Numerical investigation on hybridization of woven fabric armour to enhance ballistic protection

The soft ballistic armour design requirement involves maximum ballistic energy absorption with lower backface deformation at minimum possible weight. Yarn mechanical properties play a primary role in influencing the above armour characteristics. The study reported to date has analysed the yarn properties, which will yield maximum ballistic energy absorption. However, finding the optimal combination of yarn mechanical properties that will simultaneously satisfy all the above objectives is still a matter of investigation. In view of this, the study first introduces a new parameter, "Inertial Work " (product of armour mass and backface deformation) which enables categorization of armour backface deformation in a mass normalized manner. Further, Specific Ballistic Energy Absorption (SBEA) parameter is introduced for comparison across the fabrics of different densities. The woven fabrics widely used in the ballistic protection domain Kevlar 29, Zylon AS and Spectra 1000 were extensively analysed numerically to study their ballistic response. FE simulation results showed that a single material armour would prove insufficient to simultaneously attain the above design characteristics. Hence a concept of hybridized multilayer-multimaterial armour was established to address this lacuna. It was found that hybridization significantly influenced the ballistic performance of armour. The arrangement of maximum layers of high toughness, low modulus - high failure strain material (Kevlar 29) in front, followed by a material with similar toughness but higher strength (Zylon AS) and then minimum layers of low toughness and low failure strain material (Spectra 1000) at the back resulted in higher SBEA and lower Inertial work.