Background and motivation
Each structure shows a characteristic natural vibration defined by a frequency (natural frequency, eigenfrequency) and an oscillation shape (mode shape, eigenmode). If the frequencies of external vibrations acting on a structure match the eigenfrequencies, the vibration amplitude can increase strongly. It is important to avoid these resonance phenomena, because they can lead to structural destruction. One way to prevent resonance is to shift the eigenfrequencies in such a way that they do not coincide with external frequencies anymore. And that is exactly what this project is about: increasing (maximizing) structural eigenfrequencies using biologically inspired structures and optimization processes.
In cooperation with the German Electron Synchrotron (DESY) in Hamburg, the research findings will be applied to a magnet carrier structure (girder) for the new PETRA IV particle accelerator in order to achieve high eigenfrequencies and a high rigidity as well as a low mass.
Investigating the influence of structural components on the natural vibrations of structures is of great interest for many areas of application. Possible fields of application include mechanical engineering, aerospace, automotive, construction, and optics.
Objectives and approach
The project includes several small projects that are carried out:
- Influence of biologically inspired, complex lattice structures on the eigenfrequencies
- Influence of biologically inspired, complex honeycomb structures on the eigenfrequencies
- Influence of structural deformations according to the mode shapes, as can be found in diatoms, on the eigenfrequencies
- Generating a development process for an optimized, biologically inspired magnet carrier structure (girder) for the currently planned particle accelerator PETRA IV (DESY)
- Influence of biologically inspired, complex structures on the damping properties
- Formulation of general principles to maximize structural eigenfrequencies (algorithms) that are integrated into an optimization software
Some of these sub-projects have been completed and the results have been published. Please take a look at the information about each sub-project below
Talk at the “International Conference on Vibration Problems“ 2021 in Zurich, Switzerland (January 14th-15th, 2021)
"Shape Adaptation of 1D, 2D, and 3D Structures to Increase the Eigenfrequencies" (S. Andresen, S. K. Linnemann, L. M. Lottes, O. Savysko, R. Kienzler)
Within the framework of this project final theses can be carried out. Unsolicited applications are welcome and can be sent to Sandra Coordes. It is important to us that the application contains your own motivation, educational background and previous practical experience.
S. Andresen, (2021): Impact of Bio-inspired Structural Irregularities on Plate Eigenfrequencies. In: Sapountzakis E.J., Banerjee M., Biswas P., Inan E. (eds) Proceedings of the 14th International Conference on Vibration Problems. Lecture Notes in Mechanical Engineering. Springer, Singapore.
S. Andresen, L. M. Lottes, S. K. Linnemann, R. Kienzler (2020): Shape adaptation of beams (1D) and plates (2D) to maximise eigenfrequencies. Advances in Mechanical Engineering Volume 12(11). pp 1-18
S. Andresen, A. Bäger, C. Hamm, (2020): "Eigenfrequency maximisation by using irregular lattice structures". Journal of Sound and Vibration
Andresen, S. (2019): “Improving vibration characteristics by using bio-inspired structures“, In: Kesel, A.B., Zehren, D. (Eds): Bionik: Patente aus der Natur. Innovationspotenziale für Technologieanwendungen, 9. Bremer Bionik-Kongress
Andresen S. (2018): “Optimizing the PETRA IV Girder by Using Bio-Inspired Structures”, In: Schaa V.R.W., Tavakoli K., Tilmont M. (Eds): Proceedings of the 10th Mechanical Engineering Design of Synchrotron radiation equipment and Instrumentation (MEDSI’18) Conference, JACoW Publishing, Geneva, Switzerland, pp. 297-301.
Andresen, S. (2018): „Untersuchung von Eigenschwingung und Leichtbaupotenzial unterschiedlicher Gitterstrukturen am Beispiel von Magnetuntergestellen von Teilchenbeschleunigern“, NAFEMS Online-Magazin 4, 57-63