Rheological Hysteresis in Soft Glassy Materials

摘要: The nonlinear rheology of a soft glassy material is captured by its constitutive relation, shear stress versus rate, which most generally obtained sweeping up or down the rate over finite temporal window. For huge amount complex fluids, and sweeps do not superimpose define rheological hysteresis loop. By means extensive rheometry coupled to time-resolved velocimetry, we unravel local scenario involved in for various types well-studied materials. We introduce two observables that quantify macroscopic respectively, as function sweep $\ensuremath{\delta}{t}^{\ensuremath{-}1}$. Strikingly, both present robust maximum with $\ensuremath{\delta}t$, defines single material-dependent time scale grows continuously from vanishingly small values simple yield fluids large strongly time-dependent In line recent theoretical arguments, these experimental results hint at universal scale-based framework materials, where inhomogeneous flows characterized bands and/or pluglike flow play central role.