Failure analysis of 3-D woven and 3-D knitted structures

Abstract

Attributable to complex structural characteristics, the 3-D hierarchical structures possess different failure modes as compared to the traditional laminate structures, resulting in improved impact resistance properties. In this work, a comprehensive study of ballistic performance of 3-D woven and 3-D knitted structures has been undertaken and suitability of these structures for various applications on the basis of their geometrical distinctiveness has also been described. Different material systems have been investigated which are considered to be suitable for ballistic applications. Ballistic testing has been performed on leading 3-D hierarchical structures woven/knitted by polyamides (aramid, PA-6) and ultra-high-molecular-weight-polyethylene (UHMWPE) filaments to study their failure mechanisms against 30. Cal FMJ projectiles. The experimentation has been performed utilizing light-gas gun apparatus, under the instructions provided by internationally known standard NIJ-0101.06. Furthermore, appropriate sabot design has been scrutinized which is crucial to the whole experimental procedure, as sabots hold the projectile into the gas gun barrel and plays the key role in keeping the projectile straight and maintaining its velocity. Damage patterns were found to be different in knitted and woven structures; as knitted structures showed smaller damage affected region as compared to woven preforms.