The in-plane torsion test assesses the material response in a shear stress state simultaneously for all material orientations. Together with full field Digital Image Correlation (DIC) this is a powerful experiment to investigate the large strain material response.
Mini-Punch Experiment
The mini punch experiment probes the stress state of equi-biaxial tension, which is very important when chracterizing a material.
V-Bending Experiment
V-bending probes one of the most critical stress states in the characterization of ductile fracture. Using digital image correlation the surface strains can be measured all the way to fracture.
The mini punch experiment probes the stress state of equi-biaxial tension, which is very important when chracterizing a material.
Bi-Axial Testing
A bi-axial experimental setup enables various loading conditions ranging from simple shear to plane strain tension with a so-called "butterfly" specimen. It consists of a vertical and a horizontal actuator that can be controlled independently.
Testing at the micro-scale under a microscope is the method of choice when small components (e.g. cast parts or welds) need to be assessed or if not enough material is available to test at large scale. Sample sizes can reach down to a width of 0.5mm, i.e. 20x smaller than conventional specimens.
Data from experiments is used to model the plastic response of various materials. Once the model parameters have been identified, numerical simulations are performed to further investigate the material behavior.
Finite Element Analysis is used to look at what is hidden from direct access during an experiment. With accurate plasticity models at hand, the material behavior inside a specimen can be investigated.
FEA softwares are used in conjunction with constitutive models implemented in user defined subroutines to simulate experiments at coupon or component level. The analysis, when compared with experimental data, allows to validate the accuracy of the in-house developed material models. The image below compares a mini punch experiment (top) with a numerical simulation (bottom).
Laminography, a planar computed tomography (CT) technique, allows observing internal material deformation and damage during a test (in-situ). We collaborate with Prof. Thilo Morgeneyer (Ecole des Mines, France) on this topic. The image below shows a micro-crack developing at the interface with an intermetallic that triggered macroscopic failure (aluminum alloy under shear dominated loading).
Scanning Electron Microscopy (SEM)
The SEM can obtain high quality images of objects at the micro-/nano scale. It is an essential tool to investigate the origins of the mechanisms of ductile fracture. Below, fracture of an intermetallic particle (white) drives the macroscopic failure of an aluminum alloy under shear loading.
Electron Back-Scattered Diffraction (EBSD)
Electron Backscatter Diffraction (EBSD) allows characterizing the crystalline nature (i.e. grain orientation, size and texture) of metallic materials. The image below shows the change in grain orientation in a plastically deformed region close to a crack edge.
