A Study on the local joint flexibility (LJF) of two-planar tubular DK-joinst in jacket substructure of offshore wind turbines under in - plane bending loads

This paper presents parametric equations to predict the local joint flexibility (LJF) of two-planar tubular DK-joints in jacket substructures of offshore wind turbines subjected to two critical different types of in-plane bending (IPB) loads. Finite element (FE) package ANSYS 16 is adopted to simulate the joint with 8-node solid element. The FE method is verified based on the existing simple T/Y-joints. An inclusive parametric study is subsequently conducted to investigate the effect of non-dimensional parameters on the local joint flexibility coefficient (fLJF). According to the finding from parametric study, significant design recommendation are put forward to reduce the LJF of the joint. A set of parametric equations are developed based on 8-node solid FE models and have been assessed against the acceptance criteria of the UK DoE. Finally, the comparison of fLJF between the proposed parametric equations and existing K-joint parametric equations indicates that the use of the latter to predict the LJF of two-planar DK-joints may be considerably under-predicting

Keywords:

Local joint flexibility (LJF) , Offshore wind turbines , Parametric equations , Tubular DK-joint , In-plane bending (IPB)