The Influence of Weld Joints on the Failure Mechanism of Scaled Double Hull Structures under Collision Load in Finite Element Simulations

As a result of growing safety-related requirements in shipbuilding the design of double hulls in respect to accidents and collisions is mainly orientated on damage stability calculations. In order to increase the collision resistance and thereby the damage stability of ships the concept of an alternative stiffening system (English: plates strengthened stiffeners, German: Plattenverstärkte Profilsteifen – PVPS) invented by Röhr et al. (2008) was investigated for practical use within the scope of the project SideColl, funded by the German Federal Ministry of Economics and Technology (BMWi). A collision experiment with a scaled double hull structure is performed with the alternative stiffening system. Beside the experimental investigations numerical simulations with the finite element software LS-Dyna are conducted. With the adaption of suitable discretizations and fracture criteria in the finite element model the structural response in terms of the force-displacement curve are well predicted. Furthermore, the crack initiation and the failure mechanism are captured in good agreement with the experiment. An equivalent model for weld joints is applied to the double hull structure to reproduce the different material behavior at plastic deformations and fracture in the numerical analysis.