What holds materials together -- on the inside
Everyone knows what happens if you drop a coffee cup – it usually shatters into several pieces. Ideally, we just smile and say 'break a thing, mend your luck'. However, the consequences of material fracture if it occurs in aeroplanes, ships or trains are far more serious and can cost lives, such as in the example of the ICE rail disaster in Eschede in Germany 20 years ago, which was caused by a wheel fracture. The German Research Foundation (DFG) has now approved a new research training group at Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) that is researching precisely this topic.
'A fracture is the result of a series of fracture processes. We want to conduct research into these processes in materials across all scales ranging from cracks visible to the naked eye right down to the atomic level in the nanometer range,' says Prof. Dr. Paul Steinmann, Chair of Applied Mechanics and speaker of the new research training group 2423 FRASCAL, which stands for Fracture across Scales. The group is dedicated to the complex interdisciplinary area of materials engineering. The DFG has now approved funding of 5.5 million euros for this research for a period of four and a half years.
Part of this research will be on plastics as materials that are gaining in significance and that are helping to make aeroplanes lighter and thus improve their fuel efficiency. In contrast to metals (such as the fractured train wheel), the fracture behaviour of plastics has not yet been researched to the same extent and by so many different areas as is now the case in the new FRASCAL research training group.
'FRASCAL is developing computer-aided simulation methods in 12 projects that can record the properties of fracture processes on various length scales,' explains Steinmann. 'We want to improve our understanding of fracture processes to such an extent that we are able to prevent undesired fractures from occurring and also use them for our benefit in certain applications.' In the case of the latter, this means processing coarse-grained granulates in a targeted way and turning them into powders with specific properties – from a lump of rock into fine sand as it were.
The multidisciplinarity of this research training group is what makes it special. The FRASCAL consortium consists of physicists, chemists, mathematicians and engineers. Thanks to interdisciplinary collaboration, the scientists involved can research what influences fracture behaviour from various perspectives. For example, mathematicians work in teams with materials scientists or chemists work with mechanical engineers.
'The scientists complement each other while still working on the FRASCAL team.' As FRASCAL is a research training group, particular emphasis is being placed on allowing doctoral candidates to carry out top-level research in this interdisciplinary setting which will then lead to a doctoral degree. The advanced teaching programme is designed to allow every researcher to gain some knowledge from the other subjects involved. This is supplemented by further training in soft skills or career planning.
The planned duration of the research training group is nine years in total. A total of eleven doctoral candidates and one postdoctoral candidate will carry out research during the first phase that has now been approved. 'We hope to train over 30 doctoral candidates during the entire duration of the research training group'.
FAU Press Office