Distinguishing thixotropy from viscoelasticity

Owing to nonlinear viscoelasticity, materials often show characteristic features that resemble those of thixotropy. This issue has been debated in the literature over past several decades, and experimental protocols have proposed distinguish thixotropy from viscoelasticity. In this work, we assess these by carrying out experiments using polymer solutions, thixotropic clay dispersions, modeling their behavior, respectively, FENE-P constitutive equation a viscoelastic aging model. We find criteria literature, such as step down jump shear rate startup at different waiting times elapsed since preshear, are inadequate marked contrast, application step-strain or step-stress after cessation preshear serves useful discriminant between materials, observe strain (or stress) eventually leads slowing relaxation dynamics function time. However, for modulus (creep compliance) curve shifts lower (higher values time until equilibrium is reached. While criterion offers robust distinction viscoelasticity systems studied here, further investigations based on other needed establish its versatility will lead greater insight into long-standing rheological categorization.