Modelling Concept Based upon Axially Symmetrical Models

Abstract

The present chapter presents identification strategies of yield stress investigation of steels based on tensile and compression tests at very high temperatures as well as in the semi-solid state. The methodologies of stress-strain curves investigation combine the possibility of direct simulation using the Gleeble 3800 thermo-mechanical simulator with the developed dedicated DEFFEM system with implemented axial-symmetrical solutions. The constitutive parameters identified by these procedures have been successfully applied in additional three-dimensional tests (see Chap. 9). Due to very high sensitivity of the material rheology to temperature changes, the testing procedure requires as uniformly distributed temperature as possible. As part of the research aimed at the development of the foundation of the methodology for determining the mentioned stress-strain relationships, comprehensive tests were performed covering the influence of the applied grips on the temperature distribution along the heating zone and in the sample cross-section, as well as macro- and microstructural tests, and comprehensive tomographic tests. The findings of the conducted tests allowed the obtained computer simulation results to be verified. The computer simulations were performed using the modelling concept based upon axially symmetrical models.