The use of the flexural modulus in the comparison of fiber orientation models for concentrated suspensions in short fiber-filled thermoplastics.

Abstract

Advances in modeling spatially varying fiber orientation within an injection molded thermoplastic composite part have led to better structural designs and manufacturing efficiencies by optimizing mold designs and processing parameters. With recent improvements in processing tolerances, the accuracy of classical fiber interaction models warrant further investigation. The isotropic diffusion fiber interaction model of Folgar-Tucker (1984) has been commonly used for decades. Recent objective modifications include the reduced strain closure of Wang, et al. (2008) and the anisotropic rotary diffusion model of Phelps and Tucker (2009). This thesis investigates the impact these diffusion models have on final processed part structural performance. A proposed macroscopic methodology that takes into account the microstructure of fiber orientation is suggested through the use of the flexural modulus for comparisons with experimental testing. Results indicate that the flexural modulus has limited use for diffusion model validation, and alternative macroscopic methods to identify fiber interaction models are suggested.