Study On The Influence Of Geometric Parameters Of Tubular Joints On Fatigue Life Of Offshore Turbine Foundation Structure

With the reduction of non-renewable energy,offshore wind power has received more and more attention.One of the important reasons for limiting the development of offshore wind power is the cost problem.The accurate prediction of the fatigue life of the wind turbine foundation structures has an important impact on the optimal design of offshore wind turbines,and the stress concentration factor is an important parameter for evaluating the fatigue life of a tubular joints.Firstly,this paper introduces the research status of stress concentration factors of tubular joints at home and abroad,and some basic theories of fatigue life calculation.Because the S-N curve changes logarithmically,even a small change will have a great impact on fatigue life,so it is necessary to consider weld modeling in fatigue analysis of tubular joints.In this paper,the geometrical simulation of the tubular joints is carried out by SolidWorks software,and the geometric model is in accordance with the AWS Structural Welding Code.After the geometric model is established,it is imported into ANSYS for finite element analysis,and the element type is selected as the solid.This paper compares the maximum stress concentration factor and the distribution of stress concentration factor under the axial loading,the in-plane bending and the out-of-plane bending,including the complete weld profile Solid FE tubular T-joint models and T-joint models without considering the effect of a weld fillet,to provide a reference for the establishment of numerical model of practical engineering.In order to facilitate the interpolation calculation of hot spot stress,ensure the accuracy of calculation and reduce the calculation time,this paper uses partition grid deviding.In addition,the influence of different geometric parameters on the stress concentration factors of tubular joints is also studied,and the variation law of maximum stress concentration factor is summarized.Provide reference for the optimal design of the wind turbine foundation structures.When ? is greater than a certain value,the maximum stress concentration factor is less affected under three loading conditions.When the tubular joints are subjected to axial and in-plane bending,the change of ? has little effect on the SCF of tubular joints;when the out-of-plane bending moment loading on the braces,the SCF of tubular joints increases with the increase of ?.With the increase of ? and ?,the stress concentration factor of T-joints increases obviously.