A basic approach for strain rate dependent energy conversion including heat transfer effects: An experimental and numerical study

Within this study the mechanical behavior of 1045 steel is characterized under compressive loading and at strain rates ranging from 10−3 to 103 s−1. To describe the measured behavior a new basic approach including rate dependent energy conversion under consideration of heat transfer effects is developed. Common phenomenological and semi-empiric constitutive relations are modified. A comparison of modelled and measured data shows a good agreement between measured and modelled values as well as between modified and non-modified constitutive relations. By applying this method isothermal flow curves of 1045 steel can be developed easily and show a good agreement with measured ones. The model of Zerilli–Armstrong seems to be the best approximation for this assignment. Implementing of the modified constitutive relations into FE-Software Deform2D allows to consider temperature effects by thermal decoupled simulations. A comparison of both sequentially coupled and decoupled calculations yield to identical results, whereby, by use of modified constitutive relations a reduction of computation time up to 20% is reached. The method is transferable to real forming processes with similar contact, loading and temperature conditions. Validation calculations on a simple forward extrusion process confirm these results and yield to a reduction of computation time up to 30%.