Fiber orientation evolution in simple shear flow from a repeatable initial fiber orientation

Experimental fiber evolution data from a rheometer can be used to determine material parameters in fiber orientation models independent from processing flows. The Folgar-Tucker orientation model was demonstrated in simple shear flow to predict distinctly different trends in the orientation evolution depending on the initial fiber orientation. Repeatable fiber orientation evolution data in a simple shear flow was used to determine material parameters in the strain reduction factor (SRF) and reduced strain closure (RSC) orientation models. The SRF and RSC orientation models were tested with different initial fiber orientations created from an injection molded plaque in order to evaluate the orientation model parameters. A stress equation incorporating fiber-fiber interactions was evaluated independently of the fiber orientation models using experimental orientation evolution data with different initial orientations.