ABSTRACT
The present paper investigates the numerical model to characterize material stress-strain law and damage evolution for cold formed Grade C450 steel. Adopting continuum damage mechanics theory developed by Lemaitre & Desmorat (2005) and the results from coupon test analyses, the deterioration with increasing strain has been examined and damage parameters have been derived. A unique approach in the range of large deformation after necking is explored with two techniques for both flat and corner regions of RHS. The first technique evaluates true stress-strain from engineering stress-strain using a weighted average method. When strains to fracture are not recorded, a second methodology devised previously by Hockett & Gillis (1970) has been extended and a new technique to derive stress/strain states to rupture from crosshead data taking into account machine stiffness has been proposed.
