A Numerical Approach on New Constitutive Model for Thixotropic Substances

Abstract

The thixotropic substances can be found in different industrial sectors, such as chemical, biomedical, manufacturing and oil. These substances show a rheological time-dependent behavior, dependent of their structural level. Generally, a constitutive model for the thixotropic substances is composed by a pair of coupled equations: the constitutive equation (based on viscoelastic models) and the rate equation (that describes the structural evolution). In many works presented in the specialized literature, the shear modulus and viscosity dependencies with the structural nature are not formally considered in the dynamical principles from that the constitutive equation is originated. In the present work, a new, thermodynamically consistent, constitutive model for thixotropic substances, where such dependences are considered, is presented and some rheological tests are analyzed in a numerical simulation point of view (code developed in MATLAB). The constitutive model is based on Jeffreys’ model and the coagulation theory of Smoluchowsky.