During the fibre bending-abrasion test, the fibre sample is cycled back and forth over a wire or thin pin under given tension and defined angle, e.g. 90°. In this test, the number of cycles up to fibre breakage is the measured variable. Concerning fibres for apparel textiles, the test provides a measure for the tendency to pilling of the woven- or knitted fabric: The smaller the cycle number to break, the lower is the tendency to pilling, since the pills that develop during textile wear would be shed within a short period. With this test, for example, Polyester fibres that show little or no pilling have a life span of less than 1000 load cycles, whereas fibres with poor pilling characteristics can reach up to 100000 cycles.

The opposite is desired for fibres used for carpets: Fibres for carpet piles must be highly resistant to bending stresses in order to avoid premature breakage during heavy wear of the carpet.

The bending-abrasion test is also suitable for staple fibre yarns concerning their resistance to cyclic stresses during subsequent processing, e.g. for warp yarn in weaving. With flax fibres, the fibres increasingly divide into small single fibrils when subjected to the bending-abrasion test, which provides information concerning processing properties.

Finally, in the area of hair care products, conclusions can be drawn regarding the influence of the treatment media on hair characteristics, such as elasticity or brittleness, by subjecting the treated human hair to the bending-abrasion test and analysing the results.

A further test method in addition to the bending-abrasion test is the cyclic stress test. Here, the fibre or yarn is subjected to an alternating change between tension and full relaxation. The measured variable is again the number of load cycles up to break occurrence. Such cyclic stress tests also supply valuable information regarding the fibre or yarn properties during processing, performance characteristics, e.g. for carpets, or the effects of special treatments in the case of human hair.

The above contents can be subject to changes by Textechno.