Engineering the geometry of novel yarns for flexible, hybrid composites Part II: Maximising the tensile properties

Part I of this study established the concept and built the theoretical basis for a novel composite yarn. Part II deals with practical aspects of producing the yarn structural parameters necessary for flexible textile composite uses. This study investigates how to maximise the number of breaks of the core or foundation component of the yarn by using the design of experiment method. The results have shown that the number of these breaks vary between 1.4 and 6 times in comparison with only one break that would result from a typical conventional ply yarn. The analysis of the results indicates that a low overfeed ratio of 121% of the undulating component can lead to ∼4.7 breaks of the foundation component in comparison with only ∼2.6 breaks that would result using an overfeed ratio of 158%. To increase the number of breaks of the foundation component, it is necessary to use a high number of wraps, a low overfeed ratio, more than one input yarn for the foundation component and an undulating component of high tensile strength, which enhances its synergy with the foundation component by self-locking during breaking. Increasing the number of breaks of the yarn enhances the performance and safety of flexible composites.