Advanced characterization on the yield and hardening behavior of sheet metal at torsional load using digital image correlation and back calculation methods
Sprache des Vortragstitels:
Englisch
Original Tagungtitel:
ACEX2019 - 13th International Conference on Advanced Computational Engineering and Experimenting
Sprache des Tagungstitel:
Englisch
Original Kurzfassung:
The in-plane torsion test represents an appropriate test method for material characterization of
sheet metal in terms of yielding and calibration of kinetic hardening laws. For this a torsion test rig was build
up at the institute of structural lightweight design at the Johannes Kepler University Linz. Torsion tests using
different sheet metals have been conducted using this test rig. Compared to the corresponding uni axial tensile
test, the in-plane torsion test provides measurement data up to higher levels of equivalent strain. A
challenge represents one more the analysis of the shear- and equivalent strain. There are several methods on
strain analysis based on the gained raw data existing.
The main focus in terms of strain investigation in this contribution is set on a DIC supported strain
analysis method based on distortion tracking of single points on the specimen. Due to the in- plane situation
the distortion tracking of single points on the specimen is possible by using 2D image correlation software. The
used test stand is designed in a way that pictures from the area of deformation can be taken during the test by
using a common reflex camera. Usually a statistic pattern has to be brushed on the specimen for tracking single
points on the specimen by using digital image correlation software. Tests with different sheet metals, performed
on the torsions test stand, showed that the resolution of the taken pictures, together with the inherent pattern of
the specimen is sufficient for the use of common 2D image correlation software. So there is no need to brush
additional statistic pattern on the specimen for the use of 2D image correlation software in terms of distortion
tracking. This contribution discusses an approach of shear strain evaluation based on experimental data out of
the torsional test by using digital image correlation methods.