Wool-fibre Crimp Part I: The Effects of Microfibrillar Geometry

摘要

Microfibrils differ in their geometrical arrangement between the orthocortex and the paracortx of a wool fibre. An inestigation is reported as to whether these differences, combiend with a large shrinkage perpendicular to the fibre direction as the fibre dries from an intial wet state, could account for the curvature of the fibre. The orthocortical microfibrils are characterised by `whorl-like' structures, and the initial investigation models a single whorl as an assembly of uniform helices. A finite-element model is developed to extend the modelling to characterisea more realstic fibre. The model shows that, even with conservative assumptions regarding the internal geometry and shrinkage, realistic fibre curvatures are calculated, and this supports the hypothesis.