Abstract
The formulas for velocity distribution, tension and running time of viscoelastic yarn, which runs between feed-roller and take-up roller in a steady state, are obtained using one-dimensional constitutive equation of the integral type described in a convected coordinate system. The formulas may be expressed simply by creep compliance of yarn, draw ratio and feed-roller velocity.
Predictions of velocity distribution, tension and running time agree with the experiments of polyethylene terephthalate monofilament yarn. The tension increases with feed-roller velocity and draw ratio. Both calculated and observed curves of velocity distribution along a yarn are convex upward and increase monotonically. However, the observed results are smaller than the calculated ones. Furthermore, the velocity gradient increases with draw ratio in calculations. The observed velocity gradient is larger than the calculated one. Lastly, the running time decreases with draw ratio and this tendency is remarkable at low feed-roller velocities.
