Internal mechanical characteristics of woven fabrics have a great influence on the behavior of different types of fabrics even for apparel application with deformations like yarn running, tearing and drape and other simple deformations, or industrial fabrics undergoing fragment impact, projectile penetration or other large deformations. Frictional forces, which are involved in load transfer and energy absorption, determine directly the magnitude of the interactions within the fabric. As a physical study, pullout test is a conventional and suitable method to investigate the effects of yarn properties and the structural characteristics of weave on fabric mechanical behavior. Frictional specifications of the fabric yarns influence fabric strength and efficiency and its ability in absorbing energy. First part of this study is concerned with formulating an analytical model on yarn pullout force in plain-woven fabrics. The model can predict variations in the internal mechanical parameters of woven fabrics based on a force-balance analysis. These parameters are yarn-to-yarn friction coefficient, normal load at crossovers, lateral forces, lateral strain, weave angle variations and pullout force. These parameters were predicted using fabric deformation data, which were measured by image processing method during a yarn pullout test and the information of, weave angle of fabric, its modulus, and density, which were obtained experimentally. Yarn pullout force was calculated through Amonton’s friction law to evaluate the efficiency of the presented Force-Balance model. This study demonstrates that the force-balance model is correlated quantitatively with the experimental yarn pullout results.
