Twisted impregnated yarns: elastic properties

Twisted yarns are normally used for increasing the lateral cohesion of fila ments and also for ease of handling. By twisting yarns, the microdamage can be localized, leading to possible increase in the failure strength of the yarns. In this paper, an analytical method is presented for predicting the elastic properties of twisted impregnated yarns made of long unbroken filam ents. In the analysis, various degrees of twist in filaments at different r adii of the yarn and possible migration and microbuckling are considered. T he effects of the twist angle and the extent of migration and microbuckling on the elastic properties and the pre-straining of the yarn are presented.