Strain Localization and Percolation of Stable Structure in Amorphous Solids

Spontaneous strain localization occurs during mechanical tests of a model amorphous solid simulated using molecular dynamics. The degree of localization depends upon the extent of structural relaxation prior to mechanical testing. In the most rapidly quenched samples higher strain rates lead to increased localization, while the more gradually quenched samples exhibit the opposite strain rate dependence. This transition coincides with the $k$-core percolation of atoms with quasi-crystal-like short range order. The authors infer the existence of a related microstructural length scale.