P 1410 – Extension of DIN EN 1993-1-10 to offshore conditions for notch cases on hollow section joints for jacket construction
To date, jacket structures in offshore applications have no standard rules for design with regard to material selection and toughness requirements. Therefore, the aim of this project is to transfer the concept of toughness verification based on material selection rules, which is well established in civil engineering, to jacket structures in offshore applications. Using fracture mechanics concepts for brittle fracture-resistant component design, a reference geometry is first identified, crack assumptions are made, and a crack propagation calculation is performed based on the determined load collective. This results in the fracture mechanics limit state analysis, on the basis of which toughness requirements are derived. It also takes into account the influences of strain rate, cold forming and the specific offshore application conditions. The fracture mechanics concept of material selection established in the field of building and bridge construction is thus successfully transferred to jacket structures. In addition, a methodology is being developed for the first time in the project to derive toughness requirements on the component in a specific application with the aid of a damage mechanics model. The Modified Bai-Wierzbicki model is used, which can simulate plasticity, ductile damage and brittle failure as a function of stress state, strain rate and temperature. For comparability between fracture mechanics and damage mechanics, the same boundary conditions are considered. Damage mechanics also derives toughness requirements, confirms the results of fracture mechanics and shows its conservative calculation method.
All research reports in german language only!
Prof. Dr.-Ing. B. Kühn, P. Krahl, M.Eng, Univ.-Prof. Dr.-Ing. S. Münstermann, D. Lenz, M.Sc.