Berlin 2018 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 25: Topical Session (Symposium MM): Fundamentals of Fracture

MM 25.5: Talk

Tuesday, March 13, 2018, 12:45–13:00, TC 006

Precursors of fracture and failure in hierarchical materials — •Paolo Moretti, Bastien Dietemann, and Michael Zaiser — Friedrich-Alexander-Universität Erlangen-Nürnberg

Hierarchical materials are characterized by repeated microstructural features, which appear at different length scales in a self-similar fashion. Biological materials provide important examples of this type of hierarchical arrangement: connective tissue exhibits a hierarchical fiber organization which at different length scales comprises molecules, microfibrils, fibers, and fiber bundles. We study precursors of failure in hierarchical network models of of hierarchical materials where fibrous assemblies are held together by multi-level (hierarchical) cross-links. Our large-scale simulation study shows that when such structures are loaded towards failure, precursory avalanche activity displays generic scale invariance: irrespective of load, precursor events (avalanches) exhibit broad, power-law distributions of sizes without apparent cut-offs. We argue that this behavior can be traced back to the hierarchical microstrcuture, whose construction parameters can be harnessed in order to tune precursor activity and failure. This complex scenario results in super-rough crack morphologies, with large deflections that are reminiscent of crack shapes as encountered in biological materials.