Computer Simulation With A Powerful Predictor Of Polyester Filament Yarn Tensile Fracture

Tension strength of yarn is greatly affected by the strength of fiber. This study introduces a method of breaking progress simulation as well as strength prediction of polyester filament yarn via computer simulation techniques.The study starts with the dispersibility of polyester monofils in filament yarns. The fiber strength values can be fitted and analyzed by Weibull distribution functions and then Weibull parameters of the polyester fibers can be calculated. The resulte shows that the strength values of polyester monofils are well fitted in two-parameter Weibull distribution.Due to asynchronism of breaking of filament yarns and frictions between constituent monofils, the breaking of monofil has influences on both axial and cross section. The concept of critical length is based on the axial influence. Geometrical and mechanical models of filament critical length are established and then the filament critical length can be calculated. The effect of critical length can also be analyzed, which consists of twist, friction factor and monofil fineness.The stress should be distributed in the section of critical length in the axial direction based on stress distribution rule, which plays a vital role in strength prediction. Equal-load-sharing and local-load-sharing roles are used in this article. In accordance with the desired critical length and stress distribution rules, breaking models of filament yarn can be built. The breaking progrees simulation and strength predition can be pursued by means of Matlab programming. Results show that the predicted values are smaller and highly dispersed using local-load-sharing rule. However, the predicted values are close to measured value using equal-load-sharing role. All predicted values are well fitted with two-parameter Weibull distribution by both sharing roles, and the predicted values are increasing with the increase of the yarn twist, fast to slowly.