Frieze group analysis of asymmetric response to large-amplitude oscillatory shear

Several attempts have been made recently to develop universal analysis techniques for the stress response to large-amplitude oscillatory shear (LAOS) in a variety of materials from viscous and viscoelastic to viscoplastic. All previous attempts have assumed, tacitly or otherwise, that such responses display a minimum number of symmetries in stress/strain. We present the stress response to LAOS of a glassy suspension of multiarm star polymers, which exhibits a complete lack of any type of symmetry during the 10 000 s experimental window. We also present new physical interpretations of previously defined parameters and conjecture that the lack of symmetry observed in the stress response is a consequence of the aging process, which can be viewed as slow cage rearrangement and evolution of heterogeneities.