| The support structure tubular joints of offshore wind turbines are easy to produce fatiguebecause of the effect of harsh environmental conditions such as effect of wind load, wave loadand current load, as well as seawater corrosion. Even worse, it is possible to cause the wholeproject construction accidents when fatigue failure happens in just a few joints. Therefore,fatigue analysis for the joints in dangerous partial is required when support structure design iscompleted. Besides, partial strengthen and optimization for tubular joints are needed whenanalysis result doesn’t meet requirements. In this paper, taken jacket offshore wind turbine asan example, I did fatigue performance research and fatigue damage calculation on tubularjoints. The main contents are as follows:1. The fatigue assessment method was studied, including fatigue design method, timedomain fatigue assessment method and frequency domain method in conventional fatigueanalysis.2. Wind load and wave load were introduced, including the calculation of aerodynamicload and deterministic and random wave load.3. Research and optimization for the fatigue performance of tubular joints. Taking Ttubular joint as a example, fatigue performance was researched in axial loading、in-planeloading、out-plane loading. Stress concentration factor was calculated under monocyclicstrengthen, bicyclic strengthen and tricyclic strengthen conditions. Tricyclic strengthen waschosen when compared results of all conditions above. On the basis,a research was done onstress concentration factor influenced by the size of ring. According to the result, an advisablesize was given.4. Fatigue analysis of jacket offshore wind turbine support structure. Using softwareSACS, the fatigue damage was calculated under wind load and wave load. Summed theresults with square and the square root method and the direct sum method, and thencomparing the results after the superimposition, the latter damage was significantly lowerthan the former... |
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