NUMERICAL-SIMULATION OF THE FLOW AND FIBER ORIENTATION IN REINFORCED THERMOPLASTIC INJECTION-MOLDED PRODUCTS

This paper describes a fully three-dimensional transient finite elemen t method for calculating the flow behavior and fiber orientation durin g filling of injection molded parts. The fiber-fiber interaction is ta ken into account. The momentum and continuity equations are first solv ed with the viscoelastic stress treated as used body force. The kineti c equation for the orientation tensor is then integrated with known ki nematics using the standard Galerkin method. The calculation is perfor med on a time-dependent flow domain. Since the method is truly three-d imensional, singular regions such as the pole front or near injection gates and solid boundaries, where decoupled approximations are not val id, are naturally dealt with. The material anisotropy behavior is mode led by using the Doi-Doraiswamy-Metzner model. Numerical results, invo lving the Poiseuille flow and the filling of an end-gated plate, empha sizing the importance of the three-dimensional coupling calculations b etween the flow and orientation are presented.