A thermomechanically coupled material model for TRIP-steel

• Strain rate dependency of TRIP-steel is studied using a thermomechanically coupled model.
• Thermodynamical restrictions are shown and an appropriate heat equation is derived.
• Temperature dependent parameters of the model are determined at low strain rates.
• Tensile tests at elevated strain rates are simulated with the gained model parameters.
• Good agreement is observed between simulations and experimental data.

The transformation behavior of TRIP-steels is strongly dependent on temperature. Especially inelastic deformations lead to a temperature rise, if the heat cannot be dissipated, for instance under high strain rate loadings. Therefore, realistic mechanical models for TRIP-steel need a thermomechanical coupling to take the interaction between strain rate and transformation behavior into account. The objective of this study is the investigation of the thermodynamical consistency of an material model for a high alloyed cast TRIP-steel and the formulation of an appropriate thermomechanical coupling approach. The discussion is given in the framework of thermodynamics of inelastic processes for small deformations. Subsequently, the gained heat equation is adapted to large deformations. A parameter identification procedure is performed to determine the temperature dependent material parameters at low strain rates. Furthermore, a numerical example is given using the identified parameters for a thermomechanical coupling analysis at elevated strain rates. The simulation results at elevated strain rates are in good agreement with experimental data. Therewith, a future support of structure design through simulations is possible.