The Strength Analysis And Structural Optimization Design Of Wind Turbine Hub Components

Hub, pitch bearing and the connecting bolt is the key components that connect bladeand spindle of wind turbine. Aerodynamic load, inertia force and gravity generated byrotation of fan blade are transport to hub through the pitch bearing, the connected partsand components are easy to produce stress concentration and fatigue damage with avariety of static load and alternating load; in addition, the hub connecting the fan spindle,the bending moment generated by the weight effect on the tower, which play an veryimportant role on the tower strength and life,so the good design, reliable quality andsuperior performance are the decisive factor to guarantee the normal and stable operationof the wind turbine.With the large scale of wind turbine, the weight, size and load of wind turbinecomponents is also growing, test on such a large product is relatively difficult, along withthe rapid development of computer technology, both home and abroad mostly use thefinite element method for its design and research.The key of finite element analysis is build a reasonable and effective finite elementmodel, basis on the theoretical analysis, using computer aided modeling, finite elementanalysis and modern computing technology, the paper research on the modeling of pitchbearings and connecting bolt of wind turbine, do structural optimization design of hub,the results provide a theoretical basis for wind power unit operation and furtheroptimization design.Using the engineering calculation and finite element analysis methods, with theconnection of pitch bearing inner ring and blade as the research object,establishing avariety of model,researching on the element type of bolt,establishment of contact pairand analysis the results with different element type and contact relationships,put forwardreasonable and feasible finite element calculation scheme of bolt connection structure.Using the simplified Hertz contact theory, established the nonlinear spring elementmodel and ball entity unit model, through contrast and analysis the results of finiteelement calculation, proposed the reasonable method to analysis the bearing contactstress, the research work provide the theory basis for the design and check of largebearing design.Based on the strength, stiffness and fatigue analysis for the hub of1.5MW windturbine, do topology optimization of hub, according to the overall density distribution, use the drilling method to make the hub loss weight as further optimization design,whichshould ensure the hub does not decrease the strength, stiffness and fatigue life. the weightof hub can caused the bending moment which act on the spindle and transport form thespindle to the tower, by reducing the weight of the hub, the component stress on spindleand the tower can be reduced, thereby improving strength performance of the spindle,tower and overall structural of wind turbine.