Morphometry of Wool Fibres

Abstract

THE occurrence of irregularities in the shape of the cross-section of wool fibres along their length is well known. The variations are in the area and ellipticity of the cross-section as well as the inclination of the major axis of the ellipse. Efforts have been made to take account of these irregularities in the interpretation of mechanical tests on fibres both theoretically^1–3 and experimentally⁴. Disagreement and high variance of results exist in published determinations^5–7 of fibre breaking stress and its dependence on average fibre diameter, breed and age of sheep. Some recent experiments⁸ basing the breaking stress on the minimum instead of the mean cross-sectional area within the test length showed a lower variance and indicated the importance of examining the area variations in greater detail as suggested long ago by Rossouw⁹. This has been done with a newly developed fibre rotator and a much finer structure of irregularity has been found than might have been expected.