Róbert Bertóti Róbert Bertóti

Dr.-Ing. Róbert Bertóti

Research Area Simulation - Associated Project

Modeling the flow-induced anisotropic effective viscosity of DiCoFRP

Advisors: Böhlke (ITM), Schneider (ITM), Hrymak (UWO)


During mold filling of DiCoFRP, the fibers immersed in the polymer matrix permanently reorientate as the deformation evolves (Fig. 1). An anisotropic fiber orientation state causes anisotropic effective viscosity. To determine the anisotropic viscosity through measurements is a challenging exercise and not solved until yet. To overcome this, mean field (Fig. 2) and full field (Fig. 3) homogenization methods are used to determine the anisotropic effective viscosity of DiCoFRP.



Fig. 1: Discrete pole figures of fiber orientation evolution in a simple shear flow



                      a)                                                                     b)

Fig. 2: (a) The effective directional elongational viscosity, (b) the effective shear viscosity of an aligned suspension, determined by mean field homogenization, relative to the matrix viscosity, considering different cf fiber volume fractions, in the case of l/d=10, where l denotes the fiber length and d the fiber diameter

         (a)                  (b)                  (c)                   (d)                  (e)                   (f)        

Fig. 3.: Unidirectional synthetic microstructures, for the full field homogenization, in different sized, square column shaped (LxWxW) volume elements: (a) L=1.1l, (b) L=2.2l, (c) L=3.3l, (d) W=5d, (e) W=10d, (f) W=20d, where l denotes the fiber length, d is the fiber diameter, L the volume element length and W the volume element width