In this paper a numerical study of solid bar behavior under various mechanical loads is presented using fully coupled thermal structural analysis with large strain / large deformation formulation. The analysis is based on a new energy conservation equation [
], which the authors believe represents the most complete formulation of the first principle of thermodynamics in contemporary computational mechanics. In the numerical analysis was used the finite element method (FEM), utilizing the updated Lagrange method and the extended NoIHKH material model [
], modified for large strain / large deformation cyclic plasticity of metals. In the stress update calculation [
] was used the Jaumann objective rate in the form of the Green-Naghdi objective rate, formulated with the aid of the rotated Cauchy stress tensor. The rotation tensor was expressed with the Rodriguez formula. The case was implemented into a finite element code using “proper” linearization, which means that no simplifications were used in a gradient or an element volume expression in the current configuration. The presented results represent some of the first outcomes of the fully coupled thermal structural analysis utilizing the new energy conservation equation with large strain/ large deformation formulation, which the authors consider to be positive. The new energy conservation equation can still be improved by introducing a heat source in it to take into account the amount of energy dissipated into heat during plastic deformation, but to propose a mathematical formula for the heat source is rather an experimental problem than a mathematical one. If the new energy conservation equation proves to be experimentally correct, in the future more complex problems will be able to be solved, mainly in the area of fast/ultra fast thermoelasticity or thermoplasticity.