Fatigue curves elaborated for selected worsted wool yarns

There is not any elaborated methodology for making diagrams of fatigue strength curves for yarns presented in world wide literature. Thus, we proposed our own methodology for measuring the properties of fatigue strength, using worsted wool yarns as an example. The object of the research presented was worsted wool single yarn with linear density of 16 tex and 25 tex produced with the use of a FIOMAX 2000 ring spinning machine from MESDAN. In order to prepare a graphical presentation of fatigue strength we carried out tests on seven groups measuring series, which corresponded with the specific amplitude of load through a given cycle. We increased the number of series with respect to the stochastic character of the yarn strength properties. As a result of this we obtained a very good fitting of Wohler characteristics with experimental observations.