Search results for "Shear elasticity"
showing 3 items of 3 documents
Do we understand the solid-like elastic properties of confined liquids?
2021
Recently, in polymeric liquids, unexpected solid-like shear elasticity has been discovered, which gave rise to a controversial discussion about its origin (1⇓–3). The observed solid-like shear modulus G depends strongly on the distance L between the plates of the rheometer according to a power law G ∝ L − p with a nonuniversal exponent ranging between p = 2 and p = 3 . Zaccone and Trachenko (4) have published an article in which they claim to explain these findings by a nonaffine contribution to the liquid shear modulus. The latter is represented as Δ G ∝ − ∑ λ = L , T 1 V … [↵][1]1To whom correspondence may be addressed. Email: giancarlo.ruocco{at}roma1.infn.it. [1]: #xref-corresp-1-1
Heterogeneous shear elasticity of glasses: the origin of the boson peak
2013
The local elasticity of glasses is known to be inhomogeneous on a microscopic scale compared to that of crystalline materials. Their vibrational spectrum strongly deviates from that expected from Debye's elasticity theory: The density of states deviates from Debye's law, the sound velocity shows a negative dispersion in the boson-peak frequency regime and there is a strong increase of the sound attenuation near the boson-peak frequency. By comparing a mean-field theory of shear-elastic heterogeneity with a large-scale simulation of a soft-sphere glass we demonstrate that the observed anomalies in glasses are caused by elastic heterogeneity. By observing that the macroscopic bulk modulus is …
Shear elasticity of mixed cyanide orientational glass
1993
Four mixed crystals of KBr:KCN and NaCN:KCN, complemented by KCN, have been investigated by torque-shear measurements. The real and imaginary parts of the shear compliance ${\mathit{s}}_{44}$ at a measuring frequency of 2 Hz have been determined. Zero-field-cooling--field-cooling--remanent-shear-strain cycles have been performed. For (KBr${)}_{0.47}$(KCN${)}_{0.53}$ the creep after zero-field cooling and the elastic aftereffect after field cooling have been followed within a time window from 0.1 to ${10}^{4}$ s. Results on the nonlinear part of the shear compliance have been obtained. It is shown that the field-cooled strain represents the static limit of the elastic response. The results a…