Avalanches, loading and finite size effects in 2D amorphous plasticity: results from a finite element model

TL;DR

This paper presents a finite element model to study shear band formation and strain avalanches in 2D amorphous materials, revealing that critical avalanche statistics are robust against surface and size effects.

Contribution

It introduces a novel eigenstrain-based finite element model for amorphous plasticity, enabling analysis of surface and finite size effects on avalanche behavior.

Findings

Critical exponents are unaffected by surface and size effects.

Model validates simpler scalar lattice models for avalanche statistics.

Surface and boundary conditions have limited impact on avalanche distributions.

Abstract

Crystalline plasticity is strongly interlinked with dislocation mechanics and nowadays is relatively well understood. Concepts and physical models of plastic deformation in amorphous materials on the other hand - where the concept of linear lattice defects is not applicable - still are lagging behind. We introduce an eigenstrain-based finite element lattice model for simulations of shear band formation and strain avalanches. Our model allows us to study the influence of surfaces and finite size effects on the statistics of avalanches. We find that even with relatively complex loading conditions and open boundary conditions, critical exponents describing avalanche statistics are unchanged, which validates the use of simpler scalar lattice-based models to study these phenomena.