Simulation of necking using a damage coupled finite element method

Necking is a strain localization phenomenon that can cause catastrophic fracture in metal forming. Therefore, the prediction of necking is important. In the present work, an elasto-plastic constitutive equation accounting for isotropic hardening coupled with damage is implemented in the finite element code ABAQUS. A damage variable, that provides a mesoscopic description of material degradation, is used to quantify the degree of damage due to excessive strain. Using the implicit integration scheme, a cylindrical rod loaded under uniaxial tension is successfully simulated by the finite element code with a specially designed user-defined material subroutine (UMAT). In addition, the distribution of damage caused by the deformation is computed.