Failure assessment of transition piece of jacket offshore wind turbine

The present study performs a failure assessment of the transition piece of a jacket offshore wind turbine based on a nonlinear finite element analysis. The extreme and fatigue loads acting on the offshore wind turbines increases since the size of the wind turbine increases. Therefore, it is aimed here to develop a multi-dimensional failure criterion to be used in the early stages of the design. Once the structure is subjected above its design loads, it is expected to fail either by tension failure (rupture), buckling, or both. High amplitude plastic strains occurred at the welded-tubular connections, because of the extreme loads and high stress concentration, are dealt with the low-cycle fatigue damage approaches. Using the Neuber's rule, the global stress range is transformed into a true level of stress-strain, where there is a high-stress concentration located. Moreover, the nonlinear structural behaviour under compression is assessed by performing a FE analysis accounting for the nonlinearities related to geometry and material properties.