Advanced characterization on the yield and hardening behavior of sheet metal at torsional load using digital image correlation and back calculation methods

Description

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.

Period	04 Jul 2019
Event title	ACEX2019 - 13th International Conference on Advanced Computational Engineering and Experimenting
Event type	Conference
Location	GreeceShow on map