Effectiveness of recent fiber-interaction diffusion models for orientation and the part stiffness predictions in injection molded short-fiber reinforced composites

Two fiber fiber interaction models for predicting the fiber orientation and resulting stiffness of a short-fiber reinforced thermoplastic composite are investigated, the isotropic rotary diffusion of Folgar and Tucker (1984) [1] and the anisotropic rotary diffusion of Phelps and Tucker (2009) [6]. This study employs several fiber orientation tensor closure approximations for both diffusion models and results are compared to those from the numerically exact spherical harmonic approach. Results are presented for variations in the fiber orientation and the processed part stiffness. A significant difference was observed between the stiffness predicted by both rotary diffusion models. It is worth noting that not all closures behave the same between the diffusion models, thus encouraging further studies to refine and validate the new fiber interaction models and solution approaches. A study of the predicted flexural modulus is presented, and results suggest that flexural modulus experiments may aid in further refining the fiber interaction models. (c) 2012 Elsevier Ltd. All rights reserved.