Material Models and Property Prediction based on CT-Scans


Erik Glatt, Stefan Rief and Andreas Wiegmann
Fraunhofer ITWM, Kaiserslautern, Germany


Abstract 

Computer Aided Engineering of new materials

Computer Tomography (CT) images in combination with current computer hardware and new algorithms  typify the
recent advances in computerized material design. The properties can be computed directly on the  images. At the
same time, the images are useful for developing geometric material models. These parameterized  models can
produce virtual CT images, from which the properties of new materials can be predicted using  property
computations. Once model parameters with improved properties are determined, the manufacture of  the new,
superior material is worthwhile. And afterwards, CT is again the method of choice to verify that  the real material
geometry corresponds to the predicted (virtual) optimal one.
Several groups at Fraunhofer Institute for Industrial Mathematics (ITWM) use this approach in a  number of
projects, with either public or industrial funding. Some of these projects will be discussed here  under the
perspective of using CT-images. The main applications are the design of filter media, the design  and property
prediction of layers in Proton Exchange Membrane (PEM) fuel cells, and the simulation of paper  dewatering felts.
Interesting and computable are also pore size distributions, one-phase and two-phase flows,  filter efficiency and
filter life time, electrical and thermal conductivity and effective elastic properties.
To warrant the transferability of the results and the knowledge gained in these projects, all  material models and
material property computations are usable by ITWMs partners and customers through the GeoDict  simulation
software suite. See www.geodict.com.

Modeling of materials based on CT-Images

CT provides the best impression of a materialís geometry, as long as the available resolution is  just below 1 ?m
and the contrast is appropriate. Fibrous materials, also called nonwoven, found in diverse  application areas such
as hygiene, filtration or carpeting, pose challenges to CT in both respects. Synthetic fibers  often show little
contrast, and increasingly smaller fibers are used, particularly in filtration applications.  Fiber diameters that are
significantly below 1 ?m require very high resolution CT. Nonwoven models are also suitable for  fiber-reinforced
composites where the fiber-free space is simply occupied by a matrix material instead of air.  Besides fibers,
models for various components of PEM fuel cells, ceramics, woven textiles and woven wire meshes,  and felts are
considered. Figure 1 shows a variety of materials, partly as real CT and partly as virtual CT.


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Last modified: Mon Oct 11 14:00:15 W. Europe Standard 2010