Regensburg 2022 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 10: Poster Session 1

MM 10.17: Poster

Montag, 5. September 2022, 18:00–20:00, P2

Kinetic trapping in brittle crack opening — •Tobias Müller and Bernd Meyer — Interdisciplinary Center for Molecular Materials and Computer Chemistry Center, FAU Erlangen-Nürnberg, Germany

In the 1920s, Griffith introduced his continuum approach for fracture. Since then great efforts were made to describe crack propagation more precisely within continuum mechanics. Nevertheless, it is evident that the atomic structure of the crack tip itself plays a major role in crack advancement, thus making it necessary to extend the concept of Griffith to the discrete atomic level. This enables the possibility to investigate essential and material-specific processes, such as local bond rearrangements and path-dependent activation barriers. In general, crack opening is a complex chemical process on a multi-dimensional potential energy surface with many local minima and saddle points. The complexity even increases if parameters such as temperature, pressure or chemical environments are included. Here we discuss first DFT-based geometry optimizations for silicon to study brittle fracture mechanics. We show that cracks can propagate via a multitude of local energy minimum configurations connected by a variety of energy barriers. We highlight the complex nature of crack advancement and the complexity of modelling and finding the correct fracture pathway even for a material with a simple crystal structure such as silicon.