Toward modeling anisotropic yield stress and consistency induced by fiber in fiber-reinforced viscoplastic fluids

Julien Férec (1) , Arnaud Perrot (1) , Gilles Ausias (1)

1 LIMATB - Laboratoire d'Ingénierie des Matériaux de Bretagne

A model is developed for suspensions of rigid fibers in a non-Newtonian fluid exhibiting a yield stress by taking into account hydrodynamic and fiber–fiber interactions. To be applied to fiber-reinforced viscoplastic fluids such as cementitious pastes or mortars, the matrix behavior is described by a Herschel–Bulkley law. The model is able to predict shear thinning and shear thickening behaviors as well as anisotropic yield stress depending on the fiber orientation. The extra stress term involves structural tensors, where exact analytical solutions have been proposed for an isotropic fiber orientation in simple shear flow. The model predictions show a good agreement with the yield stress values of steel fibers dispersed in kaolin pastes.

Mots clés: Reinforced viscoplastic fluid; Anisotropic yield stress; Fiber suspension; Herschel–Bulkley fluid; Orientation tensors; Interaction tensors

Domaines: Mécanique des fluides [physics.class-ph]

Julien Férec, Arnaud Perrot, Gilles Ausias. Toward modeling anisotropic yield stress and consistency induced by fiber in fiber-reinforced viscoplastic fluids. Journal of Non-Newtonian Fluid Mechanics, 2015, 220, pp.69-76. ⟨10.1016/j.jnnfm.2014.08.009⟩. ⟨hal-01113109⟩