Anisotropy of Wool

Abstract

The quantitative relationship is examined between torsion and tensile experiments done on wool fibers at various conditions of humidity and temperature. The relation ship between torsion and tension measurements on a two component fiber depends on the volume fraction of the two mechanically distinct components. The two me chanical phases of the wool fiber are first assumed to be isotropic, but no assumption is made about their volume fraction. On this basis a mechanically elastic phase refers to approximately 5% of the fiber, not about 50% as is sometimes supposed. The re maining 95% of the fiber acts mechanically as a water penetrable viscoelastic matrix. Allowance for anistropy in the mechanically elastic phase does not significantly affect its volume fraction. If the viscoelastic matrix phase is regarded as constituting 95% of the fiber, it can be considered as mechanically isotropic at all water contents. Because of the low filament volume fraction obtained, the results suggest that the microfibril is not the mechanical unit corresponding to the water unaffected phase of the two phase model.