High strain properties of advanced high strength spot welded steels

Abstract

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] This research was conducted to investigate and characterize the high strain rate compressive loading behavior of DP600 GI, an advanced high strength spot welded steels, using the split Hopkinson pressure bar or the Kolsky bar apparatus. The high strain rates properties of weldments are needed to evaluate the mechanical response of a spot welded structure, such as an automobile body, when subjected to dynamic loads during a crash or other dynamic inputs. The true stress-strain response of the spot welds and the parent sheet metal was obtained by analyzing the strain history obtained from the Hopkinson bar and using the Johnson-Cook constitutive model. The findings provide an understanding of the differences between the strain rate sensitivity of the base metal and weld metal. The effect of strain rate on the microstructure and microhardness of the various materials was also examined.