Improved prediction of strain distribution during mechanical and hydro-mechanical deep drawing processes using microstructure-based dynamic strain hardening and anisotropy

Abstract

Interstitial free (IF) and drawing quality (DQ) steel sheets were subjected to conventional mechanical deep drawing and hydro-mechanical deep drawing operations. Detailed macroscopic strain measurements were made at different cup depths. These were simulated using PAM-STAMP, a commercial finite element–based software. For continuum-based finite element simulations, the required key material properties are strain hardening exponent (n) and anisotropy index ( $\overline{r}$ ). These were kept either constant or dynamically varied during the simulation. The constant properties were taken from conventional tensile tests of the original material, while the dynamic variation in properties was extrapolated from developments in the crystallographic texture and in-grain misorientation. Considering dynamic properties during simulation provided a superior prediction of macroscopic strains. This study clearly demonstrates the need for considering evolution of critical continuum properties, such as work hardening and anisotropy index, through appropriate microstructural inputs for more realistic macroscopic predictions.