ABSTRACT
To predict how a material will behave under deformation in any manufacturing operation will depend on the approach selected to describe its macroscopic behavior. For most thermoplastic materials containing continuous fibers, fiber preforms, or collimated fibers (long discontinuous fibers in an oriented fiber assembly), one can treat them as a homogeneous material with anisotropic viscosity or transversely isotropic viscosity with inextensibility in the fiber direction. However, at the microscopic level there are many phenomena taking place that are conglomerated into constitutive constants at the macroscopic level to allow for prediction of the deformation rate relationship with the applied force.
