Modeling the manufacturing of industrial heterofilaments

The materials processing of man-made fibers dates back to the end of the 19th century. Examples of fiber applications include textiles, reinforcing fibers, and recently optic fibers. In this dissertation, the manufacturing of heterofilaments (multi-component, composite fibers) is modeled. Many studies model the manufacture of single-component filaments, but no modeling of the melt spinning of multi-component filaments has been published.; The modeling is approached with the following objectives: to describe the mechanics of the heterofilament liquid jet problem; to introduce a model that will capture the important mechanical behavior of the heterofilament liquid jet; to examine the steady state behavior predicted by the model in several important processing regimes; to deduce how the mechanical properties of the core and the sheath components are combined in the heterofilament manufacturing process to produce the mechanical properties of the final composite fiber; and to illustrate how the model can be used to optimize a heterofilament manufacturing process.; Three interfacial models are introduced for the core/sheath boundary: the bonded model, the viscous model, and the stick-slip model. The Newtonian time dependent problems for the bonded, viscous, and stick-slip interfacial models are formulated and the fully-populated regime, viscosity regimes, inertia regimes, surface tension regimes, gravity regimes, incompressibility regimes, and ambiance regimes are investigated.