FE analysis on 3D networked woven fabrics for ballistic protection

  • Wang Xu

Student thesis: Master of Philosophy

Abstract

Soft body armour consists of a fabric panel formed by layering numerous plies of plain woven fabrics together. The ways plain fabrics assembled together are believed to affect the stress distribution in the panel upon impact and may influence the ballistic resistance. Novel networked woven structures are employed in this research, where plain woven fabrics are separated and linked together in a predesigned fashion so as to enable stress propagation in the through-the-thickness direction as well as in the fabric planes. This research aims to verify the ballistic performance of the networked structure in comparison to panels made from layer plying based on 2-layer examples. For the networked structure, the influence of the length of separate and joint sections in the networked structure was investigated for their ballistic performance under high-velocity impact. Finite element (FE) simulation was employed to analyse the energy absorption performance of these two structures. In addition, the discrepancy between ballistic performance caused by varying the length of two sections in the networked structure was also studied numerically. A close-to-reality geometrical model was created for predicting the ballistic performance of the networked structure, and the model of single layer plain weave was validated with historical data including the residual velocities under different impact velocities, number of fractured yarns, and fabric fractured time. The results indicated a good agreement between the results from the FE modelling and the historic experimental data. The energy absorption of the 2-layer plain fabric panel and 2-layer networked fabric was calculated and compared using the FE method. It was found that networked panel absorbed 16.6% more energy than plain assembly with similar fabric construction and the same amount of material. Both the ply failure time and panel failure time of the 2-layer panel were earlier than that of the networked panel. The primary yarns in the networked structure contributed to more kinetic energy (KE) and internal energy (IE) absorption, and the secondary yarns absorbed more KE than that of the 2-layer panel. Also, the primary yarns in the 2-layer panel were found to fail earlier compared to that of the networked panel. It was also found that the networked panel was able to propagate more stress to the adjacent secondary yarns. Models for networked panels with different length ratios between the separate and joint sections were studied for parametric analysis. It was found that a shorter length of the separate section in the networked structure would result in earlier fractured time, and a longer length of the separate section would reduce the energy absorption. Increasing the length of the joint section would lead to more energy absorption though improvement is not significant. The influences of the structural parameters of the networked panels on different forms of energy were also investigated.
Date of Award1 Aug 2018
Original languageEnglish
Awarding Institution
  • The University of Manchester
SupervisorXiaogang Chen (Supervisor) & Lindsey Taylor (Supervisor)

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