Inverse Stress Relaxation in Textile Yarns After the Blockage of Viscoelastic Recovery

Abstract

Viscoelastic properties of acetate and polyester multifilament yarns in the compound loading cycle are theoretically and
experimentally studied and the features of inverse stress relaxation (IR) after the blockage of viscoelastic recovery of the
yarns are revealed in the study. Modelling method of the processes at the referred loading cycle is proposed on the basis
of generalized Maxwell model. Analysing the behaviour of the model possessing different relaxation time spectra it was
found that the longer is free recovery of the model until its blockage the less is the resulting recovery power of the
model. The duration of recovery is more sensitive to the changes in the amount of the resulting IR in the model
possessing more short relaxation times. To prove the theoretical findings the experimental investigation was provided
with acetate (16.6 tex) and polyester (15.6 tex) multifilament yarns analysing their behavior in the same loading cycle.
The experiments confirmed basic theoretical findings. Some differences in the reaction of acetate and polyester yarn to
the blockage of their viscoelastic recovery are shown.