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Contribution of numerical and experimental modelling of plastic instabilities of thin sheets hydroforming. In this study, one presents experimental and numerical methodologies which aim to improve the plastic instabilities localisation induced during the 3D thin sheet hydroforming. This methodology is based on elastoplastic constitutive equations accounting for non-linear anisotropic hardening coupled to ductile damage. The experimental study is dedicated to the identification of material parameters from the global measure of tensile tests of anisotropic specimens. The validation of the procedure suggested could be carried out thanks to a confrontation between numerical simulations and experimental results obtained on thin sheets textured of mild steel. The application is then made to the simulation of hydroforming processes of these sheets with forecast of the ductile damage. Several cases of experimental and numerical tests free expansion with circular and elliptic dies and conditioned expansion in various dies are presented. Comparisons with the experimental results will be realized. [ABSTRACT FROM AUTHOR]