EXTENSIONAL DEFORMATION AND ORIENTATION OF RUNNING FILAMENT IN MELT SPINNING

Effect of Melt Spinning Variables on the Structural Changes of Recycled and Bottle Grade Filament Yarn PET

Hydrodynamic induced deformation and orientation of a microscopic elastic filament.

We describe simulations of an elastic filament immersed in a fluid and subjected to a body force. The coupling between the fluid flow and the friction that the filament experiences induces bending and alignment perpendicular to the force. With increasing force there are four shape regimes, ranging from slight distortion to an unsteady tumbling motion. We also find marginally stable structures. ...

Optimal Control of Melt Spinning Processes

An optimal control problem for a mathematical model of a melt spinning process is considered. Newtonian and non–Newtonian models are used to describe the rheology of the polymeric material, the fiber is made of. The extrusion velocity of the polymer at the spinneret as well as the velocity and temperature of the quench air serve as control variables. A constrained optimization problem is derive...

Extensional deformation of non-Newtonian liquid bridges

A numerical method for simulating the extensional dynamics of elongating ®laments of non-Newtonian ̄uids in a ®lament stretching rheometer is presented. The boundary element method, in conjunction with either the Oldroyd-B or the generalized multimode Upper-Convected Maxwell constitutive model, is used to calculate the transient evolution of the liquid interface, the applied force on the station...

Buckling transition of a semiflexible filament in extensional flow.

An analytical expression for the fluctuation-rounded stretch-coil transition of semiflexible polymers in extensional flows is derived. The competition between elasticity and tension is known to cause a buckling instability in filaments placed near hyperbolic stagnation points and the effect of thermal fluctuations on this transition has yet to receive full quantitative treatment. Motivated by t...