Study Additional Damping Structure Of Large Wind Turbine Blades

Blade is the core component of wind turbine to capture wind energy.People’s pursuit of minimizing the generating cost makes wind turbine unitbecoming more large-scale. Meanwhile, blade is becoming larger, slender andmore flexible, and is prone to vibration. The vibration of blade reducesreliability of blade, even may break blade and endanger wind turbine unit.Therefore, the vibration of large-scaled blade is becoming an urgent task in thedevelopment of wind turbine.Aimed at the vibration of blade, based on the energy dissipation principleof additional damping structure, the method of improving blade structuraldamping by laying additional damping on the blade internal surface to dissipatemore vibration energy as heat and reduce vibration of blade was proposed in thispaper. This project has important value to the development of blade.In order to obtain the natural vibration character of blade, taken a1.5MWblade as an example, established model and analyzed the vibration modal of theblade, which affords reference to the design of blade additional dampingstructure. The principle and type of additional damping was introduced.Additional damping blade structure was proposed. The impact of the relateddesign factors on the dynamic character of four sides simply supportedadditional damping plate was studied, and the general conclusion of additionaldamping design was obtained in this paper. The comprehensive optimal modelof the location and thickness of Constrained Layer Damping (CLD) was builtand the design method of CLD dissipation ratio unification was put forward,which provides an important basis for the design of blade additional dampingstructure.According to the analysis of blade failure result from vibration, the target ofblade additional damping was determined, and the type of damping structure andmaterial was selected. The location and thickness of CLD of a1.5MW bladewere got by using the dissipation ratio unification design method. The impact of CLD on the inherent character and mechanical property of the blade wereanalyzed. The result indicates that constrained layer damping could greatlyimprove the blade structural loss factor, and has a small bad effect onmechanical property.