Experimental and numerical investigation of the responses of scaled tanker side double-hull structures laterally punched by conical and knife edge indenters

This paper addresses experimental and finite-element simulation studies on scaled double-hull side structures quasi-statically punched at the mid-span by conical and knife edge indenters to examine their fracture behaviors and energy dissipation mechanisms. The specimen, scaled from a tanker double side, accounts for one span of the stringers in length and two spans of the web frames in width. The experimental results show that a double hull punched by a conical indenter shows much stronger resistance than that of a double hull punched by a knife edge indenter in severe collisions due to a difference in the fracture mode, while the double hull performs better in minor collisions punched by the knife edge indenter due to the deformation mode. In addition, numerical simulations are also carried out for the corresponding scenarios by the explicit LS-DYNA finite element solver. A relatively fine mesh in the contact area is used to capture the fracture initiation and propagation of the two specimens. The resistance-penetration curves and the deformations are compared with those observed in experiments, and these results match well. The numerical analysis discusses some aspects of particular relevance to the response of ship structures suffering accidental loads, including the importance of specifying the modeled welds, the influences of failure criteria, material relations on simulating complex structures, and application of scaling laws in assessing the impact response of full-scale structure.