Softening,localization and stabilization: capture of discontinuous solutions in J2 platicity

This paper exploits the concept of stabilization techniques to improve the behaviour of mixed linear/linear simplicial elements (triangles and tetrahedra) in incompressible or nearly incompressible situations. Elasto-J2-plastic constitutive behaviour has been considered with linear and exponential softening. Two diferent stabilization methods are used to attain global stability of the corresponding discrete finite element formulation. Implementation and computational aspects are also discussed, showing that a robust application of the proposed formulation is feasible. Numerical examples show that the formulation derived is free of volumètric locking and spurious oscillations of the pressure, and also that the results obtained are practically mesh independent, comparin very favourably with those obtained with the Standard, non-stabilized, approaches.