Strength assessment of aluminium and steel stiffened panels with openings on longitudinal girders

The ultimate compressive strength of equivalent stiffened panels made of aluminium and steel is analysed numerically and compared. This equivalence is established based on the design formulations as defined by the Classification Society Rules. Novel web girders, with openings for passing pipes and cables, are designed, and their importance on the ultimate strength of stiffened plates is assessed. This type of structural configuration is often applied in the design of the ship decks and superstructures. A series of finite element analyses are performed in order to evaluate the ultimate compressive strength of the equivalent aluminium and steel stiffened panels employing different design solutions. The welded heat-affected zone of aluminium structures and different boundary conditions in finite element analyses are considered. The results have shown that the equivalent stiffened panels yield at the same compressive load, but the aluminium panels have higher ultimate strength than the steel panels. Finally, the effect of the openings on web girders, heat-affected zone and boundary conditions are discussed.