My work is about design, production and mechanical characterization of microarchitectures. Miniaturized structural design which is optimized according to the loading situation, enables to benefit from mechanical size effects occurring in the nanometer scale. Thus, cellular materials with both high strength and low density may be fabricated. Main focus of the work is on the structural design and investigation of the mechanical size effect, as well as their interaction.
It has been a long-standing effort in engineering to create materials with low density but high strength. In the last century, major advancements have been made in optimizing classical lightweight materials such as aluminum alloys or composite materials with respect to these properties. However, the lightest solid materials have a density in the range of 1 g/cm³. Certain natural cellular materials such as bone and wood, on the other hand, remain strong despite having considerably lower densities. They have an optimized architecture and their basic material is hierarchically structured, actually consisting of nanometer-size building blocks, providing enhanced material strength because of size dependent effects.
Applying 3D laser lithography, which allows for producing almost arbitrary structures with sub-micron resolving power, micro-truss and –shell structures may be manufactured. In conjunction with conformal coating techniques multi-material designs can be fabricated. It has been shown that such artificially created cellular materials exceed the strength-to-weight ratio of all natural and engineering materials with a density below 1 g/cm³. Ratios comparable to those of advanced metallic alloys or technical ceramics have been obtained.