Ji Hoon Kim

TL;DR: In this paper, a constitutive model for the plastic flow stresses under various strain rates was provided, which represented both Hollomon-like and Voce-like hardening laws and the ratio between the two hardening types was efficiently controlled as a function of strain rate.

TL;DR: In this article, an apparatus was designed, simulated, optimized, and constructed to enable the large-strain, continuous tension/compression testing of sheet materials at elevated temperature.

TL;DR: In this article, a new displacement-controlled draw-bend test was developed, carried out, and simulated using a coupled thermo-mechanical finite element model, incorporating 3D solid elements and a novel constitutive law taking into account the effects of strain, strain rate and temperature on flow stress.

TL;DR: In this article, a constitutive model for describing the temperature-dependent asymmetric cyclic behavior of magnesium alloy sheets is proposed, where the asymmetric hardening behavior is classified into three modes − twinning (T), untwinning (U), and slip (S) depending on the corresponding dominant deformation mode.

TL;DR: Large-strain monotonic and cyclic loading tests of AZ31B magnesium alloy sheets were performed with a newly developed testing system, at different temperatures, ranging from room temperature to 250 °C, and a critical temperature was identified to account for the transition between the twinning-Dominant and slip-dominant deformation mechanisms.