Analytical approach of mechanical behavior of carpet yarn by mechanical models

The viscoelastic models for describing mechanical behavior of polypropylene carpet yarn are presented in this paper. Since carpet yarn is subjected to tensile and frictional forces during tufting, the mechanical properties are important material features especially in vibration analysis. In this paper, the standard linear model and the standard nonlinear model are developed to simulate the polypropylene yarn tensile, stress relaxation and creep behaviors. The obtained formulas are fitted with experimental data and the ideal model parameters are determined by applying least squares. The results showed that the standard linear model fits well the tensile, relaxation and creep experimental curves, and will be employed to analyze the vibration characteristics of yarn during the tufting.