Numerical modelling study of a modified sandbag system for ballistic protection

• Published in: Journal of computational science 2021-07, Vol.53, p.101403, Article 101403
• Main Authors: Thawani, B., Hazael, R., Critchley, R.
• Format: Article
• Language: English
• Subjects: Ballistic plate; Compaction; Energy absorption; Sandbag; Simulation
• ISSN: 1877-7503; 1877-7511
• DOI: 10.1016/j.jocs.2021.101403

•Modification of the sandbag by addition of a plate reduced penetration by 15 mm because of the increased compaction of sand.•Placing the plate in the layer of compressed sand ahead of the projectile increases the compaction of sand.•Plexiglass and polycarbonate had the highest energy absorption and deformation.•Steel had the least energy absorption and deformation. Concrete and Aluminium showed a balance between energy absorption and deformation.•Plates of different thickness provided different levels of resistance against impact due to change in the areal density of the system. Modern field fortification systems are very large and cause a logistical burden during setup, thus setting the requirement for their modification. A simulation study was conducted to study the correlation between the compaction of sand and the energy absorbed by it when impacted by a solid steel projectile at 850 m/s. Furthermore, the sandbag was modified by the addition of plates in the system to observe the change in projectile penetration and the energy absorption behaviour of the sand. The factors considered for this study were the plate thickness (15 mm, 25 mm), plate material (aluminium, concrete, plexiglass, polycarbonate, steel) and plate location (226 mm, 236 mm, 256 mm from the point of impact). It was observed that a layer of compressed sand is formed around the projectile, aiding the energy absorption and dissipation process during impact. Upon addition of the plate, it was observed that the modified system (plate and sand) absorbed maximum energy when the plate is placed closest to the point of maximum penetration without the plate. It was also noted that the addition of the plate enhanced energy absorption characteristics of the system compared to conventional sandbags because of increased compaction of sand. From the study, it was observed that the plexiglass and polycarbonate plates had the maximum energy absorption and maximum deformation. The steel plate had the least energy absorption and minimal deformation. Concrete and Aluminium had comparable areal density, energy absorption and lowest deformation, making them the preferred choice of plate material for a modified sandbag. The numerical studies were verified using a gas gun and a modified sandbag with Aluminium plates to show that the addition of a plate improves compaction behaviour of sand.