Effect of Tensile Pre-strain and Specimen Orientation on Tearing Resistance Parameters of DP 780 Steel Sheet Determined Using Essential Work of Fracture Method

Essential work of fracture (EWF) concept has been used to characterize the tearing resistance of a 1-mm-thick automotive grade dual-phase 780 steel sheet. The present study has been done to observe the effect of tensile pre-strain, specimen orientation and notch root radius on tearing resistance parameters obtained from EWF testing of double-edge notched tensile (DENT) specimens. Additionally, the estimated crack tip opening angle (CTOA, ψe) obtained through EWF testing has been compared with its fracture mechanics counterpart, i.e., stable crack tip opening angle value (φc) obtained via an experimental route using DENT specimens, adopting the essence of the standard CTOA testing procedure prescribed in ASTM 2472.