Edge tracing technique to study post--necking behavior and failure in
Al--alloys and anisotropic plasticity in line pipe steels
Abstract
The recently developed Edge Tracing (ET) method allows to estimate the
radial deformation in axisymmetric tensile specimens via analysis of
digital images recorded during the experiments. Images are processed to
detect the sample’s contours and therefore, estimate the minimal
cross–section diameter. This technique was mainly developed to
characterize the elastic–plastic behavior well beyond the necking
strain. The aim of this work is to extend the ET method to two case
studies. Firstly, the post–necking behavior and failure of a low
ductility Al–alloy are investigated. Low ductility alloys tend to fail
brutally after reaching the maximum load. The major result is the
capture of the sharp load drop which allowed to calibrate parameters of
a GTN damage model. Secondly, the anisotropic elastic–plastic behavior
of a “vintage” line pipe steel is characterized by a direct
measurement of the Lankford coefficient. Assembled experimental data
allowed to model the anisotropic plasticity in different loading
directions.