Numerical analysis on tensile strength of the sisal hemp/PET filament island phase structure composite rope core yarn by infinitesimal method

In this study, a simple mechanical model was established using infinitesimal method to investigate the tensile strength of a novel sisal hemp/PET filament island phase structure composite rope core yarn with improved mechanical properties comparing with the traditional sisal hemp rope core yarn. The result revealed that the tensile strength of the composite rope core yarns depends on the linear density, breaking elongation, Poisson’s ratio of the composite rope and modulus, twist angle, friction coefficient of strings. Six island phase structure composite rope core yarn with the same radius but different sisal hemp to PET filament ratio was prepared, and the tensile strength of the composite rope core was measured. The experimental results were in good agreement with the predicted results, indicating that this model provides a convenient and valuable approach in predicting the tensile strength of composite rope core yarn based on its material composition and spinning parameters. This work not only gives the simple calculation method for estimating the breaking strength of the composite rope core, but also has important significance for the optimal design of the composite rope core yarns.