Modeling of Ductile Failure Based on Continuum Damage Mechanics Coupled with Anisotropic Plasticity

Ductile failure is one of the subjects that many researches on which have been done, up to now. X100 pipeline steel is one of the recently developed materials for gas transfer pipe production. Regarding the metallurgical structure and different treatments, this material has a correct balance between strength (yield stress of 690MPa) and toughness (150% true strain at failure in simple tension). Moreover this material is severely anisotropic in plastic deformation. In this article Continuum Damage Mechanics (CDM), which is a new method with high capabilities, is used to predict the failure of X100 steel. At first the CDM model is modified to take into account the effect of anisotropic plasticity (Hill quadratic plasticity), then according to damage formulations, an FE subroutine is developed to model the failure behavior of this material. Material parameters which are needed in damage and plasticity models are extracted from a series of experiments. Experiments and simulations on smooth and notched specimens show that this model has a good capability to predict the failure in different loading conditions.