2018/05/21 by Mehdi Bouzid, Bavand Keshavarz, Michela Geri +3 · 45 citations
Biochemistry, Genetics and Molecular Biology · Chemical Engineering · Materials Science · Physics and Astronomy · #Chirp #Constitutive equation #Frequency response #Hydrogels: synthesis, properties, applications #Material Dynamics and Properties #Mesoscopic physics #Rheology #Rheology and Fluid Dynamics Studies #Standard linear solid model #Sweep frequency response analysis #Viscoelasticity #cond-mat.soft
paper · pdf · doi:10.1122/1.5018715
published in Journal of Rheology 62(4), 1037-1050 (American Institute of Physics)
arxiv created 2018/05/21 · openalex created_date 2018/06/01 · openalex publication_date 2018/07/01 · arxiv updated 2018/08/15 · openalex updated_date 2026/08/05
We use molecular dynamics simulations to investigate the linear viscoelastic response of a model three-dimensional particulate gel. The numerical simulations are combined with a novel test protocol (the optimally windowed chirp or OWCh), in which a continuous exponentially varying frequency sweep windowed by a tapered cosine function is applied. The mechanical response of the gel is then analyzed in the Fourier domain. We show that (i) OWCh leads to an accurate computation of the full frequency spectrum at a rate significantly faster than with the traditional discrete frequency sweeps, and with a reasonably high signal-to-noise ratio, and (ii) the bulk viscoelastic response of the microscopic model can be described in terms of a simple mesoscopic constitutive model. The simulated gel response is in fact well described by a mechanical model corresponding to a fractional Kelvin-Voigt model with a single Scott-Blair (or springpot) element and a spring in parallel. By varying the viscous damping and the particle mass used in the microscopic simulations over a wide range of values, we demonstrate the existence of a single master curve for the frequency dependence of the viscoelastic response of the gel that is fully predicted by the constitutive model. By developing a fast and robust protocol for evaluating the linear viscoelastic spectrum of these soft solids, we open the path toward novel multiscale insight into the rheological response for such complex materials.