This study consists in assimilating the phenomena of rupture and slip of fibers in textile yarns during of traction and relaxation.

To achieve this study, it is necessary to take account of:

·   Mechanical and physical characteristics of textile fibers (smoothness, tenacity, lengthening of fibers …).

·   Parameters of development of the yarn (ring or rotor spinning yarn).

·   Torsion.

Correlations between the parameters of manufacture with the dynamometric properties of the fibers will be studied by using the experimental designs to see the parameters which influence the rupture of yarns using the methods of modeling of the rheological behavior.

mechanical and physical characteristics of textile fibers, rupture and slip of fibers in textile yarns, tenacity, regression equation, mechanical behavior of yarns, breaking load, breaking strain.