Experimental Evaluation of Ductile Fracture of Sheet Metals under Plane
Stress States
Abstract
The four variables Mohr-Coulomb model was established to study the
ductile fracture of metal sheets under plane stress states. Beginning
with the recorded minor and major strain distributing on the deformation
area of uniaxial tension samples, a series of key parameters relative to
the M-C model, including strain ratio, stress triaxiality, Lode angle
parameter and equivalent strain during all the loading period have been
studied for their inherent relationship, by utilizing Moving Regression
algorithm. Then the determined M-C model could be described as the
function of equivalent ultimate strain against the stress triaxiality.
In the present study, three types of samples including 0° pure shear,
45° shear-tension and regular tension were testified suitable to
numerically resolve the W-shaped M-C curve. M-C model and its
transformed curve constructed in the minor/major strain
Cartesian-coordinate could extend the conventional FLC into the field of
shear loading, providing a guide to assess the material resistance
against the ductile failures under various plane stress conditions.