Strain-rate frequency superposition in large-amplitude oscillatory shear

Abstract

In a recent work, Wyss, et.al. [Phys. Rev. Lett., 98, 238303 (2007)] have noted a property of 'soft solids' under oscillatory shear, the so-called strain-rate frequency superposition (SRFS). We extend this study to the case of soft solids under large-amplitude oscillatory shear (LAOS). We show results from LAOS studies in a monodisperse hydrogel suspension, an aqueous gel, and a biopolymer suspension, and show that constant strain-rate frequency sweep measurements with soft solids can be superimposed onto master curves for higher harmonic moduli, with the same shift factors as for the linear viscoelastic moduli. We show that the behavior of higher harmonic moduli at low frequencies in constant strain-rate frequency sweep measurements is similar to that at large strain amplitudes in strain-amplitude sweep tests. We show surface plots of the harmonic moduli and the energy dissipation rate per unit volume in LAOS for soft solids, and show experimentally that the energy dissipated per unit volume depends on the first harmonic loss modulus alone, in both the linear and the nonlinear viscoelastic regime.

Describing and prescribing the constitutive response of yield stress fluids using large amplitude oscillatory shear stress (LAOStress)

“…7 over the domain [0, 2π/ω]. It is well known that, for a sinusoidal forcing, the energy dissipated within the material per cycle only depends on the first viscous Fourier coefficient (Ganeriwala and Rotz, 1987;Kalelkar et al, 2010;Ewoldt et al, 2010). Geometrically, this parameter E d represents the area enclosed within the elastic Lissajous curves shown in Fig.…”

Application of the Arrhenius Equation in Predicting the Temperature Susceptibility of Unmodified and Modified Bituminous Binder

“…When the material is subjected to sinusoidal strain, the resultant stress waveform may contain higher-order harmonic contribution. It is understood that the energy dissipation due to sinusoidal strain is purely due do the first-order harmonic stress [33]. Hence, the energy dissipation is computed using Equation 3, where 𝜖 1 represents first-order harmonic strain, 𝜎 1 is the first-order harmonic stress and 𝛿 1 is the corresponding lag.…”