Good Vibrations

Investigating the influence of structural components on the natural vibration of structures is of great interest for many applications. Possible fields of application include mechanical engineering, aerospace, construction and optics.

In nature, there are various regular and irregular lattice and honeycomb structures, which often fulfil different functions. The shells of marine unicellular organisms in particular show a great variety of such geometries. For example, the silicate shells of diatoms are very light and permeable and reveal at the same time high strength. Furthermore, the structures are expected to exhibit special vibration properties due to their structural irregularities in in order to protect the algae from external vibrations caused by predators.

This project investigates how a directed use of these structural irregularities influences the vibration properties favorably. In cooperation with the German Electron Synchrotron (DESY) in Hamburg, the magnet underframes of a new particle accelerator PETRA IV will be optimized in order to achieve a high first natural frequency and stiffness as well as a low mass (http://photon-science.desy.de/facilities/petra_iv_project/index_eng.html).

In first studies, parametric constructions of various three-dimensional lattice and honeycomb structures were carried out using algorithms that generate structures based on biological structures. The use of multi-criteria optimization calculations using the evolution strategy allowed the discovery of best possible parameter combinations to achieve the desired properties. The results showed a high potential of the lattice and honeycomb structures to influence the vibration properties of structures. More precisely, structures of equal stiffness and different first natural frequency could be developed, whereas the masses always remained within a permissible range. In general, irregular structures led to significantly higher natural frequencies and stiffness than regular structures. Further approaches to the generation and modification of irregular structures, including the use of topology optimization, confirmed their potential to positively influence the natural frequencies of lightweight structures.