Fraunhofer Institute for Industrial Mathematics ITWM
Fraunhofer Institute for Industrial Mathematics ITWM
Experiment zur Schaumausdehnung durch maschengestrickte Textilien an der TU Chemnitz
© TU Chemnitz
Verschiedene Testergebnisse des Experimentes zur Schaumausdehnung durch maschengestrickte Textilien an der TU Chemnitz

Foam Expansion

We simulate the predicted foam expansion through knitted textiles with the help of our platform CoRheoS and compare the results with the experimentally produced Polyurethane foams by the TU Chemnitz.

© TU Chemnitz

RIM Processes of Polyurethane Foams to Develop Composite Materials

Project FoamInTextil

Composite structures are considered to be lightweight and stable. Textile reinforced composites materials made from polyurethane (PU) foams are perfect candidates due to their enhanced physico-mechanical characteristics. Using the FOAM software in our CoRheoS simulation platform, we can simulate the form filling process.

 

PU-Foams are Complex and Difficult to Study

In the RIM process (Reaction Injection Molding) of PU foams, a polymer mixture is injected into a mold in which the material develops over a period of time from a low molecular weight emulsion to a complex polymer foam matrix via polymerization.

A comparison of the foam expansion shows the great consistency of the experimentally produced foam at the TU Chemnitz and our prediction simulated by our platform CoRheos.
© TU Chemnitz / Fraunhofer ITWM
A comparison of the foam expansion shows the great consistency of the experimentally produced foam by the TU Chemnitz and our prediction simulated with our platform CoRheos.

The expanding foam exhibits complex physical behavior during the production phase, which is initiated by premixing adequate reactants followed by gas and heat creation as well as evolution of material properties resulting in PU foam formation. This makes PU foams extremely difficult to study. We design mathematical models that describe the dynamics of expanding foams and apply them to study the RIM process of PU foams.

 

Developing Optimal Simulation Tools for Industrial Applications

Using our FOAM software, we carry out relevant numerical studies to understand and evaluate the foam expansion process. In this way, we are able to predict the required amount of material to completely fill the mold as well as optimize the foam process and mold design. 

In order to investigate the expansion process in textile structures, especially knitted spacer fabrics, we use TexMath to determine the relevant permeability tensors. TexMath is an in-house developed software product for the modeling and analysis of textile materials. The spatial variations of the tensors caused by unequal compression of the structure can be analyzed by TexMath. We then use this data in FOAM and extend our numerical studies to predict the foam expansion through knitted textiles.

Our findings are in strong agreement with the experimental data obtained at the Chair of Structural Lightweight Structures and Plastics Processing at Chemnitz University of Technology. In summary, we provide simulation tools for efficient industrial application that help in the optimization, manufacture, and development of composites.

Employees of the TU Chemnitz produced a Polyurethane foam with the help of a RIM Process (Reaction Injection Moulding).
© TU Chemnitz
Employees of the TU Chemnitz produced a Polyurethane foam with the help of a RIM Process (Reaction Injection Moulding).

Our Software Solutions

For the simulation of the foam filling process we used the following software solutions:

FOAM

Our FOAM solver simulates the expansion process of PU foams in any given geometry and offers the possibility to calculate the foam formation process as well as the resulting foam density in advance.

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TexMath

The software is used for the modeling and simulation of fiber structures and technical textiles.

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