The Ballistic Response of Cross-Stiffened Panels from a Rocket-Propelled Grenade

Cruise ships often transit the littoral zone of developing countries where piracy thrives. The attack against Seaborne Spirit on November 5, 2005 was countered successfully by the ship's crew but the toll could have been a lot heavier that day. Nowadays, although international forces police high-risk waters, the risk map is constantly evolving, and there have been instances where even naval vessels had to change their route in order to avoid perilous areas. In the Seaborne Spirit attack approximately 100 miles off the Somali Coast, although the crew thwarted the pirates from coming any closer to the ship, the assailants managed to launch a rocket-propelled grenade (RPG) that miraculously failed to explode when it hit the ship's side. This paper carried out the analysis of blast and impact in a fluid–structure interaction model with LS-DYNA solver. The aim of the present paper is to investigate the ballistic response of cross-stiffened panels, commonly used in ship and offshore structures, from the impact with an RPG warhead. It was found that although an RPG alone cannot threaten a highly redundant structure as a ship or an offshore platform, the developed jet from the shaped charge is certainly threatening to passengers and crew.