Mechanical instabilities in higher order molecular self-similar structures

Many hierarchically structured materials found in nature are built according to the principle of self-similarity. Mimicking this principle to develop new molecular structures is becoming increasingly realistic due to modern synthesis techniques. The use of self-similar structures in nanotechnological applications requires that their complex mechanical behavior can be understood, represented in mathematical models, and reliably predicted using computer-aided simulations.

The goal of this project is to gain fundamental insights into the cause and effect of mechanical instabilities in higher-order self-similar structures - using the example of the 'super' carbon nanotubes recently introduced to the scientific community. Mechanical instabilities, such as the initiation and propagation of defects or rod-like buckling and shell-like buckling, can lead to failure of the overall structure. The interaction of such phenomena across multiple hierarchical levels will be studied in detail here. Since the atomistic models commonly used at the molecular level are inefficient for higher order structures, novel cross-scale models are developed by exploiting self-similarity. In the course of numerical implementation, these models are then embedded in the formalism of the finite element method.

The knowledge gained from the project is expected to make important contributions in the development of novel bottom-up materials with hierarchical structure.