Collège de doctorat en Sciences de l’Ingénieur Architecture – Géologie- Construction

This numerical investigation of an advanced Gurson–Tvergaard–Needleman(GTN) model is an extension of the original work of Ben Bettaieb et al. (2011). The model hasbeen implemented as a user-defined material model subroutine (VUMAT) in the Abaqus/explicitFE code. The current damage model extends the previous version by integrating the threedamage mechanisms: nucleation, growth and coalescence of voids. Physically based voidnucleation and growth laws are considered, including an effect of the kinematic hardening.These new contributions are based and validated on experimental results provided by high-resolution X-ray absorption tomography measurements. Also, the numerical implementation ofthe kinematic hardening in this damage extension has obliged to readapt the classical triaxialitydefinition. Besides, a secondary fracture initiation criterion based on the ultimate average inter-cavities distance has been integrated to localize and quantify with good accuracy the straindistribution just before the material fails apart. The current damage model is applied in industrialconditions to predict the damage evolution, the stress state and the fracture initiation in varioustensile thin flat sheet geometries and the cross-die drawing tests.