MECHANICAL-PROPERTIES OF FABRICS WOVEN FROM YARNS PRODUCED BY DIFFERENT SPINNING TECHNOLOGIES - YARN FAILURE AS A FUNCTION OF GAUGE LENGTH

In a study of yarn strength translation into woven fabric behavior, experiments were conducted to establish the effect of test gauge length on yarn properties. Yarns produced on each of the three major spinning systems were tensile tested at varying gauge lengths. Yarn strength data were fit to two-parameter Weibull distributions and corresponding shape and scale parameters were determined. Strength increased as gauge lengths decreased, a trend indicated by the weakest-link theory. At very short gauge lengths, however, the data deviated from prediction based on the weakest-link theory, thus suggesting a change in the yarn failure mechanism, as one would expect when the gauge length approximates the staple length. More direct evidence of such a change is provided in SEM photomicrographs of tensile failures of long versus short gauge test specimens. Combined fiber slippage/pullout and breakage prevailed at longer gauges, whereas a greater extent of fiber breakage with less slippage occurred at shorter gauge lengths. The balance between fiber slippage and fiber breakage varied with yarn structure as produced on different spinning systems. Finally, tensile tests were conducted on plain and twill weave fabrics woven from yarns produced on the different spinning systems. The resultant fabric tenacities approximated corresponding yarn tenacities only for the shortest gauge lengths.