Shear modulus and shear-stress fluctuations in polymer glasses

Abstract

Using molecular dynamics simulation of a standard coarse-grained polymer glass model we investigate by means of the stress-fluctuation formalism the shear modulus $\mu$ as a function of temperature $T$ and sampling time $\Delta t$. While the ensemble-averaged modulus $\mu (T)$ is found to decrease continuously for all $\Delta t$ sampled, its standard deviation $\delta \mu (T)$ is non-monotonous with a striking peak at the glass transition. Confirming the effective time-translational invariance of our systems, $\mu (\Delta t)$ can be understood using a weighted integral over the shear-stress relaxation modulus $G(t)$. While the crossover of $\mu (T)$ gets sharper with increasing $\Delta t$, the peak of $\delta \mu (T)$ becomes more singular. % It is thus elusive to predict the modulus of a single configuration at the glass transition.

arXiv comment5 pages, 6 figure, published at PRL

References in corpus (19)

• Fractal free energy landscapes in structural glasses
• Breakdown of Elasticity in Amorphous Solids
• Disorder-assisted melting and the glass transition in amorphous solids
• Vibrations of amorphous, nanometric structures: When does continuum theory apply?
• Relaxation in yield stress systems through elastically interacting activated events
• Shear modulus of simulated glass-forming model systems: Effects of boundary condition, temperature and sampling time
• Replica theory of the rigidity of structural glasses
• The shear modulus of glasses: results from the full replica symmetry breaking solution
• Glass elasticity from particle trajectories
• Mode-Coupling as a Landau Theory of the Glass Transition
• Emergence of Long-range Correlations and Rigidity at the Dynamic Glass Transition
• Shear stress relaxation and ensemble transformation of shear stress autocorrelation functions revisited
• Fluctuation-dissipation relation between shear stress relaxation modulus and shear stress autocorrelation function revisited
• Discontinuous shear modulus determines the glass transition temperature
• Impulsive correction to the elastic moduli obtained using the stress-fluctuation formalism in systems with truncated pair potential
• Breakdown of Nonlinear Elasticity in Amorphous Solids at Finite Temperatures
• Shear-stress fluctuations in self-assembled transient elastic networks
• Simple-average expressions for shear-stress relaxation modulus
• Shear-strain and shear-stress fluctuations in generalized Gaussian ensemble simulations of isotropic elastic networks

Cited by in corpus (4)

• Emergence of long-ranged stress correlations at the liquid to glass transition
• Shear-stress fluctuations and relaxation in polymer glasses
• Shear-stress fluctuations in free-standing polymer films
• The Initiation of Shear Band Formation in Deformed Metallic Glasses from Soft Localized Domains