Analysis On Strength And Dynamic Stability Of Offshore Wind Turbine Blade

Electricity generation by wind power is being developed from the land to the offshore.Due to the great variability of offshore wind speed,the stress subjected to blades is complicated,which causes the wind turbine blades to work improperly,and even makes the blades fail and damage.For that reason,the research on strength and vibration stability analysis for wind turbine blades is becoming a key issue which needs to be urgently solved under complicated offshore wind conditions.In view of this,based on 3D blade model built by UG software,ANSYS,Matlab and Profili are employed to study the influences of random wind speed and rotational angular velocity on vibration and strength of blades and search the dynamic instability region on blades relevant parameters under the condition of particular sea wind.The research work was done by using the models aforementioned as follows:1)The basic aerodynamics theory of wind turbine was applied to build blade aerodynamic model in the case of stationary and rotating working,and the dynamic control equation of blade structure was also established based on coupling vibration model of bending and torsion for the blade by using generalized coordinates and systemic Lagrange equation.2)By introducing Davenport spectrum model which is closer to the actual working condition,Matlab and Profili were employed to calculate the random wind load,and the 3D modeling software named UG was used to solve the structured mesh generation which is hardly carried out for the irregular model by finite element methods.3)Dynamic characteristics of the wind turbine blades under different wind speeds were simulated and analyzed under the condition of stationary and rotating working,and then contrast analysis of stresses and strength check were achieved in the same two cases.4)The effects of average wind speed and elasticity modulus on blade dynamic stability were explored,and the quantitative relationships between maximum displacement,maximum mises stress,elastic modulus and the average wind speed were obtained.The research results in this thesis will lay the foundation for further research on the issues of intensity,instability and wreck for wind turbine blades under complex offshore wind conditions,and provide technical references for safety design of wind turbine blades.