Initial conditions for simulating glass fiber orientation in the filling of center-gated disks

This work is concerned with the effect that initial conditions play in simulating long (>1 mm) glass fiber (LGF) orientation in the filling of a center-gated disk (CGD). For the CGD, most orientation simulations begin at the gate and make assumptions about the initial fiber orientation entering the mold. This paper reports on a method for simulating LGF orientation in a CGD by simulating the sprue, gate, and mold (S–G–M) as a single domain. The velocity field solution is determined using a finite element method including the advancing front. To predict LGF orientation, rigid and flexible fiber models are employed using parameters obtained from rheology. It is observed that predicting LGF orientation in systems with either model is highly sensitive to the choice of initial conditions. Furthermore, the flexible fiber model is observed to be more successful at predicting LGF orientation based on agreement with experimental results.