Stability And Fatigue Strength Analysis Of MW Wind Turbine Tower

The public voice for improving the environment of earth is rising, along with the globalclimate warming and the deterioration of ecological environment becoming serious. Theattention is increasingly paid to the wind power as clean and renewable energy by nationalgovernments. High tower is increasingly applied as the main bearing component of the windturbines, which is heading for high power direction. Operation security and reliability of thesystem are affected by the strength of tower, which is the important component of windturbine design. Therefore, it is of great importance to analyze the strength of tower.In this thesis,2MW wind turbine tower of one Co. is studied based on cylinder towerunder bearing load and constraint conditions. The finite element model of tower isestablished with the finite element software ANSYS12.0for different types to performstrength design. The main contents are concluded as follows:（1）Statics analysis-the finite element SOLID186is adopted to analyze the resistanceof ultimate load damage for the tower and to find stress, strain, stiffness and displacementdeformation under ultimate conditions. The stress at dangerous point is checked withstrength theory and overload damage is prevented to ensure safe and reliable operation ofwind turbine in heavy weather conditions.（2）Dynamic characteristics analysis-the impeller at the top of tower, ladder, platformas accessories in tower and foundation stiffness on the effect of dynamic characteristics oftower are considered. The finite element BEAM188is adopted to find the vibration modalof tower (modal and harmony response analysis). Simultaneously the mechanicscharacteristics of free vibration of wind turbine tower are researched to avoid resonance andto meet the requirements of vibration design.（3）Buckling analysis-in response of phenomenon tower collapse during the operationof wind turbine, based on the theory of pressure bar stability, the finite element SHELL93and the nonlinear buckling analysis method are used to calculate the nonlinear buckingeigenvalues and buckling modes of tower with the axial loads. The bucking eigenvalues canbe used as the upper limit of bearing capacity to inspect if the bearing capacity of tower canbe met in the non-ideal environment.（4）Fatigue strength analysis-linear damage accumulation verification method isadopted to analyze the fatigue strength of tower. The dangerous point (where the stress is maximum) is determined, the fatigue status is analyzed through fatigue analysis module tocheck fatigue strength and estimate the safety service life of tower.Analysis result shows that the tower strength is assured, which is safe and reliableduring the operation of wind turbine.