1957 Volume 13 Issue 2 Pages 95-101
It is well known that the characteristic performance of the force-extension curve of fibre assemblies such as card sliver, top and roving mainly depends on gauge length and density of fibre packing in assembly. In preceding paper, the general forms of relation between the elastic behaviour and gauge length of sliver were discussed.
In this paper, using same method as described in previous reports, the effects of volume fraction upon the stress-strain relation, the breaking elongation and the rupture force of compressed sliver were investigated.
In the theoretical treatments, the following results were obtained in the range of small values of fraction (_??_/ρ).
(1) Initial Young's modulus E0 was proportional to the cubic power of (_??_/ρ).
(2) Initial Poisson's ratio ∑0 was nearly constant for various (_??_/ρ)
(3) Rupture force PM of sliver having volume fraction (_??_/ρ) was given by where k was linear density of sliver, a and b were constants determined by gauge length.
The dependencies of the volume fraction on the observed values of E0 and ∑0 in the measurements of the lateral contruction and the force required to stretch crimped rayon staple sliver having volume fractions of 0.01 to 0.04 coincided with the theoretical relations (1), (2).
It is also found that the experimental relations between PM and (_??_/ρ) for the wool top slivers reported by Anderson, Cox and Hardy1) agreed fairly well with the theoretical formula (3) over the volume fraction range of 0.04 to 0.1.
