G. A. V. Leaf

1—THE INITIAL LOAD–EXTENSION BEHAVIOUR OF PLAIN-WOVEN FABRICS

An analysis of the initial load–extension behaviour of plain-woven fabrics is presented, Castiglianos theorem being used as the principal method of attack. Yarn compression and extension are taken into account in addition to yarn bending rigidity. The theory is compared with some experimental data.

26—THE ELASTIC RESISTANCE TO BENDING OF PLAIN-WOVEN FABRICS

The elastic resistance to bending of woven fabrics has previously been considered in terms of the existence in the yarns of rigid and elastic sections. The difficulties inherent in such a model and the noticeable differences between the predicted and experimental findings are examined in this paper. Two models of a plain-woven fabric in which the yarn cross-sections are incompressible are then analysed theoretically to obtain the predicted relationship between the applied couple and the curvature of the fabric. In the first model, the yarns are considered to be unset, i.e., if released from the fabric, they would be uncrimped, and in the second model they are considered to be completely set, i.e., if released from the fabric, they would retain all their crimp. The predicted bending resistance does not agree with the behaviour of actual fabrics owing to the difficulty of defining the ‘radius’ of the yarn in the fabric, but many puzzling qualitative aspects of the bending behaviour of woven fabrics are, as ...

32—THE MECHANICS OF AN IDEALIZED WEFT-KNITTED STRUCTURE

This paper describes a model of relaxed plain weft-knitting and, by consideration of the forces acting between loops, both in the interlacing region and at possible course- and wale-jamming points, derives equations whose numerical solution gives the loop shape, fabric dimensions, and magnitudes of the forces and couples acting on the yarn.

The Initial Bending Behaviour of Plain-woven Fabrics

The relation between the flexural rigidity of a plain-woven fabric and the fabric and yarn parameters, such as thread spacing and crimp, yarn flexural rigidity, etc., is discussed. Some experimental data to test the theory are presented.

9—THE UNWINDING OF YARNS FROM PACKAGES PART I: THE THEORY OF YARN-UNWINDING

This paper reviews the theory of unwinding from yarn packages and discusses the effect of air drag and gravity on the balloon parameters.

15—THE INITIAL SHEAR MODULUS OF PLAIN-WOVEN FABRICS

A theoretical expression for the initial shear modulus of a plain-woven fabric is derived and is then compared with the moduli of a range of woven fabrics.

Fibre Behaviour in the Twisting Zone of a Friction-spinning Process

A simple model of a fibre landing in the twisting zone of a friction spinner is described. The effects of fibre properties, air flow in the feeding tube, landing angle, and initial fibre configuration on the shape of the fibre after landing are considered.

A Study of the Frictional Properties of 1×1 Rib-knitted Cotton Fabrics

A new frictional constant is suggested to characterize the surface mechanical properties of 1×1 rib-knitted cotton fabrics. This study examines the influence of structural variables on the frictional properties of knitted cotton fabrics. The results indicate that both the loop length and the yarn linear density influence the fabric-on-fabric frictional properties. The variation in the structure of knitted fabrics is reflected in the frictional properties as defined by the new frictional constant. A statistical relationship is established between the frictional constant and the variables that exert some influence such as the loop length and the yarn linear density.

10—THE UNWINDING OF YARNS FROM PACKAGES PART II: UNWINDING FROM CYLINDRICAL PACKAGES

The particular case of unwinding from cylindrical packages is considered. Tables of balloon parameters are given for various unwinding conditions, and empirical formulae for estimating these parameters are presented.

21—THE NATURE OF INTER-FIBRE FRICTIONAL EFFECTS IN WOVEN-FABRIC BENDING

Inter-fibre friction in woven-fabric bending is discussed in terms of the fibre and fabric characteristics that influence its effect on a fabrics bending resistance. A model of the contribution of inter-fibre friction to fabric bending is developed. This model is combined with an existing model of the contribution of fibre bending to produce a new three-element model of a woven fabric in bending. The behaviour of this model is compared with experimental measurements on real fabrics in cyclic bending.