Anisotropic viscous behavior of sheet molding compounds (SMC) during compression molding

To improve the knowledge on the rheology of sheet molding compounds (SMC) during compression molding, a specific rheometer was designed, allowing to perform homogeneous experiments on SMC specimen under various mechanical loading, strain rates and fiber contents. Results gained during experiments underlined the key role played both by the strain rate and the fiber content. A viscous and transversely isotropic model was then proposed and used to fit stress levels recorded during the experiments. This model that requires few constitutive parameters rather well describes the main features of SMC rheology.