Role of Fragility of the Glass Formers in the Yielding Transition under Oscillatory Shear

We study the effect of the fragility of glass formers on the yielding transition under oscillatory shear via extensive computer simulations. Employing sphere assemblies interacting with a harmonic potential as our model glass former, we tune fragility by changing the system’s density - higher density corresponds to large fragility. Our study reveals significant differences in the yielding transition between strong and fragile glass formers. While both glass formers exhibit similar behaviour under poorly annealed initial conditions, the yielding transition shifts to larger values with increased annealing for fragile glasses while remaining relatively constant for strong glasses. We rationalize our results by introducing a new elastoplastic model, which qualitatively reproduces the simulation results and offers valuable insight into the physics of yielding transition under oscillatory shear deformation.