53—THE MECHANICAL PROPERTIES OF TWISTED CONTINUOUS-FILAMENT YARNS

This paper deals essentially with certain theoretical aspects of the mechanical properties of twisted continuous-filament yarns. In particular, the effect of the equalization of filament tensions on initial modulus, tenacity, and breaking extension is discussed. Equalization of filament tensions may occur as a result of reducing inter-filament frictional forces to a low value. It has the effect of increasing tenacity and extension at break relative to a yarn in which equalization of tensions is prevented by high frictional forces. The significance of filament bending strains is also discussed and it is shown that these may be of considerable importance in relation to tenacity and extension at break for yarns consisting of filaments with extensions at break of the order of 10% or less. Some experimental data are presented which tend to support the theory in regard to the effect of the equalization of filament tension.