Numerical Study of Inter-yarn Friction on the Failure of Fabrics upon Ballistic Impacts

This paper investigates the influence of inter-yarn friction in fabrics on the ballistic performances of the target including failure. Finite element (FE) method was adopted for the study, where FE models were established for two types of fabrics based on the yarn properties of Twaron® and Dyneema®, respectively. Numerical analyses on the responses of the primary and secondary yarns in the fabrics subjected to ballistic impact were carried out based on these fabric models. The results show that larger inter-yarn friction leads to less slippage of primary yarns at impact centre. In addition, higher inter-yarn friction make more involvement of the secondary yarns join in loading the impact energy, so as to alleviate the loads in primary yarns and prolong the failure of primary yarns. However,if the inter-yarn friction is too high, beyond coefficient of static friction (CSF) of 0.8 and coefficient of kinetic friction (CKF) of 0.75, the action would be counterproductive. The reason is that the stress at those inter-yarn friction levels would be more concentrated on the primary yarns, resulting in an earlier failure of a fabric.