Critical remarks on “viscous potentials” and modeling of viscoelastic solids

Abstract In the recent paper (Melly and Czekanski 2026), a viscoelasticity theory was formulated in terms of “viscous potentials.” Such formulation started proliferating in scientific literature (e.g. Pioletti et al. 1998, Ghahfarokhi et al. 2020, Upadhyay et al. 2020). Seemingly simple, it has an intrinsic flaw – the inability to accommodate strain jumps. The jumps lead to unphysical infinities in stresses, which is unacceptable. We emphasize this issue in the present note.