On the ballistic impact behavior of foam-filled honeycomb core/composite skin sandwich panels

This paper develops a numerical model to simulate the ballistic impact of projectile on a sandwich panel with a foam-filled honeycomb core and a composite skin to study the effect of adding foam to the sandwich panel on its ballistic behavior. Therefore, focusing the material model of different components, a range of validation studies were performed based on the experimental results available in the literature. These validation studies were performed for high-velocity impact of the projectile on the honeycomb, the foam-filled honeycomb, and the sandwich panel with the honeycomb core and composite skin. The numerical models of validation studies were accurate in predicting the ballistic limit velocities of different impacts, because of using suitable material models including strain rate effect for aluminum honeycomb and also fracture model for foam and Hashin damage for composite as a VUMAT subroutine. The ballistic behavior of the sandwich panel consisting of a composite skin with different layers and the foamless and foam-filled honeycomb core has been studied to investigate the effect of adding foam to the honeycomb core. The results show that adding foam to the honeycomb core of the sandwich panel increases energy absorption by plastic deformations of the foam and frictional dissipation energy, which increases the ballistic limit velocity and its specific energy absorption. According to the results, adding suitable foam to the core of a sandwich panel with two-layer composite skins has much better specific energy absorption than increasing the number of skin layers up to eight.