Simulation of Large Deformation Elasto-plastic Impact Problems Using Two Different Objective Stress Measures

A comparative study of two different incremental objective stress measures - Jaumann stress rate measure and a new incremental objective stress - are compared for simulations of large deformation, dynamic, elasto-plastic, contact-impact problems. Elasto- plastic behaviour is modelled by an associated flow rule based on the von Mises yield criterion and power law type isotropic hardening. The material and geometric non-linearities are handled by using the updated Lagrangian method. A node-to-segment interface model is used for developing the contact stiffness matrix. Contact constraints are imposed using Lagrange multiplier method. Coulomb's friction law is used for calculating the friction forces. A finite element - finite difference scheme is used for spatial and temporal discretization respectively. Some dynamic large deformation contact-impact problems are numerically simulated. The response is computed and compared using both the Jaumann stress rate and the new incremental objective stress. It is shown that the response of the new incremental objective stress is comparable with the response of the Jaumann stress rate measure.