(180d) Title: Modeling of Polymer Melts Containing Short and Long Glass Fiber. Part II: the Simulation of Injection Molded Parts

The simulation of mold filling of thermoplastics containing fibers is usually done by decoupling the flow and the fiber orientation and assuming Hele-Shaw flow. In this research we present efforts to avoid this decoupling and include fluids with viscoelastic response. In particular, we extend Doi's theory for rod-like systems to simulate the rheological behavior of fiber filled thermoplastic composites. The constitutive equations along with the equations of motion are solved using a discontinuous Galerkin method. First simple shear flow at the start up of flow is considered and then the approach is extended to the filling of a center-gated disk. The position of the front as a function of time for a given injection pressure is compared to the theoretical predictions. More importantly the predictions of the fiber orientation are compared to that of the decoupled approach. In the case of short fibers, the predicted orientation is compared to the experimentally measured values. Additional work is being carried out to determine whether the approach can be extended to long fiber composites (~11 mm long).