Page 83 - Fiber Fracture
P. 83
68 J.W.S. Hearle
Axial Splitting
The theory of bent beams shows that variable curvature is accommodated by shear
stresses, which are a maximum on the central plane. In fibres undergoing flex fatigue
these shear stresses can cause failure by axial splitting, Fig. lOf,g.
Fig. IO. (a,b) Polyester fibres after a single bend. (c-e) Flex fatigue in polyester: kink-band fracture. (9
Flex fatigue: shear splitting in nylon. (8) Flex fatigue: shear splitting in polyester. For further explanation,
see Fig. 1.
Fig. 11. Biaxial rotation fatigue. (a,b) Thick polyester fibre. (c) Finer polyester fibre. For further explanation,
see Fig. 1.
