Ballistic Response of a Glass Fiber Composite for Two Levels of Threat

Abstract

This paper presents the behavior of composite panels based on glass fiber unidirectional fabrics and a bi-component epoxy resin under ballistic impacts that characterize two threat levels: FB2 and FB3, according to EN 1523:2004. The tested panels had characteristics kept in narrow ranges: thickness 18.26 ± 0.22 mm, mass ratio fabrics/panel 0.788 ± 0.015, surface density 27.51 ± 0.26 kg/m2. After testing the panels, the failure mechanisms of the panel were evidenced by scanning electron microscopy and photographs. Here the authors present a finite-element model at meso scale that was used for evaluating if the composite, initially tested at level FB2 (9 mm FMJ, v0 = 375 m/s), could withstand the higher level of impact, FB3 (projectile type .357 Magnum and impact velocity of v0 = 433 m/s). Simulation was performed in Explicit Dynamics (Ansys), keeping the same target but changing the projectile for the two different levels of threat. The results of the simulation were encouraging for making tests at level FB3, indicating the importance of alternating actual tests with simulations in order to achieve better protection with reduced surface weight. The simulation illustrated differences in impact duration and number of layers broken on the panel for each level. Validation of the model was based on the number of broken layers and the dimension of the delamination zone between the last two layers. Scanning electron microscopy was used for identifying failure mechanisms at the micro and meso scale. We found that damage to the composite was intensively dependent on impact velocity, this being quantitatively evaluated using the number of layers broken, the effect of delamination on separating layers and the deformation of the last layer.

Numerical simulation of composite materials with sisal and glass fibers for ballistic impact resistance

“…These parameters include impact velocity and angles. The behavior of composite panels based on glass fiber woven fabrics and a bi-component epoxy resin under ballistic impacts was evaluated using a finite-element model at the meso scale [20] while considering parameters such as projectile material, size, and speed [44]. The development of a comprehensive framework for the design of composite structures at different levels requires accurate mathematical and computational models that can simulate the dynamic impact on composite panels [45].…”

“…Additionally, the orientation of the fibers in the impact direction has been found to improve the impact energy absorption and overall mechanical response of the composites [50,51]. Finite element simulations have been used to evaluate the behavior of composite panels under ballistic impacts, providing insights into the number of layers broken, delamination effects, and deformation patterns [20].…”

“…This hybridization can result in a material with improved ballistic performance and impact resistance, making it suitable for use in protective applications [18,19]. The combination of biodegradable and renewable sisal fibers with synthetic and durable glass fibers also provides environmental benefits by using a sustainable and renewable resource [20]. Overall, the hybridization of glass and sisal fibers offers a promising solution to improve the performance and sustainability of materials used in protective applications [21,22].…”