Bending rigidity of yarns using beam method on a two-support configuration

This article presents a simple, quick and reasonably accurate approach for measuring the bending rigidity of yarns. The Beam Method was adapted and applied using a bending frame that has a fixed support and a simple support. The yarns were left to bend under the effect of their own weight. The accuracy and the precision of that bending frame was assessed over time using an isotropic material and compared against the Ring-Loop Method and the KES-FB-2 Pure Bending Tester (i.e. Kawabata’s device). It was found that the precision of that bending frame was acceptable over time. However, it gave at least 1.6 times greater values of bending rigidity than the KES-FB-2 Pure Bending Tester, though the relationship between these two methods was linear and significant. Moreover, the spun yarns appeared to have high levels of variability of the bending rigidity. This study is important as it overcame the challenges faced when using other methods to measure the bending rigidity of yarn. It also provided a comprehensive account of the variation in this property. Further, it gave an indication of the highly non-uniform structure of spun yarns and the impact of yarn defects on the bending properties of yarns.