Cryogenic crashworthiness of LNG fuel storage tanks

Shipping is gradually embracing natural gas as bunker fuel. The most viable way to store natural gas on board is in its liquid form. Gas needs to be cooled to cryogenic temperatures and in practice moderately pressurized. On board ships, solely double walled pressure tanks are used for this purpose. Loss of containment due to a collision, is one of the hazards to be addressed, because of both the flammable nature of natural gas and the low temperatures which will cause brittle fracture of the ship's structure when spilled. This paper reports how the crash energy absorbing capacity of cryogenic tanks has been investigated, computationally and experimentally. Results show that the tanks can absorb a significant amount of energy without bursting. This information is considered in the frame of a larger picture and the required distances by the guidelines between the ship hull and tank on the deck is open to discussions.