Yarn pull-out can be an important energy absorption mechanism during the ballistic impact of woven Kevlar® fabric. This study reports the effects of fabric length, number of yarns pulled, arrangement of yarns, and transverse tension on the force-displacement curves for yam pull-out tests on Kevlar® KM-2 fabric under laboratory conditions. A semi-empirical model is presented for predicting the yam pull-out force and energy as a function of pull-out distance, including both yarn uncrimping and subsequent yam translation. This model is found to replicate the experimental data with a high degree of accuracy, and should prove useful for understanding ballistic experiments and improving computational modeling of fabrics.
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