Finite-element and finite-difference simulations of the mechanical behavior of austenitic steels at different strain rates and temperatures

Presented in this paper are the computational results on deformation of austenitic steels at different strain rates and temperatures. To describe the dynamic response of steels a relaxation constitutive equation was developed using a thermomechanical physically-based model. On the base of experimental data on uniaxial loading of new steels in the range of strain rates from 0.001 to 500 s^-1 the model parameters were derived, and dynamic responses of the steels were predicted, within the range of strain rates up to 8000 s^-1 and at initial temperatures from 77 to 600 K, with the strains exceeding 60% being calculated. A plane stress analysis was performed using the ABAQUS finite-element procedure with a user-defined subroutine developed. The physically-based model was developed to take into consideration an evolution of the dislocation density and the Lüders band propagation. Plane strain simulations of thermomechanical response of HSLA-65 steel were carried out for different strain rates and initial temperatures at the initial stage of compression (strain <10%).