Analytical approach of creep behavior of carpet yarn.

Based on mechanical models, the creep behavior of carpet yarns after dynamic loading was investigated. For prediction the creep elongation, the frequently used mechanical models reported in the literature were analyzed. The mechanical models which were used in this article were: standard linear model, four-element model, two-component Kelvin's model, and Eyring's model. The obtained creep formulas were fitted to experimental creep data, and the parameters of the model can be obtained using the Marquardt algorithm for nonlinear regression. When comparing the experimental creep curve with the fitted curve from the mechanical model, it is clear that the four-element model explain the experimental creep curve better. During tufting machine stops, the carpet yarns were undergone constant load. The confirmed viscoelastic model will be used to calculate total creep elongation during carpet machine stoppage. Thus, the start-up marks which occurred at carpet machine restarts can be exactly eliminated by adjusting the feeding length according to the creep elongation. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 [ABSTRACT FROM AUTHOR]