3—THE STRENGTH OF SLIVERS OF RELATIVELY LOW TWIST

This paper deals with an approximate theory of yarn strength, which applies specifically to low-twisted yarns and slivers. This is based on a previous analysis given by one of the authors and on a sinipUfying assumption with regard to the tension distribution among the fibres. It is shown that it is important to use the more accurate formula than that due to Amontons for the connexion between frictional force and load, namely, F =μW n, It has been found that a good explanation of the breaking strength of twisted rovings is obtained, provided that tbe twist is so low that fibre breakage can be neglected. The analysis leads to a new formula for the strength of such structures that does not involve empirical factors and gives excellent agreement with experiment.