NONLINEAR BUCKLING ANALYSIS OF SLENDER HYBRID CONNECTIONS IN OFFSHORE WIND ENERGY CONVERTERS

摘要

For tubular support structures of Offshore Wind Energy Converters hybrid connections are the common type for joining Monopile and tower. They will also be used for high slender Monopile foundations in future. The buckling design of steel shell structures are only valid for tower and substructure but cannot be applied for hybrid connections. Within this paper the buckling strength of hybrid connections with high slenderness ratios is investigated. At first the state-of-the art for buckling design of steel sections is presented and several types of imperfections are discussed. Different material properties and the main geometrical dimensions of hybrid connections are considered. Additionally the method of quasi-collapse-affine-imperfections is presented. The different variables are implemented in a non-linear numerical model. For a reference structure the buckling strength is calculated and the influence of the imperfections in the buckling resistance is evaluated. The results from the numerical investigation are compared with analytical design procedures acc. to the standards.