Foams

The outstanding properties of foams make them suitable for a wide range of applications. Foams play an important role in the design of lightweight components, due to their low density:

• Structural foams - for example, made from PMI (polymethacrylimide) or PET (polyethylene terephthalate) - are processed together with composite materials to form sandwich components commonly used in industries such as aviation.
• Particle foams - such as expanded polystyrene (EPS) or expanded polypropylene (EPP) - can be used to produce molded parts for the packaging industry.
• Metal foams are used as crash absorbers in vehicles, protective devices in sports equipment and impact protection in industrial plants. Their advantages are high energy absorption, mechanical and thermal strength and low weight, making them efficient materials for these applications.
• Some foams - such as EPP or metallic foams - are also suitable for use in crash absorbers, due to their high energy absorption.
• Polymer foams are a typical insulating material due to their cellular structure which largely includes trapped air.

Um die typischen Kennwerte all dieser Schaumstoffeigenschaften zu ermitteln, ist ein immenser Versuchsaufwand erforderlich. Die Einflüsse unterschiedlicher Parameter wie Zellgrößen, Zellwanddicken oder Zellverteilung zu Beginn des Herstellungsprozesses zu ermitteln, ist ohne größere Anpassungen eine schwierige bis unmögliche Aufgabe.

Digital material design with GeoDict allows to change and optimize all these parameters in the computer, before manufacturing any prototypes. Only the most promising configurations are then produced as prototypes and for validation.

The GeoDict software is a digital material laboratory that offers a user-friendly complete solution for the development of tailor-made foams. In this digital workflow, samples of existing materials are scanned in a µCT and the data is imported into the software to create a 3D structure model. Then, a complete analysis of the geometric properties, such as cell size and cell size distribution, is carried out on the 3D structure model.

When no image data is available, complex microstuctures may be generated using the FoamGeo and GrainGeo modules of GeoDict. Then, the macroscopic material properties of the foam can be computed and predicted, based on the properties of the digitized microstructure model. A large number of solvers are developed in-house and available for this purpose - for example, for structural mechanics, conductivity, or fluid mechanics.