},

journal = {International Journal Of Damage Mechanics},

volume = {28},

number = {4},

pages = {481-501},

abstract = {In this paper, a multiscale model of ductile damage and its effects on the inelastic behavior of face centered cubic polycrystalline metallic materials, such as the evolution of their crystallographic textures, are investigated. The constitutive equations are written in the framework of rate-dependent polycrystalline plasticity at the microscopic scale. Plasticity and damage are coupled through a ductile damage variable introduced at the scale of the crystallographic slip systems of each grain. When homogenized to the macro-scale, this becomes an approximate phenomenological measure of the macroscopic ductile damage which can describe the material degradation by initiation, growth, and coalescence of micro-defects. In this paper, thermally activated intergranular (or creep) damage is not taken into account. Both theoretical and numerical aspects of the model are presented. The model is implemented into a generalpurpose finite element code in order to analyze the effects of texture evolution and ductile damage initiation in the grains with favorably oriented slip systems. The capability of the proposed model to predict the plastic strain localization and the induced textural evolution, as well as the effects of the ductile damage and its evolution up to the final macroscopic failure are studied for a classical tensile loading path, applied to a representative volume element and to a 3D tensile specimen on which a parametric study has been carried out.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}