Flow heterogeneities in supercooled liquids and glasses under shear

Abstract

Using extensive non-equilibrium molecular dynamics simulations, we investigate a glassforming binary Lennard-Jones mixture under shear. Both supercooled liquids and glasses are considered. Our focus is on the characterization of inhomogeneous flow patterns such as shear bands that appear as a transient response to the external shear. For the supercooled liquids, we analyze the crossover from Newtonian to non-Newtonian behavior with increasing shear rate $\dot{\gamma }$. Above a critical shear rate ${\dot{\gamma }}_c$ where a non-Newtonian response sets in, the transient dynamics are associated with the occurrence of short-lived vertical shear bands, i.e. bands of high mobility that form perpendicular to the flow direction. In the glass states, long-lived horizontal shear bands, i.e. bands of high mobility parallel to the flow direction, are observed in addition to vertical ones. The systems with shear bands are characterized in terms of mobility maps, stress-strain relations, mean-squared displacements, and (local) potential energies. The initial formation of a horizontal shear band provides an efficient stress release, corresponds to a local minimum of the potential energy, and is followed by a slow broadening of the band towards the homogeneously flowing fluid in the steady-state. Whether a horizontal or a vertical shear band forms cannot be predicted from the initial undeformed sample. Furthermore, we show that with increasing system size the probability for the occurrence of horizontal shear bands increases.

arXiv comment15 pages, 13 figures

References in corpus (34)

• Scaling behavior in the $\beta$-relaxation regime of a supercooled Lennard-Jones mixture
• Shear Banding of Complex Fluids
• A random critical point separates brittle and ductile yielding transitions in amorphous materials
• Nonequilibrium dynamics and fluctuation-dissipation relation in a sheared fluid
• Transient Shear Banding in a Simple Yield Stress Fluid
• Shear localization in a model glass
• Shear banding and flow-concentration coupling in colloidal glasses
• Evaluation of the "disorder temperature" and "free volume" formalisms via simulations of shear banding in amorphous solids
• Microscopic Mechanism of Shear Bands in Amorphous Solids
• Long-range strain correlations in sheared colloidal glasses
• Criteria for shear banding in time-dependent flows of complex fluids
• Glass stability changes the nature of yielding under oscillatory shear
• From Equilibrium to Steady State: The Transient Dynamics of Colloidal Liquids under Shear
• Formation and growth of shear bands in glasses: existence of an underlying directed percolation transition
• Inhomogeneous shear flows in soft jammed materials with tunable attractive forces
• Strain localisation above the yielding point in cyclically deformed glasses
• Fast generation of ultrastable computer glasses by minimization of an augmented potential energy
• Do solids flow?
• Flow curves of dense colloidal dispersions: schematic model analysis of the shear-dependent viscosity near the colloidal glass transition
• Brittle yielding of amorphous solids at finite shear rates
• Structural relaxation and rheological response of a driven amorphous system
• Onset of flow in a confined colloidal glass under an imposed shear stress
• Shear localization in 3-Dimensional Amorphous Solids
• Role of fluctuations in the yielding transition of two-dimensional glasses
• Heterogeneous dynamics during yielding of glasses: effect of aging
• Do thermodynamically stable rigid solids exist?
• Shear Transformation Zones: State Determined or Protocol Dependent?
• Emergence and persistence of flow inhomogeneities in the yielding and fluidization of dense soft solids
• Mechanical Failure in Amorphous Solids: Scale Free Spinodal Criticality
• Shear Band Broadening in Simulated Glasses
• A computational study of transient shear banding in soft jammed solids
• Long-range strain correlations in 3D quiescent glass forming liquids
• A nucleation theory for yielding of nearly defect-free crystals: understanding rate dependent yield points
• Exploring structural inhomogeneities in glasses during cavitation

Cited by in corpus (7)

• Role of fluctuations in the yielding transition of two-dimensional glasses
• Predicting the location of shear band initiation in a metallic glass
• Continuum modelling of shear start-up in soft glassy materials
• Brittle yielding in supercooled liquids below the critical temperature of mode coupling theory
• Rheological response of a glass-forming liquid having large bidispersity
• Computational Methods toward Ultrastable Glasses
• On the yielding of a defect-rich model crystal under shear: insights from molecular dynamics simulations