Viscoelastic Hysteresis. Part I. Model Predictions

Hysteresis loops on a shear stress versus shear rate plot have been reported by numerous investigators studying polymeric fluids. Both clockwise and counterclockwise loops have been observed. Currently available nonlinear viscoelastic models can be used to derive expressions for these hysteresis loops as well as for the corresponding normal stress hysteresis loops. It is suggested that the hysteresis loop experiment may be particularly useful for the testing of nonlinear viscoelastic models.