SKM 2021 – wissenschaftliches Programm
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SYAM: Symposium Amorphous materials: structure, dynamics, properties
SYAM 1: Amorphous materials: structure, dynamics, properties
SYAM 1.4: Hauptvortrag
Dienstag, 28. September 2021, 15:15–15:45, Audimax 1
Signatures of the spatial extent of plastic events in the yielding transition in amorphous solids — •Celine Ruscher1,2, Daniel Korchinski2, and Joerg Rottler2 — 1Institut Charles Sadron, Strasbourg, France — 2Stewart Blusson Quantum Matter Institute, The University of British Columbia, Vancouver, Canada
Amorphous solids are yield stress materials whose flow consists of periods of elastic loading interrupted by rapid stress drops, or avalanches, coming from microscopic rearrangements known as shear transformations (STs). From the microscopic point of view, the density of STs, or density of local residual stresses, P(x), governs the statistical properties of global collective failure events at the yielding transition.
Using atomistic simulations, we reveal the evolution of P(x) upon deformation. A pseudogap form P(x) ∼ xθ is observed in the freshly quenched state and in the early stages of deformation. After a few percent strain, however, P(x) starts to develop a system size dependent plateau in the small x limit. To explain the origin of the plateau we consider a mesoscopic elastoplastic approach. Our results show how the spatial extent of avalanches in the stationary regime has a profound effect on the distribution of local residual stresses x. While the entrance into the plateau is set by the lower cutoff of the mechanical noise produced by individual STs, the departure from the usually assumed power-law pseudogap form comes from stress fluctuations induced by collective avalanches.