Crimping of wool fibers

Two mechanisms for generating additional crimps in wool fibers have been inves tigated, each of which involves putting the fibers through an extend/release cycle. The first mechanism, which can occur in single fibers with a bilateral structure, is thought to involve differential stress relaxation in the ortho and para cortices of the fibers. This leads to differences in the unstressed lengths of the cortices and causes crimping in the unconstrained fibers. The second mechanism of crimping, which is operative only in fiber assemblies, involves partial drafting as the assembly is extended, followed by buckling of slipped fibers as the assembly is released. This mechanism is not restricted to fibers with a bilateral structure.