An Elasto-visco-plastic Model of Cell Aggregates
Résumé
Concentrated cell suspensions exhibit different mechanical behavior depending on the mechanical stress or deformation they undergo. These systems have a mixed rheological nature: cells behave elastically or viscoelastically, they can adhere to each other whereas the carrying fluid is usually Newtonian. We report here on a new elasto-visco-plastic model which is able to describe the mechanical properties of a concentrated cell suspension or aggregate. It is based on the idea that the rearrangement of adhesion bonds during the deformation of the aggregate is related to the existence of a yield stress in the macroscopic constitutive equation. We compare the predictions of this new model with three experimental situations: steady shear rate, oscillatory shearing tests as well as relaxation after application of a prescribed deformation. All of these experiments are shown to agree with the predictions of the model.
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