An energy model of yarn bending

Abstract

This paper describes a new energy model of yarn bending. The fibre bending and torsion energy terms are considered. The fibre helices could be naturally curved. Fibre helices in a bent yarn are generated by a rotating vector. The singularity of torsion along a bent fibre helix is discussed. By allowing the rotation speed of the rotating vector to vary exponentially along the fibre path, a more realistic fibre path can be defined and the singular point of torsion can be avoided. Fibres are allowed to self-detwist in order to minimise the total potential energy of the bent yarn. Inter-fibre frictional effects have been neglected. Experimental work on yarn bending has been performed to validate the new model. A good level of agreement has been found between the theory and the experiment.