Hot-spot stress caused by out-of-plane bending moments of three-planar tubular Y-joints

Abstract Tripod substructures have been widely used in China for building offshore wind turbines (OWTs); correspondingly, three-planar tubular Y-joints have gained considerable attention, especially in the fatigue design. The out-of-plane bending moment load is a classical load type for steel tubular joints based on the mechanical analysis of the whole structure. This study examines the performance of hot-spot stresses (HSSs) in three-planar tubular Y-joints subject to out-of-plane bending moments. First, the HSS expression of three-planar tubular Y-joints is presented. Test research is performed to discover strain distribution patterns and then to validate the finite element (FE) models. Using this FE method, a dataset composed of 1920 cases is assembled and a set of design equations are thereafter derived after a series of analyses of geometric parameters. An evaluation based on a recognized acceptance criterion of proposed parametric equations is carried out.