In this paper an alternative J₂ material model with isotropic hardening for finite-strain thermal-structural elastoplastic analyses is presented. The model is based on a new nonlinear continuum theory of finite deformations of elastoplastic media which allows to describe the plastic flow in terms of various instances of the yield surface and corresponding stress measures in the body initial and current configurations. The approach also allows to develop thermodynamically consistent material models in every respect. Consequently, the models not only do comply with the principles of material modeling, but also use constitutive equations, evolution equations and even 'normality rules' during return mapping which can be expressed in terms of power conjugate stress and strain measures or their objective rates. Therefore, such models and the results of the analyses employing them no longer depend on the description and the particularities of the material model formulation. Here we briefly present an improved version of our former material model to model ductile-to-brittle failure mode transition of a ductile material and demonstrate the model in a numerical example using a fully coupled thermal-structural finite element analysis.

This work is supported by: VEGA 1/0740/16; RFSW project no. 26240220031