Integration of thixotropy into Giesekus model for characterization of human blood

Abstract

Recent work modeling the rheological behavior of human blood indicates that blood has all the hallmark features of a complex material, including shear-thinning, viscoelastic behavior, yield stress, and thixotropy. Using a recently developed linear superposition technique to account for the effects of thixotropy with the Giesekus model and recently collected human blood rheological data from a strain-controlled rheometer, we perform parametric and statistical analysis of the parameter values of 5 donors. The work is validated with the incorporation of a recent thixotropic framework to model elastic and viscoelastic contributions from the microstructure. The elastic and viscoelastic stress contributions from the microstructure are then linearly superimposed with the viscoelastic backbone solution for stress given by the classic Giesekus rheological model. Demonstrated here are a parametric and statistical analysis and a comparison of the ability of the new enhanced thixotropic Giesekus model to predict large amplitude oscillatory shear and uni-directional large amplitude oscillatory shear flow. In addition, there is a new methodology to model the normal forces of blood. We compare this approach to other recently developed enhanced thixotropic Oldroyd-8 inspired models.