Dynamics of Large-Scale Plastic Deformation and the Necking Instability in Amorphous Solids

TL;DR

This paper investigates the necking instability in amorphous solids using shear transformation zone theory, revealing rate-dependent behavior and unique plastic flow characteristics during large-scale deformation.

Contribution

It introduces an Eulerian framework for modeling large-scale plastic deformation in amorphous solids, capturing nonlinear dynamics and rate effects beyond traditional theories.

Findings

Higher strain rates delay necking onset

Material hardens outside the neck region

Plastic flow within the neck differs from conventional theories

Abstract

We use the shear transformation zone (STZ) theory of dynamic plasticity to study the necking instability in a two-dimensional strip of amorphous solid. Our Eulerian description of large-scale deformation allows us to follow the instability far into the nonlinear regime. We find a strong rate dependence; the higher the applied strain rate, the further the strip extends before the onset of instability. The material hardens outside the necking region, but the description of plastic flow within the neck is distinctly different from that of conventional time-independent theories of plasticity.