The fatigue damage of a local joint is the key factor accounting for the structural failure of a jacket-type offshore wind turbine. Meanwhile, the structure experiences a complex multiaxial stress state under wind and wave random loading. This paper aims to develop a multi-scale modeling method for a jacket-type offshore wind turbine, in which local joints of the jacket are modeled in a detail by using solid elements, and other components are modeled via the common beam element. Considering the multiaxial stress state of the local joint, multi-axial fatigue damage analysis based on the multiaxial S–N curve is performed using equivalent Mises and Lemaitre methods. The uniaxial fatigue damage data of the jacket model calculated using the multi-scale finite element model are compared with those of the conventional beam model. The results show that the tubular joint of jacket leg and brace connections can be modeled using the multi-scale method, since the uniaxial fatigue damage degree can reach a 15% difference. The comparison of uniaxial and multiaxial fatigue results obtained using the multi-scale finite element model shows that the difference can be about 15% larger. It is suggested that the multi-scale finite element model should be used for better accuracy in the multiaxial fatigue analysis of the jacket-type offshore wind turbine under wind and wave random loading.

The Moso bamboo, a renewable green building material used in various new green buildings, have received extensive attention with the promotion of the concept of green buildings. To explore the mechanical properties of Moso bamboo connections with external clamp steel plates, the 16 specimens were designed by changing the bolt diameters and the end distances of the bolt holes. Their static tension tests were conducted to investigate bearing capacities and failure modes of different connection configurations. Based on test results, three failure modes of these connections were obtained, including the shear failure of bolt shank, bearing failure of bolt hole and punching shear failure of the Moso bamboo. The influence of bolt diameters and end distances of bolt holes on bearing capacities of the connections was quantitatively analyzed. Based on a simplified mechanical model, the analytical models were deduced for the bolt shear failure and the bearing failure of bolt holes. The results showed that the predictive values are in substantial agreement with the experimental results. Finally, the design and manufacturing suggestions are recommended for this Moso bamboo connections.