Discontinuous yielding transition of amorphous materials with low bulk modulus

The yielding transition of amorphous materials is studied with a two-dimensional Hamiltonian model that allows both shear and volume deformations. The model is investigated as a function of the relative value of the bulk modulus B with respect to the shear modulus mu. When the ratio B/mu is small enough, the yielding transition becomes discontinuous, yet reversible. If the system is driven at constant strain rate in the coexistence region, a spatially localized shear band is observed while the rest of the system remains blocked. The crucial role of volume fluctuations in the origin of this behavior is clarified in a mean field version of the model.

Automated summary

The yielding transition of amorphous materials is studied using a two-dimensional Hamiltonian model that allows both shear and volume deformations. When the ratio of bulk modulus B to shear modulus mu is small enough, the yielding transition becomes discontinuous and reversible, leading to the observation of a spatially localized shear band when the system is driven at constant strain rate in the coexistence region. The crucial role of volume fluctuations in this behavior is clarified in a mean field version of the model.