A Study of the Relationship Between Breaking Time and Breaking Load for Fabrics Tested on CRE and CRT Machines
1959
Tweedie, Audrey S. | Mitton, Margaret T. | Fry, J Margaret
A study has been made of the relation between breaking time and breaking load for six different fabrics, using 1-in. ravelled strips with 3-in. initial clamp separation, tested on a constant-rate-of-specimen-extension (CRE) machine operated at a number of rates of extension, i.e., cross-head speed. The fabrics used were cotton nainsook, heavy cotton duck, acetate/viscose gabardine, viscose crepe, and nylon taffeta, so as to cover a range of extensibilities and breaking loads. In general these fabrics showed a decrease in breaking load with increase in breaking time, as has also been reported in the literature for studies on fibers and yarns. Tests were also carried out on constant-rate-of-traverse (CRT) pendulum machines at two or three different speeds for each fabric. Good agreement was obtained between the breaking loads measured on the CRE and CRT machines when compared at equal breaking times. To put the measurement of breaking load of fabrics on a constant-breaking-time basis appears to offer the best means of obtaining comparable results with different types and capacities of testing machines. A breaking time of 20 ± 3 sec. has recently been proposed by ISO/TC 38 for single-strand testing of yarns on CRE, CRT, and CRL (constant-rate-of-loading) machines. The data obtained in this study on fabrics suggest that a breaking time of 20 ± 3 sec. will also be suitable for the measurement of the break ing load of fabrics on different types and capacities of machines. No evidence was ob tained in favor of a longer breaking time such as the 60 ± 10 sec. commonly used with CRL machines abroad.
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