Tracking Down the Fracture Phenomenon: From Elementary Events to Propagation
Guest Speaker：Assoc. Prof. Franz Bamer, Group Laeder, RWTH Aachen University, Germany
Inviter: Assoc.Prof. Feili Lai
Date&Time: Friday, 25 September, 10:00-11:00
Venue: Yiucheng Lecture Hall（500）, Xu Zuyao Building
Biography:
Dr. Franz Bamer is an Associate Professor and independent group leader in Computational Mechanics at the Institute of General Mechanics, RWTH Aachen University, Germany, where he leads a research team working across solid mechanics, structural dynamics, nanomechanics, and machine learning. His work bridges scales, from atomistic simulations of disordered materials such as silica and metallic glass to model order reduction techniques for large-scale infrastructure systems.
Franz began his career as a construction engineer in Vienna before pursuing doctoral research at TU Wien, where he earned his PhD with distinction in 2014 under Prof. Christian Bucher, and later served as a postdoctoral researcher and lecturer there. He joined RWTH Aachen University in 2015, rising to independent group leader in 2019 and completing his habilitation in Mechanics in 2025 with a thesis titled "From Nanostructure to Infrastructure." He has held visiting research positions at Johns Hopkins University (USA) and Huazhong University of Science and Technology (China).
Franz has authored 58 peer-reviewed journal articles (h-index 26 on Google Scholar) and secured more than €760,000 in competitive DFG funding as principal investigator. He received a Theodore von Kármán Fellowship and is a two-time recipient of the Open Seed Fund within the excellence initiative of Germany. He has taught extensively across bachelor's and master's programs in English and German, and co-organized the 2022 GAMM conference, which drew 1,200 participants. Outside the lab, Franz brings the discipline of a former competitive swimmer — with several regional and national titles — to his research career.
Abstract:
While crystalline solids are well understood using long-developed frameworks such as crystal plasticity, our understanding of the deformation of disordered solids remains embryonic. In this presentation, we will break down the inelastic deformation of disordered solids into elementary events using athermal quasistatic molecular mechanics simulations. Such elementary events occur in preexisting point defects hidden in the material matrix. We present several strategies to identify such defects before mechanical loading using thermodynamic and purely geometrical indicators. To obtain susceptibility maps of regions prone to atomic-scale rearrangements, we present a strategy that predicts fracture propagation along minimum-cost energy paths. We present our methodologies on two-dimensional silica structures that are statistically equivalent to imaged two-dimensional silica samples. This way, we can predict fracture propagation from purely geometrical input data without considering any information about the potential energy landscape.