Dresden 2026 – wissenschaftliches Programm
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DY: Fachverband Dynamik und Statistische Physik
DY 44: Poster: Active Matter, Soft Matter, and Fluids
DY 44.17: Poster
Mittwoch, 11. März 2026, 15:00–18:00, P5
Power-Law to Maxwell Transition in Soft Glassy Materials under Large Amplitude Oscillations — •Raffaele Mendozza1, Shanay Zafari1, Sarah Köster1, and Peter Sollich1,2 — 1Institute for Theoretical Physics, University of Göttingen, Göttingen, Germany — 2Department of Mathematics, King's College London, London, United Kingdom
Soft glassy materials, such as colloidal suspensions and biological networks, exhibit complex rheological behaviour. We present a modified version of the Soft Glassy Rheology (SGR) model, introducing an upper cutoff on the yield rate that prevents unphysical yield rate increases at large strains. In the nonlinear response to step strains, the modified model exhibits a crossover from short-time exponential (Maxwell-like) relaxation to the power law relaxation obtained in the original model. This qualitatively reproduces results from strain-ramp experiments on actin networks. Under large amplitude oscillatory strain (LAOS) we similarly find Maxwell-like viscoelastic spectra at higher frequencies, crossing over to the original SGR power-law spectrum at low frequencies. We demonstrate that this can be rationalized qualitatively by Fourier transforming the nonlinear step strain results. The nonlinear spectra break the usual phase angle relations for power law (linear) response, however, which we explain using a quasistatic approximation. The stress response to LAOS at fixed frequency becomes more anharmonic for increasing strain amplitudes up to a critical value; beyond this point, harmonicity is eventually restored due to the crossover to Maxwell behavior.
Keywords: rheology; glass; viscoelasticity; biophysics; mesoscopic modeling