In this thesis, ductile damage criteria available in the finite element commercial code ABAQUS were evaluated, first. For this propose, a few two dimensional benchmark problems and three dimentional metal forming processes were considered. After the simulatio results of damage evolution, crack initiation and fracture modes were predicted. By comparing numerical simulations and reported experimental tests appropriate models for predicting the damage evolution in sheet metal forming processes were determined. Then, Lemaitre's ductile damage model was selected due to its simplicity and its damage parameters for DIN 1623 St14 steel were determined by using standard tensile and Vickers micro-hardness tests.A fully coupled elastic-plastic-damage model based on Lemaitre's ductile damage model was developed and implemented into ABAQUS explicit code. Due to using the plane stress and finite strain theories, model can quickly and accurately predict deformation and damage of parts. Also, damage initiation, propagation, and fracture in some sheet metal forming operations were predicted and validated with experimental tests. Comparison of the results showed that finite strain combined with continuum damage mechanics can be used as a quick and accurate tool to predict ductile damage, fracture, and forming limits in sheet metal forming processes. Keywords ductile damage, plane stress, finite strain, fracture, sheet metal forming.
