Aalto Science Institute takes up fractal structural design with new Science Fellow
Rayneau-Kirkhope’s work explores fractal design and its theoretical limits. The research looks to mimic natural designs that have hierarchical and self-similar structures. This means that their structural patterns look roughly the same regardless of the level of magnification.
– My current work focuses on the use of hierarchical and fractal patterns to create lightweight structures that are stable under a given loading, explains Rayneau-Kirkhope.
– I find great interest in studying hierarchical structures found in nature. The optimisation process involved in creating them is generally very interesting and often not well understood.
For instance the spongy, or trabecular, bone found near joints is a prime natural example of a material of optimal stiffness, strength and minimum weight. The optimisation process of the structure of this network of struts and fibres is ongoing throughout the lifetime of the bone and results in complex hierarchical designs. These Rayneau-Kirkhope strives to mimic and to investigate their theoretical limits with the calculative methods of statistical physics.
Most recently, Rayneau-Kirkhope has analysed compression-bearing structures that can in principle have any degree of hierarchy. He developed a theoretical framework for an optimal hierarchical order that a structure needs in order to withstand a given load.
By optimising these structures on all length-scales Rayneau-Kirkhope and his colleagues were able to show considerable efficiency compared with conventional designs. Their work was published in the journal Physical Review Letters in November 2012.
– Through varying the hierarchical order of the structure, we can systematically vary the scaling of a material against the loading that must be withstood.
With rapid prototyping techniques – an advanced form of 3D printing – Rayneau-Kirkhope was also able to verify the plausibility of the designs they calculated.
Rayneau-Kirkhope’s work also predicts highly efficient metamaterials, which could be fully optimised for a variety of load-bearing situations.
– One of the biggest positives in the AScI fellowship is the relative freedom to pursue a variety of academic work. From my perspective the main goals are to continue to explore the possibilities of hierarchical design but also to start looking at more general optimisation procedures, Rayneau-Kirkhope expects.
– I am hoping to collaborate with numerous groups during my time here.
Ultralight Fractal Structures from Hollow Tubes (Physical Review Letters)
Ultralight fractal structures could bear heavy loads (physicsworld.com)
Focus: Fractal Structures Do More with Less (physics.aps.org)
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