Unified viscoplasticity modelling for a SiMo 4.06 cast iron under isothermal low-cycle fatigue-creep and thermo-mechanical fatigue loading conditions

•A unified viscoplastic model is proposed for SiMo 4.06 between 20 °C and 650 °C.•Low-cycle fatigue-creep and thermo-mechanical fatigue tests are simulated.•The model is based on non-linear kinematic hardening and hyperbolic sine flow rule.•Mean stress evolution and effect of static recovery are incorporated.•Strain range dependency is suggested for isotropic hardening and for elastic modulus. In this paper, a SiMo 4.06 cast iron is subjected to Low-Cycle Fatigue (LCF) loading and Thermo-Mechanical Fatigue (TMF) loading in the temperature range between 20 °C and 650 °C. Strain-controlled experiments were performed for various strain rates, with and without a tensile strain dwell. A modified unified viscoplastic material model is proposed for simulating the temperature- and time-dependent cyclic behaviour of the material. The constitutive model is based on the non-linear kinematic hardening rule of Chaboche, in which several features are added in order to incorporate strain rate sensitivity, the strain range dependency of the cyclic hardening and the elastic modulus, static recovery and mean stress evolution. A good correlation was achieved between the simulated results and the experimental results.