In this paper, a new approach is proposed for stress state - dependent flow localization in bifurcation failure model bounded through ductile damage in dynamically loaded sheets. Onset of localized necking is considered in phenomenological way for different strain rates to draw the forming limit diagram (FLD). Using a strain metal hardening exponent in the Vertex theory related to the strain ra...

Tensile stress-strain curve is of high importance in mechanics of materials particularly in numerical simulations of material deformations. The curve is usually obtained by experiment but is limited by necking phenomenon. Engineering stress-strain curve is converted to true stress-strain curve through simple formulas. The conversion, however, is correct up the point of necking. From this point ...

Forming limit curves (FLCs), which are constructed using the strains at localised necking, most widely used tools for evaluation of formability sheet metals. Fracture forming (FFLCs) more recently developed, complementary instead fracture. Since depends strongly on conditions such as strain state, temperature and rate, models predicting FLCs FFLCs essential optimisation further application hot ...

Low, intermediate and high strain rate tensile experiments are carried out on flat smooth, notched and central-hole tensile specimens extracted from advanced high strength steel sheets. A split Hopkinson pressure bar testing system is used in conjunction with a load inversion device to perform the high strain rate tension experiments. Selected surface strains, as well as local displacements, ar...