Fatigue Analysis On Foundation Of Offshore Wind Turbine Under Multiple Loads And Coupling Action

Wind energy is a clean energy. Global is researching the wind power technologynowadays. In consideration of the huge wind power on the ocean, offshore wind powerbecomes the important field of new energy power generation, especially the offshorewind turbine. Offshore wind turbine is acted on periodically by various loads, so thefatigue design of offshore wind turbines needs high quality. The structure of offshorewind turbines vibrate under the action of high-intensitive wind and wave, even resonate.In consideration of this, article rely on the Doctoral Scientific Fund Project of theMinistry of Education(2012552211004) and the Key Project of Natural Science ofFoundation of Chongqing(cstc2013jj3002), and make fatigue analysis under the actionof various loads using theoretical analysis and numerical simulation.The paper mainly emphases on the following contents:1. Contrast the common theory of pile-soil interaction under the transverse load inthe load form, geological condition, and embedment depth and soil deformation. Afterthat, select P-y curve method as the most suitable calculation method. Calculate the P-ycurves of the soil around the pile foundation based on project case.2. Describe the wave process with stochastic process. Contrast the common wavespectrum and then choose P-M spectrum as the wave spectrum. The hydrodynamicforces on the pile were calculated by Morison equation with the P-M spectrum. The dataof operation load from offshore wind turbine manufacturer. The wave load andoperation load can provide data which analysis coupling effect.3. Build the mechanical model of pile-soil interaction by P-y curve calculated.Recommend element characteristics which used to build the offshore wind turbine pilefoundation model in ANSYS. We make a modal analysis to get the natural vibrationcharacteristics of foundation.4. On the basis of tripod type foundation, article caculate stress amplitude ofcritical area using hot stess method. The S-N curve and Miner linear accumulativedamage method are employed to calculate the fatigue damage.5. Article obtain the dangerous conditions by contrasting fatigue damage on thedifferent conditons for tripod type foudation, and the maximal area of the fatiguedamage. Then article forecast the life of tripod type foudation rely on linearaccumulative damage method for offshore wind turbine.