In this project, we aim to investigate
the micromechanical deformation of the fiber network in two cases: under
in-plane compression and during cyclic changes of the ambient humidity.
In-plane compression is present in multiple forming processes, like
and deep drawing. The in-plane compressive behavior is decisive for the
performance of the material in the forming processes. However, only a little
research has been done on this load case and standardized testing procedures
don’t give insight into the deformation on the network and a fiber scale.
The interaction of moisture and the structure of the paperboard is an important
aspect of the materials behavior because packaging materials are exposed to
varying humidity in many applications. The micromechanical aspects of
hygroexpansion and the mechanisms behind dried-in strains are however not
Two in-situ devices for the applications have been constructed and
build. Pre-trails of the in-situ devices have been performed using laboratory
μCT scanners. The superior phase contrast, scanning time and resolution of
synchrotrons in comparison to laboratory x-ray sources promise a better
image quality for the subsequent segmentation of the fibers. Therefore, two
applications for beam time at DESY in Hamburg were filed and currently, the
experiments are prepared for the acquisition.
Malte Wallmeier is a post-doc at KTH, Stockholm. The purpose of his short visit
is to start a collaboration concerning the analysis of images he is going to
present during his talk.