Importance of viscoelasticity in the thixotropic behavior of human blood

Abstract

Recent work modeling the rheological behavior of thixo-elasto-viscoplastic (TEVP) materials such as human blood indicates that it has all of the hallmark features of a complex material, including shear-thinning, viscoelasticity, a yield stress, and thixotropy. After decades of modeling steady-state human blood rheological data, and the development of simple steady-state models, like the Casson and Herschel–Bulkley, the advancement and evolution of TEVP modeling to transient flow conditions now has reinvigorated interest. Using recently collected human blood rheological data, over a wide range of flow conditions from steady state to various oscillatory shear flows, we show and compare modeling efforts with the original and a viscoelasticity-enhanced version of the enhanced Apostolidis–Armstrong–Beris (EAAB) model. The viscoelasticity enhancement is then justified by its ability to improve predictions of small and large amplitude oscillatory shear as well as uni-directional oscillatory shear flow. The new viscoelastic parameter is then incorporated into a methodology to estimate the viscoelastic time scale of human blood. Lastly, we compare our new TEVP modeling approach with another recently developed TEVP model, mHAWB, for context.