Fatigue Analysis Of Self-Elevating Wind Turbine Installation Vessel Under Operating Conditions

With the global scarcity of energy resources,wind energy is gaining attention as a renewable and clean energy source.The offshore self-elevating wind turbine installation vessel with self-propelled capability belongs to the category of large offshore engineering equipment that can carry loads.The hull structure has a large range of stress changes and is prone to fatigue damage.Therefore,the design requirements for structural fatigue strength are high.In practical engineering calculations,environmental loads are often considered while neglecting the impact of working loads on fatigue performance.Based on the research of a 2200 ton self-propelled and self-elevating wind turbine installation vessel independently designed by domestic enterprises,this article analyzes the effect of working load on structural fatigue under operating conditions.The main work content is as follows:Firstly,the existing fatigue analysis methods for marine engineering structures are summarized and analyzed.The advantages and disadvantages are compared and the applicability is judged.According to the structure of the self-elevating wind turbine installation vessel,the overall structural model of the self-elevating wind turbine installation vessel is established by SACS software.The calculated working conditions of the wind turbine installation vessel under operation are divided into two working conditions: environmental load acting alone and environmental load acting jointly with working load.Secondly,combined with the environmental parameters under operation and the working parameters of the crane,the overall strength of the self-elevating wind turbine installation ship structure under different calculation conditions is checked by using the load resistance coefficient method.The spectrum analysis method is used to calculate the fatigue damage of the self-elevating wind turbine installation ship structure under environmental load,working load alone,and the combined action of environmental load and working load.The structural fatigue damage value is obtained under the target working condition.Finally,the average stress and fatigue damage values of the structure under the ambient load alone and the combined ambient load and working load are compared to analyze the effect of the working load on the fatigue performance of the self-elevating wind turbine installation vessel under the operating conditions.By introducing the fatigue damage caused by the selfpropelled condition of a self-elevating wind turbine installation vessel,the overall structural fatigue life changes after adding working loads are analyzed.It is concluded that the average stress of the overall structure enlarges and the fatigue damage parts increase after considering the working load.However,the overall fatigue life of the structure decreases slightly and the fatigue life still meets the requirements of the structural design life.