Page 85 - Fiber Fracture

70 J.W.S. Hearle

Fig. 12. Surface abrasion. (a) Kevlar pulled to-and-fro over a pin. (b) Wool against a rotating pin. (c) Nylon
against a rotating pin. (d) Yam-on-yarn abrasion of polyester. (e) From wet nylon rope after tension cycling.
(f,g) From worn nylon Hovercraft rope. For further explanation, see Fig. 1.

Failure in Use

The most commonly observed form of failure in the ordinary use of textile fabrics
is multiple splitting, which may be caused by bending with variable curvature, twisting
or a combination of bending and twisting. Another common form is kink-band failure
when fibres are forced to buckle into sharp kinks, which may be followed by axial
splitting. After breakage, continued wear rubs away material to give a rounded fibre end,
Fig. 13a.

CONCLUSION

The aim of this paper has been to illustrate the diversity of form of fibre fracture.
Any discussion of the mechanics involved in fibre fracture must be in the context of
the pattern of deformation and cracking. Some brief explanations of the mechanisms
involved and some examples of the materials and circumstances leading to particular
forms of break have been included. Many more examples, both from laboratory testing
and failure in use, are given in the Atlas of Fibre Fracture and Damage to Textiles by