An Eshelby model for highly viscous flow

Abstract

The recent Eshelby description of the highly viscous flow leads to the prediction of a factor of two different viscosities in stationary and alternating flow, in agreement with experimental evidence. The Kohlrausch barrier density increase with increasing barrier height finds a physical justification in the Adam-Gibbs increase of the number of structural alternatives of the Eshelby region with its increasing size. The new Ansatz allows to determine the number of atoms or molecules in the rearranging Eshelby domains from a combination of dynamic shear relaxation and calorimetric data.

Optically trapped delayed elasticity in germanium selenide glass fibers

“…This picture of the delayed elasticity is also equivalent to the picture proposed by Mazurin, with a two‐levels model. This two levels model (or “double‐well potential”) is actually consistent with the Eshelby's inclusion approach . Once the RU has reached a new level, it is able to recover its initial level if the external stress is released.…”

“…The mechanism of these events is supposed to be fundamentally the same below as well as above the glass transition . The effect of a relaxing event is very similar to that of an Eshelby's inclusion with a stress‐relaxing inclusion . The scenario of the relaxation‐recovery processes are schematized in Figure , with a single RU and its neighborhood.…”

“…At this step, if the external stress is removed, the shoved neighborhood will urge the RU to recover its initial state, by redistributing the ShS on it (see Figure D), inducing the delayed elastic recovery. To be consistent with the linear viscoelasticity, the initial and new state of RU must have a similar energy level (as the example of two states depicted by Buchenau). As long as the RU stays in this stressed state, the sample is still macroscopically distorted.…”